2 files changed, 142 insertions, 119 deletions

diff --git a/include/isogfx/asset.h b/include/isogfx/asset.h
new file mode 100644
index 0000000..298c469
--- /dev/null
+++ b/include/isogfx/asset.h
@@ -0,0 +1,132 @@
+/*
+ * File format definitions for isogfx assets.
+ *
+ * All formats are defined so that they can be simply read into memory and used
+ * by the engine. Likewise, a tool that generates these formats can generate
+ * the structures in memory and then write them as is to a file.
+ */
+#pragma once
+
+#include <assert.h>
+#include <stdint.h>
+
+// Maximum length of path strings in .TS and .TM files.
+#define ISOGFX_MAX_PATH_LENGTH 128
+
+// -----------------------------------------------------------------------------
+// Tile set (TS) file format.
+// -----------------------------------------------------------------------------
+
+typedef struct Ts_Tile {
+  uint16_t width;     // Tile width in pixels.
+  uint16_t height;    // Tile height in pixels.
+  Pixel    pixels[1]; // Count: width * height.
+} Ts_Tile;
+
+typedef struct Ts_TileSet {
+  uint16_t num_tiles;
+  uint16_t max_tile_width;  // Maximum tile width in pixels.
+  uint16_t max_tile_height; // Maximum tile height in pixels.
+  Ts_Tile  tiles[1];        // Count: num_tiles.
+} Ts_TileSet;
+
+// -----------------------------------------------------------------------------
+// Tile map (TM) file format.
+// -----------------------------------------------------------------------------
+
+typedef struct Tm_Layer {
+  union {
+    char tileset_path[ISOGFX_MAX_PATH_LENGTH]; // Relative to the Tm_Map file.
+  };
+  Tile tiles[1]; // Count: world_width * world_height.
+} Tm_Layer;
+
+typedef struct Tm_Map {
+  uint16_t world_width;  // World width in number of tiles.
+  uint16_t world_height; // World height in number of tiles.
+  uint16_t base_tile_width;
+  uint16_t base_tile_height;
+  uint16_t num_layers;
+  Tm_Layer layers[1]; // Count: num_layers.
+} Tm_Map;
+
+// -----------------------------------------------------------------------------
+// Sprite sheet file format.
+// -----------------------------------------------------------------------------
+
+/// A row of sprites in a sprite sheet.
+///
+/// Each row in a sprite sheet can have a different number of columns.
+///
+/// The pixels of the row follow a "sprite-major" order. It contains the
+/// 'sprite_width * sprite_height' pixels for the first column/sprite, then the
+/// second column/sprite, etc.
+///
+/// Pixels are 8-bit indices into the sprite sheet's colour palette.
+typedef struct Ss_Row {
+  uint16_t num_cols;  /// Number of columns in this row.
+  uint8_t  pixels[1]; /// Count: num_cols * sprite_width * sprite_height.
+} Ss_Row;
+
+typedef struct Ss_Palette {
+  uint16_t num_colours;
+  Pixel    colours[1]; /// Count: num_colors.
+} Ss_Palette;
+
+/// Sprite sheet top-level data definition.
+///
+/// Sprite width and height are assumed constant throughout the sprite sheet.
+typedef struct Ss_SpriteSheet {
+  uint16_t   sprite_width;  /// Sprite width in pixels.
+  uint16_t   sprite_height; /// Sprite height in pixels.
+  uint16_t   num_rows;
+  Ss_Palette palette; /// Variable size.
+  Ss_Row     rows[1]; /// Count: num_rows. Variable offset.
+} Ss_SpriteSheet;
+
+// -----------------------------------------------------------------------------
+// Data accessors.
+// -----------------------------------------------------------------------------
+
+/// Return the next tile in the tile set.
+static inline const Ts_Tile* ts_tileset_get_next_tile(
+    const Ts_TileSet* tileset, const Ts_Tile* tile) {
+  assert(tileset);
+  assert(tile);
+  return (const Ts_Tile*)((const uint8_t*)tile + sizeof(Ts_Tile) +
+                          ((tile->width * tile->height - 1) * sizeof(Pixel)));
+}
+
+/// Return the next layer in the tile map.
+static inline const Tm_Layer* tm_map_get_next_layer(
+    const Tm_Map* map, const Tm_Layer* layer) {
+  assert(map);
+  assert(layer);
+  return (const Tm_Layer*)((const uint8_t*)layer + sizeof(Tm_Layer) +
+                           ((map->world_width * map->world_height - 1) *
+                            sizeof(Tile)));
+}
+
+/// Return the ith row in the sprite sheet.
+static inline const Ss_Row* get_sprite_sheet_row(
+    const Ss_SpriteSheet* sheet, int row) {
+  assert(sheet);
+  assert(row >= 0);
+  assert(row < sheet->num_rows);
+  // Skip over the palette.
+  const Ss_Row* rows =
+      (const Ss_Row*)(&sheet->palette.colours[0] + sheet->palette.num_colours);
+  return &rows[row];
+}
+
+/// Return the ith sprite in the row.
+static inline const uint8_t* get_sprite_sheet_sprite(
+    const Ss_SpriteSheet* sheet, const Ss_Row* row, int col) {
+  assert(sheet);
+  assert(row);
+  assert(col >= 0);
+  assert(col < row->num_cols);
+  const int sprite_offset = col * sheet->sprite_width * sheet->sprite_height;
+  const uint8_t* sprite   = &row->pixels[sprite_offset];
+  return sprite;
+}
diff --git a/src/isogfx.c b/src/isogfx.c
index 52c4ae2..baf422f 100644
--- a/src/isogfx.c
+++ b/src/isogfx.c
@@ -1,5 +1,7 @@
 #include <isogfx/isogfx.h>
 
+#include <isogfx/asset.h>
+
 #include <filesystem.h>
 #include <mem.h>
 #include <mempool.h>
@@ -38,115 +40,6 @@ typedef struct vec2 {
 } vec2;
 
 // -----------------------------------------------------------------------------
-// Tile set (TS) and tile map (TM) file formats.
-// -----------------------------------------------------------------------------
-
-/// Maximum length of path strings in .TS and .TM files.
-#define MAX_PATH_LENGTH 128
-
-typedef struct Ts_Tile {
-  uint16_t width;     /// Tile width in pixels.
-  uint16_t height;    /// Tile height in pixels.
-  Pixel    pixels[1]; /// Count: width * height.
-} Ts_Tile;
-
-typedef struct Ts_TileSet {
-  uint16_t num_tiles;
-  uint16_t max_tile_width;  /// Maximum tile width in pixels.
-  uint16_t max_tile_height; /// Maximum tile height in pixels.
-  Ts_Tile  tiles[1];        /// Count: num_tiles.
-} Ts_TileSet;
-
-typedef struct Tm_Layer {
-  union {
-    char tileset_path[MAX_PATH_LENGTH]; // Relative to the Tm_Map file.
-  };
-  Tile tiles[1]; /// Count: world_width * world_height.
-} Tm_Layer;
-
-typedef struct Tm_Map {
-  uint16_t world_width;  /// World width in number of tiles.
-  uint16_t world_height; /// World height in number of tiles.
-  uint16_t base_tile_width;
-  uint16_t base_tile_height;
-  uint16_t num_layers;
-  Tm_Layer layers[1]; // Count: num_layers.
-} Tm_Map;
-
-static inline const Tm_Layer* tm_map_get_next_layer(
-    const Tm_Map* map, const Tm_Layer* layer) {
-  assert(map);
-  assert(layer);
-  return (const Tm_Layer*)((const uint8_t*)layer + sizeof(Tm_Layer) +
-                           ((map->world_width * map->world_height - 1) *
-                            sizeof(Tile)));
-}
-
-static inline const Ts_Tile* ts_tileset_get_next_tile(
-    const Ts_TileSet* tileset, const Ts_Tile* tile) {
-  assert(tileset);
-  assert(tile);
-  return (const Ts_Tile*)((const uint8_t*)tile + sizeof(Ts_Tile) +
-                          ((tile->width * tile->height - 1) * sizeof(Pixel)));
-}
-
-// -----------------------------------------------------------------------------
-// Sprite sheet file format.
-// -----------------------------------------------------------------------------
-
-/// A row of sprites in a sprite sheet.
-///
-/// Each row in a sprite sheet can have a different number of columns.
-///
-/// The pixels of the row follow a "sprite-major" order. It contains the
-/// 'sprite_width * sprite_height' pixels for the first column/sprite, then the
-/// second column/sprite, etc.
-///
-/// Pixels are 8-bit indices into the sprite sheet's colour palette.
-typedef struct Ss_Row {
-  uint16_t num_cols;  /// Number of columns in this row.
-  uint8_t  pixels[1]; /// Count: num_cols * sprite_width * sprite_height.
-} Ss_Row;
-
-typedef struct Ss_Palette {
-  uint16_t num_colours;
-  Pixel    colours[1]; /// Count: num_colors.
-} Ss_Palette;
-
-/// Sprite sheet top-level data definition.
-///
-/// Sprite width and height are assumed constant throughout the sprite sheet.
-typedef struct Ss_SpriteSheet {
-  uint16_t   sprite_width;  /// Sprite width in pixels.
-  uint16_t   sprite_height; /// Sprite height in pixels.
-  uint16_t   num_rows;
-  Ss_Palette palette; /// Variable size.
-  Ss_Row     rows[1]; /// Count: num_rows. Variable offset.
-} Ss_SpriteSheet;
-
-static inline const Ss_Row* get_sprite_sheet_row(
-    const Ss_SpriteSheet* sheet, int row) {
-  assert(sheet);
-  assert(row >= 0);
-  assert(row < sheet->num_rows);
-  // Skip over the palette.
-  const Ss_Row* rows =
-      (const Ss_Row*)(&sheet->palette.colours[0] + sheet->palette.num_colours);
-  return &rows[row];
-}
-
-static inline const uint8_t* get_sprite_sheet_sprite(
-    const Ss_SpriteSheet* sheet, const Ss_Row* row, int col) {
-  assert(sheet);
-  assert(row);
-  assert(col >= 0);
-  assert(col < row->num_cols);
-  const int sprite_offset = col * sheet->sprite_width * sheet->sprite_height;
-  const uint8_t* sprite   = &row->pixels[sprite_offset];
-  return sprite;
-}
-
-// -----------------------------------------------------------------------------
 // Renderer state.
 // -----------------------------------------------------------------------------
 
@@ -204,8 +97,8 @@ static inline ivec2 ivec2_scale(ivec2 a, int s) {
 }
 
 static inline ivec2 iso2cart(ivec2 iso, int s, int t, int w) {
-  return (ivec2){
-      .x = (iso.x - iso.y) * (s / 2) + (w / 2), .y = (iso.x + iso.y) * (t / 2)};
+  return (ivec2){.x = (iso.x - iso.y) * (s / 2) + (w / 2),
+                 .y = (iso.x + iso.y) * (t / 2)};
 }
 
 // Method 1.
@@ -221,9 +114,8 @@ static inline vec2 cart2iso(vec2 cart, int s, int t, int w) {
   const double one_over_s = 1. / (double)s;
   const double one_over_t = 1. / (double)t;
   const double x          = cart.x - (double)(w / 2);
-  return (vec2){
-      .x = (one_over_s * x + one_over_t * cart.y),
-      .y = (-one_over_s * x + one_over_t * cart.y)};
+  return (vec2){.x = (one_over_s * x + one_over_t * cart.y),
+                .y = (-one_over_s * x + one_over_t * cart.y)};
 }
 
 static const Pixel* tile_xy_const_ref(
@@ -752,11 +644,10 @@ static Pixel alpha_blend(Pixel src, Pixel dst) {
       (double)((uint16_t)s * (uint16_t)src.a +  \
                (uint16_t)d * one_minus_alpha) / \
       255.0)
-  return (Pixel){
-      .r = blend(src.r, dst.r),
-      .g = blend(src.g, dst.g),
-      .b = blend(src.b, dst.b),
-      .a = src.a};
+  return (Pixel){.r = blend(src.r, dst.r),
+                 .g = blend(src.g, dst.g),
+                 .b = blend(src.b, dst.b),
+                 .a = src.a};
 }
 
 /// Draw a rectangle (tile or sprite).