tilespec.c

Go to the documentation of this file.

/***********************************************************************
 Freeciv - Copyright (C) 1996 - A Kjeldberg, L Gregersen, P Unold
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
***********************************************************************/
 
/***********************************************************************
  Functions for handling the tilespec files which describe
  the files and contents of tilesets.
  original author: David Pfitzner <dwp@mso.anu.edu.au>
***********************************************************************/
 
#ifdef HAVE_CONFIG_H
#include <fc_config.h>
#endif
 
#include <stdio.h>
#include <stdlib.h>             /* exit */
#include <stdarg.h>
#include <string.h>
 
/* utility */
#include "astring.h"
#include "bitvector.h"
#include "capability.h"
#include "deprecations.h"
#include "fcintl.h"
#include "log.h"
#include "mem.h"
#include "rand.h"
#include "registry.h"
#include "shared.h"
#include "string_vector.h"
#include "support.h"
 
/* common */
#include "base.h"
#include "effects.h"
#include "game.h"               /* game.control.num_city_styles */
#include "government.h"
#include "map.h"
#include "modpack.h"
#include "movement.h"
#include "nation.h"
#include "player.h"
#include "road.h"
#include "specialist.h"
#include "unit.h"
#include "unitlist.h"
 
/* client/include */
#include "dialogs_g.h"
#include "graphics_g.h"
#include "gui_main_g.h"
#include "mapview_g.h"          /* For update_map_canvas_visible */
#include "menu_g.h"
#include "themes_g.h"
 
/* client */
#include "citydlg_common.h"     /* For generate_citydlg_dimensions() */
#include "client_main.h"
#include "climap.h"             /* For client_tile_get_known() */
#include "colors_common.h"
#include "control.h"            /* For fill_xxx */
#include "editor.h"
#include "goto.h"
#include "gui_properties.h"
#include "helpdata.h"
#include "options.h"            /* For fill_xxx */
#include "svgflag.h"
#include "themes_common.h"
 
#include "tilespec.h"
 
#define TILESPEC_CAPSTR "+Freeciv-tilespec-3.4-Devel-2026-Jan-11 duplicates_ok"
/*
 * Tilespec capabilities acceptable to this program:
 *
 * +Freeciv-3.2-tilespec
 *    - basic format for Freeciv versions 3.2.x; required
 *
 * +Freeciv-tilespec-3.2-Devel-YYYY.MMM.DD
 *    - tilespec of the development version at the given date
 *
 * duplicates_ok
 *    - we can handle existence of duplicate tags (lattermost tag which
 *      appears is used; tilesets which have duplicates should specify
 *      "duplicates_ok")
 */
 
#define SPEC_CAPSTR "+Freeciv-spec-3.4-Devel-2026.Oct.03"
/*
 * Individual spec file capabilities acceptable to this program:
 *
 * +Freeciv-3.2-spec
 *    - basic format for Freeciv versions 3.2.x; required
 */
 
#define TILESPEC_SUFFIX ".tilespec"
#define TILE_SECTION_PREFIX "tile_"
 
/* This the way directional indices are now encoded: */
#define MAX_INDEX_CARDINAL              64
#define MAX_INDEX_HALF                  16
#define MAX_INDEX_VALID                 256
 
#define NUM_TILES_HP_BAR 11
#define NUM_TILES_DIGITS 10
#define MAX_NUM_UPKEEP_SPRITES 10
 
#define SPECENUM_NAME extrastyle_id
#define SPECENUM_VALUE0 ESTYLE_ROAD_ALL_SEPARATE
#define SPECENUM_VALUE0NAME "RoadAllSeparate"
#define SPECENUM_VALUE1 ESTYLE_ROAD_PARITY_COMBINED
#define SPECENUM_VALUE1NAME "RoadParityCombined"
#define SPECENUM_VALUE2 ESTYLE_ROAD_ALL_COMBINED
#define SPECENUM_VALUE2NAME "RoadAllCombined"
#define SPECENUM_VALUE3 ESTYLE_RIVER
#define SPECENUM_VALUE3NAME "River"
#define SPECENUM_VALUE4 ESTYLE_SINGLE1
#define SPECENUM_VALUE4NAME "Single1"
#define SPECENUM_VALUE5 ESTYLE_SINGLE2
#define SPECENUM_VALUE5NAME "Single2"
#define SPECENUM_VALUE6 ESTYLE_3LAYER
#define SPECENUM_VALUE6NAME "3Layer"
#define SPECENUM_VALUE7 ESTYLE_CARDINALS
#define SPECENUM_VALUE7NAME "Cardinals"
#define SPECENUM_COUNT ESTYLE_COUNT
#include "specenum_gen.h"
 
/* This could be moved to common/map.h if there's more use for it. */
enum direction4 {
  DIR4_NORTH = 0, DIR4_SOUTH, DIR4_EAST, DIR4_WEST
};
static const char direction4letters[4] = "udrl";
/* This must correspond to enum edge_type. */
static const char edge_name[EDGE_COUNT][3] = {"ns", "we", "ud", "lr"};
 
static const int DIR4_TO_DIR8[4] =
    { DIR8_NORTH, DIR8_SOUTH, DIR8_EAST, DIR8_WEST };
 
enum match_style {
  MATCH_NONE,
  MATCH_SAME,           /* "boolean" match */
  MATCH_PAIR,
  MATCH_FULL
};
 
enum sprite_type {
  CELL_WHOLE,           /* Entire tile */
  CELL_CORNER           /* Corner of tile */
};
 
enum spec_file_types {
  SFILE_COMMON,
  SFILE_SVG,
  SFILE_PIXEL,
  SFILE_LAST
};
 
struct anim {
  int frames;
  int time;
  int time_per_frame;
  struct sprite **sprites;
  bool show_always;
};
 
struct drawing_data {
  bool init;
 
  char *name;
 
  int num_layers; /* 1 thru MAX_NUM_LAYERS. */
#define MAX_NUM_LAYERS 3
 
  struct drawing_layer {
    bool is_tall;
    int offset_x, offset_y;
 
#define MAX_NUM_MATCH_WITH 8
    enum match_style match_style;
    int match_index[1 + MAX_NUM_MATCH_WITH];
    int match_indices; /* 0 = no match_type, 1 = no match_with */
 
    enum sprite_type sprite_type;
 
    struct sprite_vector base;
    struct sprite *match[MAX_INDEX_CARDINAL];
    struct sprite **cells;
 
    /* List of those sprites in 'cells' that are allocated by some other
     * means than load_sprite() and thus are not freed by unload_all_sprites(). */
    struct sprite_vector allocated;
  } layer[MAX_NUM_LAYERS];
 
  bool is_reversed;
 
  int blending; /* Layer, 0 = none */
  struct sprite *blender;
  struct sprite *blend[4]; /* Indexed by a direction4 */
};
 
struct city_style_threshold {
  struct anim *cst;
};
 
struct city_sprite {
  struct {
    int land_num_thresholds;
    struct city_style_threshold *land_thresholds;
  } *styles;
  int num_styles;
};
 
struct river_sprites {
  struct anim
    *spec[MAX_INDEX_CARDINAL],
    *outlet[MAX_INDEX_CARDINAL];
};
 
struct citizen_graphic {
  /* Each citizen type has up to MAX_NUM_CITIZEN_SPRITES different
   * sprites, as defined by the tileset. */
  int count;
  struct sprite *sprite[MAX_NUM_CITIZEN_SPRITES];
};
 
struct citizen_set {
  struct citizen_graphic citizen[CITIZEN_LAST];
  struct citizen_graphic specialist[SP_MAX];
};
 
struct style_citizen_set {
  struct citizen_set *sets;
  int num_styles;
};
 
struct named_sprites {
  struct sprite
    *indicator[INDICATOR_COUNT][NUM_TILES_PROGRESS],
    *treaty_thumb[2],     /* 0=disagree, 1=agree */
    *arrow[ARROW_LAST], /* 0=right arrow, 1=plus, 2=minus */
 
    *icon[ICON_COUNT],
 
    *events[E_COUNT],
 
    /* The panel sprites for showing tax % allocations. */
    *tax_luxury, *tax_science, *tax_gold,
    *dither_tile;     /* Only used for isometric view */
 
  struct {
    struct sprite
      *tile,
      *worked_tile,
      *unworked_tile;
  } mask;
 
  struct sprite *tech[A_LAST];
  struct sprite *building[B_LAST];
  struct sprite *government[G_LAST];
 
  struct {
    struct anim *icon[U_LAST][ACTIVITY_LAST];
    struct anim *facing[U_LAST][DIR8_MAGIC_MAX][ACTIVITY_LAST];
  } units;
 
  struct sprite_vector nation_flag;
  struct sprite_vector nation_shield;
 
  struct citizen_set default_citizens;
  struct style_citizen_set style_citizen_sets;
 
  struct sprite *spaceship[SPACESHIP_COUNT];
  struct {
    int hot_x, hot_y;
    struct sprite *frame[NUM_CURSOR_FRAMES];
  } cursor[CURSOR_LAST];
  struct {
    struct sprite_vector unit;
    struct sprite *nuke;
  } explode;
  struct {
    int num_stack_sprites;
    bool no_more_stack_sprites;
    struct anim
      *select,
      *action_decision_want;
    struct sprite
      *hp_bar[NUM_TILES_HP_BAR],
      *vet_lev[MAX_VET_LEVELS],
      *auto_attack,
      *auto_worker,
      *auto_explore,
      *fortified,
      *fortifying,
      *go_to,                   /* goto is a C keyword :-) */
      *cultivate,
      *plant,
      *pillage,
      *sentry,
      **stack,
      *loaded,
      *transform,
      *connect,
      *patrol,
      *convert,
      *battlegroup[MAX_NUM_BATTLEGROUPS],
      *lowfuel,
      *tired;
  } unit;
  struct {
    struct sprite
      *unhappy[MAX_NUM_UPKEEP_SPRITES],
      *output[O_LAST][MAX_NUM_UPKEEP_SPRITES];
  } upkeep;
  struct {
    struct sprite
      *disorder,
      *size[NUM_TILES_DIGITS],
      *size_tens[NUM_TILES_DIGITS],
      *size_hundreds[NUM_TILES_DIGITS],
      *tile_foodnum[NUM_TILES_DIGITS],
      *tile_shieldnum[NUM_TILES_DIGITS],
      *tile_tradenum[NUM_TILES_DIGITS];
    struct city_sprite
      *tile,
      *single_wall,
      *wall[NUM_WALL_TYPES],
      *occupied;
    struct sprite_vector worked_tile_overlay;
    struct sprite_vector unworked_tile_overlay;
  } city;
  struct citybar_sprites citybar;
  struct editor_sprites editor;
  struct {
    struct {
      struct sprite *specific;
      struct sprite *turns[NUM_TILES_DIGITS];
      struct sprite *turns_tens[NUM_TILES_DIGITS];
      struct sprite *turns_hundreds[NUM_TILES_DIGITS];
    } s[GTS_COUNT];
    struct sprite *waypoint;
  } path;
  struct {
    struct sprite *attention;
    struct sprite *infratile;
  } user;
  struct {
    struct sprite
      *fog,
      **fullfog,
      *darkness[MAX_INDEX_CARDINAL]; /* First unused */
  } tx;                         /* Terrain extra */
  struct {
    struct sprite
      *activity,
      *rmact;
    enum extrastyle_id extrastyle;
    union {
      struct anim *single;
      struct anim *cardinals[MAX_INDEX_CARDINAL];
      struct {
        struct anim
          *foreground,
          *middleground,
          *background;
      } bmf;
      struct {
        struct anim
        /* For extrastyles ESTYLE_ROAD_ALL_SEPARATE and ESTYLE_ROAD_PARITY_COMBINED */
          *isolated,
          *corner[8]; /* Indexed by direction; only non-cardinal dirs used. */
        union {
          /* For ESTYLE_ROAD_ALL_SEPARATE */
          struct anim *dir[8];     /* All entries used */
          /* ESTYLE_ROAD_PARITY_COMBINED */
          struct {
            struct anim
              *even[MAX_INDEX_HALF],    /* First unused */
              *odd[MAX_INDEX_HALF];     /* First unused */
          } combo;
          /* ESTYLE_ALL_SEPARATE */
          struct anim *total[MAX_INDEX_VALID];
          struct river_sprites rivers;
        } ru;
      } road;
    } u;
  } extras[MAX_EXTRA_TYPES];
  struct {
    struct sprite
      *main[EDGE_COUNT],
      *city[EDGE_COUNT],
      *worked[EDGE_COUNT],
      *unavailable,
      *nonnative,
      *selected[EDGE_COUNT],
      *coastline[EDGE_COUNT],
      *borders[EDGE_COUNT][2];
  } grid;
  struct {
    struct sprite_vector overlays;
  } colors;
  struct {
    struct sprite *color; /* Generic background color */
    struct sprite *graphic; /* Generic background graphic */
  } background;
  struct {
    struct sprite *grid_borders[EDGE_COUNT][2];
    struct sprite *color;
    struct sprite *background;
  } player[MAX_NUM_PLAYER_SLOTS];
 
  struct drawing_data *drawing[MAX_NUM_ITEMS];
};
 
struct specfile {
  struct sprite *big_sprite;
  char *file_name;
};
 
#define SPECLIST_TAG specfile
#define SPECLIST_TYPE struct specfile
#include "speclist.h"
 
#define specfile_list_iterate(list, pitem) \
    TYPED_LIST_ITERATE(struct specfile, list, pitem)
#define specfile_list_iterate_end  LIST_ITERATE_END
 
/*
 * Information about an individual sprite. All fields except 'sprite' are
 * filled at the time of the scan of the specfile. 'Sprite' is
 * set/cleared on demand in load_sprite()/unload_sprite().
 */
struct small_sprite {
  int ref_count;
 
  /* The sprite is in this file. */
  char *file;
 
  /* Or, the sprite is in this file at the location. */
  struct specfile *sf;
  int x, y, width, height;
 
  /* A little more (optional) data. */
  int hot_x, hot_y;
 
  struct sprite *sprite;
};
 
/* 'struct small_sprite_list' and related functions. */
#define SPECLIST_TAG small_sprite
#define SPECLIST_TYPE struct small_sprite
#include "speclist.h"
#define small_sprite_list_iterate(list, pitem)                              \
  TYPED_LIST_ITERATE(struct small_sprite, list, pitem)
#define small_sprite_list_iterate_end LIST_ITERATE_END
 
/* 'struct sprite_hash' and related functions. */
#define SPECHASH_TAG sprite
#define SPECHASH_ASTR_KEY_TYPE
#define SPECHASH_IDATA_TYPE struct small_sprite *
#include "spechash.h"
#define sprite_hash_iterate(hash, tag_name, sprite)                         \
  TYPED_HASH_ITERATE(const char *, struct small_sprite *,                   \
                     hash, tag_name, sprite)
#define sprite_hash_iterate_end HASH_ITERATE_END
 
/* 'struct anim_hash' and related functions. */
#define SPECHASH_TAG anim
#define SPECHASH_ASTR_KEY_TYPE
#define SPECHASH_IDATA_TYPE struct anim *
#include "spechash.h"
#define anim_hash_iterate(hash, tag_name, sprite)                          \
  TYPED_HASH_ITERATE(const char *, struct anim *,                          \
                     hash, tag_name, anim)
#define anim_hash_iterate_end HASH_ITERATE_END
 
/* 'struct drawing_hash' and related functions. */
static void drawing_data_destroy(struct drawing_data *draw);
 
#define SPECHASH_TAG drawing
#define SPECHASH_CSTR_KEY_TYPE
#define SPECHASH_IDATA_TYPE struct drawing_data *
#define SPECHASH_IDATA_FREE drawing_data_destroy
#include "spechash.h"
 
#define SPECHASH_TAG estyle
#define SPECHASH_ASTR_KEY_TYPE
#define SPECHASH_ENUM_DATA_TYPE extrastyle_id
#include "spechash.h"
 
struct tileset {
  char name[512];
  char given_name[MAX_LEN_NAME];
  char version[MAX_LEN_NAME];
  int priority;
 
  char *summary;
  char *description;
  float scale;
 
  char *for_ruleset;
 
  enum mapview_layer layer_order[LAYER_COUNT];
 
  enum ts_type type;
  int hex_width, hex_height;
  int ts_topo_idx;
 
  int normal_tile_width, normal_tile_height;
  int full_tile_width, full_tile_height;
  int unit_tile_width, unit_tile_height;
  int small_sprite_width, small_sprite_height;
 
  int max_upkeep_height;
  int svg_height;
 
  int default_time_per_frame;
 
  char *main_intro_filename;
 
  enum direction8 unit_default_orientation;
 
  enum fog_style fogstyle;
  enum darkness_style darkness_style;
 
  int unit_flag_offset_x, unit_flag_offset_y;
  int city_flag_offset_x, city_flag_offset_y;
  int unit_offset_x, unit_offset_y;
  int city_offset_x, city_offset_y;
  int city_size_offset_x, city_size_offset_y;
 
  int citybar_offset_y;
  int tilelabel_offset_y;
  int activity_offset_x;
  int activity_offset_y;
  int select_offset_x;
  int select_offset_y;
  int stack_size_offset_x;
  int stack_size_offset_y;
  int occupied_offset_x;
  int occupied_offset_y;
  int unit_upkeep_offset_y;
  int unit_upkeep_small_offset_y;
 
#define NUM_CORNER_DIRS 4
#define TILES_PER_CORNER 4
  int num_valid_tileset_dirs, num_cardinal_tileset_dirs;
  int num_index_valid, num_index_cardinal;
  enum direction8 valid_tileset_dirs[8], cardinal_tileset_dirs[8];
 
  struct tileset_layer {
    char **match_types;
    size_t match_count;
  } layers[MAX_NUM_LAYERS];
 
  struct specfile_list *specfiles;
  struct small_sprite_list *small_sprites;
 
  /* This hash table maps tilespec tags to struct small_sprites. */
  struct sprite_hash *sprite_hash;
 
  /* This hash table maps terrain graphic strings to drawing data. */
  struct drawing_hash *tile_hash;
 
  struct estyle_hash *estyle_hash;
 
  struct anim_hash *anim_hash;
 
  struct named_sprites sprites;
 
  struct color_system *color_system;
 
  struct extra_type_list *style_lists[ESTYLE_COUNT];
 
  struct extra_type_list *flagged_bases_list;
 
  int num_preferred_themes;
  char** preferred_themes;
};
 
struct tileset *tileset = nullptr;
struct tileset *unscaled_tileset = nullptr;
 
static bool focus_unit_state = FALSE;
 
static bool tileset_update = FALSE;
 
static int global_anim_time = 0;
 
static struct tileset *tileset_read_toplevel(const char *tileset_name,
                                             bool verbose, int topology_id,
                                             float scale);
 
static int fill_unit_type_sprite_array(const struct tileset *t,
                                       struct drawn_sprite *sprs,
                                       const struct unit_type *putype,
                                       enum unit_activity activity,
                                       enum direction8 facing);
static int fill_unit_sprite_array(const struct tileset *t,
                                  struct drawn_sprite *sprs,
                                  const struct unit *punit,
                                  int stack, bool backdrop);
static bool load_river_sprites(struct tileset *t,
                               struct river_sprites *store, const char *tag_pfx);
 
static void tileset_setup_base(struct tileset *t,
                               const struct extra_type *pextra,
                               const char *tag);
static void tileset_setup_road(struct tileset *t,
                               struct extra_type *pextra,
                               const char *tag);
 
static bool is_extra_drawing_enabled(struct extra_type *pextra);
 
static int fill_basic_road_sprite_array(const struct tileset *t,
                                        struct drawn_sprite *sprs,
                                        const struct extra_type *pextra);
static int fill_basic_base_sprite_array(const struct tileset *t,
                                        struct drawn_sprite *sprs,
                                        const struct extra_type *pextra);
 
static void tileset_player_free(struct tileset *t, int plrid);
 
static void tileset_setup_specialist_type(struct tileset *t,
                                          struct citizen_set *set,
                                          Specialist_type_id id,
                                          const char *tag_group,
                                          const char *set_name,
                                          bool required);
static void tileset_setup_citizen_types_default_set(struct tileset *t);
static void tileset_setup_citizen_types(struct tileset *t,
                                        struct citizen_set *set,
                                        const char *tag_group,
                                        const char *set_name,
                                        bool required);
 
/************************************************************************/
void tileset_error(enum log_level level, const char *tset_name,
                   const char *format, ...)
{
  char buf[2048];
  va_list args;
 
  va_start(args, format);
  fc_vsnprintf(buf, sizeof(buf), format, args);
  va_end(args);
 
  log_base(level, "%s", buf);
 
  if (level <= LOG_NORMAL) {
    show_tileset_error(level == LOG_FATAL, tset_name, buf);
 
    if (level == LOG_FATAL) {
      exit(EXIT_FAILURE);
    }
  }
}
 
/************************************************************************/
static struct drawing_data *drawing_data_new(void)
{
  struct drawing_data *draw = fc_calloc(1, sizeof(*draw));
 
  draw->name = nullptr;
 
  return draw;
}
 
/************************************************************************/
static void drawing_data_destroy(struct drawing_data *draw)
{
  int i;
 
  fc_assert_ret(draw != nullptr);
 
  if (draw->name != nullptr) {
    free(draw->name);
  }
  for (i = 0; i < 4; i++) {
    if (draw->blend[i]) {
      free_sprite(draw->blend[i]);
    }
  }
  for (i = 0; i < draw->num_layers; i++) {
    int vec_size = sprite_vector_size(&draw->layer[i].allocated);
    int j;
 
    for (j = 0; j < vec_size; j++) {
      free_sprite(draw->layer[i].allocated.p[j]);
    }
 
    sprite_vector_free(&draw->layer[i].base);
    sprite_vector_free(&draw->layer[i].allocated);
    free(draw->layer[i].cells);
  }
  free(draw);
}
 
/************************************************************************/
struct tileset *get_tileset(void)
{
  if (unscaled_tileset != nullptr) {
    return unscaled_tileset;
  } else {
    return tileset;
  }
}
 
/************************************************************************/
const char *tileset_basename(const struct tileset *t)
{
  return t->name;
}
 
/************************************************************************/
bool tileset_is_isometric(const struct tileset *t)
{
  return t->type == TS_ISOMETRIC;
}
 
/************************************************************************/
int tileset_hex_width(const struct tileset *t)
{
  return t->hex_width;
}
 
/************************************************************************/
int tileset_hex_height(const struct tileset *t)
{
  return t->hex_height;
}
 
/************************************************************************/
int tileset_tile_width(const struct tileset *t)
{
  return t->normal_tile_width;
}
 
/************************************************************************/
int tileset_tile_height(const struct tileset *t)
{
  return t->normal_tile_height;
}
 
/************************************************************************/
int tileset_full_tile_width(const struct tileset *t)
{
  return t->full_tile_width;
}
 
/************************************************************************/
int tileset_full_tile_height(const struct tileset *t)
{
  return t->full_tile_height;
}
 
/************************************************************************/
int tileset_unit_width(const struct tileset *t)
{
  return t->unit_tile_width;
}
 
/************************************************************************/
int tileset_unit_height(const struct tileset *t)
{
  return t->unit_tile_height;
}
 
/************************************************************************/
static int calculate_max_upkeep_height(const struct tileset *t)
{
  int i;
  int max = 0;
 
  for (i = 0; i < MAX_NUM_UPKEEP_SPRITES; i++) {
    if (t->sprites.upkeep.unhappy[i] != nullptr) {
      int width, height;
 
      /* TODO: We want only height, getting the width might waste CPU
       * depending on gui-specific implementation. */
      get_sprite_dimensions(t->sprites.upkeep.unhappy[i], &width, &height);
 
      max = MAX(max, height);
    }
  }
 
  output_type_iterate(o) {
    for (i = 0; i < MAX_NUM_UPKEEP_SPRITES; i++) {
      if (t->sprites.upkeep.output[o][i] != nullptr) {
        int width, height;
 
        /* TODO: We want only height, getting the width might waste CPU
         * depending on gui-specific implementation. */
        get_sprite_dimensions(t->sprites.upkeep.output[o][i], &width, &height);
 
        max = MAX(max, height);
      }
    }
  } output_type_iterate_end;
 
  return max;
}
 
/************************************************************************/
static int tileset_upkeep_height(const struct tileset *t)
{
  /* Return cached value */
  return t->max_upkeep_height;
}
 
/************************************************************************/
int tileset_unit_with_upkeep_height(const struct tileset *t)
{
  int uk_bottom = tileset_unit_layout_offset_y(tileset) + tileset_upkeep_height(tileset);
  int u_bottom = tileset_unit_height(tileset);
 
  return MAX(uk_bottom, u_bottom);
}
 
/************************************************************************/
int tileset_unit_with_small_upkeep_height(const struct tileset *t)
{
  int uk_bottom = tileset_unit_layout_small_offset_y(tileset) + tileset_upkeep_height(tileset);
  int u_bottom = tileset_unit_height(tileset);
 
  return MAX(uk_bottom, u_bottom);
}
 
/************************************************************************/
int tileset_unit_layout_offset_y(const struct tileset *t)
{
  return t->unit_upkeep_offset_y;
}
 
/************************************************************************/
int tileset_unit_layout_small_offset_y(const struct tileset *t)
{
  return t->unit_upkeep_small_offset_y;
}
 
/************************************************************************/
int tileset_small_sprite_width(const struct tileset *t)
{
  return t->small_sprite_width;
}
 
/************************************************************************/
int tileset_citybar_offset_y(const struct tileset *t)
{
  return t->citybar_offset_y;
}
 
/************************************************************************/
int tileset_tilelabel_offset_y(const struct tileset *t)
{
  return t->tilelabel_offset_y;
}
 
/************************************************************************/
float tileset_scale(const struct tileset *t)
{
  return tileset->scale;
}
 
/************************************************************************/
int tileset_small_sprite_height(const struct tileset *t)
{
  return t->small_sprite_height;
}
 
/************************************************************************/
const char *tileset_main_intro_filename(const struct tileset *t)
{
  return t->main_intro_filename;
}
 
/************************************************************************/
int tileset_num_city_colors(const struct tileset *t)
{
  return t->sprites.city.worked_tile_overlay.size;
}
 
/************************************************************************/
bool tileset_use_hard_coded_fog(const struct tileset *t)
{
  return FOG_AUTO == t->fogstyle;
}
 
/************************************************************************/
static struct tileset *tileset_new(void)
{
  struct tileset *t = fc_calloc(1, sizeof(*t));
 
  t->specfiles = specfile_list_new();
  t->small_sprites = small_sprite_list_new();
 
  return t;
}
 
/************************************************************************/
static const char *dir_get_tileset_name(enum direction8 dir)
{
  switch (dir) {
  case DIR8_NORTH:
    return "n";
  case DIR8_NORTHEAST:
    return "ne";
  case DIR8_EAST:
    return "e";
  case DIR8_SOUTHEAST:
    return "se";
  case DIR8_SOUTH:
    return "s";
  case DIR8_SOUTHWEST:
    return "sw";
  case DIR8_WEST:
    return "w";
  case DIR8_NORTHWEST:
    return "nw";
  }
  log_error("Wrong direction8 variant: %d.", dir);
  return "";
}
 
/************************************************************************/
static enum direction8 dir_by_tileset_name(const char *str)
{
  enum direction8 dir;
 
  for (dir = direction8_begin();
       dir != direction8_end();
       dir = direction8_next(dir)) {
    if (strcmp(dir_get_tileset_name(dir), str) == 0) {
      return dir;
    }
  }
 
  return direction8_invalid();
}
 
/************************************************************************/
static bool is_valid_tileset_dir(const struct tileset *t,
                                 enum direction8 dir)
{
  if (t->hex_width > 0) {
    return dir != DIR8_NORTHEAST && dir != DIR8_SOUTHWEST;
  } else if (t->hex_height > 0) {
    return dir != DIR8_NORTHWEST && dir != DIR8_SOUTHEAST;
  } else {
    return TRUE;
  }
}
 
/************************************************************************/
static bool is_cardinal_tileset_dir(const struct tileset *t,
                                    enum direction8 dir)
{
  if (t->hex_width > 0 || t->hex_height > 0) {
    return is_valid_tileset_dir(t, dir);
  } else {
    return (dir == DIR8_NORTH || dir == DIR8_EAST
            || dir == DIR8_SOUTH || dir == DIR8_WEST);
  }
}
 
/************************************************************************/
static int ts_topology_index(int actual_topology)
{
  int idx;
 
  if ((actual_topology & TF_HEX)
      && (actual_topology & TF_ISO)) {
    idx = TS_TOPO_ISOHEX;
  } else if (actual_topology & TF_ISO) {
    idx = TS_TOPO_SQUARE;
  } else if (actual_topology & TF_HEX) {
    idx = TS_TOPO_HEX;
  } else {
    idx = TS_TOPO_SQUARE;
  }
 
  return idx;
}
 
/************************************************************************/
int index_ts_topology(int idx)
{
  switch (idx) {
  case TS_TOPO_SQUARE:
    return TF_ISO;
  case TS_TOPO_HEX:
    return TF_HEX;
  case TS_TOPO_ISOHEX:
    return TF_HEX | TF_ISO;
  }
 
  return 0;
}
 
struct ts_list_data {
  struct strvec *list;
  int topo;
};
 
/************************************************************************/
static void ts_list_cb(const char *modpack_name, const char *filename,
                       void *data)
{
  struct ts_list_data *tsdata = (struct ts_list_data *)data;
  const char *target = modpack_tileset_target(modpack_name);
  struct tileset *t = tileset_read_toplevel(target,
                                            FALSE, tsdata->topo, 1.0f);
 
  if (t != nullptr) {
    strvec_append(tsdata->list, target);
    tileset_free(t);
  }
}
 
/************************************************************************/
const struct strvec *get_tileset_list(const struct option *poption)
{
  static struct strvec *tilesets[3] = { nullptr, nullptr, nullptr };
  int topo = option_get_cb_data(poption);
  int idx;
 
  idx = ts_topology_index(topo);
 
  fc_assert_ret_val(idx < ARRAY_SIZE(tilesets), nullptr);
 
  if (tilesets[idx] == nullptr) {
    struct ts_list_data data;
 
    /* Note: this means you must restart the client after installing a new
       tileset. */
    tilesets[idx] = strvec_new();
    data.list = tilesets[idx];
    data.topo = topo;
    modpack_tileset_cache_iterate(ts_list_cb, &data);
  }
 
  return tilesets[idx];
}
 
/************************************************************************/
static char *tilespec_fullname(const char *tileset_name)
{
  if (tileset_name) {
    char fname[strlen(tileset_name) + strlen(TILESPEC_SUFFIX) + 1];
    const char *dname;
 
    fc_snprintf(fname, sizeof(fname),
                "%s%s", tileset_name, TILESPEC_SUFFIX);
 
    dname = fileinfoname(get_data_dirs(), fname);
 
    if (dname) {
      return fc_strdup(dname);
    }
  }
 
  return nullptr;
}
 
/************************************************************************/
static bool check_tilespec_capabilities(struct section_file *file,
                                        const char *which,
                                        const char *us_capstr,
                                        const char *filename,
                                        bool verbose)
{
  enum log_level level = verbose ? LOG_ERROR : LOG_DEBUG;
 
  const char *file_capstr = secfile_lookup_str(file, "%s.options", which);
 
  if (file_capstr == nullptr) {
    log_base(level, "\"%s\": %s file doesn't have a capability string",
             filename, which);
    return FALSE;
  }
  if (!has_capabilities(us_capstr, file_capstr)) {
    log_base(level, "\"%s\": %s file appears incompatible:",
             filename, which);
    log_base(level, "  datafile options: %s", file_capstr);
    log_base(level, "  supported options: %s", us_capstr);
    return FALSE;
  }
  if (!has_capabilities(file_capstr, us_capstr)) {
    log_base(level, "\"%s\": %s file requires option(s) "
             "that client doesn't support:", filename, which);
    log_base(level, "  datafile options: %s", file_capstr);
    log_base(level, "  supported options: %s", us_capstr);
    return FALSE;
  }
 
  return TRUE;
}
 
/************************************************************************/
static void tileset_free_toplevel(struct tileset *t)
{
  int i, j;
 
  if (t->main_intro_filename) {
    free(t->main_intro_filename);
    t->main_intro_filename = nullptr;
  }
 
  if (t->preferred_themes) {
    for (i = 0; i < t->num_preferred_themes; i++) {
      free(t->preferred_themes[i]);
    }
    free(t->preferred_themes);
    t->preferred_themes = nullptr;
  }
  t->num_preferred_themes = 0;
 
  if (t->tile_hash) {
    drawing_hash_destroy(t->tile_hash);
    t->tile_hash = nullptr; /* Helpful for sanity. */
  }
  if (t->estyle_hash) {
    estyle_hash_destroy(t->estyle_hash);
    t->estyle_hash = nullptr;
  }
  for (i = 0; i < ESTYLE_COUNT; i++) {
    if (t->style_lists[i] != nullptr) {
      extra_type_list_destroy(t->style_lists[i]);
      t->style_lists[i] = nullptr;
    }
  }
 
  if (t->flagged_bases_list != nullptr) {
    extra_type_list_destroy(t->flagged_bases_list);
    t->flagged_bases_list = nullptr;
  }
 
  for (i = 0; i < MAX_NUM_LAYERS; i++) {
    struct tileset_layer *tslp = &t->layers[i];
 
    if (tslp->match_types) {
      for (j = 0; j < tslp->match_count; j++) {
        free(tslp->match_types[j]);
      }
      free(tslp->match_types);
      tslp->match_types = nullptr;
    }
  }
 
  if (t->color_system) {
    color_system_free(t->color_system);
    t->color_system = nullptr;
  }
 
  if (t->summary != nullptr) {
    free(t->summary);
    t->summary = nullptr;
  }
  if (t->description != nullptr) {
    free(t->description);
    t->description = nullptr;
  }
  if (t->for_ruleset != nullptr) {
    free(t->for_ruleset);
    t->for_ruleset = nullptr;
  }
}
 
/************************************************************************/
void tileset_free(struct tileset *t)
{
  int i;
 
  tileset_free_tiles(t);
  tileset_free_toplevel(t);
  for (i = 0; i < ARRAY_SIZE(t->sprites.player); i++) {
    tileset_player_free(t, i);
  }
  specfile_list_destroy(t->specfiles);
  small_sprite_list_destroy(t->small_sprites);
  free(t);
}
 
/************************************************************************/
static void ts_cb(const char *modpack_name, const char *filename, void *data)
{
  int topo_id = *((int *)data);
  struct tileset *t = tileset_read_toplevel(modpack_tileset_target(modpack_name),
                                            FALSE, topo_id, 1.0f);
 
  if (t != nullptr) {
    if (tileset == nullptr) {
      tileset = t;
    } else if (t->priority > tileset->priority
               || (topo_id >= 0
                   && tileset_topo_index(tileset) != tileset_topo_index(t))) {
      tileset_free(tileset);
      tileset = t;
    } else {
      tileset_free(t);
    }
  }
}
 
/************************************************************************/
bool tilespec_try_read(const char *tileset_name, bool verbose, int topo_id,
                       bool global_default)
{
  bool original;
 
  if (tileset_name == nullptr
      || !(tileset = tileset_read_toplevel(tileset_name, verbose,
                                           topo_id, 1.0f))) {
    original = FALSE;
    modpack_tileset_cache_iterate(ts_cb, &topo_id);
 
    if (tileset == nullptr) {
      tileset_error(LOG_FATAL, nullptr, _("No usable default tileset found, aborting!"));
    }
 
    log_verbose("Trying tileset \"%s\".", tileset->name);
  } else {
    original = TRUE;
  }
  option_set_default_ts(tileset);
 
  if (global_default) {
    gui_options.default_topology = tileset_topo_index(tileset);
  }
 
  return original;
}
 
/************************************************************************/
bool tilespec_reread(const char *new_tileset_name,
                     bool game_fully_initialized, float scale)
{
  int id;
  struct tile *center_tile;
  enum client_states state = client_state();
  const char *name = new_tileset_name ? new_tileset_name : tileset->name;
  char tileset_name[strlen(name) + 1], old_name[strlen(tileset->name) + 1];
  bool new_tileset_in_use;
  int ts_topo;
 
  /* Make local copies since these values may be freed down below */
  sz_strlcpy(tileset_name, name);
  sz_strlcpy(old_name, tileset->name);
 
  log_normal(_("Loading tileset \"%s\"."), tileset_name);
 
  /* Step 0:  Record old data.
   *
   * We record the current mapcanvas center, etc.
   */
  center_tile = get_center_tile_mapcanvas();
 
  /* Step 1:  Cleanup.
   *
   * Free old tileset or keep it in memory if we are loading the same
   * tileset with scaling and old one was not scaled.
   */
 
  if (strcmp(tileset_name, old_name) == 0 && tileset->scale == 1.0f
      && scale != 1.0f) {
    if (unscaled_tileset) {
      tileset_free(unscaled_tileset);
    }
    unscaled_tileset = tileset;
  } else {
    tileset_free(tileset);
  }
 
  /* Step 2:  Read.
   *
   * We read in the new tileset. This should be pretty straightforward.
   */
  tileset = tileset_read_toplevel(tileset_name, FALSE, -1, scale);
  if (tileset != nullptr) {
    new_tileset_in_use = TRUE;
  } else {
    new_tileset_in_use = FALSE;
 
    if (!(tileset = tileset_read_toplevel(old_name, FALSE, -1, scale))) {
      log_fatal("Failed to re-read the currently loaded tileset.");
      exit(EXIT_FAILURE);
    }
  }
  tileset_load_tiles(tileset);
  if (game_fully_initialized) {
    tileset_use_preferred_theme(tileset);
  }
 
  if (game_fully_initialized) {
    if (game.client.ruleset_ready) {
      tileset_background_init(tileset);
    } /* else we'll get round to it on PACKET_RULESET_GAME */
    players_iterate(pplayer) {
      tileset_player_init(tileset, pplayer);
    } players_iterate_end;
    boot_help_texts(); /* "About Current Tileset" */
  }
 
  /* Step 3: Setup
   *
   * This is a seriously sticky problem. On startup, we build a hash
   * from all the sprite data. Then, when we connect to a server, the
   * server sends us ruleset data a piece at a time and we use this data
   * to assemble the sprite structures. But if we change while connected
   *  we have to reassemble all of these. This should just involve
   * calling tilespec_setup_*** on everything. But how do we tell what
   * "everything" is?
   *
   * The below code just does things straightforwardly, by setting up
   * each possible sprite again. Hopefully it catches everything, and
   * doesn't mess up too badly if we change tilesets while not connected
   * to a server.
   */
  if (!game.client.ruleset_ready) {
    /* The ruleset data is not sent until this point. */
    return new_tileset_in_use;
  }
 
  if (tileset_map_topo_compatible(wld.map.topology_id, tileset, &ts_topo)
      == TOPO_INCOMP_HARD) {
    tileset_error(LOG_NORMAL, tileset_name,
                  _("Map topology (%s) and tileset (%s) incompatible."),
                  describe_topology(wld.map.topology_id), describe_topology(ts_topo));
  }
 
  terrain_type_iterate(pterrain) {
    tileset_setup_tile_type(tileset, pterrain);
  } terrain_type_iterate_end;
  unit_type_iterate(punittype) {
    tileset_setup_unit_type(tileset, punittype);
  } unit_type_iterate_end;
  governments_iterate(gov) {
    tileset_setup_government(tileset, gov);
  } governments_iterate_end;
  extra_type_iterate(pextra) {
    tileset_setup_extra(tileset, pextra);
  } extra_type_iterate_end;
  nations_iterate(pnation) {
    tileset_setup_nation_flag(tileset, pnation);
  } nations_iterate_end;
  improvement_iterate(pimprove) {
    tileset_setup_impr_type(tileset, pimprove);
  } improvement_iterate_end;
  advance_iterate(padvance) {
    tileset_setup_tech_type(tileset, padvance);
  } advance_iterate_end;
  specialist_type_iterate(sp) {
    tileset_setup_specialist_type_default_set(tileset, sp);
  } specialist_type_iterate_end;
 
  tileset->sprites.style_citizen_sets.sets
    = fc_malloc(game.control.num_city_styles
                * sizeof(tileset->sprites.style_citizen_sets.sets[0]));
 
  for (id = 0; id < game.control.num_city_styles; id++) {
    tileset_setup_city_tiles(tileset, id);
  }
 
  if (state < C_S_RUNNING) {
    /* Below redraws do not apply before this. */
    return new_tileset_in_use;
  }
 
  /* Step 4:  Draw.
   *
   * Do any necessary redraws.
   */
  generate_citydlg_dimensions();
  tileset_changed();
  can_slide = FALSE;
  center_tile_mapcanvas(center_tile);
  /* update_map_canvas_visible forces a full redraw. Otherwise with fast
   * drawing we might not get one. Of course this is slower. */
  update_map_canvas_visible();
  can_slide = TRUE;
 
  return new_tileset_in_use;
}
 
/************************************************************************/
void tilespec_reread_callback(struct option *poption)
{
  const char *tileset_name;
  enum client_states state = client_state();
 
  if (state == C_S_RUNNING || state == C_S_OVER) {
    int opt = option_get_cb_data(poption);
 
    /* Also iso map topology counts as 'square' tileset topology */
    if (opt != (wld.map.topology_id & (TF_ISO | TF_HEX))
        && (opt != 0 || ((wld.map.topology_id & TF_HEX) == TF_HEX))) {
      /* Changed option was not for current topology */
      return;
    }
  }
 
  tileset_name = option_str_get(poption);
 
  fc_assert_ret(tileset_name != nullptr && tileset_name[0] != '\0');
 
  tileset_update = TRUE;
  tilespec_reread(tileset_name, client.conn.established, 1.0f);
 
  /* As it's going to be 'current' tileset, make it global default if
   * options saved. */
  gui_options.default_topology = tileset_topo_index(tileset);
 
  tileset_update = FALSE;
  menus_init();
}
 
/************************************************************************/
void tilespec_reread_frozen_refresh(const char *tname)
{
  tileset_update = TRUE;
  tilespec_reread(tname, TRUE, 1.0f);
  tileset_update = FALSE;
  menus_init();
}
 
/************************************************************************/
static struct sprite *load_gfx_file(const char *gfx_filename, bool svgflag)
{
  const char **gfx_fileexts, *gfx_fileext;
  struct sprite *s;
 
  if (svgflag) {
    gfx_fileexts = ordered_gfx_fextensions();
  } else {
    gfx_fileexts = gfx_fileextensions();
  }
 
  /* Try out all supported file extensions to find one that works. */
  while ((gfx_fileext = *gfx_fileexts++)) {
    const char *real_full_name;
    char full_name[strlen(gfx_filename) + strlen(".")
                   + strlen(gfx_fileext) + 1];
 
    sprintf(full_name, "%s.%s", gfx_filename, gfx_fileext);
    if ((real_full_name = fileinfoname(get_data_dirs(), full_name))) {
      log_debug("trying to load gfx file \"%s\".", real_full_name);
      s = load_gfxfile(real_full_name,
                       svgflag && !strcmp("svg", gfx_fileext));
      if (s) {
        return s;
      }
    }
  }
 
  log_error("Could not load gfx file \"%s\".", gfx_filename);
 
  return nullptr;
}
 
/************************************************************************/
static void ensure_big_sprite(struct specfile *sf, const char *tset_name)
{
  struct section_file *file;
  const char *gfx_filename;
 
  if (sf->big_sprite) {
    /* Looks like it's already loaded. */
    return;
  }
 
  /* Otherwise load it. The big sprite will sometimes be freed and will have
   * to be reloaded, but most of the time it's just loaded once, the small
   * sprites are extracted, and then it's freed. */
  if (!(file = secfile_load(sf->file_name, TRUE))) {
    tileset_error(LOG_FATAL, tset_name,
                  _("Could not open '%s':\n%s"), sf->file_name, secfile_error());
  }
 
  if (!check_tilespec_capabilities(file, "spec",
                                   SPEC_CAPSTR, sf->file_name, TRUE)) {
    tileset_error(LOG_FATAL, tset_name,
                  _("Specfile %s has incompatible capabilities"), sf->file_name);
  }
 
  gfx_filename = secfile_lookup_str(file, "file.gfx");
 
  sf->big_sprite = load_gfx_file(gfx_filename, FALSE);
 
  if (!sf->big_sprite) {
    tileset_error(LOG_FATAL, tset_name,
                  _("Could not load gfx file for the spec file \"%s\"."),
                  sf->file_name);
  }
  secfile_destroy(file);
}
 
/************************************************************************/
static void scan_specfile(struct tileset *t, struct specfile *sf,
                          bool duplicates_ok)
{
  struct section_file *file;
  struct section_list *sections;
  int i;
 
  if (!(file = secfile_load(sf->file_name, TRUE))) {
    tileset_error(LOG_FATAL, tileset_name_get(t),
                  _("Could not open '%s':\n%s"), sf->file_name, secfile_error());
  }
  if (!check_tilespec_capabilities(file, "spec",
                                   SPEC_CAPSTR, sf->file_name, TRUE)) {
    tileset_error(LOG_FATAL, tileset_name_get(t),
                  _("Specfile %s has incompatible capabilities"), sf->file_name);
  }
 
  /* Currently unused */
  secfile_entry_ignore(file, "info.artists");
 
  /* Not used here */
  secfile_entry_ignore(file, "file.gfx");
 
  if ((sections = secfile_sections_by_name_prefix(file, "grid_"))) {
    section_list_iterate(sections, psection) {
      int j, k;
      int x_top_left, y_top_left, dx, dy;
      int pixel_border_x;
      int pixel_border_y;
      const char *sec_name = section_name(psection);
 
      pixel_border_x = secfile_lookup_int_default(file, 0, "%s.pixel_border",
                                                  sec_name);
      pixel_border_y = secfile_lookup_int_default(file, pixel_border_x, "%s.pixel_border_y",
                                                  sec_name);
      pixel_border_x = secfile_lookup_int_default(file, pixel_border_x, "%s.pixel_border_x",
                                                  sec_name);
      if (!secfile_lookup_int(file, &x_top_left, "%s.x_top_left", sec_name)
          || !secfile_lookup_int(file, &y_top_left,
                                 "%s.y_top_left", sec_name)
          || !secfile_lookup_int(file, &dx, "%s.dx", sec_name)
          || !secfile_lookup_int(file, &dy, "%s.dy", sec_name)) {
        log_error("%s grid \"%s\" invalid: %s",
                  sf->file_name, sec_name, secfile_error());
        continue;
      }
 
      j = -1;
      while (secfile_entry_lookup(file, "%s.tiles%d.tag",
                                  sec_name, ++j) != nullptr) {
        struct small_sprite *ss;
        int row, column;
        int xr, yb;
        const char **tags;
        size_t num_tags;
        int hot_x, hot_y;
 
        if (!secfile_lookup_int(file, &row, "%s.tiles%d.row", sec_name, j)
            || !secfile_lookup_int(file, &column, "%s.tiles%d.column",
                                   sec_name, j)
            || !(tags = secfile_lookup_str_vec(file, &num_tags,
                                               "%s.tiles%d.tag",
                                               sec_name, j))) {
          log_error("%s small sprite \"%s.tiles%d\" invalid: %s",
                    sf->file_name, sec_name, j, secfile_error());
          continue;
        }
        hot_x = secfile_lookup_int_default(file, 0, "%s.tiles%d.hot_x",
                                           sec_name, j);
        hot_y = secfile_lookup_int_default(file, 0, "%s.tiles%d.hot_y",
                                           sec_name, j);
 
        /* There must be at least 1 because of the while(): */
        fc_assert_action(num_tags > 0, continue);
 
        xr = x_top_left + (dx + pixel_border_x) * column;
        yb = y_top_left + (dy + pixel_border_y) * row;
 
        ss = fc_malloc(sizeof(*ss));
        ss->ref_count = 0;
        ss->file = nullptr;
        ss->x = xr;
        ss->y = yb;
        ss->width = dx;
        ss->height = dy;
        ss->sf = sf;
        ss->sprite = nullptr;
        ss->hot_x = hot_x;
        ss->hot_y = hot_y;
 
        small_sprite_list_prepend(t->small_sprites, ss);
 
        if (!duplicates_ok) {
          for (k = 0; k < num_tags; k++) {
            if (!sprite_hash_insert(t->sprite_hash, tags[k], ss)) {
              log_error("warning: %s already has a sprite for \"%s\".",
                        tileset_name_get(t), tags[k]);
            }
          }
        } else {
          for (k = 0; k < num_tags; k++) {
            (void) sprite_hash_replace(t->sprite_hash, tags[k], ss);
          }
        }
 
        free(tags);
        tags = nullptr;
      }
    } section_list_iterate_end;
    section_list_destroy(sections);
  }
 
  /* Load "extra" sprites. Each sprite is one file. */
  i = -1;
  while (secfile_entry_lookup(file, "extra.sprites%d.tag", ++i) != nullptr) {
    struct small_sprite *ss;
    const char **tags;
    const char *filename;
    size_t num_tags, k;
    int hot_x, hot_y;
 
    if (!(tags = secfile_lookup_str_vec(file, &num_tags,
                                        "extra.sprites%d.tag", i))
        || !(filename = secfile_lookup_str(file,
                                           "extra.sprites%d.file", i))) {
      log_error("%s extra sprite \"extra.sprites%d\" invalid: %s",
                sf->file_name, i, secfile_error());
      continue;
    }
    hot_x = secfile_lookup_int_default(file, 0, "extra.sprites%d.hot_x", i);
    hot_y = secfile_lookup_int_default(file, 0, "extra.sprites%d.hot_y", i);
 
    ss = fc_malloc(sizeof(*ss));
    ss->ref_count = 0;
    ss->file = fc_strdup(filename);
    ss->sf = nullptr;
    ss->sprite = nullptr;
    ss->hot_x = hot_x;
    ss->hot_y = hot_y;
 
    small_sprite_list_prepend(t->small_sprites, ss);
 
    if (!duplicates_ok) {
      for (k = 0; k < num_tags; k++) {
        if (!sprite_hash_insert(t->sprite_hash, tags[k], ss)) {
          log_error("warning: %s already have a sprite for \"%s\".",
                    tileset_name_get(t), tags[k]);
        }
      }
    } else {
      for (k = 0; k < num_tags; k++) {
        (void) sprite_hash_replace(t->sprite_hash, tags[k], ss);
      }
    }
    free(tags);
  }
 
  secfile_check_unused(file);
  secfile_destroy(file);
}
 
/************************************************************************/
static char *tilespec_gfx_filename(const char *gfx_filename,
                                   const char *tset_name)
{
  const char  *gfx_current_fileext;
  const char **gfx_fileexts = gfx_fileextensions();
 
  while ((gfx_current_fileext = *gfx_fileexts++)) {
    const char *real_full_name;
    char *full_name =
      fc_malloc(strlen(gfx_filename) + strlen(".")
                + strlen(gfx_current_fileext) + 1);
 
    sprintf(full_name, "%s.%s", gfx_filename, gfx_current_fileext);
 
    real_full_name = fileinfoname(get_data_dirs(), full_name);
    free(full_name);
    if (real_full_name) {
      return fc_strdup(real_full_name);
    }
  }
 
  tileset_error(LOG_FATAL, tset_name,
                _("Couldn't find a supported gfx file extension for \"%s\"."),
                gfx_filename);
 
  return nullptr;
}
 
/************************************************************************/
static bool tileset_scan_single_list(struct tileset *t,
                                     const char *spec_filenames[],
                                     int num_spec_files, bool verbose,
                                     bool duplicates_ok)
{
  int i;
 
  for (i = 0; i < num_spec_files; i++) {
    struct specfile *sf = fc_malloc(sizeof(*sf));
    const char *dname;
 
    log_debug("spec file %s", spec_filenames[i]);
 
    sf->big_sprite = nullptr;
    dname = fileinfoname(get_data_dirs(), spec_filenames[i]);
    if (!dname) {
      if (verbose) {
        log_error("Can't find spec file \"%s\".", spec_filenames[i]);
      }
 
      return FALSE;
    }
    sf->file_name = fc_strdup(dname);
    scan_specfile(t, sf, duplicates_ok);
 
    specfile_list_prepend(t->specfiles, sf);
  }
 
  return TRUE;
}
 
/************************************************************************/
static int check_sprite_type(const char *sprite_type, const char *tile_section)
{
  if (fc_strcasecmp(sprite_type, "corner") == 0) {
    return CELL_CORNER;
  }
  if (fc_strcasecmp(sprite_type, "single") == 0) {
    return CELL_WHOLE;
  }
  if (fc_strcasecmp(sprite_type, "whole") == 0) {
    return CELL_WHOLE;
  }
  log_error("[%s] unknown sprite_type \"%s\".", tile_section, sprite_type);
  return CELL_WHOLE;
}
 
/************************************************************************/
static struct tileset *tileset_read_toplevel(const char *tileset_name,
                                             bool verbose, int topology_id,
                                             float scale)
{
  struct section_file *file;
  char *fname;
  const char *c;
  int i;
  size_t num_spec_files[SFILE_LAST];
  const char **spec_filenames[SFILE_LAST];
  size_t num_layers;
  const char **layer_order;
  size_t num_preferred_themes;
  struct section_list *sections = nullptr;
  const char *file_capstr;
  bool duplicates_ok, is_hex;
  enum direction8 dir;
  struct tileset *t = nullptr;
  const char *extraname;
  const char *tstr;
  int topo;
  bool svg;
  enum spec_file_types slist_type;
  const char *type_name;
  bool vsup;
 
  fname = tilespec_fullname(tileset_name);
 
  if (fname == nullptr) {
    if (verbose) {
      log_error("Can't find tileset \"%s\".", tileset_name);
    }
 
    return nullptr;
  }
  log_verbose("tilespec file is \"%s\".", fname);
 
  if (!(file = secfile_load(fname, TRUE))) {
    log_error("Could not open '%s':\n%s", fname, secfile_error());
    free(fname);
 
    return nullptr;
  }
 
  if (!check_tilespec_capabilities(file, "tilespec",
                                   TILESPEC_CAPSTR, fname, verbose)) {
    secfile_destroy(file);
    free(fname);
 
    return nullptr;
  }
 
  t = tileset_new();
  t->scale = scale;
  file_capstr = secfile_lookup_str(file, "%s.options", "tilespec");
  duplicates_ok = (file_capstr != nullptr
                   && has_capabilities("+duplicates_ok", file_capstr));
 
  tstr = secfile_lookup_str(file, "tilespec.name");
  /* Tileset name found */
  sz_strlcpy(t->given_name, tstr);
  tstr = secfile_lookup_str_default(file, "", "tilespec.version");
  if (tstr[0] != '\0') {
    /* Tileset version found */
    sz_strlcpy(t->version, tstr);
  } else {
    /* No version information */
    t->version[0] = '\0';
  }
 
  tstr = secfile_lookup_str_default(file, "", "tilespec.summary");
  if (tstr[0] != '\0') {
    int len;
 
    /* Tileset summary found */
    len = strlen(tstr);
    t->summary = fc_malloc(len + 1);
    fc_strlcpy(t->summary, tstr, len + 1);
  } else {
    /* No summary */
    if (t->summary != nullptr) {
      free(t->summary);
      t->summary = nullptr;
    }
  }
 
  tstr = secfile_lookup_str_default(file, "", "tilespec.description");
  if (tstr[0] != '\0') {
    int len;
 
    /* Tileset description found */
    len = strlen(tstr);
    t->description = fc_malloc(len + 1);
    fc_strlcpy(t->description, tstr, len + 1);
  } else {
    /* No description */
    if (t->description != nullptr) {
      free(t->description);
      t->description = nullptr;
    }
  }
 
  tstr = secfile_lookup_str_default(file, nullptr, "tilespec.for_ruleset");
  if (tstr != nullptr) {
    t->for_ruleset = fc_strdup(tstr);
  } else {
    t->for_ruleset = nullptr;
  }
 
  sz_strlcpy(t->name, tileset_name);
  if (!secfile_lookup_int(file, &t->priority, "tilespec.priority")
      || !secfile_lookup_bool(file, &is_hex, "tilespec.is_hex")) {
    log_error("Tileset \"%s\" invalid: %s", t->name, secfile_error());
    goto ON_ERROR;
  }
 
  tstr = secfile_lookup_str(file, "tilespec.type");
  if (tstr == nullptr) {
    log_error("Tileset \"%s\": no tileset type", t->name);
    goto ON_ERROR;
  }
 
  t->type = ts_type_by_name(tstr, fc_strcasecmp);
  if (!ts_type_is_valid(t->type)) {
    log_error("Tileset \"%s\": unknown tileset type \"%s\"", t->name, tstr);
    goto ON_ERROR;
  }
 
  if (t->type == TS_ISOMETRIC) {
    topo = TF_ISO;
  } else {
    topo = 0;
  }
 
  /* Read hex-tileset information. */
  t->hex_width = t->hex_height = 0;
  if (is_hex) {
    int hex_side;
 
    if (!secfile_lookup_int(file, &hex_side, "tilespec.hex_side")) {
      log_error("Tileset \"%s\" invalid: %s", t->name, secfile_error());
      goto ON_ERROR;
    }
    hex_side = hex_side * t->scale;
    if (t->type == TS_ISOMETRIC) {
      t->hex_width = hex_side;
    } else {
      t->hex_height = hex_side;
    }
 
    topo |= TF_HEX;
 
    /* Hex tilesets are drawn the same as isometric. */
    /* FIXME: There will be other legal values to be used with hex
     * tileset in the future, and this would just overwrite it. */
    t->type = TS_ISOMETRIC;
  }
 
  if (topology_id >= 0) {
    if (((topology_id & TF_HEX) && topology_id != (topo & (TF_ISO | TF_HEX)))
        || (!(topology_id & TF_HEX) && (topo & TF_HEX))) {
      /* Not of requested topology */
      goto ON_ERROR;
    }
  }
 
  t->ts_topo_idx = ts_topology_index(topo);
 
  /* Needed for older compilers to not give "used uninitialized" warning */
  vsup = FALSE;
 
  switch (t->type) {
  case TS_ISOMETRIC:
    vsup = gui_properties.views.isometric;
    break;
  case TS_OVERHEAD:
    vsup = gui_properties.views.overhead;
    break;
  case TS_3D:
    vsup = gui_properties.views.d3;
    break;
  }
 
  if (!vsup) {
    /* TRANS: "Overhead" or "Isometric" */
    log_normal(_("Client does not support %s tilesets."),
               _(ts_type_name(t->type)));
    log_normal(_("Using default tileset instead."));
 
    fc_assert(tileset_name != nullptr);
 
    goto ON_ERROR;
  }
 
  tileset_type_set(t->type);
 
  /* Create arrays of valid and cardinal tileset dirs. These depend
   * entirely on the tileset, not the topology. They are also in clockwise
   * rotational ordering. */
  t->num_valid_tileset_dirs = t->num_cardinal_tileset_dirs = 0;
  dir = DIR8_NORTH;
  do {
    if (is_valid_tileset_dir(t, dir)) {
      t->valid_tileset_dirs[t->num_valid_tileset_dirs] = dir;
      t->num_valid_tileset_dirs++;
    }
    if (is_cardinal_tileset_dir(t, dir)) {
      t->cardinal_tileset_dirs[t->num_cardinal_tileset_dirs] = dir;
      t->num_cardinal_tileset_dirs++;
    }
 
    dir = dir_cw(dir);
  } while (dir != DIR8_NORTH);
 
  fc_assert(t->num_valid_tileset_dirs % 2 == 0); /* Assumed elsewhere. */
  t->num_index_valid = 1 << t->num_valid_tileset_dirs;
  t->num_index_cardinal = 1 << t->num_cardinal_tileset_dirs;
 
  if (!secfile_lookup_int(file, &t->normal_tile_width,
                          "tilespec.normal_tile_width")
      || !secfile_lookup_int(file, &t->normal_tile_height,
                             "tilespec.normal_tile_height")) {
    log_error("Tileset \"%s\" invalid: %s", t->name, secfile_error());
    goto ON_ERROR;
  }
  t->normal_tile_width = ceil(t->scale * t->normal_tile_width);
  /* Adjust width to be multiple of 8 */
  if (scale != 1.0f) {
    i = t->normal_tile_width;
    while (i % 8 != 0) {
      i++;
    }
    t->scale = (t->scale * i) / t->normal_tile_width;
    t->normal_tile_width = i;
  }
  t->normal_tile_height = ceil(t->scale * t->normal_tile_height);
  if (t->type == TS_ISOMETRIC) {
    t->full_tile_width = t->normal_tile_width;
    if (tileset_hex_height(t) > 0) {
      t->full_tile_height = t->normal_tile_height;
    } else {
      t->full_tile_height = 3 * t->normal_tile_height / 2;
    }
  } else {
    t->full_tile_width = t->normal_tile_width;
    t->full_tile_height = t->normal_tile_height;
  }
  t->unit_tile_width
    = secfile_lookup_int_default(file, t->full_tile_width, "tilespec.unit_width");
  t->unit_tile_height
    = secfile_lookup_int_default(file, t->full_tile_height, "tilespec.unit_height");
  if (!secfile_lookup_int(file, &t->small_sprite_width,
                          "tilespec.small_tile_width")
      || !secfile_lookup_int(file, &t->small_sprite_height,
                             "tilespec.small_tile_height")) {
    log_error("Tileset \"%s\" invalid: %s", t->name, secfile_error());
    goto ON_ERROR;
  }
  if (t->unit_tile_width != t->full_tile_width && t->scale != 1.0f) {
    t->unit_tile_width = ceil(t->unit_tile_width * t->scale);
  }
  if (t->unit_tile_height != t->full_tile_height && t->scale != 1.0f) {
    t->unit_tile_height = ceil(t->unit_tile_height * t->scale);
  }
  t->small_sprite_width = t->small_sprite_width * t->scale;
  t->small_sprite_height = t->small_sprite_height * t->scale;
  log_verbose("tile sizes %dx%d, %d%d unit, %d%d small",
              t->normal_tile_width, t->normal_tile_height,
              t->full_tile_width, t->full_tile_height,
              t->small_sprite_width, t->small_sprite_height);
 
  tstr = secfile_lookup_str(file, "tilespec.fog_style");
  if (tstr == nullptr) {
    log_error("Tileset \"%s\": no fog_style", t->name);
    goto ON_ERROR;
  }
 
  t->fogstyle = fog_style_by_name(tstr, fc_strcasecmp);
  if (!fog_style_is_valid(t->fogstyle)) {
    log_error("Tileset \"%s\": unknown fog_style \"%s\"", t->name, tstr);
    goto ON_ERROR;
  }
 
  tstr = secfile_lookup_str(file, "tilespec.darkness_style");
  if (tstr == nullptr) {
    log_error("Tileset \"%s\": no darkness_style", t->name);
    goto ON_ERROR;
  }
 
  t->darkness_style = darkness_style_by_name(tstr, fc_strcasecmp);
  if (!darkness_style_is_valid(t->darkness_style)) {
    log_error("Tileset \"%s\": unknown darkness_style \"%s\"", t->name, tstr);
    goto ON_ERROR;
  }
 
  if (t->darkness_style == DARKNESS_ISORECT
      && (t->type == TS_OVERHEAD || t->hex_width > 0 || t->hex_height > 0)) {
    log_error("Invalid darkness style set in tileset \"%s\".", t->name);
    goto ON_ERROR;
  }
 
  if (!secfile_lookup_int(file, &t->unit_flag_offset_x,
                          "tilespec.unit_flag_offset_x")
      || !secfile_lookup_int(file, &t->unit_flag_offset_y,
                             "tilespec.unit_flag_offset_y")
      || !secfile_lookup_int(file, &t->city_flag_offset_x,
                             "tilespec.city_flag_offset_x")
      || !secfile_lookup_int(file, &t->city_flag_offset_y,
                             "tilespec.city_flag_offset_y")
      || !secfile_lookup_int(file, &t->unit_offset_x,
                             "tilespec.unit_offset_x")
      || !secfile_lookup_int(file, &t->unit_offset_y,
                             "tilespec.unit_offset_y")
      || !secfile_lookup_int(file, &t->activity_offset_x,
                             "tilespec.activity_offset_x")
      || !secfile_lookup_int(file, &t->activity_offset_y,
                             "tilespec.activity_offset_y")
      || !secfile_lookup_int(file, &t->select_offset_x,
                             "tilespec.select_offset_x")
      || !secfile_lookup_int(file, &t->select_offset_y,
                             "tilespec.select_offset_y")
      || !secfile_lookup_int(file, &t->stack_size_offset_x,
                             "tilespec.stack_size_offset_x")
      || !secfile_lookup_int(file, &t->stack_size_offset_y,
                             "tilespec.stack_size_offset_y")
      || !secfile_lookup_int(file, &t->city_offset_x,
                             "tilespec.city_offset_x")
      || !secfile_lookup_int(file, &t->city_offset_y,
                             "tilespec.city_offset_y")
      || !secfile_lookup_int(file, &t->city_size_offset_x,
                             "tilespec.city_size_offset_x")
      || !secfile_lookup_int(file, &t->city_size_offset_y,
                             "tilespec.city_size_offset_y")
      || !secfile_lookup_int(file, &t->citybar_offset_y,
                             "tilespec.citybar_offset_y")
      || !secfile_lookup_int(file, &t->tilelabel_offset_y,
                             "tilespec.tilelabel_offset_y")
      || !secfile_lookup_int(file, &t->occupied_offset_x,
                             "tilespec.occupied_offset_x")
      || !secfile_lookup_int(file, &t->occupied_offset_y,
                             "tilespec.occupied_offset_y")) {
    log_error("Tileset \"%s\" invalid: %s", t->name, secfile_error());
    goto ON_ERROR;
  }
 
  t->unit_upkeep_offset_y = secfile_lookup_int_default(file, tileset_tile_height(t),
                                                       "tilespec.unit_upkeep_offset_y");
  t->unit_upkeep_small_offset_y = secfile_lookup_int_default(file, t->unit_upkeep_offset_y,
                                                             "tilespec.unit_upkeep_small_offset_y");
  t->svg_height = secfile_lookup_int_default(file, 44, "tilespec.svg_height");
  t->default_time_per_frame = secfile_lookup_int_default(file, 3, "tilespec.time_per_frame");
 
  t->city_size_offset_x = t->scale * t->city_size_offset_x;
  t->city_size_offset_y = t->scale * t->city_size_offset_y;
  t->select_offset_x = t->scale * t->select_offset_x;
  t->select_offset_y = t->scale * t->select_offset_y;
  t->stack_size_offset_x = t->scale * t->stack_size_offset_x;
  t->stack_size_offset_y = t->scale * t->stack_size_offset_y;
  t->unit_flag_offset_x = t->scale * t->unit_flag_offset_x;
  t->unit_flag_offset_y = t->scale * t->unit_flag_offset_y;
  t->city_flag_offset_x = t->scale * t->city_flag_offset_x;
  t->city_flag_offset_y = t->scale * t->city_flag_offset_y;
  t->unit_offset_x = t->scale * t->unit_offset_x;
  t->unit_offset_y = t->scale * t->unit_offset_y;
  t->activity_offset_x = t->scale * t->activity_offset_x;
  t->activity_offset_y = t->scale * t->activity_offset_y;
  t->city_offset_x = t->scale * t->city_offset_x;
  t->city_offset_y = t->scale * t->city_offset_y;
  t->citybar_offset_y = t->scale * t->citybar_offset_y;
  t->tilelabel_offset_y = t->scale * t->tilelabel_offset_y;
  t->occupied_offset_x = t->scale * t->occupied_offset_x;
  t->occupied_offset_y = t->scale * t->occupied_offset_y;
  t->svg_height *= t->scale;
 
  if (t->scale != 1.0f
      && t->unit_upkeep_offset_y != tileset_tile_height(t)) {
    t->unit_upkeep_offset_y = t->scale * t->unit_upkeep_offset_y;
  }
  if (t->scale != 1.0f
      && t->unit_upkeep_small_offset_y != t->unit_upkeep_offset_y) {
    t->unit_upkeep_small_offset_y = t->scale * t->unit_upkeep_small_offset_y;
  }
 
  c = secfile_lookup_str_default(file, nullptr,
                                 "tilespec.unit_default_orientation");
  if (!c) {
    /* This is valid, but tileset must specify icon for every unit */
    t->unit_default_orientation = direction8_invalid();
  } else {
    dir = dir_by_tileset_name(c);
 
    if (!direction8_is_valid(dir)) {
      tileset_error(LOG_ERROR, tileset_name,
                    _("Unknown unit_default_orientation \"%s\""), c);
      goto ON_ERROR;
    } else {
      /* Default orientation is allowed to not be a valid one for the
       * tileset */
      t->unit_default_orientation = dir;
    }
  }
 
  c = secfile_lookup_str(file, "tilespec.main_intro_file");
  t->main_intro_filename = tilespec_gfx_filename(c, tileset_name_get(t));
  log_debug("intro file %s", t->main_intro_filename);
 
  /* Layer order */
  num_layers = 0;
  layer_order = secfile_lookup_str_vec(file, &num_layers,
                                       "tilespec.layer_order");
  if (layer_order != nullptr) {
    for (i = 0; i < num_layers; i++) {
      int j;
      enum mapview_layer layer = mapview_layer_by_name(layer_order[i],
                                                       fc_strcasecmp);
 
      /* Check for wrong layer names. */
      if (!mapview_layer_is_valid(layer)) {
        log_error("layer_order: Invalid layer \"%s\" in %s",
                  layer_order[i], tileset_name_get(t));
        goto ON_ERROR;
      }
      /* Check for duplicates. */
      for (j = 0; j < i; j++) {
        if (t->layer_order[j] == layer) {
          log_error("layer_order: Duplicate layer \"%s\" in %s",
                    layer_order[i], tileset_name_get(t));
          goto ON_ERROR;
        }
      }
      t->layer_order[i] = layer;
    }
 
    /* Now check that all layers are present. Doing it now allows for a more
     * comprehensive error message. */
    for (i = 0; i < LAYER_COUNT; i++) {
      int j;
      bool found = FALSE;
 
      for (j = 0; j < num_layers; j++) {
        if (i == t->layer_order[j]) {
          found = TRUE;
          break;
        }
      }
      if (!found) {
        log_error("layer_order: Missing layer \"%s\" in %s",
                  mapview_layer_name(i), tileset_name_get(t));
        goto ON_ERROR;
      }
    }
 
    free(layer_order);
  } else {
    /* There is no layer_order tag in the specfile -> use the default */
    for (i = 0; i < LAYER_COUNT; i++) {
      t->layer_order[i] = i;
    }
  }
 
  /* Terrain layer info. */
  for (i = 0; i < MAX_NUM_LAYERS; i++) {
    struct tileset_layer *tslp = &t->layers[i];
    int j, k;
 
    tslp->match_types =
        (char **) secfile_lookup_str_vec(file, &tslp->match_count,
                                         "layer%d.match_types", i);
    for (j = 0; j < tslp->match_count; j++) {
      tslp->match_types[j] = fc_strdup(tslp->match_types[j]);
 
      for (k = 0; k < j; k++) {
        if (tslp->match_types[k][0] == tslp->match_types[j][0]) {
          tileset_error(LOG_FATAL, tileset_name,
                        _("[layer%d] match_types: \"%s\" initial "
                          "('%c') is not unique."),
                        i, tslp->match_types[j], tslp->match_types[j][0]);
          /* FIXME: Returns nullptr. */
        }
      }
    }
  }
 
  /* Tile drawing info. */
  sections = secfile_sections_by_name_prefix(file, TILE_SECTION_PREFIX);
  if (sections == nullptr || 0 == section_list_size(sections)) {
    tileset_error(LOG_ERROR, tileset_name,
                  _("No [%s] sections present."),
                  TILE_SECTION_PREFIX);
    goto ON_ERROR;
  }
 
  fc_assert(t->tile_hash == nullptr);
 
  t->tile_hash = drawing_hash_new();
 
  section_list_iterate(sections, psection) {
    const char *sec_name = section_name(psection);
    struct drawing_data *draw = drawing_data_new();
    const char *sprite_type;
    int l;
    const char *terrain_name;
 
    terrain_name = secfile_lookup_str(file, "%s.tag", sec_name);
 
    if (terrain_name != nullptr) {
      draw->name = fc_strdup(terrain_name);
    } else {
      tileset_error(LOG_ERROR, _("No terrain tag given in section [%s] in %s."),
                    sec_name, tileset_name_get(t));
      drawing_data_destroy(draw);
      goto ON_ERROR;
    }
 
    draw->blending = secfile_lookup_int_default(file, 0, "%s.blend_layer",
                                                sec_name);
    draw->blending = CLIP(0, draw->blending, MAX_NUM_LAYERS);
 
    draw->is_reversed = secfile_lookup_bool_default(file, FALSE,
                                                    "%s.is_reversed",
                                                    sec_name);
    draw->num_layers = secfile_lookup_int_default(file, 0, "%s.num_layers",
                                                  sec_name);
    draw->num_layers = CLIP(1, draw->num_layers, MAX_NUM_LAYERS);
 
    for (l = 0; l < draw->num_layers; l++) {
      struct drawing_layer *dlp = &draw->layer[l];
      struct tileset_layer *tslp = &t->layers[l];
      const char *match_type;
      const char **match_with;
      size_t count;
 
      dlp->is_tall
        = secfile_lookup_bool_default(file, FALSE, "%s.layer%d_is_tall",
                                      sec_name, l);
      dlp->offset_x
        = secfile_lookup_int_default(file, 0, "%s.layer%d_offset_x",
                                     sec_name, l);
      dlp->offset_y
        = secfile_lookup_int_default(file, 0, "%s.layer%d_offset_y",
                                     sec_name, l);
      dlp->offset_x = ceil(t->scale * dlp->offset_x);
      dlp->offset_y = ceil(t->scale * dlp->offset_y);
 
      match_type = secfile_lookup_str_default(file, nullptr,
                                              "%s.layer%d_match_type",
                                              sec_name, l);
      if (match_type) {
        int j;
 
        /* Determine our match_type. */
        for (j = 0; j < tslp->match_count; j++) {
          if (fc_strcasecmp(tslp->match_types[j], match_type) == 0) {
            break;
          }
        }
        if (j >= tslp->match_count) {
          log_error("[%s] invalid match_type \"%s\" in %s.",
                    sec_name, match_type, tileset_name_get(t));
        } else {
          dlp->match_index[dlp->match_indices++] = j;
        }
      }
 
      match_with = secfile_lookup_str_vec(file, &count,
                                          "%s.layer%d_match_with",
                                          sec_name, l);
      if (match_with) {
        int j, k;
 
        if (count > MAX_NUM_MATCH_WITH) {
          log_error("[%s] match_with has too many types (%d, max %d) in %s",
                    sec_name, (int) count, MAX_NUM_MATCH_WITH,
                    tileset_name_get(t));
          count = MAX_NUM_MATCH_WITH;
        }
 
        if (1 < dlp->match_indices) {
          log_error("[%s] previous match_with ignored in %s.",
                    sec_name, tileset_name_get(t));
          dlp->match_indices = 1;
        } else if (1 > dlp->match_indices) {
          log_error("[%s] missing match_type, using \"%s\" in %s.",
                    sec_name, tslp->match_types[0], tileset_name_get(t));
          dlp->match_index[0] = 0;
          dlp->match_indices = 1;
        }
 
        for (k = 0; k < count; k++) {
          for (j = 0; j < tslp->match_count; j++) {
            if (fc_strcasecmp(tslp->match_types[j], match_with[k]) == 0) {
              break;
            }
          }
          if (j >= tslp->match_count) {
            log_error("[%s] layer%d_match_with: invalid  \"%s\".",
                      sec_name, l, match_with[k]);
          } else if (1 < count) {
            int m;
 
            for (m = 0; m < dlp->match_indices; m++) {
              if (dlp->match_index[m] == j) {
                log_error("[%s] layer%d_match_with: duplicate \"%s\" in %s.",
                          sec_name, l, match_with[k], tileset_name_get(t));
                break;
              }
            }
            if (m >= dlp->match_indices) {
              dlp->match_index[dlp->match_indices++] = j;
            }
          } else {
            dlp->match_index[dlp->match_indices++] = j;
          }
        }
        free(match_with);
        match_with = nullptr;
      }
 
      /* Check match_indices */
      switch (dlp->match_indices) {
      case 0:
      case 1:
        dlp->match_style = MATCH_NONE;
        break;
      case 2:
        if (dlp->match_index[0] == dlp->match_index[1] ) {
          dlp->match_style = MATCH_SAME;
        } else {
          dlp->match_style = MATCH_PAIR;
        }
        break;
      default:
        dlp->match_style = MATCH_FULL;
        break;
      };
 
      sprite_type
        = secfile_lookup_str_default(file, "whole", "%s.layer%d_sprite_type",
                                     sec_name, l);
      dlp->sprite_type = check_sprite_type(sprite_type, sec_name);
 
      switch (dlp->sprite_type) {
      case CELL_WHOLE:
        /* OK, no problem */
        break;
      case CELL_CORNER:
        if (dlp->is_tall
            || dlp->offset_x > 0
            || dlp->offset_y > 0) {
          log_error("[%s] layer %d: you cannot have tall terrain or\n"
                    "a sprite offset with a cell-based drawing method in %s.",
                    sec_name, l, tileset_name_get(t));
          dlp->is_tall = FALSE;
          dlp->offset_x = dlp->offset_y = 0;
        }
        break;
      };
    }
 
    if (!drawing_hash_insert(t->tile_hash, draw->name, draw)) {
      log_error("warning: multiple tile sections containing terrain tag \"%s\" in %s.",
                draw->name, tileset_name_get(t));
      goto ON_ERROR;
    }
  } section_list_iterate_end;
  section_list_destroy(sections);
  sections = nullptr;
 
  t->estyle_hash = estyle_hash_new();
 
  for (i = 0; i < ESTYLE_COUNT; i++) {
    t->style_lists[i] = extra_type_list_new();
  }
  t->flagged_bases_list = extra_type_list_new();
 
  for (i = 0; (extraname = secfile_lookup_str_default(file, nullptr,
                                                      "extras.styles%d.name",
                                                      i)); i++) {
    const char *style_name;
    enum extrastyle_id style;
 
    style_name = secfile_lookup_str_default(file, "Single1",
                                            "extras.styles%d.style", i);
    style = extrastyle_id_by_name(style_name, fc_strcasecmp);
    if (!extrastyle_id_is_valid(style)) {
      log_error("Unknown extra style \"%s\" for extra \"%s\" in %s.",
                style_name, extraname, tileset_name_get(t));
      goto ON_ERROR;
    }
 
    if (!estyle_hash_insert(t->estyle_hash, extraname, style)) {
      log_error("warning: duplicate extrastyle entry [%s] in %s.",
                extraname, tileset_name_get(t));
      goto ON_ERROR;
    }
  }
 
  svg = is_svg_flag_enabled();
 
  spec_filenames[SFILE_COMMON] = secfile_lookup_str_vec(file,
                                                        &(num_spec_files[SFILE_COMMON]),
                                                        "tilespec.files");
 
  if (svg) {
    slist_type = SFILE_SVG;
    type_name = "svg";
 
    /* Avoid "unused entry" warning about the other list */
    secfile_entry_ignore_by_path(file, "tilespec.files_pixel");
  } else {
    slist_type = SFILE_PIXEL;
    type_name = "pixel";
 
    /* Avoid "unused entry" warning about the other list */
    secfile_entry_ignore_by_path(file, "tilespec.files_svg");
  }
 
  spec_filenames[slist_type]
    = secfile_lookup_str_vec(file, &(num_spec_files[slist_type]),
                             "tilespec.files_%s", type_name);
  if ((spec_filenames[SFILE_COMMON] == nullptr
       || num_spec_files[SFILE_COMMON] == 0)
      && (spec_filenames[slist_type] == nullptr
          || num_spec_files[slist_type] == 0)) {
    log_error("No tile graphics files specified in \"%s\" for %s mode.",
              type_name, fname);
    goto ON_ERROR;
  }
 
  fc_assert(t->sprite_hash == nullptr);
  t->sprite_hash = sprite_hash_new();
 
  fc_assert(t->anim_hash == nullptr);
  t->anim_hash = anim_hash_new();
 
  if (!tileset_scan_single_list(t, spec_filenames[SFILE_COMMON],
                                num_spec_files[SFILE_COMMON],
                                verbose, duplicates_ok)) {
    goto ON_ERROR;
  }
 
  if (!tileset_scan_single_list(t, spec_filenames[slist_type],
                                num_spec_files[slist_type],
                                verbose, duplicates_ok)) {
    goto ON_ERROR;
  }
 
  free(spec_filenames[SFILE_COMMON]);
  free(spec_filenames[slist_type]);
 
  t->color_system = color_system_read(file);
 
  t->preferred_themes
    = (char **) secfile_lookup_str_vec(file, &num_preferred_themes,
                                       "tilespec.preferred_themes");
  t->num_preferred_themes = num_preferred_themes;
  for (i = 0; i < t->num_preferred_themes; i++) {
    t->preferred_themes[i] = fc_strdup(t->preferred_themes[i]);
  }
 
  secfile_check_unused(file);
  secfile_destroy(file);
  log_verbose("Finished reading \"%s\".", fname);
  free(fname);
 
  return t;
 
ON_ERROR:
  secfile_destroy(file);
  free(fname);
  tileset_free(t);
 
  if (sections != nullptr) {
    section_list_destroy(sections);
  }
 
  return nullptr;
}
 
/************************************************************************/
static const char *citizen_rule_name(enum citizen_category citizen)
{
  /* These strings are used in reading the tileset. Do not
   * translate. */
  switch (citizen) {
  case CITIZEN_HAPPY:
    return "happy";
  case CITIZEN_CONTENT:
    return "content";
  case CITIZEN_UNHAPPY:
    return "unhappy";
  case CITIZEN_ANGRY:
    return "angry";
  default:
    break;
  }
  log_error("Unknown citizen type: %d.", (int) citizen);
 
  return nullptr;
}
 
/************************************************************************/
static const char *cardinal_index_str(const struct tileset *t, int idx)
{
  static char c[64];
  int i;
 
  c[0] = '\0';
  for (i = 0; i < t->num_cardinal_tileset_dirs; i++) {
    int value = (idx >> i) & 1;
 
    cat_snprintf(c, sizeof(c), "%s%d",
                 dir_get_tileset_name(t->cardinal_tileset_dirs[i]), value);
  }
 
  return c;
}
 
/************************************************************************/
static char *valid_index_str(const struct tileset *t, int idx)
{
  static char c[64];
  int i;
 
  c[0] = '\0';
  for (i = 0; i < t->num_valid_tileset_dirs; i++) {
    int value = (idx >> i) & 1;
 
    cat_snprintf(c, sizeof(c), "%s%d",
                 dir_get_tileset_name(t->valid_tileset_dirs[i]), value);
  }
 
  return c;
}
 
/************************************************************************/
static struct anim *anim_new(int frames, int time_per_frame)
{
  struct anim *ret = fc_malloc(sizeof(struct anim));
 
  ret->frames = frames;
  ret->time = -1;
  ret->time_per_frame = time_per_frame;
  ret->sprites = fc_malloc(frames * sizeof(struct sprite *));
  ret->show_always = FALSE;
 
  return ret;
}
 
/************************************************************************/
static void anim_free(struct anim *a)
{
  if (a != nullptr) {
    free(a->sprites);
    free(a);
  }
}
 
/************************************************************************/
static struct sprite *load_sprite(struct tileset *t, const char *tag_name,
                                  bool scale, bool smooth, bool svgflag)
{
  struct small_sprite *ss;
  float sprite_scale = 1.0f;
 
  log_debug("load_sprite(tag='%s')", tag_name);
  /* Lookup information about where the sprite is found. */
  if (!sprite_hash_lookup(t->sprite_hash, tag_name, &ss)) {
    return nullptr;
  }
 
  fc_assert(ss->ref_count >= 0);
 
  if (!ss->sprite) {
    /* If the sprite hasn't been loaded already, then load it. */
    fc_assert(ss->ref_count == 0);
 
    if (ss->file) {
      int w, h;
      struct sprite *s;
 
      if (scale) {
        s = load_gfx_file(ss->file, svgflag);
 
        if (s != nullptr) {
          get_sprite_dimensions(s, &w, &h);
          ss->sprite = crop_sprite(s, 0, 0, w, h,
                                   nullptr, -1, -1, t->scale, smooth);
          free_sprite(s);
        }
      } else {
        ss->sprite = load_gfx_file(ss->file, svgflag);
      }
 
      if (!ss->sprite) {
        tileset_error(LOG_FATAL, tileset_name_get(t),
                      _("Couldn't load gfx file \"%s\" for sprite '%s'."),
                      ss->file, tag_name);
      }
    } else {
      int sf_w, sf_h;
 
      ensure_big_sprite(ss->sf, tileset_name_get(t));
      get_sprite_dimensions(ss->sf->big_sprite, &sf_w, &sf_h);
      if (ss->x < 0 || ss->x + ss->width > sf_w
          || ss->y < 0 || ss->y + ss->height > sf_h) {
        tileset_error(LOG_ERROR, tileset_name_get(t),
                      _("Sprite '%s' in file \"%s\" isn't within the image!"),
                      tag_name, ss->sf->file_name);
        return nullptr;
      }
      if (scale) {
        sprite_scale = t->scale;
      }
      ss->sprite = crop_sprite(ss->sf->big_sprite, ss->x, ss->y, ss->width,
                               ss->height, nullptr, -1, -1, sprite_scale,
                               smooth);
    }
  }
 
  /* Track the reference count so we know when to free the sprite. */
  ss->ref_count++;
 
  return ss->sprite;
}
 
/************************************************************************/
static struct sprite *create_plr_sprite(struct color *pcolor)
{
  struct sprite *sprite;
 
  fc_assert_ret_val(pcolor != nullptr, nullptr);
 
  sprite = create_sprite(tileset->full_tile_width,
                         tileset->full_tile_height, pcolor);
 
  return sprite;
}
 
/************************************************************************/
static void unload_sprite(struct tileset *t, const char *tag_name)
{
  struct small_sprite *ss;
 
  sprite_hash_lookup(t->sprite_hash, tag_name, &ss);
  fc_assert_ret(ss);
  fc_assert_ret(ss->ref_count >= 1);
  fc_assert_ret(ss->sprite);
 
  ss->ref_count--;
 
  if (ss->ref_count == 0) {
    /* Nobody's using the sprite anymore, so we should free it. We know
     * where to find it if we need it again. */
    log_debug("freeing sprite '%s'.", tag_name);
    free_sprite(ss->sprite);
    ss->sprite = nullptr;
  }
}
 
/************************************************************************/
static bool sprite_exists(const struct tileset *t, const char *tag_name)
{
  /* Lookup information about where the sprite is found. */
  return sprite_hash_lookup(t->sprite_hash, tag_name, nullptr);
}
 
/* Not very safe, but convenient: */
#define SET_SPRITE(field, tag)                                    \
  do {                                                            \
    t->sprites.field = load_sprite(t, tag, TRUE, TRUE, FALSE);    \
    if (t->sprites.field == nullptr) {                            \
      tileset_error(LOG_FATAL, tileset_name_get(t),               \
                    _("Sprite for tag '%s' missing."), tag);      \
    }                                                             \
  } while (FALSE)
 
 
#define SET_SPRITE_NOTSMOOTH(field, tag)                          \
  do {                                                            \
    t->sprites.field = load_sprite(t, tag, TRUE, FALSE, FALSE);   \
    if (t->sprites.field == nullptr) {                            \
      tileset_error(LOG_FATAL, tileset_name_get(t),               \
                    _("Sprite for tag '%s' missing."), tag);      \
    }                                                             \
  } while (FALSE)
 
#define SET_SPRITE_UNSCALED(field, tag)            \
  do {                  \
    t->sprites.field = load_sprite(t, tag, FALSE, FALSE, FALSE);  \
    if (t->sprites.field == nullptr) {                            \
      tileset_error(LOG_FATAL, tileset_name_get(t),               \
                    _("Sprite for tag '%s' missing."), tag);      \
    }                                                             \
  } while (FALSE)
 
/* Sets sprites.field to tag or (if tag isn't available) to alt */
#define SET_SPRITE_ALT(field, tag, alt)                                     \
  do {                                                                      \
    t->sprites.field = load_sprite(t, tag, TRUE, TRUE, FALSE);              \
    if (!t->sprites.field) {                                                \
      t->sprites.field = load_sprite(t, alt, TRUE, TRUE, FALSE);            \
    }                                                                       \
    if (t->sprites.field == nullptr) {                                      \
      tileset_error(LOG_FATAL, tileset_name_get(t),                         \
                    _("Sprite for tags '%s' and alternate '%s' are "        \
                      "both missing."), tag, alt);                          \
    }                                                                       \
  } while (FALSE)
 
/* Sets sprites.field to tag or (if tag isn't available) to deprecated alt */
#define SET_SPRITE_DEPR_ALT(field, tag, alt, ver)                           \
  do {                                                                      \
    t->sprites.field = load_sprite(t, tag, TRUE, TRUE, FALSE);              \
    if (!t->sprites.field) {                                                \
      t->sprites.field = load_sprite(t, alt, TRUE, TRUE, FALSE);            \
      if (t->sprites.field != nullptr) {                                    \
        log_deprecation(_("%s: Using tag \"%s\" deprecated by \"%s\" in %s"), \
                        tileset_name_get(t), alt, tag, ver);                \
      }                                                                     \
    }                                                                       \
    if (t->sprites.field == nullptr) {                                      \
      tileset_error(LOG_FATAL, tileset_name_get(t),                         \
                    _("Sprite for tags '%s' and alternate '%s' are "        \
                      "both missing."), tag, alt);                          \
    }                                                                       \
  } while (FALSE)
 
/* Sets sprites.field to tag, or nullptr if not available */
#define SET_SPRITE_OPT(field, tag) \
  t->sprites.field = load_sprite(t, tag, TRUE, TRUE, FALSE)
 
#define SET_SPRITE_ALT_OPT(field, tag, alt)                                  \
  do {                                                                       \
    t->sprites.field = tiles_lookup_sprite_tag_alt(t, LOG_VERBOSE, tag, alt, \
                                                   nullptr, "sprite",        \
                                                   #field, TRUE);            \
  } while (FALSE)
 
#define SET_ANIM(field, tag)                                      \
  do {                                                            \
    t->sprites.field = anim_load(t, tag, 0);                      \
    if (t->sprites.field == nullptr) {                            \
      tileset_error(LOG_FATAL, tileset_name_get(t),               \
                    _("Animation for tag '%s' missing."), tag);   \
    }                                                             \
  } while (FALSE)
 
/* Sets sprites.field to tag, or nullptr if not available */
#define SET_ANIM_OPT(field, tag) \
  t->sprites.field = anim_load(t, tag, 0)
 
/************************************************************************/
static struct anim *anim_load(struct tileset *t, const char *tag,
                              int time_per_frame)
{
  int frames = 0;
  char buf[1500];
  struct anim *ret;
  int i;
 
  do {
    fc_snprintf(buf, sizeof(buf), "%s:%d", tag, frames++);
  } while (sprite_exists(t, buf));
 
  if (--frames == 0) {
    return nullptr;
  }
 
  if (time_per_frame <= 0) {
    time_per_frame = t->default_time_per_frame;
  }
 
  ret = anim_new(frames, time_per_frame);
 
  for (i = 0; i < frames; i++) {
    fc_snprintf(buf, sizeof(buf), "%s:%d", tag, i);
    ret->sprites[i] = load_sprite(t, buf, TRUE, TRUE, FALSE);
    if (ret->sprites[i] == nullptr) {
      tileset_error(LOG_FATAL, tileset_name_get(t),
                    _("Animation sprite for tag '%s' missing."), buf);
    }
  }
 
  anim_hash_insert(t->anim_hash, tag, ret);
 
  return ret;
}
 
/************************************************************************/
static void anim_advance_time(struct anim *a)
{
  a->time++;
}
 
/************************************************************************/
static struct sprite *anim_get_current_frame(struct anim *a)
{
  int time;
 
  if (!gui_properties.animations && !a->show_always) {
    return a->sprites[0];
  }
 
  if (a->time >= 0) {
    time = a->time;
  } else {
    time = global_anim_time;
  }
 
  return a->sprites[(time / a->time_per_frame) % a->frames];
}
 
/************************************************************************/
void tileset_setup_specialist_type_default_set(struct tileset *t,
                                               Specialist_type_id id)
{
  tileset_setup_specialist_type(t, &t->sprites.default_citizens, id,
                                nullptr, "default set", TRUE);
}
 
/************************************************************************/
static void tileset_setup_specialist_type(struct tileset *t,
                                          struct citizen_set *set,
                                          Specialist_type_id id,
                                          const char *tag_group,
                                          const char *set_name,
                                          bool required)
{
  /* Load the specialist sprite graphics. */
  char buffer[512];
  int j;
  struct specialist *spe = specialist_by_number(id);
  const char *tag = spe->graphic_str;
  const char *graphic_alt = spe->graphic_alt;
 
  for (j = 0; j < MAX_NUM_CITIZEN_SPRITES; j++) {
    /* Try tag name + index number */
    if (tag_group != nullptr) {
      fc_snprintf(buffer, sizeof(buffer), "%s.%s_%d", tag_group, tag, j);
    } else {
      fc_snprintf(buffer, sizeof(buffer), "%s_%d", tag, j);
    }
    set->specialist[id].sprite[j] = load_sprite(t, buffer,
                                                FALSE, FALSE, FALSE);
 
    /* Break if no more index specific sprites are defined */
    if (!set->specialist[id].sprite[j]) {
      break;
    }
  }
 
  if (j == 0) {
    /* Try non-indexed */
    set->specialist[id].sprite[j] = load_sprite(t, tag,
                                                FALSE, FALSE, FALSE);
 
    if (set->specialist[id].sprite[j]) {
      j = 1;
    }
  }
 
  if (j == 0) {
    /* Try the alt tag */
    for (j = 0; j < MAX_NUM_CITIZEN_SPRITES; j++) {
      /* Try alt tag name + index number */
      if (tag_group != nullptr) {
        fc_snprintf(buffer, sizeof(buffer), "%s.%s_%d",
                    tag_group, graphic_alt, j);
      } else {
        fc_snprintf(buffer, sizeof(buffer), "%s_%d", graphic_alt, j);
      }
      set->specialist[id].sprite[j] = load_sprite(t, buffer,
                                                  FALSE, FALSE, FALSE);
 
      /* Break if no more index specific sprites are defined */
      if (!set->specialist[id].sprite[j]) {
        break;
      }
    }
  }
 
  if (j == 0) {
    /* Try alt tag non-indexed */
    set->specialist[id].sprite[j] = load_sprite(t, graphic_alt,
                                                FALSE, FALSE, FALSE);
 
    if (set->specialist[id].sprite[j]) {
      j = 1;
    }
  }
 
  set->specialist[id].count = j;
 
  /* Still nothing? Give up. */
  if (j == 0 && required) {
    /* TRANS: First %s is a graphics tag of the specialist, second one
     *        is a citizen set name; 'citizen_graphic' from styles.ruleset */
    tileset_error(LOG_FATAL, tileset_name_get(t),
                  _("No graphics for specialist \"%s\" in %s."),
                  tag, set_name);
  }
}
 
/************************************************************************/
static void tileset_setup_citizen_types_default_set(struct tileset *t)
{
  tileset_setup_citizen_types(t, &t->sprites.default_citizens, nullptr,
                              "default set", TRUE);
}
 
/************************************************************************/
static void tileset_setup_citizen_types(struct tileset *t,
                                        struct citizen_set *set,
                                        const char *tag_group,
                                        const char *set_name,
                                        bool required)
{
  int i, j;
  char buffer[512];
 
  /* Load the citizen sprite graphics, no specialist. */
  for (i = 0; i < CITIZEN_LAST; i++) {
    const char *name = citizen_rule_name(i);
 
    for (j = 0; j < MAX_NUM_CITIZEN_SPRITES; j++) {
      if (tag_group != nullptr) {
        fc_snprintf(buffer, sizeof(buffer), "citizen.%s.%s_%d",
                    tag_group, name, j);
      } else {
        fc_snprintf(buffer, sizeof(buffer), "citizen.%s_%d", name, j);
      }
      set->citizen[i].sprite[j] = load_sprite(t, buffer, FALSE, FALSE, FALSE);
      if (!set->citizen[i].sprite[j]) {
        break;
      }
    }
    set->citizen[i].count = j;
    if (j == 0 && required) {
      /* TRANS: First %s is type of the citizen ("happy" ... "angry"), second one
       *        is a citizen set name; 'citizen_graphic' from styles.ruleset */
      tileset_error(LOG_FATAL, tileset_name_get(t),
                    _("No graphics for citizen \"%s\" in %s."),
                    name, set_name);
    }
  }
}
 
/************************************************************************/
static struct anim *get_city_anim(const struct city_sprite *city_sprite,
                                  const struct city *pcity)
{
  /* Get style and match the best tile based on city size */
  int style = style_of_city(pcity);
  int num_thresholds;
  struct city_style_threshold *thresholds;
  int img_index;
 
  fc_assert_ret_val(style < city_sprite->num_styles, nullptr);
 
  num_thresholds = city_sprite->styles[style].land_num_thresholds;
  thresholds = city_sprite->styles[style].land_thresholds;
 
  if (num_thresholds == 0) {
    return nullptr;
  }
 
  /* Get the sprite with the index defined by the effects. */
  img_index = pcity->client.city_image;
  if (img_index == -100) {
    /* Server doesn't know right value as this is from old savegame.
     * Guess here based on *client* side information as was done in
     * versions where information was not saved to savegame - this should
     * give us right answer of what city looked like by the time it was
     * put under FoW. */
    img_index = get_city_bonus(pcity, EFT_CITY_IMAGE);
  }
  img_index = CLIP(0, img_index, num_thresholds - 1);
 
  return thresholds[img_index].cst;
}
 
/************************************************************************/
static int load_city_thresholds_anims(struct tileset *t, const char *tag,
                                      char *graphic, char *graphic_alt,
                                      struct city_style_threshold **thresholds)
{
  char buffer[128];
  char *gfx_in_use = graphic;
  int num_thresholds = 0;
  struct anim *anim;
  int size;
 
  *thresholds = nullptr;
 
  for (size = 0; size < MAX_CITY_SIZE; size++) {
    fc_snprintf(buffer, sizeof(buffer), "%s_%s_%d",
                gfx_in_use, tag, size);
    if ((anim = anim_load(t, buffer, 0))) {
      num_thresholds++;
      *thresholds = fc_realloc(*thresholds, num_thresholds * sizeof(**thresholds));
      (*thresholds)[num_thresholds - 1].cst = anim;
    } else if (size == 0) {
      if (gfx_in_use == graphic) {
        /* Try again with graphic_alt. */
        size--;
        gfx_in_use = graphic_alt;
      } else {
        /* Don't load any others if the 0 element isn't there. */
        break;
      }
    }
  }
 
  return num_thresholds;
}
 
/************************************************************************/
static struct city_sprite *load_city_sprite(struct tileset *t,
                                            const char *tag)
{
  struct city_sprite *city_sprite = fc_malloc(sizeof(*city_sprite));
  int style;
 
  /* Store number of styles we have allocated memory for.
   * game.control.num_city_styles might change if client disconnects from
   * server and connects new one. */
  city_sprite->num_styles = game.control.num_city_styles;
  city_sprite->styles = fc_malloc(city_sprite->num_styles
                                  * sizeof(*city_sprite->styles));
 
  for (style = 0; style < city_sprite->num_styles; style++) {
    city_sprite->styles[style].land_num_thresholds
      = load_city_thresholds_anims(t, tag, city_styles[style].graphic,
                                   city_styles[style].graphic_alt,
                                   &city_sprite->styles[style].land_thresholds);
  }
 
  return city_sprite;
}
 
/************************************************************************/
static void free_city_sprite(struct city_sprite *city_sprite)
{
  int style;
 
  if (!city_sprite) {
    return;
  }
  for (style = 0; style < city_sprite->num_styles; style++) {
    if (city_sprite->styles[style].land_thresholds) {
      free(city_sprite->styles[style].land_thresholds);
    }
  }
  free(city_sprite->styles);
  free(city_sprite);
}
 
/************************************************************************/
static void tileset_lookup_sprite_tags(struct tileset *t)
{
  char buffer[512], buffer2[512];
  const int W = t->normal_tile_width, H = t->normal_tile_height;
  int i, j, f;
 
  fc_assert_ret(t->sprite_hash != nullptr);
 
  SET_SPRITE_UNSCALED(treaty_thumb[0], "treaty.disagree_thumb_down");
  SET_SPRITE_UNSCALED(treaty_thumb[1], "treaty.agree_thumb_up");
 
  for (j = 0; j < INDICATOR_COUNT; j++) {
    const char *names[] = {"science_bulb", "warming_sun", "cooling_flake"};
 
    for (i = 0; i < NUM_TILES_PROGRESS; i++) {
      fc_snprintf(buffer, sizeof(buffer), "s.%s_%d", names[j], i);
      SET_SPRITE_UNSCALED(indicator[j][i], buffer);
    }
  }
 
  SET_SPRITE(arrow[ARROW_RIGHT], "s.right_arrow");
  SET_SPRITE(arrow[ARROW_PLUS], "s.plus");
  SET_SPRITE(arrow[ARROW_MINUS], "s.minus");
  if (t->type == TS_ISOMETRIC) {
    SET_SPRITE(dither_tile, "t.dither_tile");
  }
 
  if (tileset_is_isometric(tileset)) {
    SET_SPRITE_NOTSMOOTH(mask.tile, "mask.tile");
  } else {
    SET_SPRITE(mask.tile, "mask.tile");
  }
  SET_SPRITE(mask.worked_tile, "mask.worked_tile");
  SET_SPRITE(mask.unworked_tile, "mask.unworked_tile");
 
  SET_SPRITE_UNSCALED(tax_luxury, "s.tax_luxury");
  SET_SPRITE_UNSCALED(tax_science, "s.tax_science");
  SET_SPRITE_UNSCALED(tax_gold, "s.tax_gold");
 
  tileset_setup_citizen_types_default_set(t);
 
  for (i = 0; i < SPACESHIP_COUNT; i++) {
    const char *names[SPACESHIP_COUNT]
      = {"solar_panels", "life_support", "habitation",
         "structural", "fuel", "propulsion", "exhaust"};
 
    fc_snprintf(buffer, sizeof(buffer), "spaceship.%s", names[i]);
    SET_SPRITE(spaceship[i], buffer);
  }
 
  for (i = 0; i < CURSOR_LAST; i++) {
    const char *names[CURSOR_LAST] =
             {"goto", "patrol", "paradrop", "teleport", "nuke", "select",
              "invalid", "attack", "edit_paint", "edit_add", "wait"};
 
    for (f = 0; f < NUM_CURSOR_FRAMES; f++) {
      struct small_sprite *ss;
 
      fc_assert(ARRAY_SIZE(names) == CURSOR_LAST);
      fc_snprintf(buffer, sizeof(buffer), "cursor.%s%d", names[i], f);
      SET_SPRITE(cursor[i].frame[f], buffer);
 
      if (sprite_hash_lookup(t->sprite_hash, buffer, &ss)) {
        t->sprites.cursor[i].hot_x = ss->hot_x;
        t->sprites.cursor[i].hot_y = ss->hot_y;
      }
    }
  }
 
  for (i = 0; i < ICON_COUNT; i++) {
    const char *names[ICON_COUNT] = {"freeciv", "citydlg"};
 
    fc_snprintf(buffer, sizeof(buffer), "icon.%s", names[i]);
    SET_SPRITE(icon[i], buffer);
  }
 
  for (i = 0; i < E_COUNT; i++) {
    const char *tag = get_event_tag(i);
 
    SET_SPRITE(events[i], tag);
  }
 
  SET_SPRITE(explode.nuke, "explode.nuke");
 
  sprite_vector_init(&t->sprites.explode.unit);
  for (i = 0; ; i++) {
    struct sprite *sprite;
 
    fc_snprintf(buffer, sizeof(buffer), "explode.unit_%d", i);
    sprite = load_sprite(t, buffer, TRUE, TRUE, FALSE);
    if (!sprite) {
      break;
    }
    sprite_vector_append(&t->sprites.explode.unit, sprite);
  }
 
  SET_SPRITE(unit.auto_attack,  "unit.auto_attack");
  /* TODO: Drop backward compatibility with "unit.auto_settler" tag. */
  SET_SPRITE_DEPR_ALT(unit.auto_worker, "unit.auto_worker", "unit.auto_settler", "3.3");
  SET_SPRITE(unit.auto_explore, "unit.auto_explore");
  SET_SPRITE(unit.fortified,    "unit.fortified");
  SET_SPRITE(unit.fortifying,   "unit.fortifying");
  SET_SPRITE(unit.go_to,        "unit.goto");
  SET_SPRITE(unit.cultivate,    "unit.cultivate");
  SET_SPRITE(unit.plant,        "unit.plant");
  SET_SPRITE(unit.pillage,      "unit.pillage");
  SET_SPRITE(unit.sentry,       "unit.sentry");
  SET_SPRITE(unit.convert,      "unit.convert");
  t->sprites.unit.stack = fc_malloc(sizeof(struct sprite *));
  t->sprites.unit.num_stack_sprites = 1;
  SET_SPRITE(unit.stack[0],     "unit.stack");
  t->sprites.unit.no_more_stack_sprites = FALSE;
  SET_SPRITE(unit.loaded,       "unit.loaded");
  SET_SPRITE(unit.transform,    "unit.transform");
  SET_SPRITE(unit.connect,      "unit.connect");
  SET_SPRITE(unit.patrol,       "unit.patrol");
  for (i = 0; i < MAX_NUM_BATTLEGROUPS; i++) {
    fc_snprintf(buffer, sizeof(buffer), "unit.battlegroup_%d", i);
    fc_snprintf(buffer2, sizeof(buffer2), "city.size_%d", i + 1);
    fc_assert(MAX_NUM_BATTLEGROUPS < NUM_TILES_DIGITS);
    SET_SPRITE_ALT(unit.battlegroup[i], buffer, buffer2);
  }
  SET_SPRITE(unit.lowfuel, "unit.lowfuel");
  SET_SPRITE(unit.tired, "unit.tired");
 
  t->sprites.unit.action_decision_want = anim_load(t, "unit.action_decision_want",
                                                   0);
 
  for (i = 0; i < NUM_TILES_HP_BAR; i++) {
    fc_snprintf(buffer, sizeof(buffer), "unit.hp_%d", i*10);
    SET_SPRITE(unit.hp_bar[i], buffer);
  }
 
  for (i = 0; i < MAX_VET_LEVELS; i++) {
    /* Veteran level sprites are optional.  For instance "green" units
     * usually have no special graphic. */
    fc_snprintf(buffer, sizeof(buffer), "unit.vet_%d", i);
    t->sprites.unit.vet_lev[i] = load_sprite(t, buffer, TRUE, TRUE, FALSE);
  }
 
  t->sprites.unit.select = anim_load(t, "unit.select", 1);
  if (t->sprites.unit.select != nullptr) {
    t->sprites.unit.select->show_always = TRUE;
    t->sprites.unit.select->time = 0; /* Not using global anim time */
  }
 
  SET_SPRITE(citybar.shields, "citybar.shields");
  SET_SPRITE(citybar.food, "citybar.food");
  SET_SPRITE(citybar.trade, "citybar.trade");
  SET_SPRITE(citybar.occupied, "citybar.occupied");
  SET_SPRITE(citybar.background, "citybar.background");
  sprite_vector_init(&t->sprites.citybar.occupancy);
  for (i = 0; ; i++) {
    struct sprite *sprite;
 
    fc_snprintf(buffer, sizeof(buffer), "citybar.occupancy_%d", i);
    sprite = load_sprite(t, buffer, TRUE, TRUE, FALSE);
    if (!sprite) {
      break;
    }
    sprite_vector_append(&t->sprites.citybar.occupancy, sprite);
  }
  if (t->sprites.citybar.occupancy.size < 2) {
    tileset_error(LOG_FATAL, tileset_name_get(t),
                  _("Missing necessary citybar.occupancy_N sprites."));
  }
 
#define SET_EDITOR_SPRITE(x) SET_SPRITE(editor.x, "editor." #x)
  SET_EDITOR_SPRITE(erase);
  SET_EDITOR_SPRITE(brush);
  SET_EDITOR_SPRITE(copy);
  SET_EDITOR_SPRITE(paste);
  SET_EDITOR_SPRITE(copypaste);
  SET_EDITOR_SPRITE(startpos);
  SET_EDITOR_SPRITE(terrain);
  SET_EDITOR_SPRITE(terrain_resource);
  SET_EDITOR_SPRITE(terrain_special);
  SET_EDITOR_SPRITE(unit);
  SET_EDITOR_SPRITE(city);
  SET_EDITOR_SPRITE(vision);
  SET_EDITOR_SPRITE(territory);
  SET_EDITOR_SPRITE(properties);
  SET_EDITOR_SPRITE(road);
  SET_EDITOR_SPRITE(military_base);
#undef SET_EDITOR_SPRITE
 
  SET_SPRITE(city.disorder, "city.disorder");
 
  /* Fallbacks for goto path turn numbers:
   *   path.step_%d, path.exhausted_mp_%d
   *   --> path.turns_%d
   *       --> city.size_%d */
#define SET_GOTO_TURN_SPRITE(state, state_name, factor, factor_name)        \
  fc_snprintf(buffer, sizeof(buffer), "path." state_name "_%d" #factor, i); \
  SET_SPRITE_OPT(path.s[state].turns ## factor_name [i], buffer);           \
  if (t->sprites.path.s[state].turns ## factor_name [i] == nullptr) {       \
    t->sprites.path.s[state].turns ## factor_name [i] =                     \
        t->sprites.path.s[GTS_MP_LEFT].turns ## factor_name [i];            \
  }
 
  for (i = 0; i < NUM_TILES_DIGITS; i++) {
    fc_snprintf(buffer, sizeof(buffer), "city.size_%d", i);
    SET_SPRITE(city.size[i], buffer);
    fc_snprintf(buffer2, sizeof(buffer2), "path.turns_%d", i);
    SET_SPRITE_ALT(path.s[GTS_MP_LEFT].turns[i], buffer2, buffer);
    SET_GOTO_TURN_SPRITE(GTS_TURN_STEP, "step",,);
    SET_GOTO_TURN_SPRITE(GTS_EXHAUSTED_MP, "exhausted_mp",,);
 
    fc_snprintf(buffer, sizeof(buffer), "city.size_%d0", i);
    SET_SPRITE(city.size_tens[i], buffer);
    fc_snprintf(buffer2, sizeof(buffer2), "path.turns_%d0", i);
    SET_SPRITE_ALT(path.s[GTS_MP_LEFT].turns_tens[i], buffer2, buffer);
    SET_GOTO_TURN_SPRITE(GTS_TURN_STEP, "step", 0, _tens);
    SET_GOTO_TURN_SPRITE(GTS_EXHAUSTED_MP, "exhausted_mp", 0, _tens);
 
    fc_snprintf(buffer, sizeof(buffer), "city.size_%d00", i);
    SET_SPRITE_OPT(city.size_hundreds[i], buffer);
    fc_snprintf(buffer2, sizeof(buffer2), "path.turns_%d00", i);
    SET_SPRITE_ALT_OPT(path.s[GTS_MP_LEFT].turns_hundreds[i], buffer2,
                       buffer);
    SET_GOTO_TURN_SPRITE(GTS_TURN_STEP, "step", 00, _hundreds);
    SET_GOTO_TURN_SPRITE(GTS_EXHAUSTED_MP, "exhausted_mp", 00, _hundreds);
 
    fc_snprintf(buffer, sizeof(buffer), "city.t_food_%d", i);
    SET_SPRITE(city.tile_foodnum[i], buffer);
    fc_snprintf(buffer, sizeof(buffer), "city.t_shields_%d", i);
    SET_SPRITE(city.tile_shieldnum[i], buffer);
    fc_snprintf(buffer, sizeof(buffer), "city.t_trade_%d", i);
    SET_SPRITE(city.tile_tradenum[i], buffer);
  }
#undef SET_GOTO_TURN_SPRITE
 
  /* Must have at least one upkeep sprite per output type (and unhappy) */
  /* The rest are optional; we copy the previous sprite for unspecified ones */
  fc_strlcpy(buffer, "upkeep.unhappy", sizeof(buffer));
  SET_SPRITE(upkeep.unhappy[0], buffer);
  for (i = 1; i < MAX_NUM_UPKEEP_SPRITES; i++) {
    fc_snprintf(buffer2, sizeof(buffer2), "upkeep.unhappy%d", i+1);
    if (sprite_exists(t, buffer2)) {
      SET_SPRITE(upkeep.unhappy[i], buffer2);
      fc_strlcpy(buffer, buffer2, sizeof(buffer));
    } else {
      SET_SPRITE(upkeep.unhappy[i], buffer);
    }
  }
  output_type_iterate(o) {
    fc_snprintf(buffer, sizeof(buffer),
                "upkeep.%s", get_output_identifier(o));
    SET_SPRITE_OPT(upkeep.output[o][0], buffer);
    for (i = 1; i < MAX_NUM_UPKEEP_SPRITES; i++) {
      fc_snprintf(buffer2, sizeof(buffer2),
                  "upkeep.%s%d", get_output_identifier(o), i+1);
      if (sprite_exists(t, buffer2)) {
        SET_SPRITE(upkeep.output[o][i], buffer2);
        fc_strlcpy(buffer, buffer2, sizeof(buffer));
      } else {
        /* Optional, as maybe the upkeep 1 sprite didn't exist either */
        SET_SPRITE_OPT(upkeep.output[o][i], buffer);
      }
    }
  } output_type_iterate_end;
 
  t->max_upkeep_height = calculate_max_upkeep_height(t);
 
  SET_SPRITE(user.attention, "user.attention");
  SET_SPRITE(user.infratile, "user.infratile");
 
  SET_SPRITE_OPT(path.s[GTS_MP_LEFT].specific, "path.normal");
  SET_SPRITE_OPT(path.s[GTS_EXHAUSTED_MP].specific, "path.exhausted_mp");
  SET_SPRITE_OPT(path.s[GTS_TURN_STEP].specific, "path.step");
  SET_SPRITE(path.waypoint, "path.waypoint");
 
  SET_SPRITE_NOTSMOOTH(tx.fog, "tx.fog");
 
  sprite_vector_init(&t->sprites.colors.overlays);
  for (i = 0; ; i++) {
    struct sprite *sprite;
 
    fc_snprintf(buffer, sizeof(buffer), "colors.overlay_%d", i);
    sprite = load_sprite(t, buffer, TRUE, TRUE, FALSE);
    if (!sprite) {
      break;
    }
    sprite_vector_append(&t->sprites.colors.overlays, sprite);
  }
  if (i == 0) {
    tileset_error(LOG_FATAL, tileset_name_get(t),
                  _("Missing overlay-color sprite colors.overlay_0."));
  }
 
  /* Chop up and build the overlay graphics. */
  sprite_vector_reserve(&t->sprites.city.worked_tile_overlay,
                        sprite_vector_size(&t->sprites.colors.overlays));
  sprite_vector_reserve(&t->sprites.city.unworked_tile_overlay,
                        sprite_vector_size(&t->sprites.colors.overlays));
  for (i = 0; i < sprite_vector_size(&t->sprites.colors.overlays); i++) {
    struct sprite *color, *color_mask;
    struct sprite *worked, *unworked;
 
    color = *sprite_vector_get(&t->sprites.colors.overlays, i);
    color_mask = crop_sprite(color, 0, 0, W, H, t->sprites.mask.tile, 0, 0,
                             1.0f, FALSE);
    worked = crop_sprite(color_mask, 0, 0, W, H,
                         t->sprites.mask.worked_tile, 0, 0, 1.0f, FALSE);
    unworked = crop_sprite(color_mask, 0, 0, W, H,
                           t->sprites.mask.unworked_tile, 0, 0, 1.0f, FALSE);
    free_sprite(color_mask);
    t->sprites.city.worked_tile_overlay.p[i] =  worked;
    t->sprites.city.unworked_tile_overlay.p[i] = unworked;
  }
 
 
  {
    SET_SPRITE(grid.unavailable, "grid.unavailable");
    SET_SPRITE_OPT(grid.nonnative, "grid.nonnative");
 
    for (i = 0; i < EDGE_COUNT; i++) {
      int be;
 
      if (i == EDGE_UD && t->hex_width == 0) {
        continue;
      } else if (i == EDGE_LR && t->hex_height == 0) {
        continue;
      }
 
      fc_snprintf(buffer, sizeof(buffer), "grid.main.%s", edge_name[i]);
      SET_SPRITE(grid.main[i], buffer);
 
      fc_snprintf(buffer, sizeof(buffer), "grid.city.%s", edge_name[i]);
      SET_SPRITE(grid.city[i], buffer);
 
      fc_snprintf(buffer, sizeof(buffer), "grid.worked.%s", edge_name[i]);
      SET_SPRITE(grid.worked[i], buffer);
 
      fc_snprintf(buffer, sizeof(buffer), "grid.selected.%s", edge_name[i]);
      SET_SPRITE(grid.selected[i], buffer);
 
      fc_snprintf(buffer, sizeof(buffer), "grid.coastline.%s", edge_name[i]);
      SET_SPRITE(grid.coastline[i], buffer);
 
      for (be = 0; be < 2; be++) {
        fc_snprintf(buffer, sizeof(buffer), "grid.borders.%c",
                    edge_name[i][be]);
        SET_SPRITE(grid.borders[i][be], buffer);
      }
    }
  }
 
  switch (t->darkness_style) {
  case DARKNESS_NONE:
    /* Nothing. */
    break;
  case DARKNESS_ISORECT:
    {
      /* Isometric: take a single tx.darkness tile and split it into 4. */
      struct sprite *darkness = load_sprite(t, "tx.darkness",
                                            TRUE, FALSE, FALSE);
      const int ntw = t->normal_tile_width, nth = t->normal_tile_height;
      int offsets[4][2] = {{ntw / 2, 0}, {0, nth / 2}, {ntw / 2, nth / 2}, {0, 0}};
 
      if (!darkness) {
        tileset_error(LOG_FATAL, tileset_name_get(t),
                      _("Sprite tx.darkness missing."));
      }
      for (i = 0; i < 4; i++) {
        t->sprites.tx.darkness[i] = crop_sprite(darkness, offsets[i][0],
                                                offsets[i][1], ntw / 2,
                                                nth / 2, nullptr, 0, 0, 1.0f,
                                                FALSE);
      }
    }
    break;
  case DARKNESS_CARD_SINGLE:
    for (i = 0; i < t->num_cardinal_tileset_dirs; i++) {
      enum direction8 dir = t->cardinal_tileset_dirs[i];
 
      fc_snprintf(buffer, sizeof(buffer), "tx.darkness_%s",
                  dir_get_tileset_name(dir));
      SET_SPRITE_NOTSMOOTH(tx.darkness[i], buffer);
    }
    break;
  case DARKNESS_CARD_FULL:
    for (i = 1; i < t->num_index_cardinal; i++) {
      fc_snprintf(buffer, sizeof(buffer), "tx.darkness_%s",
                  cardinal_index_str(t, i));
      SET_SPRITE_NOTSMOOTH(tx.darkness[i], buffer);
    }
    break;
  case DARKNESS_CORNER:
    t->sprites.tx.fullfog = fc_realloc(t->sprites.tx.fullfog,
                                       81 * sizeof(*t->sprites.tx.fullfog));
    for (i = 0; i < 81; i++) {
      /* Unknown, fog, known. */
      char ids[] = {'u', 'f', 'k'};
      char buf[512] = "t.fog";
      int values[4], vi, k = i;
 
      for (vi = 0; vi < 4; vi++) {
        values[vi] = k % 3;
        k /= 3;
 
        cat_snprintf(buf, sizeof(buf), "_%c", ids[values[vi]]);
      }
      fc_assert(k == 0);
 
      t->sprites.tx.fullfog[i] = load_sprite(t, buf, TRUE, FALSE, FALSE);
    }
    break;
  };
 
  /* No other place to initialize these variables */
  sprite_vector_init(&t->sprites.nation_flag);
  sprite_vector_init(&t->sprites.nation_shield);
}
 
/************************************************************************/
static bool load_river_sprites(struct tileset *t,
                               struct river_sprites *store, const char *tag_pfx)
{
  int i;
  char buffer[512];
 
  for (i = 0; i < t->num_index_cardinal; i++) {
    fc_snprintf(buffer, sizeof(buffer), "%s_s_%s",
                tag_pfx, cardinal_index_str(t, i));
    store->spec[i] = anim_load(t, buffer, 0);
    if (store->spec[i] == nullptr) {
      return FALSE;
    }
  }
 
  for (i = 0; i < t->num_cardinal_tileset_dirs; i++) {
    fc_snprintf(buffer, sizeof(buffer), "%s_outlet_%s",
                tag_pfx, dir_get_tileset_name(t->cardinal_tileset_dirs[i]));
    store->outlet[i] = anim_load(t, buffer, 0);
    if (store->outlet[i] == nullptr) {
      log_error("Missing \"%s\" for \"%s\".", buffer, tag_pfx);
      return FALSE;
    }
  }
 
  return TRUE;
}
 
/************************************************************************/
void finish_loading_sprites(struct tileset *t)
{
  specfile_list_iterate(t->specfiles, sf) {
    if (sf->big_sprite) {
      free_sprite(sf->big_sprite);
      sf->big_sprite = nullptr;
    }
  } specfile_list_iterate_end;
}
 
/************************************************************************/
void tileset_load_tiles(struct tileset *t)
{
  tileset_lookup_sprite_tags(t);
  finish_loading_sprites(t);
}
 
/************************************************************************/
struct sprite *tiles_lookup_sprite_tag_alt(struct tileset *t,
                                           enum log_level level,
                                           const char *tag, const char *alt,
                                           const char *alt2,
                                           const char *what, const char *name,
                                           bool scale)
{
  struct sprite *sp;
 
  /* (Should get sprite_hash before connection) */
  fc_assert_ret_val_msg(t->sprite_hash != nullptr, nullptr,
                        "attempt to lookup for %s \"%s\" before "
                        "sprite_hash setup", what, name);
 
  sp = load_sprite(t, tag, scale, TRUE, FALSE);
  if (sp) return sp;
 
  sp = load_sprite(t, alt, scale, TRUE, FALSE);
  if (sp) {
    log_verbose("Using alternate graphic \"%s\" "
                "(instead of \"%s\") for %s \"%s\".",
                alt, tag, what, name);
    return sp;
  }
 
  if (alt2 != nullptr) {
    sp = load_sprite(t, alt2, scale, TRUE, FALSE);
    if (sp) {
      log_verbose("Using second alternate graphic \"%s\" "
                  "(instead of \"%s\" or \"%s\") for %s \"%s\".",
                  alt2, tag, alt, what, name);
      return sp;
    }
  }
 
  tileset_error(level, tileset_name_get(t),
                _("Don't have graphics tags \"%s\" or \"%s\" for %s \"%s\"."),
                tag, alt, what, name);
 
  return nullptr;
}
 
/************************************************************************/
static bool tileset_setup_unit_direction(struct tileset *t,
                                         int uidx,
                                         const char *base_str,
                                         enum direction8 dir,
                                         enum unit_activity activity,
                                         bool has_icon)
{
  enum direction8 loaddir = dir;
  char buf[2048];
  const char *act_name = unit_activity_name(activity);
 
  if (act_name == nullptr) {
    /* gcc-9 thinks this is possible. */
    return FALSE;
  }
 
  /*
   * There may be more orientations available in this tileset than are
   * needed, if an oriented unit set has been reused between tilesets.
   *
   * Don't bother loading unused ones, unless they might be used by
   * unit_default_orientation (logic here mirrors get_unittype_sprite()).
   */
  if (!(dir == t->unit_default_orientation && !has_icon)
      && !is_valid_tileset_dir(t, dir)) {
    /* Instead we copy a nearby valid dir's sprite, so we're not caught
     * out in case this tileset is used with an incompatible topology,
     * although it'll be ugly. */
    do {
      loaddir = dir_cw(loaddir);
      /* This loop _should_ terminate... */
      fc_assert_ret_val(loaddir != dir, FALSE);
    } while (!is_valid_tileset_dir(t, loaddir));
  }
 
  fc_snprintf(buf, sizeof(buf), "%s_%s_%s", base_str,
              act_name, dir_get_tileset_name(loaddir));
 
  /* We don't use _alt graphics here, as that could lead to loading
   * real icon gfx, but alternative orientation gfx. Tileset author
   * probably meant icon gfx to be used as fallback for all orientations */
  t->sprites.units.facing[uidx][dir][activity] = anim_load(t, buf, 0);
 
  if (activity == ACTIVITY_IDLE
      && t->sprites.units.facing[uidx][dir][activity] == nullptr) {
    /* Backward compatibility: Set Idle sprite from tag with no activity defined. */
    fc_snprintf(buf, sizeof(buf), "%s_%s", base_str,
                dir_get_tileset_name(loaddir));
 
    t->sprites.units.facing[uidx][dir][activity] = anim_load(t, buf, 0);
  }
 
  if (t->sprites.units.facing[uidx][dir][activity] != nullptr) {
    return TRUE;
  }
 
  return FALSE;
}
 
/************************************************************************/
static bool tileset_setup_unit_type_from_tag(struct tileset *t,
                                             int uidx,
                                             const char *tag)
{
  bool has_icon, facing_sprites[ACTIVITY_LAST];
 
  activity_type_iterate(activity) {
    char buffer[2048];
 
    fc_snprintf(buffer, sizeof(buffer), "%s_%s",
                tag, unit_activity_name(activity));
    t->sprites.units.icon[uidx][activity] = anim_load(t, buffer, 0);
 
    if (activity == ACTIVITY_IDLE
        && t->sprites.units.icon[uidx][activity] == nullptr) {
      /* Backward compatibility: Set Idle sprite from tag with no activity defined. */
      t->sprites.units.icon[uidx][activity] = anim_load(t, tag, 0);
    }
  } activity_type_iterate_end;
 
  has_icon = t->sprites.units.icon[uidx][ACTIVITY_IDLE] != nullptr;
 
#define LOAD_FACING_SPRITE(dir)                                                 \
  if (!tileset_setup_unit_direction(t, uidx, tag, dir, activity, has_icon)) {   \
    facing_sprites[activity] = FALSE;                                           \
  }
 
  activity_type_iterate(activity) {
    facing_sprites[activity] = TRUE;
 
    LOAD_FACING_SPRITE(DIR8_NORTHWEST);
    LOAD_FACING_SPRITE(DIR8_NORTH);
    LOAD_FACING_SPRITE(DIR8_NORTHEAST);
    LOAD_FACING_SPRITE(DIR8_WEST);
    LOAD_FACING_SPRITE(DIR8_EAST);
    LOAD_FACING_SPRITE(DIR8_SOUTHWEST);
    LOAD_FACING_SPRITE(DIR8_SOUTH);
    LOAD_FACING_SPRITE(DIR8_SOUTHEAST);
 
  } activity_type_iterate_end;
 
  if (!has_icon && !facing_sprites[ACTIVITY_IDLE]) {
    /* Neither icon gfx or orientation sprites */
    return FALSE;
  }
 
  return TRUE;
 
#undef LOAD_FACING_SPRITE
}
 
/************************************************************************/
void tileset_setup_unit_type(struct tileset *t, struct unit_type *ut)
{
  int uidx = utype_index(ut);
 
  if (!tileset_setup_unit_type_from_tag(t, uidx, ut->graphic_str)
      && !tileset_setup_unit_type_from_tag(t, uidx, ut->graphic_alt)
      && !tileset_setup_unit_type_from_tag(t, uidx, ut->graphic_alt2)) {
    tileset_error(LOG_FATAL, tileset_name_get(t),
                  _("Missing %s unit sprites for tags \"%s\" and alternatives "
                    "\"%s\" and \"%s\"."),
                  utype_rule_name(ut), ut->graphic_str,
                  ut->graphic_alt, ut->graphic_alt2);
  }
 
  if (!t->sprites.units.icon[uidx][ACTIVITY_IDLE]) {
    if (!direction8_is_valid(t->unit_default_orientation)) {
      tileset_error(LOG_FATAL, tileset_name_get(t),
                    _("Unit type %s has no unoriented sprites and "
                      "tileset has no unit_default_orientation."),
                    utype_rule_name(ut));
    } else {
      /* We're guaranteed to have an oriented sprite corresponding to
       * unit_default_orientation, because tileset_setup_unit_type_from_tag()
       * checked for this. */
      fc_assert(t->sprites.units.facing[uidx][t->unit_default_orientation]
                != nullptr);
    }
  }
}
 
/************************************************************************/
void tileset_setup_impr_type(struct tileset *t,
                             struct impr_type *pimprove)
{
  t->sprites.building[improvement_index(pimprove)]
    = tiles_lookup_sprite_tag_alt(t, LOG_VERBOSE, pimprove->graphic_str,
                                  pimprove->graphic_alt, pimprove->graphic_alt2,
                                  "improvement",
                                  improvement_rule_name(pimprove), FALSE);
 
  /* Should maybe do something if nullptr, eg generic default? */
}
 
/************************************************************************/
void tileset_setup_tech_type(struct tileset *t,
                             struct advance *padvance)
{
  if (valid_advance(padvance)) {
    t->sprites.tech[advance_index(padvance)]
      = tiles_lookup_sprite_tag_alt(t, LOG_VERBOSE, padvance->graphic_str,
                                    padvance->graphic_alt, nullptr,
                                    "technology",
                                    advance_rule_name(padvance), FALSE);
 
    /* Should maybe do something if nullptr, eg generic default? */
  } else {
    t->sprites.tech[advance_index(padvance)] = nullptr;
  }
}
 
/************************************************************************/
void tileset_setup_extra(struct tileset *t,
                         struct extra_type *pextra)
{
  const int id = extra_index(pextra);
  enum extrastyle_id extrastyle;
 
  if (!fc_strcasecmp(pextra->graphic_str, "none")) {
    /* Extra without graphics */
    t->sprites.extras[id].extrastyle = extrastyle_id_invalid();
  } else {
    const char *tag;
 
    tag = pextra->graphic_str;
    if (!estyle_hash_lookup(t->estyle_hash, tag, &extrastyle)) {
      tag = pextra->graphic_alt;
      if (!estyle_hash_lookup(t->estyle_hash, tag, &extrastyle)) {
        tileset_error(LOG_FATAL, tileset_name_get(t),
                      _("No extra style for \"%s\" or \"%s\"."),
                      pextra->graphic_str,
                      pextra->graphic_alt);
      } else {
        log_verbose("Using alternate graphic \"%s\" "
                    "(instead of \"%s\") for extra \"%s\".",
                    pextra->graphic_alt, pextra->graphic_str,
                    extra_rule_name(pextra));
      }
    }
 
    t->sprites.extras[id].extrastyle = extrastyle;
 
    extra_type_list_append(t->style_lists[extrastyle], pextra);
 
    if (extra_has_flag(pextra, EF_SHOW_FLAG)) {
      extra_type_list_append(t->flagged_bases_list, pextra);
    }
 
    switch (extrastyle) {
    case ESTYLE_3LAYER:
      tileset_setup_base(t, pextra, tag);
      break;
 
    case ESTYLE_ROAD_ALL_SEPARATE:
    case ESTYLE_ROAD_PARITY_COMBINED:
    case ESTYLE_ROAD_ALL_COMBINED:
    case ESTYLE_RIVER:
      tileset_setup_road(t, pextra, tag);
      break;
 
    case ESTYLE_SINGLE1:
    case ESTYLE_SINGLE2:
      SET_ANIM(extras[id].u.single, tag);
      break;
 
    case ESTYLE_CARDINALS:
      {
        int i;
        char buffer[512];
 
        /* We use direction-specific irrigation and farmland graphics, if they
         * are available. If not, we just fall back to the basic irrigation
         * graphics. */
        for (i = 0; i < t->num_index_cardinal; i++) {
          fc_snprintf(buffer, sizeof(buffer), "%s_%s",
                      tag, cardinal_index_str(t, i));
          t->sprites.extras[id].u.cardinals[i] = anim_load(t, buffer, 0);
          if (t->sprites.extras[id].u.cardinals[i] == nullptr) {
            t->sprites.extras[id].u.cardinals[i] = anim_load(t, tag, 0);
          }
          if (t->sprites.extras[id].u.cardinals[i] == nullptr) {
            tileset_error(LOG_FATAL, tileset_name_get(t),
                          _("No cardinal-style graphics \"%s*\" for "
                            "extra \"%s\""),
                          tag, extra_rule_name(pextra));
          }
        }
      }
      break;
    case ESTYLE_COUNT:
      break;
    }
  }
 
  if (!fc_strcasecmp(pextra->activity_gfx, "none")) {
    t->sprites.extras[id].activity = nullptr;
  } else {
    t->sprites.extras[id].activity = load_sprite(t, pextra->activity_gfx,
                                                 TRUE, TRUE, FALSE);
    if (t->sprites.extras[id].activity == nullptr) {
      t->sprites.extras[id].activity = load_sprite(t, pextra->act_gfx_alt,
                                                   TRUE, TRUE, FALSE);
    }
    if (t->sprites.extras[id].activity == nullptr) {
      t->sprites.extras[id].activity = load_sprite(t, pextra->act_gfx_alt2,
                                                   TRUE, TRUE, FALSE);
    }
    if (t->sprites.extras[id].activity == nullptr) {
      tileset_error(LOG_FATAL, tileset_name_get(t),
                    _("Missing %s building activity sprite for tags \"%s\" and alternatives \"%s\" and \"%s\"."),
                    extra_rule_name(pextra), pextra->activity_gfx,
                    pextra->act_gfx_alt, pextra->act_gfx_alt2);
    }
  }
 
  if (!fc_strcasecmp(pextra->rmact_gfx, "none")) {
    t->sprites.extras[id].rmact = nullptr;
  } else {
    t->sprites.extras[id].rmact = load_sprite(t, pextra->rmact_gfx,
                                              TRUE, TRUE, FALSE);
    if (t->sprites.extras[id].rmact == nullptr) {
      t->sprites.extras[id].rmact = load_sprite(t, pextra->rmact_gfx_alt,
                                                TRUE, TRUE, FALSE);
      if (t->sprites.extras[id].rmact == nullptr) {
        t->sprites.extras[id].rmact = load_sprite(t, pextra->rmact_gfx_alt2,
                                                  TRUE, TRUE, FALSE);
        if (t->sprites.extras[id].rmact == nullptr) {
          tileset_error(LOG_FATAL, tileset_name_get(t),
                        _("Missing %s removal activity sprite for tags \"%s\" "
                          "and alternatives \"%s\" and \"%s\"."),
                        extra_rule_name(pextra), pextra->rmact_gfx,
                        pextra->rmact_gfx_alt, pextra->rmact_gfx_alt2);
        }
      }
    }
  }
}
 
/************************************************************************/
static void tileset_setup_road(struct tileset *t,
                               struct extra_type *pextra,
                               const char *tag)
{
  char full_tag_name[MAX_LEN_NAME + sizeof("_isolated")];
  const int id = extra_index(pextra);
  int i;
  enum extrastyle_id extrastyle = t->sprites.extras[id].extrastyle;
 
  /* Isolated road graphics are used by ESTYLE_ROAD_ALL_SEPARATE and
     ESTYLE_ROAD_PARITY_COMBINED. */
  if (extrastyle == ESTYLE_ROAD_ALL_SEPARATE
      || extrastyle == ESTYLE_ROAD_PARITY_COMBINED) {
    fc_snprintf(full_tag_name, sizeof(full_tag_name),
                "%s_isolated", tag);
 
    SET_ANIM(extras[id].u.road.isolated, full_tag_name);
  }
 
  if (extrastyle == ESTYLE_ROAD_ALL_SEPARATE) {
    /* ESTYLE_ROAD_ALL_SEPARATE has just 8 additional sprites for each
     * road type: one going off in each direction. */
    for (i = 0; i < t->num_valid_tileset_dirs; i++) {
      enum direction8 dir = t->valid_tileset_dirs[i];
      const char *dir_name = dir_get_tileset_name(dir);
 
      fc_snprintf(full_tag_name, sizeof(full_tag_name),
                  "%s_%s", tag, dir_name);
 
      SET_ANIM(extras[id].u.road.ru.dir[i], full_tag_name);
    }
  } else if (extrastyle == ESTYLE_ROAD_PARITY_COMBINED) {
    int num_index = 1 << (t->num_valid_tileset_dirs / 2), j;
 
    /* ESTYLE_ROAD_PARITY_COMBINED has 32 additional sprites for each road
     * type: 16 each for cardinal and diagonal directions. Each set
     * of 16 provides a NSEW-indexed sprite to provide connectors for
     * all rails in the cardinal/diagonal directions. The 0 entry is
     * unused (the "isolated" sprite is used instead). */
 
    for (i = 1; i < num_index; i++) {
      char c[64] = "", d[64] = "";
 
      for (j = 0; j < t->num_valid_tileset_dirs / 2; j++) {
        int value = (i >> j) & 1;
 
        cat_snprintf(c, sizeof(c), "%s%d",
                     dir_get_tileset_name(t->valid_tileset_dirs[2 * j]),
                     value);
        cat_snprintf(d, sizeof(d), "%s%d",
                     dir_get_tileset_name(t->valid_tileset_dirs[2 * j + 1]),
                     value);
      }
 
      fc_snprintf(full_tag_name, sizeof(full_tag_name),
                  "%s_c_%s", tag, c);
 
      SET_ANIM(extras[id].u.road.ru.combo.even[i], full_tag_name);
 
      fc_snprintf(full_tag_name, sizeof(full_tag_name),
                  "%s_d_%s", tag, d);
 
      SET_ANIM(extras[id].u.road.ru.combo.odd[i], full_tag_name);
    }
  } else if (extrastyle == ESTYLE_ROAD_ALL_COMBINED) {
    /* ESTYLE_ROAD_ALL_COMBINED includes 256 sprites, one for every possibility.
     * Just go around clockwise, with all combinations. */
    for (i = 0; i < t->num_index_valid; i++) {
      char *idx_str = valid_index_str(t, i);
 
      fc_snprintf(full_tag_name, sizeof(full_tag_name),
                  "%s_%s", tag, idx_str);
 
      SET_ANIM(extras[id].u.road.ru.total[i], full_tag_name);
    }
  } else if (extrastyle == ESTYLE_RIVER) {
    if (!load_river_sprites(t, &t->sprites.extras[id].u.road.ru.rivers, tag)) {
      tileset_error(LOG_FATAL, tileset_name_get(t),
                    _("No river-style graphics \"%s*\" for extra \"%s\""),
                    tag, extra_rule_name(pextra));
    }
  } else {
    fc_assert(FALSE);
  }
 
  /* Corner road graphics are used by ESTYLE_ROAD_ALL_SEPARATE,
   * ESTYLE_ROAD_PARITY_COMBINED and ESTYLE_ROAD_ALL_COMBINED. */
  if (extrastyle == ESTYLE_ROAD_ALL_SEPARATE
      || extrastyle == ESTYLE_ROAD_PARITY_COMBINED
      || extrastyle == ESTYLE_ROAD_ALL_COMBINED) {
    for (i = 0; i < t->num_valid_tileset_dirs; i++) {
      enum direction8 dir = t->valid_tileset_dirs[i];
 
      if (!is_cardinal_tileset_dir(t, dir)) {
        const char *dtn = dir_get_tileset_name(dir);
 
        fc_snprintf(full_tag_name, sizeof(full_tag_name),
                    "%s_c_%s", pextra->graphic_str, dtn);
 
        SET_ANIM_OPT(extras[id].u.road.corner[dir], full_tag_name);
      }
    }
  }
}
 
/************************************************************************/
static void tileset_setup_base(struct tileset *t,
                               const struct extra_type *pextra,
                               const char *tag)
{
  char full_tag_name[MAX_LEN_NAME + sizeof("_fg")];
  const int id = extra_index(pextra);
 
  fc_assert_ret(id >= 0 && id < extra_count());
 
  sz_strlcpy(full_tag_name, tag);
  strcat(full_tag_name, "_bg");
  t->sprites.extras[id].u.bmf.background = anim_load(t, full_tag_name, 0);
 
  sz_strlcpy(full_tag_name, tag);
  strcat(full_tag_name, "_mg");
  t->sprites.extras[id].u.bmf.middleground = anim_load(t, full_tag_name, 0);
 
  sz_strlcpy(full_tag_name, tag);
  strcat(full_tag_name, "_fg");
  t->sprites.extras[id].u.bmf.foreground = anim_load(t, full_tag_name, 0);
 
  if (t->sprites.extras[id].u.bmf.background == nullptr
      && t->sprites.extras[id].u.bmf.middleground == nullptr
      && t->sprites.extras[id].u.bmf.foreground == nullptr) {
    /* There was an extra style definition but no matching graphics */
    tileset_error(LOG_FATAL, tileset_name_get(t),
                  _("No graphics with tag \"%s_bg/mg/fg\" for extra \"%s\""),
                  tag, extra_rule_name(pextra));
  }
}
 
/************************************************************************/
void tileset_setup_tile_type(struct tileset *t,
                             const struct terrain *pterrain)
{
  struct drawing_data *draw;
  struct sprite *sprite;
  char buffer[MAX_LEN_NAME + 20];
  int i, l;
 
  if (!drawing_hash_lookup(t->tile_hash, pterrain->graphic_str, &draw)
      && !drawing_hash_lookup(t->tile_hash, pterrain->graphic_alt, &draw)
      && !drawing_hash_lookup(t->tile_hash, pterrain->graphic_alt2, &draw)) {
    tileset_error(LOG_FATAL, tileset_name_get(t),
                  _("Terrain \"%s\": no graphic tile \"%s\", \"%s\", or \"%s\"."),
                  terrain_rule_name(pterrain), pterrain->graphic_str,
                  pterrain->graphic_alt, pterrain->graphic_alt2);
  }
 
  if (draw->init) {
    t->sprites.drawing[terrain_index(pterrain)] = draw;
    return;
  }
 
  /* Set up each layer of the drawing. */
  for (l = 0; l < draw->num_layers; l++) {
    struct drawing_layer *dlp = &draw->layer[l];
    struct tileset_layer *tslp = &t->layers[l];
    sprite_vector_init(&dlp->base);
    sprite_vector_init(&dlp->allocated);
 
    switch (dlp->sprite_type) {
    case CELL_WHOLE:
      switch (dlp->match_style) {
      case MATCH_NONE:
        /* Load whole sprites for this tile. */
        for (i = 0; ; i++) {
          fc_snprintf(buffer, sizeof(buffer), "t.l%d.%s%d",
                      l, draw->name, i + 1);
          sprite = load_sprite(t, buffer, TRUE, FALSE, FALSE);
          if (!sprite) {
            break;
          }
          sprite_vector_reserve(&dlp->base, i + 1);
          dlp->base.p[i] = sprite;
        }
        /* Check for base sprite, allowing missing sprites above base */
        if (0 == i  &&  0 == l) {
          /* TRANS: 'base' means 'base of terrain gfx', not 'military base' */
          tileset_error(LOG_FATAL, tileset_name_get(t),
                        _("Missing base sprite for tag \"%s\"."), buffer);
        }
        break;
      case MATCH_SAME:
        /* Load 16 cardinally-matched sprites. */
        for (i = 0; i < t->num_index_cardinal; i++) {
          fc_snprintf(buffer, sizeof(buffer), "t.l%d.%s_%s",
                      l, draw->name, cardinal_index_str(t, i));
          dlp->match[i]
            = tiles_lookup_sprite_tag_alt(t, LOG_FATAL, buffer, "",
                                          nullptr, "matched terrain",
                                          terrain_rule_name(pterrain), TRUE);
        }
        break;
      case MATCH_PAIR:
      case MATCH_FULL:
        fc_assert(FALSE); /* Not yet defined */
        break;
      };
      break;
    case CELL_CORNER:
      {
        const int count = dlp->match_indices;
        int number = NUM_CORNER_DIRS;
 
        switch (dlp->match_style) {
        case MATCH_NONE:
          /* Do nothing */
          break;
        case MATCH_PAIR:
        case MATCH_SAME:
          /* N directions (NSEW) * 3 dimensions of matching */
          fc_assert(count == 2);
          number = NUM_CORNER_DIRS * 2 * 2 * 2;
          break;
        case MATCH_FULL:
        default:
          /* N directions (NSEW) * 3 dimensions of matching */
          /* could use exp() or expi() here? */
          number = NUM_CORNER_DIRS * count * count * count;
          break;
        };
 
        dlp->cells
          = fc_calloc(number, sizeof(*dlp->cells));
 
        for (i = 0; i < number; i++) {
          enum direction4 dir = i % NUM_CORNER_DIRS;
          int value = i / NUM_CORNER_DIRS;
 
          switch (dlp->match_style) {
          case MATCH_NONE:
            fc_snprintf(buffer, sizeof(buffer), "t.l%d.%s_cell_%c",
                        l, draw->name, direction4letters[dir]);
            dlp->cells[i]
              = tiles_lookup_sprite_tag_alt(t, LOG_FATAL, buffer, "",
                                            nullptr, "cell terrain",
                                            terrain_rule_name(pterrain), TRUE);
            break;
          case MATCH_SAME:
            fc_snprintf(buffer, sizeof(buffer), "t.l%d.%s_cell_%c%d%d%d",
                        l, draw->name, direction4letters[dir],
                        (value) & 1, (value >> 1) & 1, (value >> 2) & 1);
            dlp->cells[i]
              = tiles_lookup_sprite_tag_alt(t, LOG_FATAL, buffer, "",
                                            nullptr, "same cell terrain",
                                            terrain_rule_name(pterrain), TRUE);
            break;
          case MATCH_PAIR:
            fc_snprintf(buffer, sizeof(buffer), "t.l%d.%s_cell_%c_%c_%c_%c",
                        l, draw->name, direction4letters[dir],
                        tslp->match_types[dlp->match_index[(value) & 1]][0],
                        tslp->match_types[dlp->match_index[(value >> 1) & 1]][0],
                        tslp->match_types[dlp->match_index[(value >> 2) & 1]][0]);
            dlp->cells[i]
              = tiles_lookup_sprite_tag_alt(t, LOG_FATAL, buffer, "",
                                            nullptr, "cell pair terrain",
                                            terrain_rule_name(pterrain), TRUE);
            break;
          case MATCH_FULL:
            {
              int this = dlp->match_index[0];
              int n, s, e, w;
              int v1, v2, v3;
 
              v1 = dlp->match_index[value % count];
              value /= count;
              v2 = dlp->match_index[value % count];
              value /= count;
              v3 = dlp->match_index[value % count];
 
              fc_assert(v1 < count && v2 < count && v3 < count);
 
              /* Assume merged cells. This should be a separate option. */
              switch (dir) {
              case DIR4_NORTH:
                s = this;
                w = v1;
                n = v2;
                e = v3;
                break;
              case DIR4_EAST:
                w = this;
                n = v1;
                e = v2;
                s = v3;
                break;
              case DIR4_SOUTH:
                n = this;
                e = v1;
                s = v2;
                w = v3;
                break;
              case DIR4_WEST:
              default:          /* Avoid warnings */
                e = this;
                s = v1;
                w = v2;
                n = v3;
                break;
              };
 
              /* Use first character of match_types,
               * already checked for uniqueness. */
              fc_snprintf(buffer, sizeof(buffer),
                          "t.l%d.cellgroup_%c_%c_%c_%c", l,
                          tslp->match_types[n][0], tslp->match_types[e][0],
                          tslp->match_types[s][0], tslp->match_types[w][0]);
              sprite = load_sprite(t, buffer, TRUE, FALSE, FALSE);
 
              if (sprite) {
                /* Crop the sprite to separate this cell. */
                int vec_size = sprite_vector_size(&dlp->allocated);
 
                const int W = t->normal_tile_width;
                const int H = t->normal_tile_height;
                int x[4] = {W / 4, W / 4, 0, W / 2};
                int y[4] = {H / 2, 0, H / 4, H / 4};
                int xo[4] = {0, 0, -W / 2, W / 2};
                int yo[4] = {H / 2, -H / 2, 0, 0};
 
        sprite = crop_sprite(sprite, x[dir], y[dir], W / 2, H / 2,
                             t->sprites.mask.tile, xo[dir], yo[dir], 1.0f,
                             FALSE);
                /* We allocated new sprite with crop_sprite. Store its
                 * address so we can free it. */
                sprite_vector_reserve(&dlp->allocated, vec_size + 1);
                dlp->allocated.p[vec_size] = sprite;
              } else {
                log_error("Terrain graphics sprite for tag \"%s\" missing.", buffer);
              }
 
              dlp->cells[i] = sprite;
            }
            break;
          };
        }
      }
      break;
    };
  }
 
  /* Try an optional special name */
  fc_snprintf(buffer, sizeof(buffer), "t.blend.%s", draw->name);
  draw->blender
    = tiles_lookup_sprite_tag_alt(t, LOG_VERBOSE, buffer, "",
                                  nullptr, "blend terrain",
                                  terrain_rule_name(pterrain), TRUE);
 
  if (draw->blending > 0) {
    const int bl = draw->blending - 1;
 
    if (draw->blender == nullptr) {
      int li = 0;
 
      /* Try an already loaded base */
      while (draw->blender == nullptr
             &&  li < draw->blending
             &&  0 < draw->layer[li].base.size) {
        draw->blender = draw->layer[li++].base.p[0];
      }
    }
 
    if (draw->blender == nullptr) {
      /* Try an unloaded base name */
      fc_snprintf(buffer, sizeof(buffer), "t.l%d.%s1", bl, draw->name);
      draw->blender
        = tiles_lookup_sprite_tag_alt(t, LOG_FATAL, buffer, "",
                                      nullptr, "base (blend) terrain",
                                      terrain_rule_name(pterrain), TRUE);
    }
  }
 
  if (draw->blender != nullptr) {
    /* Set up blending sprites. This only works in iso-view! */
    const int W = t->normal_tile_width;
    const int H = t->normal_tile_height;
    const int offsets[4][2] = {
      {W / 2, 0}, {0, H / 2}, {W / 2, H / 2}, {0, 0}
    };
    enum direction4 dir = 0;
 
    for (; dir < 4; dir++) {
      draw->blend[dir] = crop_sprite(draw->blender, offsets[dir][0],
                                     offsets[dir][1], W / 2, H / 2,
                                     t->sprites.dither_tile, 0, 0, 1.0f,
                                     FALSE);
    }
  }
 
  draw->init = TRUE;
  t->sprites.drawing[terrain_index(pterrain)] = draw;
}
 
/************************************************************************/
void tileset_setup_government(struct tileset *t,
                              struct government *gov)
{
  t->sprites.government[government_index(gov)]
    = tiles_lookup_sprite_tag_alt(t, LOG_FATAL, gov->graphic_str,
                                  gov->graphic_alt, nullptr, "government",
                                  government_rule_name(gov), FALSE);
 
  /* Should probably do something if nullptr, eg generic default? */
}
 
/************************************************************************/
void tileset_setup_nation_flag(struct tileset *t,
                               struct nation_type *nation)
{
  char *tags[] = {nation->flag_graphic_str,
                  nation->flag_graphic_alt,
                  "unknown", nullptr};
  int i;
  struct sprite *flag = nullptr, *shield = nullptr;
  char buf[1024];
  bool svgflag = is_svg_flag_enabled();
 
  for (i = 0; tags[i] && !flag; i++) {
    fc_snprintf(buf, sizeof(buf), "f.%s", tags[i]);
    flag = load_sprite(t, buf, TRUE, TRUE, svgflag);
  }
  for (i = 0; tags[i] && !shield; i++) {
    fc_snprintf(buf, sizeof(buf), "f.shield.%s", tags[i]);
    shield = load_sprite(t, buf, TRUE, TRUE, svgflag);
  }
  if (!flag || !shield) {
    /* Should never get here because of the f.unknown fallback. */
    tileset_error(LOG_FATAL, tileset_name_get(t),
                  _("Nation %s: no national flag."), nation_rule_name(nation));
  }
 
  sprite_vector_reserve(&t->sprites.nation_flag, nation_count());
  t->sprites.nation_flag.p[nation_index(nation)] = flag;
 
  sprite_vector_reserve(&t->sprites.nation_shield, nation_count());
  t->sprites.nation_shield.p[nation_index(nation)] = shield;
}
 
/************************************************************************/
struct sprite *get_city_flag_sprite(const struct tileset *t,
                                    const struct city *pcity)
{
  return get_nation_flag_sprite(t, nation_of_city(pcity));
}
 
/************************************************************************/
static struct sprite *get_unit_nation_flag_sprite(const struct tileset *t,
                                                  const struct unit *punit)
{
  struct nation_type *pnation = nation_of_unit(punit);
 
  if (gui_options.draw_unit_shields) {
    return t->sprites.nation_shield.p[nation_index(pnation)];
  } else {
    return t->sprites.nation_flag.p[nation_index(pnation)];
  }
}
 
#define FULL_TILE_X_OFFSET ((t->normal_tile_width - t->full_tile_width) / 2)
#define FULL_TILE_Y_OFFSET (t->normal_tile_height - t->full_tile_height)
 
#define ADD_SPRITE_SIZE(s, draw_fog, x_offset, y_offset, w_in, h_in)        \
  (fc_assert(s != nullptr),                                                 \
   sprs->sprite = s,                                                        \
   sprs->foggable = (draw_fog && t->fogstyle == FOG_AUTO),                  \
   sprs->offset_x = x_offset,                                               \
   sprs->offset_y = y_offset,                                               \
   sprs->w = w_in,                                                          \
   sprs->h = h_in,                                                          \
   sprs++)
#define ADD_SPRITE(s, draw_fog, x_offset, y_offset)                         \
  ADD_SPRITE_SIZE(s, draw_fog, x_offset, y_offset, 0, 0)
#define ADD_SPRITE_SIMPLE(s) ADD_SPRITE(s, TRUE, 0, 0)
#define ADD_SPRITE_FULL(s)                                                  \
  ADD_SPRITE(s, TRUE, FULL_TILE_X_OFFSET, FULL_TILE_Y_OFFSET)
 
#define ADD_ANIM_SPRITE(s, draw_fog, x_offset, y_offset)                    \
  ADD_SPRITE(anim_get_current_frame(s), draw_fog, x_offset, y_offset)
#define ADD_ANIM_SPRITE_SIMPLE(s)                                           \
  ADD_SPRITE(anim_get_current_frame(s), TRUE, 0, 0)
#define ADD_ANIM_FULL(s)                                                    \
  ADD_SPRITE(anim_get_current_frame(s), TRUE,                               \
             FULL_TILE_X_OFFSET, FULL_TILE_Y_OFFSET)
 
#define ADD_FRAME0_SIMPLE(s) ADD_SPRITE_SIMPLE(s->sprites[0])
#define ADD_FRAME0_FULL(s)                                                  \
  ADD_SPRITE_FULL(s->sprites[0])
 
/************************************************************************/
static void build_tile_data(const struct tile *ptile,
                            struct terrain *pterrain,
                            struct terrain **tterrain_near,
                            bv_extras *textras_near)
{
  enum direction8 dir;
 
  /* Loop over all adjacent tiles. We should have an iterator for this. */
  for (dir = 0; dir < 8; dir++) {
    struct tile *tile1 = mapstep(&(wld.map), ptile, dir);
 
    if (tile1 && client_tile_get_known(tile1) != TILE_UNKNOWN) {
      struct terrain *terrain1 = tile_terrain(tile1);
 
      if (terrain1 != nullptr) {
        tterrain_near[dir] = terrain1;
        textras_near[dir] = *tile_extras(tile1);
        continue;
      }
      log_error("build_tile_data() tile (%d,%d) has no terrain!",
                TILE_XY(tile1));
    }
    /* At the edges of the (known) map, pretend the same terrain continued
     * past the edge of the map. */
    tterrain_near[dir] = pterrain;
    BV_CLR_ALL(textras_near[dir]);
  }
}
 
/************************************************************************/
static int fill_unit_type_sprite_array(const struct tileset *t,
                                       struct drawn_sprite *sprs,
                                       const struct unit_type *putype,
                                       enum unit_activity activity,
                                       enum direction8 facing)
{
  struct drawn_sprite *save_sprs = sprs;
  struct sprite *uspr = get_unittype_sprite(t, putype, activity, facing);
 
  ADD_SPRITE(uspr, TRUE,
             FULL_TILE_X_OFFSET + t->unit_offset_x,
             FULL_TILE_Y_OFFSET + t->unit_offset_y);
 
  return sprs - save_sprs;
}
 
/************************************************************************/
static int fill_unit_sprite_array(const struct tileset *t,
                                  struct drawn_sprite *sprs,
                                  const struct unit *punit,
                                  int stack, bool backdrop)
{
  struct drawn_sprite *save_sprs = sprs;
  int ihp;
  const struct unit_type *ptype = unit_type_get(punit);
 
  if (backdrop) {
    if (!gui_options.solid_color_behind_units) {
      if (!is_flagless_to_player(punit, client_player())) {
        ADD_SPRITE(get_unit_nation_flag_sprite(t, punit), TRUE,
                   FULL_TILE_X_OFFSET + t->unit_flag_offset_x,
                   FULL_TILE_Y_OFFSET + t->unit_flag_offset_y);
      }
    } else {
      /* Taken care of in the LAYER_BACKGROUND. */
    }
  }
 
  /* Add the sprite for the unit type. */
  sprs += fill_unit_type_sprite_array(t, sprs, ptype,
                                      punit->activity, punit->facing);
 
  if (t->sprites.unit.loaded && unit_transported(punit)) {
    ADD_SPRITE_FULL(t->sprites.unit.loaded);
  }
 
  if (punit->activity != ACTIVITY_IDLE) {
    struct sprite *s = nullptr;
 
    switch (punit->activity) {
    case ACTIVITY_MINE:
      if (punit->activity_target == nullptr) {
        s = t->sprites.unit.plant;
      } else {
        s = t->sprites.extras[extra_index(punit->activity_target)].activity;
      }
      break;
    case ACTIVITY_PLANT:
      s = t->sprites.unit.plant;
      break;
    case ACTIVITY_IRRIGATE:
     if (punit->activity_target == nullptr) {
        s = t->sprites.unit.cultivate;
      } else {
        s = t->sprites.extras[extra_index(punit->activity_target)].activity;
      }
      break;
    case ACTIVITY_CULTIVATE:
      s = t->sprites.unit.cultivate;
      break;
    case ACTIVITY_CLEAN:
      s = t->sprites.extras[extra_index(punit->activity_target)].rmact;
      break;
    case ACTIVITY_PILLAGE:
      s = t->sprites.extras[extra_index(punit->activity_target)].rmact;
      if (s == nullptr) {
        s = t->sprites.unit.pillage;
      }
      break;
    case ACTIVITY_EXPLORE:
      /* Drawn below as the server side agent. */
      break;
    case ACTIVITY_FORTIFIED:
      s = t->sprites.unit.fortified;
      break;
    case ACTIVITY_FORTIFYING:
      s = t->sprites.unit.fortifying;
      break;
    case ACTIVITY_SENTRY:
      s = t->sprites.unit.sentry;
      break;
    case ACTIVITY_GOTO:
      s = t->sprites.unit.go_to;
      break;
    case ACTIVITY_TRANSFORM:
      s = t->sprites.unit.transform;
      break;
    case ACTIVITY_BASE:
    case ACTIVITY_GEN_ROAD:
      s = t->sprites.extras[extra_index(punit->activity_target)].activity;
      break;
    case ACTIVITY_CONVERT:
      s = t->sprites.unit.convert;
      break;
    default:
      break;
    }
 
    if (s != nullptr) {
      ADD_SPRITE(s, TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                 FULL_TILE_Y_OFFSET + t->activity_offset_y);
    }
  }
 
  {
    struct sprite *s = nullptr;
    int offset_x = 0;
    int offset_y = 0;
 
    switch (punit->ssa_controller) {
    case SSA_NONE:
      break;
    case SSA_AUTOWORKER:
      s = t->sprites.unit.auto_worker;
      break;
    case SSA_AUTOEXPLORE:
      s = t->sprites.unit.auto_explore;
      /* Specified as an activity in the tileset. */
      offset_x = t->activity_offset_x;
      offset_y = t->activity_offset_y;
      break;
    default:
      s = t->sprites.unit.auto_attack;
      break;
    }
 
    if (s != nullptr) {
      ADD_SPRITE(s, TRUE,
                 FULL_TILE_X_OFFSET + offset_x,
                 FULL_TILE_Y_OFFSET + offset_y);
    }
  }
 
  if (unit_has_orders(punit)) {
    if (punit->orders.repeat) {
      ADD_SPRITE_FULL(t->sprites.unit.patrol);
    } else if (punit->activity != ACTIVITY_IDLE) {
      ADD_SPRITE_SIMPLE(t->sprites.unit.connect);
    } else {
      ADD_SPRITE(t->sprites.unit.go_to, TRUE,
                 FULL_TILE_X_OFFSET + t->activity_offset_x,
                 FULL_TILE_Y_OFFSET + t->activity_offset_y);
    }
  }
 
  if (t->sprites.unit.action_decision_want != nullptr
      && should_ask_server_for_actions(punit)) {
    ADD_ANIM_SPRITE(t->sprites.unit.action_decision_want, TRUE,
                    FULL_TILE_X_OFFSET + t->activity_offset_x,
                    FULL_TILE_Y_OFFSET + t->activity_offset_y);
  }
 
  if (punit->battlegroup != BATTLEGROUP_NONE) {
    ADD_SPRITE_FULL(t->sprites.unit.battlegroup[punit->battlegroup]);
  }
 
  if (t->sprites.unit.lowfuel
      && utype_fuel(ptype)
      && punit->fuel == 1
      && punit->moves_left <= 2 * SINGLE_MOVE) {
    /* Show a low-fuel graphic if the plane has 2 or fewer moves left. */
    ADD_SPRITE_FULL(t->sprites.unit.lowfuel);
  }
  if (t->sprites.unit.tired
      && punit->moves_left < SINGLE_MOVE
      && ptype->move_rate > 0) {
    /* Show a "tired" graphic if the unit has fewer than one move
     * remaining, except for units for which it's full movement. */
    ADD_SPRITE_FULL(t->sprites.unit.tired);
  }
 
  if (stack == 1 && punit->client.occupied) {
    ADD_SPRITE_FULL(t->sprites.unit.stack[0]);
  } else if (stack > 1) {
    if (gui_options.draw_unit_stack_size
        && t->sprites.unit.num_stack_sprites >= stack) {
      ADD_SPRITE(t->sprites.unit.stack[stack - 1], FALSE,
                 t->stack_size_offset_x, t->stack_size_offset_y);
    } else {
      ADD_SPRITE_FULL(t->sprites.unit.stack[0]);
    }
  }
 
  if (t->sprites.unit.vet_lev[punit->veteran]) {
    ADD_SPRITE_FULL(t->sprites.unit.vet_lev[punit->veteran]);
  }
 
  ihp = ((NUM_TILES_HP_BAR-1)*punit->hp) / ptype->hp;
  ihp = CLIP(0, ihp, NUM_TILES_HP_BAR-1);
  ADD_SPRITE_FULL(t->sprites.unit.hp_bar[ihp]);
 
  return sprs - save_sprs;
}
 
/************************************************************************/
static int fill_road_corner_sprites(const struct tileset *t,
                                    const struct extra_type *pextra,
                                    struct drawn_sprite *sprs,
                                    bool road, bool *road_near,
                                    bool hider, bool *hider_near)
{
  struct drawn_sprite *saved_sprs = sprs;
  int i;
  int extra_idx = extra_index(pextra);
 
  if (is_cardinal_only_road(pextra)) {
    return 0;
  }
 
  /* Roads going diagonally adjacent to this tile need to be
   * partly drawn on this tile. */
 
  /* Draw the corner sprite if:
   *   - There is a diagonal road (not rail!) between two adjacent tiles.
   *   - There is no diagonal road (not rail!) that intersects this road.
   * The logic is simple: roads are drawn underneath railrods, but are
   * not always covered by them (even in the corners!). But if a railroad
   * connects two tiles, only the railroad (no road) is drawn between
   * those tiles.
   */
  for (i = 0; i < t->num_valid_tileset_dirs; i++) {
    enum direction8 dir = t->valid_tileset_dirs[i];
 
    if (!is_cardinal_tileset_dir(t, dir)) {
      /* Draw corner sprites for this non-cardinal direction. */
      int cw = (i + 1) % t->num_valid_tileset_dirs;
      int ccw
        = (i + t->num_valid_tileset_dirs - 1) % t->num_valid_tileset_dirs;
      enum direction8 cwdir = t->valid_tileset_dirs[cw];
      enum direction8 ccwdir = t->valid_tileset_dirs[ccw];
 
      if (t->sprites.extras[extra_idx].u.road.corner[dir]
          && (road_near[cwdir] && road_near[ccwdir]
              && !(hider_near[cwdir] && hider_near[ccwdir]))
          && !(road && road_near[dir] && !(hider && hider_near[dir]))) {
        ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[extra_idx].u.road.corner[dir]);
      }
    }
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
static int fill_road_sprite_array(const struct tileset *t,
                                  const struct extra_type *pextra,
                                  struct drawn_sprite *sprs,
                                  bv_extras textras,
                                  bv_extras *textras_near,
                                  struct terrain *tterrain_near[8],
                                  const struct city *pcity)
{
  struct drawn_sprite *saved_sprs = sprs;
  bool road, road_near[8], hider, hider_near[8];
  bool land_near[8], hland_near[8];
  bool draw_road[8], draw_single_road;
  enum direction8 dir;
  int extra_idx = -1;
  bool cl = FALSE;
  enum extrastyle_id extrastyle;
  const struct road_type *proad = extra_road_get(pextra);
 
  extra_idx = extra_index(pextra);
 
  extrastyle = t->sprites.extras[extra_idx].extrastyle;
 
  if (extra_has_flag(pextra, EF_CONNECT_LAND)) {
    cl = TRUE;
  } else {
    int i;
 
    for (i = 0; i < 8; i++) {
      land_near[i] = FALSE;
    }
  }
 
  /* Fill some data arrays. rail_near and road_near store whether road/rail
   * is present in the given direction. draw_rail and draw_road store
   * whether road/rail is to be drawn in that direction. draw_single_road
   * and draw_single_rail store whether we need an isolated road/rail to be
   * drawn. */
  road = BV_ISSET(textras, extra_idx);
 
  hider = FALSE;
  extra_type_list_iterate(pextra->hiders, phider) {
    if (BV_ISSET(textras, extra_index(phider))) {
      hider = TRUE;
      break;
    }
  } extra_type_list_iterate_end;
 
  if (road && (!pcity || !gui_options.draw_cities) && !hider) {
    draw_single_road = TRUE;
  } else {
    draw_single_road = FALSE;
  }
 
  for (dir = 0; dir < 8; dir++) {
    bool roads_exist;
 
    /* Check if there is adjacent road/rail. */
    if (!is_cardinal_only_road(pextra)
        || is_cardinal_tileset_dir(t, dir)) {
      road_near[dir] = FALSE;
      extra_type_list_iterate(proad->integrators, iextra) {
        if (BV_ISSET(textras_near[dir], extra_index(iextra))) {
          road_near[dir] = TRUE;
          break;
        }
      } extra_type_list_iterate_end;
      if (cl) {
        land_near[dir] = (tterrain_near[dir] != T_UNKNOWN
                          && terrain_type_terrain_class(tterrain_near[dir]) != TC_OCEAN);
      }
    } else {
      road_near[dir] = FALSE;
      land_near[dir] = FALSE;
    }
 
    /* Draw rail/road if there is a connection from this tile to the
     * adjacent tile. But don't draw road if there is also a rail
     * connection. */
    roads_exist = road && (road_near[dir] || land_near[dir]);
    draw_road[dir] = roads_exist;
    hider_near[dir] = FALSE;
    hland_near[dir] = tterrain_near[dir] != T_UNKNOWN
      && terrain_type_terrain_class(tterrain_near[dir]) != TC_OCEAN;
    extra_type_list_iterate(pextra->hiders, phider) {
      bool hider_dir = FALSE;
      bool land_dir = FALSE;
 
      if (!is_cardinal_only_road(phider)
          || is_cardinal_tileset_dir(t, dir)) {
        if (BV_ISSET(textras_near[dir], extra_index(phider))) {
          hider_near[dir] = TRUE;
          hider_dir = TRUE;
        }
        if (hland_near[dir]
            && is_extra_caused_by(phider, EC_ROAD)
            && extra_has_flag(phider, EF_CONNECT_LAND)) {
          land_dir = TRUE;
        }
        if (hider_dir || land_dir) {
          if (BV_ISSET(textras, extra_index(phider))) {
            draw_road[dir] = FALSE;
          }
        }
      }
    } extra_type_list_iterate_end;
 
    /* Don't draw an isolated road/rail if there's any connection.
     * draw_single_road would be true in the first place only if start tile has road,
     * so it will have road connection with any adjacent road tile. We check from real
     * existence of road (road_near[dir]) and not from whether road gets drawn (draw_road[dir])
     * as latter can be FALSE when road is simply hidden by another one, and we don't want to
     * draw single road in that case either. */
    if (draw_single_road && road_near[dir]) {
      draw_single_road = FALSE;
    }
  }
 
  /* Draw road corners */
  sprs
    += fill_road_corner_sprites(t, pextra, sprs, road, road_near, hider, hider_near);
 
  if (extrastyle == ESTYLE_ROAD_ALL_SEPARATE) {
    /* With ESTYLE_ROAD_ALL_SEPARATE, we simply draw one road for every connection.
     * This means we only need a few sprites, but a lot of drawing is
     * necessary and it generally doesn't look very good. */
    int i;
 
    /* First draw roads under rails. */
    if (road) {
      for (i = 0; i < t->num_valid_tileset_dirs; i++) {
        if (draw_road[t->valid_tileset_dirs[i]]) {
          ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[extra_idx].u.road.ru.dir[i]);
        }
      }
    }
  } else if (extrastyle == ESTYLE_ROAD_PARITY_COMBINED) {
    /* With ESTYLE_ROAD_PARITY_COMBINED, we draw one sprite for cardinal
     * road connections, one sprite for diagonal road connections.
     * This means we need about 4x more sprites than in style 0, but up to
     * 4x less drawing is needed. The drawing quality may also be
     * improved. */
 
    /* First draw roads under rails. */
    if (road) {
      int road_even_tileno = 0, road_odd_tileno = 0, i;
 
      for (i = 0; i < t->num_valid_tileset_dirs / 2; i++) {
        enum direction8 even = t->valid_tileset_dirs[2 * i];
        enum direction8 odd = t->valid_tileset_dirs[2 * i + 1];
 
        if (draw_road[even]) {
          road_even_tileno |= 1 << i;
        }
        if (draw_road[odd]) {
          road_odd_tileno |= 1 << i;
        }
      }
 
      /* Draw the cardinal/even roads first. */
      if (road_even_tileno != 0) {
        ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[extra_idx].u.road.ru.combo.even[road_even_tileno]);
      }
      if (road_odd_tileno != 0) {
        ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[extra_idx].u.road.ru.combo.odd[road_odd_tileno]);
      }
    }
  } else if (extrastyle == ESTYLE_ROAD_ALL_COMBINED) {
    /* RSTYLE_ALL_COMBINED is a very simple method that lets us simply retrieve
     * entire finished tiles, with a bitwise index of the presence of
     * roads in each direction. */
 
    /* Draw roads first */
    if (road) {
      int road_tileno = 0, i;
 
      for (i = 0; i < t->num_valid_tileset_dirs; i++) {
        enum direction8 vdir = t->valid_tileset_dirs[i];
 
        if (draw_road[vdir]) {
          road_tileno |= 1 << i;
        }
      }
 
      if (road_tileno != 0 || draw_single_road) {
        ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[extra_idx].u.road.ru.total[road_tileno]);
      }
    }
  } else {
    fc_assert(FALSE);
  }
 
  /* Draw isolated rail/road separately (ESTYLE_ROAD_ALL_SEPARATE and
     ESTYLE_ROAD_PARITY_COMBINED only). */
  if (extrastyle == ESTYLE_ROAD_ALL_SEPARATE
      || extrastyle == ESTYLE_ROAD_PARITY_COMBINED) {
    if (draw_single_road) {
      ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[extra_idx].u.road.isolated);
    }
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
static int get_irrigation_index(const struct tileset *t,
                                struct extra_type *pextra,
                                bv_extras *textras_near)
{
  int tileno = 0, i;
 
  for (i = 0; i < t->num_cardinal_tileset_dirs; i++) {
    enum direction8 dir = t->cardinal_tileset_dirs[i];
 
    if (BV_ISSET(textras_near[dir], extra_index(pextra))) {
      tileno |= 1 << i;
    }
  }
 
  return tileno;
}
 
/************************************************************************/
static int fill_irrigation_sprite_array(const struct tileset *t,
                                        struct drawn_sprite *sprs,
                                        bv_extras textras,
                                        bv_extras *textras_near,
                                        const struct city *pcity)
{
  struct drawn_sprite *saved_sprs = sprs;
 
  /* We don't draw the irrigation if there's a city (it just gets overdrawn
   * anyway, and ends up looking bad). */
  if (!(pcity && gui_options.draw_cities)) {
    extra_type_list_iterate(t->style_lists[ESTYLE_CARDINALS], pextra) {
      if (is_extra_drawing_enabled(pextra)) {
        int eidx = extra_index(pextra);
 
        if (BV_ISSET(textras, eidx)) {
          bool hidden = FALSE;
 
          extra_type_list_iterate(pextra->hiders, phider) {
            if (BV_ISSET(textras, extra_index(phider))) {
              hidden = TRUE;
              break;
            }
          } extra_type_list_iterate_end;
 
          if (!hidden) {
            int idx = get_irrigation_index(t, pextra, textras_near);
 
            ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[eidx].u.cardinals[idx]);
          }
        }
      }
    } extra_type_list_iterate_end;
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
static int fill_city_overlays_sprite_array(const struct tileset *t,
                                           struct drawn_sprite *sprs,
                                           const struct tile *ptile,
                                           const struct city *citymode)
{
  const struct city *pcity;
  const struct city *pwork;
  struct unit *psettler;
  struct drawn_sprite *saved_sprs = sprs;
  int city_x, city_y;
  const int NUM_CITY_COLORS = t->sprites.city.worked_tile_overlay.size;
 
  if (ptile == nullptr || TILE_UNKNOWN == client_tile_get_known(ptile)) {
    return 0;
  }
  pwork = tile_worked(ptile);
 
  if (citymode) {
    pcity = citymode;
  } else {
    pcity = find_city_or_settler_near_tile(ptile, &psettler);
  }
 
  /* Below code does not work if pcity is invisible.
   * Make sure it is not. */
  fc_assert_ret_val(pcity == nullptr || pcity->tile != nullptr, 0);
 
  if (pcity && !pcity->tile) {
    pcity = nullptr;
  }
 
  if (pcity && city_base_to_city_map(&city_x, &city_y, pcity, ptile)) {
    /* FIXME: check elsewhere for valid tile (instead of above) */
 
    if (!citymode && pcity->client.colored) {
      /* Add citymap overlay for a city. */
      int idx = pcity->client.color_index % NUM_CITY_COLORS;
 
      if (pwork != nullptr && pwork == pcity) {
        ADD_SPRITE_SIMPLE(t->sprites.city.worked_tile_overlay.p[idx]);
      } else if (city_can_work_tile(pcity, ptile)) {
        ADD_SPRITE_SIMPLE(t->sprites.city.unworked_tile_overlay.p[idx]);
      }
    } else if (pwork != nullptr && pwork == pcity
               && (citymode || gui_options.draw_city_output)) {
 
      /* Add on the tile output sprites.
       * NOTE: To show correct output on end of turn
       * base_city_celebrating() must be used instead of city_celebrating()
       * mirroring the behavior of the server that does so in
       * city_tile_cache_update(). */
      bool celebrating = base_city_celebrating(pcity);
      int food = city_tile_output(pcity, ptile, celebrating, O_FOOD);
      int shields = city_tile_output(pcity, ptile, celebrating, O_SHIELD);
      int trade = city_tile_output(pcity, ptile, celebrating, O_TRADE);
 
      const int ox = t->type == TS_ISOMETRIC ? t->normal_tile_width / 3 : 0;
      const int oy = t->type == TS_ISOMETRIC ? -t->normal_tile_height / 3 : 0;
 
      food = CLIP(0, food / game.info.granularity, NUM_TILES_DIGITS - 1);
      shields = CLIP(0, shields / game.info.granularity, NUM_TILES_DIGITS - 1);
      trade = CLIP(0, trade / game.info.granularity, NUM_TILES_DIGITS - 1);
 
      ADD_SPRITE(t->sprites.city.tile_foodnum[food], TRUE, ox, oy);
      ADD_SPRITE(t->sprites.city.tile_shieldnum[shields], TRUE, ox, oy);
      ADD_SPRITE(t->sprites.city.tile_tradenum[trade], TRUE, ox, oy);
    }
  } else if (psettler && psettler->client.colored) {
    /* Add citymap overlay for a unit. */
    int idx = psettler->client.color_index % NUM_CITY_COLORS;
 
    ADD_SPRITE_SIMPLE(t->sprites.city.unworked_tile_overlay.p[idx]);
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
static int fill_terrain_sprite_blending(const struct tileset *t,
                                        struct drawn_sprite *sprs,
                                        const struct tile *ptile,
                                        const struct terrain *pterrain,
                                        struct terrain **tterrain_near)
{
  struct drawn_sprite *saved_sprs = sprs;
  const int W = t->normal_tile_width, H = t->normal_tile_height;
  const int offsets[4][2] = {
    {W/2, 0}, {0, H / 2}, {W / 2, H / 2}, {0, 0}
  };
  enum direction4 dir = 0;
 
  /*
   * We want to mark unknown tiles so that an unreal tile will be
   * given the same marking as our current tile - that way we won't
   * get the "unknown" dither along the edge of the map.
   */
  for (; dir < 4; dir++) {
    struct tile *tile1 = mapstep(&(wld.map), ptile, DIR4_TO_DIR8[dir]);
    struct terrain *other;
 
    if (!tile1
        || client_tile_get_known(tile1) == TILE_UNKNOWN
        || pterrain == (other = tterrain_near[DIR4_TO_DIR8[dir]])
        || (0 == t->sprites.drawing[terrain_index(other)]->blending
            && t->sprites.drawing[terrain_index(other)]->blender == nullptr)) {
      continue;
    }
 
    ADD_SPRITE(t->sprites.drawing[terrain_index(other)]->blend[dir], TRUE,
               offsets[dir][0], offsets[dir][1]);
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
static int fill_fog_sprite_array(const struct tileset *t,
                                 struct drawn_sprite *sprs,
                                 const struct tile *ptile,
                                 const struct tile_edge *pedge,
                                 const struct tile_corner *pcorner)
{
  struct drawn_sprite *saved_sprs = sprs;
 
  if (t->fogstyle == FOG_SPRITE && gui_options.draw_fog_of_war
      && ptile != nullptr
      && TILE_KNOWN_UNSEEN == client_tile_get_known(ptile)) {
    /* With FOG_AUTO, fog is done this way. */
    ADD_SPRITE_SIMPLE(t->sprites.tx.fog);
  }
 
  if (t->darkness_style == DARKNESS_CORNER && pcorner
      && gui_options.draw_fog_of_war) {
    int i, tileno = 0;
 
    for (i = 3; i >= 0; i--) {
      const int unknown = 0, fogged = 1, known = 2;
      int value = -1;
 
      if (!pcorner->tile[i]) {
        value = fogged;
      } else {
        switch (client_tile_get_known(pcorner->tile[i])) {
        case TILE_KNOWN_SEEN:
          value = known;
          break;
        case TILE_KNOWN_UNSEEN:
          value = fogged;
          break;
        case TILE_UNKNOWN:
          value = unknown;
          break;
        }
      }
      fc_assert(value >= 0 && value < 3);
 
      tileno = tileno * 3 + value;
    }
 
    if (t->sprites.tx.fullfog[tileno]) {
      ADD_SPRITE_SIMPLE(t->sprites.tx.fullfog[tileno]);
    }
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
static int fill_terrain_sprite_array(struct tileset *t,
                                     struct drawn_sprite *sprs,
                                     int l, /* layer_num */
                                     const struct tile *ptile,
                                     const struct terrain *pterrain,
                                     struct terrain **tterrain_near,
                                     struct drawing_data *draw)
{
  struct drawn_sprite *saved_sprs = sprs;
  struct drawing_layer *dlp = &draw->layer[l];
  int this = dlp->match_index[0];
  int that = dlp->match_index[1];
  int ox = dlp->offset_x;
  int oy = dlp->offset_y;
  int i;
 
#define MATCH(dir)                                                          \
    (t->sprites.drawing[terrain_index(tterrain_near[(dir)])]->num_layers > l        \
     ? t->sprites.drawing[terrain_index(tterrain_near[(dir)])]->layer[l].match_index[0] \
     : -1)
 
  switch (dlp->sprite_type) {
  case CELL_WHOLE:
    {
      switch (dlp->match_style) {
      case MATCH_NONE:
        {
          int count = sprite_vector_size(&dlp->base);
 
          if (count > 0) {
            /* Pseudo-random reproducible algorithm to pick a sprite. Use modulo
             * to limit the number to a handleable size [0..32000). */
            count = fc_randomly(tile_index(ptile) % 32000, count);
 
            if (dlp->is_tall) {
              ox += FULL_TILE_X_OFFSET;
              oy += FULL_TILE_Y_OFFSET;
            }
            ADD_SPRITE(dlp->base.p[count], TRUE, ox, oy);
          }
          break;
        }
      case MATCH_SAME:
        {
          int tileno = 0;
 
          for (i = 0; i < t->num_cardinal_tileset_dirs; i++) {
            enum direction8 dir = t->cardinal_tileset_dirs[i];
 
            if (MATCH(dir) == this) {
              tileno |= 1 << i;
            }
          }
 
          if (dlp->is_tall) {
            ox += FULL_TILE_X_OFFSET;
            oy += FULL_TILE_Y_OFFSET;
          }
          ADD_SPRITE(dlp->match[tileno], TRUE, ox, oy);
          break;
        }
      case MATCH_PAIR:
      case MATCH_FULL:
        fc_assert(FALSE); /* Not yet defined */
        break;
      };
      break;
    }
  case CELL_CORNER:
    {
      /* Divide the tile up into four rectangular cells. Each of these
       * cells covers one corner, and each is adjacent to 3 different
       * tiles. For each cell we pick a sprite based upon the adjacent
       * terrains at each of those tiles. Thus, we have 8 different sprites
       * for each of the 4 cells (32 sprites total).
       *
       * These arrays correspond to the direction4 ordering. */
      const int W = t->normal_tile_width;
      const int H = t->normal_tile_height;
      const int iso_offsets[4][2] = {
        {W / 4, 0}, {W / 4, H / 2}, {W / 2, H / 4}, {0, H / 4}
      };
      const int noniso_offsets[4][2] = {
        {0, 0}, {W / 2, H / 2}, {W / 2, 0}, {0, H / 2}
      };
 
      /* Put corner cells */
      for (i = 0; i < NUM_CORNER_DIRS; i++) {
        const int count = dlp->match_indices;
        int array_index = 0;
        enum direction8 dir = dir_ccw(DIR4_TO_DIR8[i]);
        int x = (t->type == TS_ISOMETRIC ? iso_offsets[i][0] : noniso_offsets[i][0]);
        int y = (t->type == TS_ISOMETRIC ? iso_offsets[i][1] : noniso_offsets[i][1]);
        int m[3] = {MATCH(dir_ccw(dir)), MATCH(dir), MATCH(dir_cw(dir))};
        struct sprite *s;
 
        /* Synthesize 4 dimensional array? */
        switch (dlp->match_style) {
        case MATCH_NONE:
          /* We have no need for matching, just plug the piece in place. */
          break;
        case MATCH_SAME:
          array_index = array_index * 2 + (m[2] != this);
          array_index = array_index * 2 + (m[1] != this);
          array_index = array_index * 2 + (m[0] != this);
          break;
        case MATCH_PAIR:
          array_index = array_index * 2 + (m[2] == that);
          array_index = array_index * 2 + (m[1] == that);
          array_index = array_index * 2 + (m[0] == that);
          break;
        case MATCH_FULL:
        default:
          if (count > 0) {
            int n[3];
            int j;
 
            for (j = 0; j < 3; j++) {
              int k;
 
              for (k = 0; k < count; k++) {
                n[j] = k; /* Default to last entry */
                if (m[j] == dlp->match_index[k]) {
                  break;
                }
              }
            }
            array_index = array_index * count + n[2];
            array_index = array_index * count + n[1];
            array_index = array_index * count + n[0];
          }
          break;
        };
 
        array_index = array_index * NUM_CORNER_DIRS + i;
 
        s = dlp->cells[array_index];
        if (s) {
          ADD_SPRITE(s, TRUE, x, y);
        }
      }
      break;
    }
  };
#undef MATCH
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
static int fill_terrain_sprite_darkness(struct tileset *t,
                                        struct drawn_sprite *sprs,
                                        const struct tile *ptile,
                                        struct terrain **tterrain_near)
{
  struct drawn_sprite *saved_sprs = sprs;
  int i, tileno;
  struct tile *adjc_tile;
 
#define UNKNOWN(dir)                                        \
  ((adjc_tile = mapstep(&(wld.map), ptile, (dir)))          \
     && client_tile_get_known(adjc_tile) == TILE_UNKNOWN)
 
  switch (t->darkness_style) {
  case DARKNESS_NONE:
    break;
  case DARKNESS_ISORECT:
    for (i = 0; i < 4; i++) {
      const int W = t->normal_tile_width, H = t->normal_tile_height;
      int offsets[4][2] = {{W / 2, 0}, {0, H / 2}, {W / 2, H / 2}, {0, 0}};
 
      if (UNKNOWN(DIR4_TO_DIR8[i])) {
        ADD_SPRITE(t->sprites.tx.darkness[i], TRUE,
                   offsets[i][0], offsets[i][1]);
      }
    }
    break;
  case DARKNESS_CARD_SINGLE:
    for (i = 0; i < t->num_cardinal_tileset_dirs; i++) {
      if (UNKNOWN(t->cardinal_tileset_dirs[i])) {
        ADD_SPRITE_SIMPLE(t->sprites.tx.darkness[i]);
      }
    }
    break;
  case DARKNESS_CARD_FULL:
    /* We're looking to find the INDEX_NSEW for the directions that
     * are unknown. We want to mark unknown tiles so that an unreal
     * tile will be given the same marking as our current tile - that
     * way we won't get the "unknown" dither along the edge of the
     * map. */
    tileno = 0;
    for (i = 0; i < t->num_cardinal_tileset_dirs; i++) {
      if (UNKNOWN(t->cardinal_tileset_dirs[i])) {
        tileno |= 1 << i;
      }
    }
 
    if (tileno != 0) {
      ADD_SPRITE_SIMPLE(t->sprites.tx.darkness[tileno]);
    }
    break;
  case DARKNESS_CORNER:
    /* Handled separately. */
    break;
  };
#undef UNKNOWN
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
static int fill_terrain_sprite_layer(struct tileset *t,
                                     struct drawn_sprite *sprs,
                                     int layer_num,
                                     const struct tile *ptile,
                                     const struct terrain *pterrain,
                                     struct terrain **tterrain_near)
{
  struct sprite *sprite;
  struct drawn_sprite *saved_sprs = sprs;
  struct drawing_data *draw = t->sprites.drawing[terrain_index(pterrain)];
  const int l = (draw->is_reversed
                 ? (draw->num_layers - layer_num - 1) : layer_num);
 
  fc_assert(layer_num < TERRAIN_LAYER_COUNT);
 
  /* Skip the normal drawing process. */
  /* FIXME: this should avoid calling load_sprite since it's slow and
   * increases the refcount without limit. */
  if (ptile->spec_sprite && (sprite = load_sprite(t, ptile->spec_sprite,
                                                  TRUE, FALSE, FALSE))) {
    if (l == 0) {
      ADD_SPRITE_SIMPLE(sprite);
      return 1;
    } else {
      return 0;
    }
  }
 
  if (l < draw->num_layers) {
    sprs += fill_terrain_sprite_array(t, sprs, l, ptile, pterrain, tterrain_near, draw);
 
    if ((l + 1) == draw->blending) {
      sprs += fill_terrain_sprite_blending(t, sprs, ptile, pterrain, tterrain_near);
    }
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
bool unit_drawn_with_city_outline(const struct unit *punit, bool check_focus)
{
  /* Display an outline for city-builder type units if they are selected,
   * and on a tile where a city can be built.
   * But suppress the outline if the unit has orders (likely it is in
   * transit to somewhere else and this will just slow down redraws). */
  return gui_options.draw_city_outlines
         && unit_is_cityfounder(punit)
         && !unit_has_orders(punit)
         && (client_tile_get_known(unit_tile(punit)) != TILE_UNKNOWN
             && city_can_be_built_here(&(wld.map), unit_tile(punit), punit, FALSE))
         && (!check_focus || unit_is_in_focus(punit));
}
 
/************************************************************************/
static int fill_grid_sprite_array(const struct tileset *t,
                                  struct drawn_sprite *sprs,
                                  const struct tile *ptile,
                                  const struct tile_edge *pedge,
                                  const struct tile_corner *pcorner,
                                  const struct unit *punit,
                                  const struct city *pcity,
                                  const struct city *citymode)
{
  struct drawn_sprite *saved_sprs = sprs;
 
  if (pedge) {
    bool known[NUM_EDGE_TILES], city[NUM_EDGE_TILES];
    bool unit[NUM_EDGE_TILES], worked[NUM_EDGE_TILES];
    int i;
    struct unit_list *pfocus_units = get_units_in_focus();
 
    for (i = 0; i < NUM_EDGE_TILES; i++) {
      int dummy_x, dummy_y;
      const struct tile *tile = pedge->tile[i];
      struct player *powner = tile ? tile_owner(tile) : nullptr;
 
      known[i] = tile && client_tile_get_known(tile) != TILE_UNKNOWN;
      unit[i] = FALSE;
      if (tile && !citymode) {
        unit_list_iterate(pfocus_units, pfocus_unit) {
          if (unit_drawn_with_city_outline(pfocus_unit, FALSE)) {
            struct tile *utile = unit_tile(pfocus_unit);
            int radius = game.info.init_city_radius_sq
              + get_target_bonus_effects(
                    nullptr,
                    &(const struct req_context) {
                      .player = unit_owner(pfocus_unit),
                      .tile = utile,
                    },
                    nullptr,
                    EFT_CITY_RADIUS_SQ
                );
 
            if (city_tile_to_city_map(&dummy_x, &dummy_y, radius,
                                      utile, tile)) {
              unit[i] = TRUE;
              break;
            }
          }
        } unit_list_iterate_end;
      }
      worked[i] = FALSE;
 
      city[i] = (tile
                 && (powner == nullptr || client.conn.playing == nullptr
                     || powner == client.conn.playing)
                 && player_in_city_map(client.conn.playing, tile));
      if (city[i]) {
        if (citymode) {
          /* In citymode, we only draw worked tiles for this city - other
           * tiles may be marked as unavailable. */
          worked[i] = (tile_worked(tile) == citymode);
        } else {
          worked[i] = (tile_worked(tile) != nullptr);
        }
      }
    }
 
    if (mapdeco_is_highlight_set(pedge->tile[0])
        || mapdeco_is_highlight_set(pedge->tile[1])) {
      ADD_SPRITE_SIMPLE(t->sprites.grid.selected[pedge->type]);
    } else if (!gui_options.draw_terrain && gui_options.draw_coastline
               && pedge->tile[0] && pedge->tile[1]
               && known[0] && known[1]
               && (is_ocean_tile(pedge->tile[0])
                   ^ is_ocean_tile(pedge->tile[1]))) {
      ADD_SPRITE_SIMPLE(t->sprites.grid.coastline[pedge->type]);
    } else {
      if (gui_options.draw_map_grid) {
        if (worked[0] || worked[1]) {
          ADD_SPRITE_SIMPLE(t->sprites.grid.worked[pedge->type]);
        } else if (city[0] || city[1]) {
          ADD_SPRITE_SIMPLE(t->sprites.grid.city[pedge->type]);
        } else if (known[0] || known[1]) {
          ADD_SPRITE_SIMPLE(t->sprites.grid.main[pedge->type]);
        }
      }
      if (gui_options.draw_city_outlines) {
        if (XOR(city[0], city[1])) {
          ADD_SPRITE_SIMPLE(t->sprites.grid.city[pedge->type]);
        }
        if (XOR(unit[0], unit[1])) {
          ADD_SPRITE_SIMPLE(t->sprites.grid.worked[pedge->type]);
        }
      }
    }
 
    if (gui_options.draw_borders
        && BORDERS_DISABLED != game.info.borders
        && known[0]
        && known[1]) {
      struct player *owner0 = tile_owner(pedge->tile[0]);
      struct player *owner1 = tile_owner(pedge->tile[1]);
 
      if (owner0 != owner1) {
        if (owner0) {
          int plrid = player_index(owner0);
          ADD_SPRITE_SIMPLE(t->sprites.player[plrid].grid_borders
                            [pedge->type][0]);
        }
        if (owner1) {
          int plrid = player_index(owner1);
          ADD_SPRITE_SIMPLE(t->sprites.player[plrid].grid_borders
                            [pedge->type][1]);
        }
      }
    }
  } else if (ptile != nullptr && TILE_UNKNOWN != client_tile_get_known(ptile)) {
    int cx, cy;
 
    if (citymode
        /* Test to ensure valid coordinates? */
        && city_base_to_city_map(&cx, &cy, citymode, ptile)
        && !client_city_can_work_tile(citymode, ptile)) {
      ADD_SPRITE_SIMPLE(t->sprites.grid.unavailable);
    }
 
    if (gui_options.draw_native && citymode == nullptr) {
      bool native = TRUE;
      struct unit_list *pfocus_units = get_units_in_focus();
 
      unit_list_iterate(pfocus_units, pfocus) {
        if (!is_native_tile(unit_type_get(pfocus), ptile)) {
          native = FALSE;
          break;
        }
      } unit_list_iterate_end;
 
      if (!native) {
        if (t->sprites.grid.nonnative != nullptr) {
          ADD_SPRITE_SIMPLE(t->sprites.grid.nonnative);
        } else {
          ADD_SPRITE_SIMPLE(t->sprites.grid.unavailable);
        }
      }
    }
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
static int fill_goto_sprite_array(const struct tileset *t,
                                  struct drawn_sprite *sprs,
                                  const struct tile *ptile,
                                  const struct tile_edge *pedge,
                                  const struct tile_corner *pcorner)
{
  struct drawn_sprite *saved_sprs = sprs;
  struct sprite *sprite;
  bool warn = FALSE;
  enum goto_tile_state state;
  int length;
  bool waypoint;
 
  if (goto_tile_state(ptile, &state, &length, &waypoint)) {
    if (length >= 0) {
      fc_assert(state >= 0);
      fc_assert(state < ARRAY_SIZE(t->sprites.path.s));
 
      sprite = t->sprites.path.s[state].specific;
      if (sprite != nullptr) {
        ADD_SPRITE(sprite, FALSE, 0, 0);
      }
 
      sprite = t->sprites.path.s[state].turns[length % 10];
      ADD_SPRITE_SIMPLE(sprite);
      if (length >= 10) {
        sprite = t->sprites.path.s[state].turns_tens[(length / 10) % 10];
        ADD_SPRITE_SIMPLE(sprite);
        if (length >= 100) {
          sprite = t->sprites.path.s[state].turns_hundreds[(length / 100)
                                                           % 10];
 
          if (sprite != nullptr) {
            ADD_SPRITE_SIMPLE(sprite);
            if (length >= 1000) {
              warn = TRUE;
            }
          } else {
            warn = TRUE;
          }
        }
      }
    }
 
    if (waypoint) {
      ADD_SPRITE(t->sprites.path.waypoint, FALSE, 0, 0);
    }
 
    if (warn) {
      /* Warn only once by tileset. */
      static char last_reported[256] = "";
 
      if (0 != strcmp(last_reported, t->name)) {
        log_normal(_("Tileset \"%s\" doesn't support long goto paths, "
                     "such as %d. Path not displayed as expected."),
                   t->name, length);
        sz_strlcpy(last_reported, t->name);
      }
    }
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
static bool is_extra_drawing_enabled(struct extra_type *pextra)
{
  bool no_disable = TRUE; /* Draw if matches no cause */
 
  if (is_extra_caused_by(pextra, EC_IRRIGATION)) {
    if (gui_options.draw_irrigation) {
      return TRUE;
    }
    no_disable = FALSE;
  }
  if (is_extra_caused_by(pextra, EC_POLLUTION)
      || is_extra_caused_by(pextra, EC_FALLOUT)) {
    if (gui_options.draw_pollution) {
      return TRUE;
    }
    no_disable = FALSE;
  }
  if (is_extra_caused_by(pextra, EC_MINE)) {
    if (gui_options.draw_mines) {
      return TRUE;
    }
    no_disable = FALSE;
  }
  if (is_extra_caused_by(pextra, EC_RESOURCE)) {
    if (gui_options.draw_specials) {
      return TRUE;
    }
    no_disable = FALSE;
  }
  if (is_extra_removed_by(pextra, ERM_ENTER)) {
    if (gui_options.draw_huts) {
      return TRUE;
    }
    no_disable = FALSE;
  }
  if (is_extra_caused_by(pextra, EC_BASE)) {
    if (gui_options.draw_fortress_airbase) {
      return TRUE;
    }
    no_disable = FALSE;
  }
  if (is_extra_caused_by(pextra, EC_ROAD)) {
    if (gui_options.draw_paths) {
      return TRUE;
    }
    no_disable = FALSE;
  }
 
  return no_disable;
}
 
/************************************************************************/
int fill_sprite_array(struct tileset *t,
                      struct drawn_sprite *sprs, enum mapview_layer layer,
                      const struct tile *ptile,
                      const struct tile_edge *pedge,
                      const struct tile_corner *pcorner,
                      const struct unit *punit, const struct city *pcity,
                      const struct city *citymode,
                      const struct unit_type *putype)
{
  int tileno, dir;
  bv_extras textras_near[8];
  bv_extras textras;
  struct terrain *tterrain_near[8];
  struct terrain *pterrain = nullptr;
  struct drawn_sprite *save_sprs = sprs;
  struct player *owner = nullptr;
  /* Unit drawing is disabled when the view options are turned off,
   * but only where we're drawing on the mapview. */
  bool do_draw_unit = (punit != nullptr && (gui_options.draw_units
                                            || ptile == nullptr
                                            || (gui_options.draw_focus_unit
                                                && unit_is_in_focus(punit))));
  bool flagless = (do_draw_unit
                   && is_flagless_to_player(punit, client_player()));
  bool solid_bg = (gui_options.solid_color_behind_units
                   && ((do_draw_unit && !flagless)
                       || (pcity != nullptr && gui_options.draw_cities)
                       || (ptile != nullptr && !gui_options.draw_terrain)));
 
  if (citymode) {
    int count = 0, i, cx, cy;
    const struct tile *const *tiles = nullptr;
    bool valid = FALSE;
 
    if (ptile) {
      tiles = &ptile;
      count = 1;
    } else if (pcorner) {
      tiles = pcorner->tile;
      count = NUM_CORNER_TILES;
    } else if (pedge) {
      tiles = pedge->tile;
      count = NUM_EDGE_TILES;
    }
 
    for (i = 0; i < count; i++) {
      if (tiles[i] && city_base_to_city_map(&cx, &cy, citymode, tiles[i])) {
        valid = TRUE;
        break;
      }
    }
    if (!valid) {
      return 0;
    }
  }
 
  if (ptile && client_tile_get_known(ptile) != TILE_UNKNOWN) {
    textras = *tile_extras(ptile);
    pterrain = tile_terrain(ptile);
 
    if (pterrain != nullptr) {
      if (layer == LAYER_TERRAIN1
          || layer == LAYER_TERRAIN2
          || layer == LAYER_TERRAIN3
          || layer == LAYER_WATER
          || layer == LAYER_ROADS) {
        build_tile_data(ptile, pterrain, tterrain_near, textras_near);
      }
    } else {
      log_error("fill_sprite_array() tile (%d,%d) has no terrain!",
                TILE_XY(ptile));
    }
  } else {
    BV_CLR_ALL(textras);
  }
 
  switch (layer) {
  case LAYER_BACKGROUND:
    /* Set up background color. */
    if (gui_options.solid_color_behind_units) {
      if (do_draw_unit && !flagless) {
        owner = unit_owner(punit);
      } else if (pcity != nullptr && gui_options.draw_cities) {
        owner = city_owner(pcity);
      }
    }
    if (owner != nullptr) {
      ADD_SPRITE_SIMPLE(t->sprites.player[player_index(owner)].background);
    } else if (ptile != nullptr && !gui_options.draw_terrain) {
      ADD_SPRITE_SIMPLE(t->sprites.background.graphic);
    }
    break;
 
  case LAYER_TERRAIN1:
    if (pterrain != nullptr && gui_options.draw_terrain && !solid_bg) {
      sprs += fill_terrain_sprite_layer(t, sprs, 0, ptile, pterrain, tterrain_near);
    }
    break;
 
  case LAYER_DARKNESS:
    if (pterrain != nullptr && gui_options.draw_terrain && !solid_bg) {
      sprs += fill_terrain_sprite_darkness(t, sprs, ptile, tterrain_near);
    }
    break;
 
  case LAYER_TERRAIN2:
    if (pterrain != nullptr && gui_options.draw_terrain && !solid_bg) {
      sprs += fill_terrain_sprite_layer(t, sprs, 1, ptile, pterrain, tterrain_near);
    }
    break;
 
  case LAYER_TERRAIN3:
    if (pterrain != nullptr && gui_options.draw_terrain && !solid_bg) {
      fc_assert(MAX_NUM_LAYERS == 3);
      sprs += fill_terrain_sprite_layer(t, sprs, 2, ptile, pterrain, tterrain_near);
    }
    break;
 
  case LAYER_WATER:
    if (pterrain != nullptr) {
      if (gui_options.draw_terrain && !solid_bg
          && terrain_type_terrain_class(pterrain) == TC_OCEAN) {
        for (dir = 0; dir < t->num_cardinal_tileset_dirs; dir++) {
          int didx = t->cardinal_tileset_dirs[dir];
 
          extra_type_list_iterate(t->style_lists[ESTYLE_RIVER], priver) {
            if (is_extra_drawing_enabled(priver)) {
              int idx = extra_index(priver);
 
              if (BV_ISSET(textras_near[didx], idx)) {
                ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[idx].u.road.ru.rivers.outlet[dir]);
              }
            }
          } extra_type_list_iterate_end;
        }
      }
 
      sprs += fill_irrigation_sprite_array(t, sprs, textras, textras_near,
                                           pcity);
 
      if (gui_options.draw_terrain && !solid_bg) {
        extra_type_list_iterate(t->style_lists[ESTYLE_RIVER], priver) {
          if (is_extra_drawing_enabled(priver)) {
            int idx = extra_index(priver);
 
            if (BV_ISSET(textras, idx)) {
              int i;
 
              /* Draw rivers on top of irrigation. */
              tileno = 0;
              for (i = 0; i < t->num_cardinal_tileset_dirs; i++) {
                enum direction8 cdir = t->cardinal_tileset_dirs[i];
 
                if (terrain_type_terrain_class(tterrain_near[cdir]) == TC_OCEAN) {
                  tileno |= 1 << i;
                } else {
                  struct road_type *proad = extra_road_get(priver);
 
                  if (proad != nullptr) {
                    extra_type_list_iterate(proad->integrators, iextra) {
                      if (BV_ISSET(textras_near[cdir], extra_index(iextra))) {
                        tileno |= 1 << i;
                      }
                    } extra_type_list_iterate_end;
                  }
                }
              }
 
              ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[idx].u.road.ru.rivers.spec[tileno]);
            }
          }
        } extra_type_list_iterate_end;
      }
    }
    break;
 
  case LAYER_ROADS:
    if (pterrain != nullptr) {
      extra_type_list_iterate(t->style_lists[ESTYLE_ROAD_ALL_SEPARATE], pextra) {
        if (is_extra_drawing_enabled(pextra)) {
          sprs += fill_road_sprite_array(t, pextra, sprs,
                                         textras, textras_near,
                                         tterrain_near, pcity);
        }
      } extra_type_list_iterate_end;
      extra_type_list_iterate(t->style_lists[ESTYLE_ROAD_PARITY_COMBINED], pextra) {
        if (is_extra_drawing_enabled(pextra)) {
          sprs += fill_road_sprite_array(t, pextra, sprs,
                                         textras, textras_near,
                                         tterrain_near, pcity);
        }
      } extra_type_list_iterate_end;
      extra_type_list_iterate(t->style_lists[ESTYLE_ROAD_ALL_COMBINED], pextra) {
        if (is_extra_drawing_enabled(pextra)) {
          sprs += fill_road_sprite_array(t, pextra, sprs,
                                         textras, textras_near,
                                         tterrain_near, pcity);
        }
      } extra_type_list_iterate_end;
    }
    break;
 
  case LAYER_SPECIAL1:
    if (pterrain != nullptr) {
      if (ptile) {
        extra_type_list_iterate(t->style_lists[ESTYLE_3LAYER], pextra) {
          if (tile_has_extra(ptile, pextra)
              && is_extra_drawing_enabled(pextra)
              && t->sprites.extras[extra_index(pextra)].u.bmf.background != nullptr) {
            bool hidden = FALSE;
 
            extra_type_list_iterate(pextra->hiders, phider) {
              if (BV_ISSET(textras, extra_index(phider))) {
                hidden = TRUE;
                break;
              }
            } extra_type_list_iterate_end;
 
            if (!hidden) {
              ADD_ANIM_FULL(t->sprites.extras[extra_index(pextra)].u.bmf.background);
            }
          }
        } extra_type_list_iterate_end;
      }
 
      extra_type_list_iterate(t->style_lists[ESTYLE_SINGLE1], pextra) {
        if (BV_ISSET(textras, extra_index(pextra))
            && is_extra_drawing_enabled(pextra)) {
          bool hidden = FALSE;
 
          extra_type_list_iterate(pextra->hiders, phider) {
            if (BV_ISSET(textras, extra_index(phider))) {
              hidden = TRUE;
              break;
            }
          } extra_type_list_iterate_end;
 
          if (!hidden) {
            ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[extra_index(pextra)].u.single);
          }
        }
      } extra_type_list_iterate_end;
    }
    break;
 
  case LAYER_GRID1:
    if (t->type == TS_ISOMETRIC) {
      sprs += fill_grid_sprite_array(t, sprs, ptile, pedge, pcorner,
                                     punit, pcity, citymode);
    }
    break;
 
  case LAYER_CITY1:
    /* City. Some city sprites are drawn later. */
    if (pcity && gui_options.draw_cities) {
      if (!gui_options.draw_full_citybar && !gui_options.solid_color_behind_units) {
        struct sprite *spr = get_city_flag_sprite(t, pcity);
        struct area_rect flag_rect;
 
        get_flag_dimensions(spr, &flag_rect, tileset_svg_flag_height(tileset));
 
        ADD_SPRITE_SIZE(spr, TRUE,
                        FULL_TILE_X_OFFSET + t->city_flag_offset_x,
                        FULL_TILE_Y_OFFSET + t->city_flag_offset_y,
                        flag_rect.w, flag_rect.h);
      }
      /* For iso-view the city.wall graphics include the full city, whereas
       * for non-iso view they are an overlay on top of the base city
       * graphic. */
      if (t->type == TS_OVERHEAD || pcity->client.walls <= 0) {
        ADD_ANIM_SPRITE(get_city_anim(t->sprites.city.tile, pcity), TRUE,
                        FULL_TILE_X_OFFSET + t->city_offset_x,
                        FULL_TILE_Y_OFFSET + t->city_offset_y);
      }
      if (t->type == TS_ISOMETRIC && pcity->client.walls > 0) {
        struct city_sprite *cspr = t->sprites.city.wall[pcity->client.walls - 1];
        struct anim *anim = nullptr;
 
        if (cspr != nullptr) {
          anim = get_city_anim(cspr, pcity);
        }
        if (anim == nullptr) {
          cspr = t->sprites.city.single_wall;
          if (cspr != nullptr) {
            anim = get_city_anim(cspr, pcity);
          }
        }
 
        if (anim != nullptr) {
          ADD_ANIM_SPRITE(anim, TRUE,
                          FULL_TILE_X_OFFSET + t->city_offset_x,
                          FULL_TILE_Y_OFFSET + t->city_offset_y);
        }
      }
      if (!gui_options.draw_full_citybar && pcity->client.occupied) {
        ADD_ANIM_SPRITE(get_city_anim(t->sprites.city.occupied, pcity), TRUE,
                        FULL_TILE_X_OFFSET + t->occupied_offset_x,
                        FULL_TILE_Y_OFFSET + t->occupied_offset_y);
      }
      if (t->type == TS_OVERHEAD && pcity->client.walls > 0) {
        struct city_sprite *cspr = t->sprites.city.wall[pcity->client.walls - 1];
        struct anim *anim = nullptr;
 
        if (cspr != nullptr) {
          anim = get_city_anim(cspr, pcity);
        }
        if (anim == nullptr) {
          cspr = t->sprites.city.single_wall;
          if (cspr != nullptr) {
            anim = get_city_anim(cspr, pcity);
          }
        }
 
        if (anim != nullptr) {
          ADD_ANIM_FULL(anim);
        }
      }
      if (pcity->client.unhappy) {
        ADD_SPRITE_FULL(t->sprites.city.disorder);
      }
    }
    break;
 
  case LAYER_SPECIAL2:
    if (pterrain != nullptr) {
      if (ptile) {
        extra_type_list_iterate(t->style_lists[ESTYLE_3LAYER], pextra) {
          if (tile_has_extra(ptile, pextra)
              && is_extra_drawing_enabled(pextra)
              && t->sprites.extras[extra_index(pextra)].u.bmf.middleground != nullptr) {
            bool hidden = FALSE;
 
            extra_type_list_iterate(pextra->hiders, phider) {
              if (BV_ISSET(textras, extra_index(phider))) {
                hidden = TRUE;
                break;
              }
            } extra_type_list_iterate_end;
 
            if (!hidden) {
              ADD_ANIM_FULL(t->sprites.extras[extra_index(pextra)].u.bmf.middleground);
            }
          }
        } extra_type_list_iterate_end;
      }
 
      extra_type_list_iterate(t->style_lists[ESTYLE_SINGLE2], pextra) {
        if (BV_ISSET(textras, extra_index(pextra))
            && is_extra_drawing_enabled(pextra)) {
          bool hidden = FALSE;
 
          extra_type_list_iterate(pextra->hiders, phider) {
            if (BV_ISSET(textras, extra_index(phider))) {
              hidden = TRUE;
              break;
            }
          } extra_type_list_iterate_end;
 
          if (!hidden) {
            ADD_ANIM_SPRITE_SIMPLE(t->sprites.extras[extra_index(pextra)].u.single);
          }
        }
      } extra_type_list_iterate_end;
    }
    break;
 
  case LAYER_UNIT:
  case LAYER_FOCUS_UNIT:
    if (do_draw_unit && XOR(layer == LAYER_UNIT, unit_is_in_focus(punit))) {
      int stack_count = ptile ? unit_list_size(ptile->units) : 0;
      bool backdrop = !pcity;
 
      if (ptile && unit_is_in_focus(punit)
          && t->sprites.unit.select != nullptr) {
        /* Special case for drawing the selection rectangle. The blinking
         * unit is handled separately, inside get_drawable_unit(). */
        ADD_ANIM_SPRITE(t->sprites.unit.select, TRUE,
                        t->select_offset_x, t->select_offset_y);
      }
 
      /* Load more stack number sprites if needed. no_more_stack_sprites guard
       * that we don't retry over and over again for every stack,
       * when it's not working. */
      if (t->sprites.unit.num_stack_sprites < stack_count
          && !t->sprites.unit.no_more_stack_sprites) {
        t->sprites.unit.stack = fc_realloc(t->sprites.unit.stack,
                                           stack_count * sizeof(struct sprite *));
 
        while (t->sprites.unit.num_stack_sprites < stack_count
               && !t->sprites.unit.no_more_stack_sprites) {
          struct sprite *spr = load_gfxnumber(t->sprites.unit.num_stack_sprites + 1);
 
          if (spr != nullptr) {
            t->sprites.unit.stack[t->sprites.unit.num_stack_sprites++] = spr;
          } else {
            t->sprites.unit.no_more_stack_sprites = TRUE;
            t->sprites.unit.stack = fc_realloc(t->sprites.unit.stack,
                         t->sprites.unit.num_stack_sprites * sizeof(struct sprite *));
          }
        }
      }
 
      sprs += fill_unit_sprite_array(t, sprs, punit, stack_count, backdrop);
    } else if (putype != nullptr && layer == LAYER_UNIT) {
      /* Only the sprite for the unit type. */
      /* FIXME: Shouldn't this still get activity and orientation of
       *        the actual unit? */
      sprs += fill_unit_type_sprite_array(t, sprs, putype, ACTIVITY_LAST,
                                          direction8_invalid());
    }
    break;
 
  case LAYER_SPECIAL3:
    if (pterrain != nullptr) {
      if (ptile) {
        bool show_flag = FALSE;
        struct player *eowner = extra_owner(ptile);
 
        extra_type_list_iterate(t->style_lists[ESTYLE_3LAYER], pextra) {
          if (is_extra_drawing_enabled(pextra)
              && tile_has_extra(ptile, pextra)
              && t->sprites.extras[extra_index(pextra)].u.bmf.foreground != nullptr) {
            bool hidden = FALSE;
 
            extra_type_list_iterate(pextra->hiders, phider) {
              if (BV_ISSET(textras, extra_index(phider))) {
                hidden = TRUE;
                break;
              }
            } extra_type_list_iterate_end;
 
            if (!hidden) {
              if (t->sprites.extras[extra_index(pextra)].u.bmf.foreground != nullptr) {
                ADD_ANIM_FULL(t->sprites.extras[extra_index(pextra)].u.bmf.foreground);
              }
            }
          }
        } extra_type_list_iterate_end;
 
        /* Show base flag. Not part of previous iteration as
         * "extras of ESTYLE_3_LAYER" != "bases" */
        if (eowner != nullptr) {
          extra_type_list_iterate(t->flagged_bases_list, pextra) {
            if (tile_has_extra(ptile, pextra)) {
              bool hidden = FALSE;
 
              extra_type_list_iterate(pextra->hiders, phider) {
                if (BV_ISSET(textras, extra_index(phider))) {
                  hidden = TRUE;
                  break;
                }
              } extra_type_list_iterate_end;
 
              if (!hidden) {
                show_flag = TRUE;
              }
            }
          } extra_type_list_iterate_end;
 
          if (show_flag) {
            ADD_SPRITE(get_nation_flag_sprite(t, nation_of_player(eowner)), TRUE,
                       FULL_TILE_X_OFFSET + t->city_flag_offset_x,
                       FULL_TILE_Y_OFFSET + t->city_flag_offset_y);
          }
        }
      }
    }
    break;
 
  case LAYER_FOG:
    sprs += fill_fog_sprite_array(t, sprs, ptile, pedge, pcorner);
    break;
 
  case LAYER_CITY2:
    /* City size. Drawing this under fog makes it hard to read. */
    if (pcity && gui_options.draw_cities && !gui_options.draw_full_citybar) {
      bool warn = FALSE;
      unsigned int size = city_size_get(pcity);
 
      ADD_SPRITE(t->sprites.city.size[size % 10], FALSE,
                 FULL_TILE_X_OFFSET + t->city_size_offset_x,
                 FULL_TILE_Y_OFFSET + t->city_size_offset_y);
      if (10 <= size) {
        ADD_SPRITE(t->sprites.city.size_tens[(size / 10)
                   % 10], FALSE,
                   FULL_TILE_X_OFFSET + t->city_size_offset_x,
                   FULL_TILE_Y_OFFSET + t->city_size_offset_y);
        if (100 <= size) {
          struct sprite *sprite
            = t->sprites.city.size_hundreds[(size / 100) % 10];
 
          if (sprite != nullptr) {
            ADD_SPRITE(sprite, FALSE,
                       FULL_TILE_X_OFFSET + t->city_size_offset_x,
                       FULL_TILE_Y_OFFSET + t->city_size_offset_y);
          } else {
            warn = TRUE;
          }
          if (1000 <= size) {
            warn = TRUE;
          }
        }
      }
 
      if (warn) {
        /* Warn only once by tileset. */
        static char last_reported[256] = "";
 
        if (0 != strcmp(last_reported, t->name)) {
          log_normal(_("Tileset \"%s\" doesn't support big cities size, "
                       "such as %d. Size not displayed as expected."),
                     t->name, size);
          sz_strlcpy(last_reported, t->name);
        }
      }
    }
    break;
 
  case LAYER_GRID2:
    if (t->type == TS_OVERHEAD) {
      sprs += fill_grid_sprite_array(t, sprs, ptile, pedge, pcorner,
                                     punit, pcity, citymode);
    }
    break;
 
  case LAYER_OVERLAYS:
    sprs += fill_city_overlays_sprite_array(t, sprs, ptile, citymode);
    if (mapdeco_is_crosshair_set(ptile)) {
      ADD_SPRITE_SIMPLE(t->sprites.user.attention);
    }
    break;
 
  case LAYER_CITYBAR:
  case LAYER_TILELABEL:
    /* Nothing. This is just a placeholder. */
    break;
 
  case LAYER_GOTO:
    if (ptile && goto_is_active()) {
      sprs += fill_goto_sprite_array(t, sprs, ptile, pedge, pcorner);
    }
    break;
 
  case LAYER_WORKERTASK:
    if (citymode != nullptr && ptile != nullptr) {
      worker_task_list_iterate(citymode->task_reqs, ptask) {
        if (ptask->ptile == ptile) {
          switch (ptask->act) {
          case ACTIVITY_MINE:
            if (ptask->tgt == nullptr) {
              ADD_SPRITE(t->sprites.unit.plant,
                         TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                         FULL_TILE_Y_OFFSET + t->activity_offset_y);
            } else {
              ADD_SPRITE(t->sprites.extras[extra_index(ptask->tgt)].activity,
                         TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                         FULL_TILE_Y_OFFSET + t->activity_offset_y);
            }
            break;
          case ACTIVITY_PLANT:
            ADD_SPRITE(t->sprites.unit.plant,
                       TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                       FULL_TILE_Y_OFFSET + t->activity_offset_y);
            break;
          case ACTIVITY_IRRIGATE:
            if (ptask->tgt == nullptr) {
              ADD_SPRITE(t->sprites.unit.cultivate,
                         TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                         FULL_TILE_Y_OFFSET + t->activity_offset_y);
            } else {
              ADD_SPRITE(t->sprites.extras[extra_index(ptask->tgt)].activity,
                         TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                         FULL_TILE_Y_OFFSET + t->activity_offset_y);
            }
            break;
          case ACTIVITY_CULTIVATE:
            ADD_SPRITE(t->sprites.unit.cultivate,
                       TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                       FULL_TILE_Y_OFFSET + t->activity_offset_y);
            break;
          case ACTIVITY_GEN_ROAD:
            if (ptask->tgt != nullptr) {
              ADD_SPRITE(t->sprites.extras[extra_index(ptask->tgt)].activity,
                         TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                         FULL_TILE_Y_OFFSET + t->activity_offset_y);
            }
            break;
          case ACTIVITY_TRANSFORM:
            ADD_SPRITE(t->sprites.unit.transform,
                         TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                         FULL_TILE_Y_OFFSET + t->activity_offset_y);
            break;
          case ACTIVITY_CLEAN:
            if (ptask->tgt != nullptr) {
              ADD_SPRITE(t->sprites.extras[extra_index(ptask->tgt)].rmact,
                         TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                         FULL_TILE_Y_OFFSET + t->activity_offset_y);
            }
            break;
          default:
            break;
          }
        }
      } worker_task_list_iterate_end;
    }
    break;
 
  case LAYER_EDITOR:
    if (ptile && editor_is_active()) {
      if (editor_tile_is_selected(ptile)) {
        int color = 2 % tileset_num_city_colors(tileset);
        ADD_SPRITE_SIMPLE(t->sprites.city.unworked_tile_overlay.p[color]);
      }
 
      if (map_startpos_get(ptile) != nullptr) {
        /* FIXME: Use a more representative sprite. */
        ADD_SPRITE_SIMPLE(t->sprites.user.attention);
      }
    }
    break;
 
  case LAYER_INFRAWORK:
    if (ptile != nullptr) {
      if (ptile->placing != nullptr) {
        const int id = extra_index(ptile->placing);
 
        if (t->sprites.extras[id].activity != nullptr) {
          ADD_SPRITE(t->sprites.extras[id].activity,
                     TRUE, FULL_TILE_X_OFFSET + t->activity_offset_x,
                     FULL_TILE_Y_OFFSET + t->activity_offset_y);
        }
      }
      if (client_infratile() == ptile) {
        ADD_SPRITE_SIMPLE(t->sprites.user.infratile);
      }
    }
    break;
 
  case LAYER_COUNT:
    fc_assert(FALSE);
    break;
  }
 
  return sprs - save_sprs;
}
 
/************************************************************************/
void tileset_setup_city_tiles(struct tileset *t, int style)
{
  const char *style_name = city_style_rule_name(style);
 
  if (style == game.control.num_city_styles - 1) {
    int i;
 
    /* Free old sprites */
    free_city_sprite(t->sprites.city.tile);
 
    for (i = 0; i < NUM_WALL_TYPES; i++) {
      free_city_sprite(t->sprites.city.wall[i]);
      t->sprites.city.wall[i] = nullptr;
    }
    free_city_sprite(t->sprites.city.single_wall);
    t->sprites.city.single_wall = nullptr;
 
    free_city_sprite(t->sprites.city.occupied);
 
    t->sprites.city.tile = load_city_sprite(t, "city");
 
    for (i = 0; i < NUM_WALL_TYPES; i++) {
      char buffer[256];
 
      fc_snprintf(buffer, sizeof(buffer), "bldg_%d", i);
      t->sprites.city.wall[i] = load_city_sprite(t, buffer);
    }
    t->sprites.city.single_wall = load_city_sprite(t, "wall");
 
    t->sprites.city.occupied = load_city_sprite(t, "occupied");
  }
 
  tileset_setup_citizen_types(t,
                              &t->sprites.style_citizen_sets.sets[style],
                              city_styles[style].citizens_graphic,
                              style_name, FALSE);
  specialist_type_iterate(sp) {
    tileset_setup_specialist_type(t,
                                  &t->sprites.style_citizen_sets.sets[style],
                                  sp,
                                  city_styles[style].citizens_graphic,
                                  style_name, FALSE);
  } specialist_type_iterate_end;
 
  if (style == game.control.num_city_styles - 1) {
    for (style = 0; style < game.control.num_city_styles; style++) {
      if (t->sprites.city.tile->styles[style].land_num_thresholds == 0) {
        tileset_error(LOG_FATAL, tileset_name_get(t),
                      _("City style \"%s\": no city graphics."),
                      city_style_rule_name(style));
      }
      if (t->sprites.city.occupied->styles[style].land_num_thresholds == 0) {
        tileset_error(LOG_FATAL, tileset_name_get(t),
                      _("City style \"%s\": no occupied graphics."),
                      city_style_rule_name(style));
      }
    }
  }
}
 
/************************************************************************/
double get_focus_unit_toggle_timeout(const struct tileset *t)
{
  if (t->sprites.unit.select != nullptr) {
    return 0.1;
  } else {
    return 0.5;
  }
}
 
/************************************************************************/
void reset_focus_unit_state(struct tileset *t)
{
  if (t->sprites.unit.select != nullptr) {
    t->sprites.unit.select->time = 0;
  } else {
    focus_unit_state = FALSE;
  }
}
 
/************************************************************************/
void focus_unit_in_combat(struct tileset *t)
{
  reset_focus_unit_state(t);
}
 
/************************************************************************/
void toggle_focus_unit_state(struct tileset *t)
{
  if (t->sprites.unit.select != nullptr) {
    anim_advance_time(t->sprites.unit.select);
  } else {
    focus_unit_state = !focus_unit_state;
  }
}
 
/************************************************************************/
void advance_global_anim_state(void)
{
  global_anim_time++;
 
  dirty_all();
  update_map_canvas(0, 0, mapview.store_width, mapview.store_height);
}
 
/************************************************************************/
struct unit *get_drawable_unit(const struct tileset *t,
                               struct tile *ptile,
                               const struct city *citymode)
{
  struct unit *punit = find_visible_unit(ptile);
 
  if (punit == nullptr) {
    return nullptr;
  }
 
  if (citymode && unit_owner(punit) == city_owner(citymode)) {
    return nullptr;
  }
 
  if (!unit_is_in_focus(punit)
      || t->sprites.unit.select != nullptr || focus_unit_state) {
    return punit;
  } else {
    return nullptr;
  }
}
 
/************************************************************************/
static void unload_all_sprites(struct tileset *t)
{
  if (t->sprite_hash != nullptr) {
    sprite_hash_iterate(t->sprite_hash, tag_name, ss) {
      while (ss->ref_count > 0) {
        unload_sprite(t, tag_name);
      }
    } sprite_hash_iterate_end;
  }
}
 
/************************************************************************/
static void free_all_anims(struct tileset *t)
{
  if (t->anim_hash != nullptr) {
    anim_hash_iterate(t->anim_hash, tag, anim) {
      (void)tag;
      anim_free(anim);
    } anim_hash_iterate_end;
  }
}
 
/************************************************************************/
void tileset_free_tiles(struct tileset *t)
{
  int i;
 
  log_debug("tileset_free_tiles()");
 
  unload_all_sprites(t);
 
  free_city_sprite(t->sprites.city.tile);
  t->sprites.city.tile = nullptr;
 
  for (i = 0; i < NUM_WALL_TYPES; i++) {
    free_city_sprite(t->sprites.city.wall[i]);
    t->sprites.city.wall[i] = nullptr;
  }
  free_city_sprite(t->sprites.city.single_wall);
  t->sprites.city.single_wall = nullptr;
 
  free_city_sprite(t->sprites.city.occupied);
  t->sprites.city.occupied = nullptr;
 
  if (t->sprite_hash) {
    sprite_hash_destroy(t->sprite_hash);
    t->sprite_hash = nullptr;
  }
 
  if (t->sprites.style_citizen_sets.sets != nullptr) {
    free(t->sprites.style_citizen_sets.sets);
    t->sprites.style_citizen_sets.sets = nullptr;
  }
 
  small_sprite_list_iterate(t->small_sprites, ss) {
    small_sprite_list_remove(t->small_sprites, ss);
    if (ss->file) {
      free(ss->file);
    }
 
    fc_assert(ss->sprite == nullptr);
 
    free(ss);
  } small_sprite_list_iterate_end;
 
  specfile_list_iterate(t->specfiles, sf) {
    specfile_list_remove(t->specfiles, sf);
    free(sf->file_name);
    if (sf->big_sprite) {
      free_sprite(sf->big_sprite);
      sf->big_sprite = nullptr;
    }
    free(sf);
  } specfile_list_iterate_end;
 
  sprite_vector_iterate(&t->sprites.city.worked_tile_overlay, psprite) {
    free_sprite(*psprite);
  } sprite_vector_iterate_end;
  sprite_vector_free(&t->sprites.city.worked_tile_overlay);
 
  sprite_vector_iterate(&t->sprites.city.unworked_tile_overlay, psprite) {
    free_sprite(*psprite);
  } sprite_vector_iterate_end;
  sprite_vector_free(&t->sprites.city.unworked_tile_overlay);
 
  if (t->sprites.tx.fullfog) {
    free(t->sprites.tx.fullfog);
    t->sprites.tx.fullfog = nullptr;
  }
 
  sprite_vector_free(&t->sprites.colors.overlays);
  sprite_vector_free(&t->sprites.explode.unit);
  sprite_vector_free(&t->sprites.nation_flag);
  sprite_vector_free(&t->sprites.nation_shield);
  sprite_vector_free(&t->sprites.citybar.occupancy);
 
  /* Index 0 is 'occupied' or 'default' stack sprite */
  for (i = 1; i < t->sprites.unit.num_stack_sprites - 1; i++) {
    free_sprite(t->sprites.unit.stack[i]);
  }
  t->sprites.unit.num_stack_sprites = 0;
  if (t->sprites.unit.stack != nullptr) {
    free(t->sprites.unit.stack);
    t->sprites.unit.stack = nullptr;
  }
 
  free_all_anims(t);
  t->sprites.unit.select = nullptr;
  t->sprites.unit.action_decision_want = nullptr;
 
  if (t->anim_hash) {
    anim_hash_destroy(t->anim_hash);
    t->anim_hash = nullptr;
  }
 
  tileset_background_free(t);
}
 
/************************************************************************/
struct sprite *get_spaceship_sprite(const struct tileset *t,
                                    enum spaceship_part part)
{
  return t->sprites.spaceship[part];
}
 
/************************************************************************/
static inline const struct citizen_graphic *
get_citizen_graphic(const struct citizen_set *set,
                    enum citizen_category type)
{
  fc_assert_ret_val(set != nullptr, nullptr);
 
  if (type < CITIZEN_SPECIALIST) {
    fc_assert_ret_val(type >= 0, nullptr);
 
    return &set->citizen[type];
  } else {
    fc_assert_ret_val(type < (CITIZEN_SPECIALIST + SP_MAX), nullptr);
 
    return &set->specialist[type - CITIZEN_SPECIALIST];
  }
}
 
/************************************************************************/
struct sprite *get_citizen_sprite(const struct tileset *t,
                                  enum citizen_category type,
                                  int citizen_index,
                                  const struct city *pcity)
{
  const struct citizen_graphic *graphic = nullptr;
  int gfx_index = citizen_index;
 
  if (pcity != nullptr) {
    int style = style_of_city(pcity);
 
    fc_assert(t->sprites.style_citizen_sets.sets != nullptr);
 
    graphic = get_citizen_graphic(&t->sprites.style_citizen_sets.sets[style],
                                  type);
 
    gfx_index += pcity->client.first_citizen_index;
  }
 
  if (graphic == nullptr || graphic->count == 0) {
    /* Fall back to default sprites */
    graphic = get_citizen_graphic(&t->sprites.default_citizens, type);
  }
 
  if (graphic->count == 0) {
    return nullptr;
  }
 
  return graphic->sprite[gfx_index % graphic->count];
}
 
/************************************************************************/
struct sprite *get_nation_flag_sprite(const struct tileset *t,
                                      const struct nation_type *pnation)
{
  return t->sprites.nation_flag.p[nation_index(pnation)];
}
 
/************************************************************************/
struct sprite *get_nation_shield_sprite(const struct tileset *t,
                                        const struct nation_type *pnation)
{
  return t->sprites.nation_shield.p[nation_index(pnation)];
}
 
/************************************************************************/
struct sprite *get_tech_sprite(const struct tileset *t, Tech_type_id tech)
{
  fc_assert_ret_val(0 <= tech && tech < advance_count(), nullptr);
 
  return t->sprites.tech[tech];
}
 
/************************************************************************/
struct sprite *get_building_sprite(const struct tileset *t,
                                   const struct impr_type *pimprove)
{
  fc_assert_ret_val(pimprove != nullptr, nullptr);
 
  return t->sprites.building[improvement_index(pimprove)];
}
 
/************************************************************************/
struct sprite *get_government_sprite(const struct tileset *t,
                                     const struct government *gov)
{
  fc_assert_ret_val(gov != nullptr, nullptr);
 
  return t->sprites.government[government_index(gov)];
}
 
/************************************************************************/
struct sprite *get_unittype_sprite(const struct tileset *t,
                                   const struct unit_type *punittype,
                                   enum unit_activity activity,
                                   enum direction8 facing)
{
  int uidx = utype_index(punittype);
  bool icon = !direction8_is_valid(facing);
 
  if (activity >= ACTIVITY_LAST) {
    activity = ACTIVITY_IDLE;
  }
 
  fc_assert_ret_val(punittype != nullptr, nullptr);
 
  if (!direction8_is_valid(facing) || !is_valid_dir(facing)) {
    facing = t->unit_default_orientation;
    /* May not have been specified, but it only matters if we don't
     * turn out to have an icon sprite */
  }
 
  if (t->sprites.units.icon[uidx][activity] != nullptr
      && (icon || t->sprites.units.facing[uidx][facing][activity] == nullptr)) {
    /* Has icon sprite, and we prefer to (or must) use it */
    if (icon) {
      return t->sprites.units.icon[uidx][activity]->sprites[0];
    } else {
      return anim_get_current_frame(t->sprites.units.icon[uidx][activity]);
    }
  } else if (t->sprites.units.icon[uidx][ACTIVITY_IDLE] != nullptr
             && (icon
                 || t->sprites.units.facing[uidx][facing][ACTIVITY_IDLE] == nullptr)) {
    /* Has icon sprite, and we prefer to (or must) use it */
    if (icon) {
      return t->sprites.units.icon[uidx][ACTIVITY_IDLE]->sprites[0];
    } else {
      return anim_get_current_frame(t->sprites.units.icon[uidx][ACTIVITY_IDLE]);
    }
  } else {
    /* We should have a valid orientation by now. Failure to have either
     * an icon sprite or default orientation should have been caught at
     * tileset load. */
    fc_assert_ret_val(direction8_is_valid(facing), nullptr);
 
    if (t->sprites.units.facing[uidx][facing][activity] == nullptr) {
      return anim_get_current_frame(t->sprites.units.facing[uidx][facing][ACTIVITY_IDLE]);
    }
 
    return anim_get_current_frame(t->sprites.units.facing[uidx][facing][activity]);
  }
}
 
/************************************************************************/
struct sprite *get_sample_city_sprite(const struct tileset *t,
                                      int style_idx)
{
  int num_thresholds
    = t->sprites.city.tile->styles[style_idx].land_num_thresholds;
 
  if (num_thresholds == 0) {
    return nullptr;
  } else {
    return (t->sprites.city.tile->styles[style_idx]
            .land_thresholds[num_thresholds - 1].cst->sprites[0]);
  }
}
 
/************************************************************************/
struct sprite *get_arrow_sprite(const struct tileset *t,
                                enum arrow_type arrow)
{
  fc_assert_ret_val(arrow >= 0 && arrow < ARROW_LAST, nullptr);
 
  return t->sprites.arrow[arrow];
}
 
/************************************************************************/
struct sprite *get_tax_sprite(const struct tileset *t, Output_type_id otype)
{
  switch (otype) {
  case O_SCIENCE:
    return t->sprites.tax_science;
  case O_GOLD:
    return t->sprites.tax_gold;
  case O_LUXURY:
    return t->sprites.tax_luxury;
  case O_TRADE:
  case O_FOOD:
  case O_SHIELD:
  case O_LAST:
    break;
  }
 
  return nullptr;
}
 
/************************************************************************/
struct sprite *get_event_sprite(const struct tileset *t, enum event_type event)
{
  return t->sprites.events[event];
}
 
/************************************************************************/
struct sprite *get_treaty_thumb_sprite(const struct tileset *t, bool on_off)
{
  return t->sprites.treaty_thumb[on_off ? 1 : 0];
}
 
/************************************************************************/
const struct sprite_vector *get_unit_explode_animation(const struct
                                                       tileset *t)
{
  return &t->sprites.explode.unit;
}
 
/************************************************************************/
struct sprite *get_nuke_explode_sprite(const struct tileset *t)
{
  return t->sprites.explode.nuke;
}
 
/************************************************************************/
const struct citybar_sprites *get_citybar_sprites(const struct tileset *t)
{
  if (gui_options.draw_full_citybar) {
    return &t->sprites.citybar;
  } else {
    return nullptr;
  }
}
 
/************************************************************************/
const struct editor_sprites *get_editor_sprites(const struct tileset *t)
{
  return &t->sprites.editor;
}
 
/************************************************************************/
struct sprite *get_cursor_sprite(const struct tileset *t,
                                 enum cursor_type cursor,
                                 int *hot_x, int *hot_y, int frame)
{
  *hot_x = t->sprites.cursor[cursor].hot_x;
  *hot_y = t->sprites.cursor[cursor].hot_y;
 
  return t->sprites.cursor[cursor].frame[frame];
}
 
/************************************************************************/
struct sprite *get_icon_sprite(const struct tileset *t, enum icon_type icon)
{
  return t->sprites.icon[icon];
}
 
/************************************************************************/
struct sprite *get_attention_crosshair_sprite(const struct tileset *t)
{
  return t->sprites.user.attention;
}
 
/************************************************************************/
struct sprite *get_indicator_sprite(const struct tileset *t,
                                    enum indicator_type indicator,
                                    int idx)
{
  idx = CLIP(0, idx, NUM_TILES_PROGRESS - 1);
 
  fc_assert_ret_val(indicator >= 0 && indicator < INDICATOR_COUNT, nullptr);
 
  return t->sprites.indicator[indicator][idx];
}
 
/************************************************************************/
struct sprite *get_unit_unhappy_sprite(const struct tileset *t,
                                       const struct unit *punit,
                                       int happy_cost)
{
  const int unhappy = CLIP(0, happy_cost, MAX_NUM_UPKEEP_SPRITES+1);
 
  if (unhappy > 0) {
    return t->sprites.upkeep.unhappy[unhappy - 1];
  } else {
    return nullptr;
  }
}
 
/************************************************************************/
struct sprite *get_unit_upkeep_sprite(const struct tileset *t,
                                      Output_type_id otype,
                                      const struct unit *punit,
                                      const int *upkeep_cost)
{
  const int upkeep = CLIP(0, upkeep_cost[otype], MAX_NUM_UPKEEP_SPRITES + 1);
 
  if (upkeep > 0) {
    return t->sprites.upkeep.output[otype][upkeep - 1];
  } else {
    return nullptr;
  }
}
 
/************************************************************************/
struct sprite *get_basic_fog_sprite(const struct tileset *t)
{
  return t->sprites.tx.fog;
}
 
/************************************************************************/
struct color_system *get_color_system(const struct tileset *t)
{
  return t->color_system;
}
 
/************************************************************************/
void tileset_use_preferred_theme(const struct tileset *t)
{
  char *default_theme_name = nullptr;
  size_t default_theme_name_sz = 0;
  int i;
 
  switch (get_gui_type()) {
  case GUI_GTK3_22:
    default_theme_name = gui_options.gui_gtk3_22_default_theme_name;
    default_theme_name_sz = sizeof(gui_options.gui_gtk3_22_default_theme_name);
    break;
  case GUI_GTK4:
    default_theme_name = gui_options.gui_gtk4_default_theme_name;
    default_theme_name_sz = sizeof(gui_options.gui_gtk4_default_theme_name);
    break;
  case GUI_GTK5:
    default_theme_name = gui_options.gui_gtk5_default_theme_name;
    default_theme_name_sz = sizeof(gui_options.gui_gtk5_default_theme_name);
    break;
  case GUI_SDL2:
    default_theme_name = gui_options.gui_sdl2_default_theme_name;
    default_theme_name_sz = sizeof(gui_options.gui_sdl2_default_theme_name);
    break;
  case GUI_SDL3:
    default_theme_name = gui_options.gui_sdl3_default_theme_name;
    default_theme_name_sz = sizeof(gui_options.gui_sdl3_default_theme_name);
    break;
  case GUI_STUB:
  case GUI_QT:
  case GUI_SDL:
  case GUI_WEB:
  case GUI_GTK2:
  case GUI_GTK3:
    break;
  }
 
  if (default_theme_name == nullptr || 0 == default_theme_name_sz) {
    /* Theme is not supported by this client. */
    return;
  }
 
  for (i = 0; i < t->num_preferred_themes; i++) {
    if (strcmp(t->preferred_themes[i], default_theme_name)) {
      if (popup_theme_suggestion_dialog(t->preferred_themes[i])) {
        log_debug("trying theme \"%s\".", t->preferred_themes[i]);
        if (load_theme(t->preferred_themes[i])) {
          (void) fc_strlcpy(default_theme_name, t->preferred_themes[i],
                            default_theme_name_sz);
          return;
        }
      }
    }
  }
  log_verbose("The tileset doesn't specify preferred themes or none of its "
              "preferred themes can be used. Using system default.");
  gui_clear_theme();
}
 
/************************************************************************/
void tileset_init(struct tileset *t)
{
  int wi;
 
  /* We currently have no city sprites loaded. */
  t->sprites.city.tile     = nullptr;
 
  for (wi = 0; wi < NUM_WALL_TYPES; wi++) {
    t->sprites.city.wall[wi] = nullptr;
  }
  t->sprites.city.single_wall = nullptr;
 
  t->sprites.city.occupied = nullptr;
 
  t->sprites.background.color = nullptr;
  t->sprites.background.graphic = nullptr;
 
  player_slots_iterate(pslot) {
    int edge, j, id = player_slot_index(pslot);
 
    for (edge = 0; edge < EDGE_COUNT; edge++) {
      for (j = 0; j < 2; j++) {
        t->sprites.player[id].grid_borders[edge][j] = nullptr;
      }
    }
 
    t->sprites.player[id].color = nullptr;
    t->sprites.player[id].background = nullptr;
  } player_slots_iterate_end;
 
  t->max_upkeep_height = 0;
}
 
/************************************************************************/
int fill_basic_terrain_layer_sprite_array(struct tileset *t,
                                          struct drawn_sprite *sprs,
                                          int layer,
                                          struct terrain *pterrain)
{
  struct drawn_sprite *save_sprs = sprs;
  struct drawing_data *draw = t->sprites.drawing[terrain_index(pterrain)];
 
  struct terrain *tterrain_near[8];
  bv_extras textra_near[8];
 
  struct tile dummy_tile; /* :( */
 
  int i;
 
 
  memset(&dummy_tile, 0, sizeof(struct tile));
 
  for (i = 0; i < 8; i++) {
    tterrain_near[i] = pterrain;
    BV_CLR_ALL(textra_near[i]);
  }
 
  i = draw->is_reversed ? draw->num_layers - layer - 1 : layer;
  sprs += fill_terrain_sprite_array(t, sprs, i, &dummy_tile,
                                    pterrain, tterrain_near, draw);
 
  return sprs - save_sprs;
}
 
/************************************************************************/
int fill_basic_extra_sprite_array(const struct tileset *t,
                                  struct drawn_sprite *sprs,
                                  const struct extra_type *pextra)
{
  int idx = extra_index(pextra);
  struct drawn_sprite *saved_sprs = sprs;
 
  switch (t->sprites.extras[idx].extrastyle) {
  case ESTYLE_SINGLE1:
  case ESTYLE_SINGLE2:
    ADD_FRAME0_SIMPLE(t->sprites.extras[idx].u.single);
    break;
  case ESTYLE_CARDINALS:
    ADD_FRAME0_SIMPLE(t->sprites.extras[idx].u.cardinals[0]);
    break;
  case ESTYLE_ROAD_ALL_SEPARATE:
  case ESTYLE_ROAD_PARITY_COMBINED:
  case ESTYLE_ROAD_ALL_COMBINED:
  case ESTYLE_RIVER:
    return fill_basic_road_sprite_array(t, sprs, pextra);
  case ESTYLE_3LAYER:
    return fill_basic_base_sprite_array(t, sprs, pextra);
  case ESTYLE_COUNT:
    fc_assert(t->sprites.extras[idx].extrastyle != ESTYLE_COUNT);
    break;
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
int fill_basic_road_sprite_array(const struct tileset *t,
                                 struct drawn_sprite *sprs,
                                 const struct extra_type *pextra)
{
  struct drawn_sprite *saved_sprs = sprs;
  int idx;
  int i;
  enum extrastyle_id extrastyle;
 
  if (!t || !sprs || !pextra) {
    return 0;
  }
 
  idx = extra_index(pextra);
 
  if (!(0 <= idx && idx < game.control.num_extra_types)) {
    return 0;
  }
 
  extrastyle = t->sprites.extras[idx].extrastyle;
 
  if (extrastyle == ESTYLE_RIVER) {
    ADD_FRAME0_SIMPLE(t->sprites.extras[idx].u.road.ru.rivers.spec[0]);
  } else {
    for (i = 0; i < t->num_valid_tileset_dirs; i++) {
      if (!t->valid_tileset_dirs[i]) {
        continue;
      }
      if (extrastyle == ESTYLE_ROAD_ALL_SEPARATE) {
        ADD_FRAME0_SIMPLE(t->sprites.extras[idx].u.road.ru.dir[i]);
      } else if (extrastyle == ESTYLE_ROAD_PARITY_COMBINED) {
        if ((i % 2) == 0) {
          ADD_FRAME0_SIMPLE(t->sprites.extras[idx].u.road.ru.combo.even[1 << (i / 2)]);
        }
      } else if (extrastyle == ESTYLE_ROAD_ALL_COMBINED) {
        ADD_FRAME0_SIMPLE(t->sprites.extras[idx].u.road.ru.total[1 << i]);
      }
    }
  }
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
int fill_basic_base_sprite_array(const struct tileset *t,
                                 struct drawn_sprite *sprs,
                                 const struct extra_type *pextra)
{
  struct drawn_sprite *saved_sprs = sprs;
  int idx;
 
  if (!t || !sprs || !pextra) {
    return 0;
  }
 
  idx = extra_index(pextra);
 
  if (!(0 <= idx && idx < game.control.num_extra_types)) {
    return 0;
  }
 
#define ADD_FRAME0_IF_NOT_NULL(x) do {\
  if ((x) != nullptr) {\
    ADD_FRAME0_FULL(x);\
  }\
} while (FALSE)
 
  /* Corresponds to LAYER_SPECIAL{1,2,3} order. */
  ADD_FRAME0_IF_NOT_NULL(t->sprites.extras[idx].u.bmf.background);
  ADD_FRAME0_IF_NOT_NULL(t->sprites.extras[idx].u.bmf.middleground);
  ADD_FRAME0_IF_NOT_NULL(t->sprites.extras[idx].u.bmf.foreground);
 
#undef ADD_FRAME0_IF_NOT_NULL
 
  return sprs - saved_sprs;
}
 
/************************************************************************/
enum mapview_layer tileset_get_layer(const struct tileset *t, int n)
{
  fc_assert(n < LAYER_COUNT);
 
  return t->layer_order[n];
}
 
/************************************************************************/
bool tileset_layer_in_category(enum mapview_layer layer,
                               enum layer_category cat)
{
  switch (layer) {
  case LAYER_BACKGROUND:
  case LAYER_TERRAIN1:
  case LAYER_DARKNESS:
  case LAYER_TERRAIN2:
  case LAYER_TERRAIN3:
  case LAYER_WATER:
  case LAYER_ROADS:
  case LAYER_SPECIAL1:
  case LAYER_SPECIAL2:
  case LAYER_SPECIAL3:
    return cat == LAYER_CATEGORY_CITY || cat == LAYER_CATEGORY_TILE;
  case LAYER_CITY1:
  case LAYER_CITY2:
    return cat == LAYER_CATEGORY_CITY;
  case LAYER_UNIT:
  case LAYER_FOCUS_UNIT:
    return cat == LAYER_CATEGORY_UNIT;
  case LAYER_GRID1:
  case LAYER_FOG:
  case LAYER_GRID2:
  case LAYER_OVERLAYS:
  case LAYER_TILELABEL:
  case LAYER_CITYBAR:
  case LAYER_GOTO:
  case LAYER_WORKERTASK:
  case LAYER_EDITOR:
  case LAYER_INFRAWORK:
    return FALSE;
  case LAYER_COUNT:
    break; /* and fail below */
  }
 
  fc_assert_msg(FALSE, "Unknown layer category: %d", cat);
  return FALSE;
}
 
/************************************************************************/
void tileset_player_init(struct tileset *t, struct player *pplayer)
{
  int plrid, i, j;
  struct sprite *color;
 
  fc_assert_ret(pplayer != nullptr);
 
  plrid = player_index(pplayer);
  fc_assert_ret(plrid >= 0);
  fc_assert_ret(plrid < ARRAY_SIZE(t->sprites.player));
 
  /* Free all data before recreating it. */
  tileset_player_free(t, plrid);
 
  if (player_has_color(pplayer)) {
    t->sprites.player[plrid].color = color
      = create_plr_sprite(get_player_color(t, pplayer));
  } else {
    /* XXX: if player hasn't been assigned a color, perhaps there's no
     * point proceeding with an arbitrary color; this should only happen
     * in pregame. Probably blank sprites would be better. */
 
    fc_assert_ret(t->sprites.background.color != nullptr);
 
    color = t->sprites.background.color;
  }
 
  t->sprites.player[plrid].background
    = crop_sprite(color, 0, 0,
                  t->normal_tile_width, t->normal_tile_height,
                  t->sprites.mask.tile, 0, 0, t->scale, FALSE);
 
  for (i = 0; i < EDGE_COUNT; i++) {
    for (j = 0; j < 2; j++) {
      struct sprite *s;
 
      if (color && t->sprites.grid.borders[i][j]) {
        s = crop_sprite(color, 0, 0,
                        t->normal_tile_width, t->normal_tile_height,
                        t->sprites.grid.borders[i][j], 0, 0, 1.0f, FALSE);
      } else {
        s = t->sprites.grid.borders[i][j];
      }
      t->sprites.player[plrid].grid_borders[i][j] = s;
    }
  }
}
 
/************************************************************************/
static void tileset_player_free(struct tileset *t, int plrid)
{
  int i, j;
 
  fc_assert_ret(plrid >= 0);
  fc_assert_ret(plrid < ARRAY_SIZE(t->sprites.player));
 
  if (t->sprites.player[plrid].color) {
    free_sprite(t->sprites.player[plrid].color);
    t->sprites.player[plrid].color = nullptr;
  }
  if (t->sprites.player[plrid].background) {
    free_sprite(t->sprites.player[plrid].background);
    t->sprites.player[plrid].background = nullptr;
  }
 
  for (i = 0; i < EDGE_COUNT; i++) {
    for (j = 0; j < 2; j++) {
      if (t->sprites.player[plrid].grid_borders[i][j]) {
        free_sprite(t->sprites.player[plrid].grid_borders[i][j]);
        t->sprites.player[plrid].grid_borders[i][j] = nullptr;
      }
    }
  }
}
 
/************************************************************************/
void tileset_background_init(struct tileset *t)
{
  /* Free all data before recreating it. */
  tileset_background_free(t);
 
  /* Generate background color */
  t->sprites.background.color
    = create_plr_sprite(ensure_color(game.plr_bg_color));
 
  /* Chop up and build the background graphics. */
  t->sprites.background.graphic
    = crop_sprite(t->sprites.background.color, 0, 0,
                  t->normal_tile_width, t->normal_tile_height,
                  t->sprites.mask.tile, 0, 0, t->scale, FALSE);
}
 
/************************************************************************/
void tileset_background_free(struct tileset *t)
{
  if (t->sprites.background.color) {
    free_sprite(t->sprites.background.color);
    t->sprites.background.color = nullptr;
  }
 
  if (t->sprites.background.graphic) {
    free_sprite(t->sprites.background.graphic);
    t->sprites.background.graphic = nullptr;
  }
}
 
/************************************************************************/
void tileset_ruleset_reset(struct tileset *t)
{
  int i;
 
  for (i = 0; i < ESTYLE_COUNT; i++) {
    if (t->style_lists[i] != nullptr) {
      extra_type_list_destroy(t->style_lists[i]);
      t->style_lists[i] = extra_type_list_new();
    }
  }
 
  if (t->flagged_bases_list != nullptr) {
    extra_type_list_destroy(t->flagged_bases_list);
    t->flagged_bases_list = extra_type_list_new();
  }
 
  if (t->sprites.style_citizen_sets.sets != nullptr) {
    free(t->sprites.style_citizen_sets.sets);
  }
 
  t->sprites.style_citizen_sets.sets
    = fc_malloc(game.control.num_city_styles
                * sizeof(t->sprites.style_citizen_sets.sets[0]));
}
 
/************************************************************************/
bool tileset_is_fully_loaded(void)
{
  return !tileset_update;
}
 
/************************************************************************/
const char *tileset_name_get(struct tileset *t)
{
  return t->given_name;
}
 
/************************************************************************/
const char *tileset_version(struct tileset *t)
{
  return t->version;
}
 
/************************************************************************/
const char *tileset_summary(struct tileset *t)
{
  return t->summary;
}
 
/************************************************************************/
const char *tileset_description(struct tileset *t)
{
  return t->description;
}
 
/************************************************************************/
char *tileset_what_ruleset(struct tileset *t)
{
  return t->for_ruleset;
}
 
/************************************************************************/
int tileset_topo_index(struct tileset *t)
{
  return t->ts_topo_idx;
}
 
/************************************************************************/
int tileset_svg_flag_height(struct tileset *t)
{
  return t->svg_height;
}
 
/************************************************************************/
struct sprite *load_popup_sprite(const char *tag)
{
  return load_sprite(tileset, tag, TRUE, TRUE, FALSE);
}
 
/************************************************************************/
void unload_popup_sprite(const char *tag)
{
  unload_sprite(tileset, tag);
}