2 files changed, 337 insertions, 217 deletions

diff --git a/src/backend.c b/src/backend.c
index 94f1728..4bb3592 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -1,5 +1,5 @@
 #include <isogfx/backend.h>
-#include <isogfx/isogfx.h>
+#include <isogfx/gfx2d.h>
 
 #include <gfx/core.h>
 #include <gfx/gfx.h>
@@ -13,7 +13,7 @@
 #include <assert.h>
 #include <stdlib.h>
 
-typedef struct IsoBackend {
+typedef struct Gfx2dBackend {
   Gfx*  gfx;
   Mesh* quad_mesh;
   /// The screen or "iso screen" refers to the colour buffer of the iso graphics
@@ -29,12 +29,12 @@ typedef struct IsoBackend {
   int    viewport_x, viewport_y, viewport_width, viewport_height;
   double stretch; // Stretch factor from iso screen dimensions to viewport
                   // dimensions.
-} IsoBackend;
+} Gfx2dBackend;
 
-IsoBackend* iso_backend_init(const IsoGfx* iso) {
+Gfx2dBackend* gfx2d_backend_init(const Gfx2d* iso) {
   assert(iso);
 
-  IsoBackend* backend = calloc(1, sizeof(IsoBackend));
+  Gfx2dBackend* backend = calloc(1, sizeof(Gfx2dBackend));
   if (!backend) {
     return nullptr;
   }
@@ -45,7 +45,7 @@ IsoBackend* iso_backend_init(const IsoGfx* iso) {
   GfxCore* gfxcore = gfx_get_core(backend->gfx);
 
   int screen_width, screen_height;
-  isogfx_get_screen_size(iso, &screen_width, &screen_height);
+  gfx2d_get_screen_size(iso, &screen_width, &screen_height);
 
   if (!((backend->screen_texture = gfx_make_texture(
              gfxcore, &(TextureDesc){.width     = screen_width,
@@ -95,10 +95,10 @@ cleanup:
   return nullptr;
 }
 
-void iso_backend_shutdown(IsoBackend** ppApp) {
+void gfx2d_backend_shutdown(Gfx2dBackend** ppApp) {
   assert(ppApp);
 
-  IsoBackend* app = *ppApp;
+  Gfx2dBackend* app = *ppApp;
   if (!app) {
     return;
   }
@@ -106,8 +106,8 @@ void iso_backend_shutdown(IsoBackend** ppApp) {
   gfx_destroy(&app->gfx);
 }
 
-void iso_backend_resize_window(
-    IsoBackend* app, const IsoGfx* iso, int width, int height) {
+void gfx2d_backend_resize_window(
+    Gfx2dBackend* app, const Gfx2d* iso, int width, int height) {
   assert(app);
   assert(iso);
 
@@ -116,7 +116,7 @@ void iso_backend_resize_window(
 
   // Virtual screen dimensions.
   int screen_width, screen_height;
-  isogfx_get_screen_size(iso, &screen_width, &screen_height);
+  gfx2d_get_screen_size(iso, &screen_width, &screen_height);
 
   // Stretch the virtual screen onto the viewport while respecting the screen's
   // aspect ratio to prevent distortion.
@@ -135,11 +135,11 @@ void iso_backend_resize_window(
   }
 }
 
-void iso_backend_render(const IsoBackend* app, const IsoGfx* iso) {
+void gfx2d_backend_render(const Gfx2dBackend* app, const Gfx2d* iso) {
   assert(app);
   assert(iso);
 
-  const Pixel* screen = isogfx_get_screen_buffer(iso);
+  const Pixel* screen = gfx2d_get_screen_buffer(iso);
   assert(screen);
   gfx_update_texture(app->screen_texture, &(TextureDataDesc){.pixels = screen});
 
@@ -162,8 +162,8 @@ void iso_backend_render(const IsoBackend* app, const IsoGfx* iso) {
   gfx_end_frame(gfxcore);
 }
 
-bool iso_backend_get_mouse_position(
-    const IsoBackend* app, double window_x, double window_y, double* x,
+bool gfx2d_backend_get_mouse_position(
+    const Gfx2dBackend* app, double window_x, double window_y, double* x,
     double* y) {
   assert(app);
 
diff --git a/src/isogfx.c b/src/gfx2d.c
index c3a87bf..f609c98 100644
--- a/src/isogfx.c
+++ b/src/gfx2d.c
@@ -1,4 +1,4 @@
-#include <isogfx/isogfx.h>
+#include <isogfx/gfx2d.h>
 
 #include <isogfx/asset.h>
 
@@ -32,11 +32,11 @@ typedef struct vec2 {
 // Renderer state.
 // -----------------------------------------------------------------------------
 
-typedef struct CoordSystem {
+typedef struct IsoCoordSystem {
   ivec2 o; // Origin.
   ivec2 x;
   ivec2 y;
-} CoordSystem;
+} IsoCoordSystem;
 
 typedef struct Screen {
   int    width;
@@ -52,9 +52,9 @@ typedef struct SpriteInstance {
   int                    frame;     // Current frame of animation.
 } SpriteInstance;
 
-typedef struct IsoGfx {
+typedef struct Gfx2d {
   Screen          screen;
-  CoordSystem     iso_space;
+  IsoCoordSystem  iso_space;
   ivec2           camera;
   double          last_animation_time;
   Tile            next_tile; // For procedurally-generated tiles.
@@ -63,7 +63,7 @@ typedef struct IsoGfx {
   SpriteInstance* head_sprite; // Head of sprites list.
   memstack        stack;
   size_t          watermark;
-} IsoGfx;
+} Gfx2d;
 
 // -----------------------------------------------------------------------------
 // Math and world / tile / screen access.
@@ -79,17 +79,58 @@ static inline ivec2 ivec2_scale(ivec2 a, int s) {
 
 static inline ivec2 ivec2_neg(ivec2 a) { return (ivec2){.x = -a.x, .y = -a.y}; }
 
-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)};
-}
-
 static inline vec2 vec2_add(vec2 a, vec2 b) {
   return (vec2){.x = a.x + b.x, .y = a.y + b.y};
 }
 
 static inline vec2 ivec2_to_vec2(ivec2 a) { return (vec2){a.x, a.y}; }
 
+/// Map map coordinates to screen coordinates, both Cartesian.
+static ivec2 map2screen(
+    ivec2 camera, int tile_width, int tile_height, int map_x, int map_y) {
+  return ivec2_add(
+      ivec2_neg(camera),
+      (ivec2){.x = map_x * tile_width, .y = map_y * tile_height});
+}
+
+// Not actually used because we pre-compute the two axis vectors instead.
+// See make_iso_coord_system() and the other definition of iso2cart() below.
+// 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)};
+// }
+
+/// Create the basis for the isometric coordinate system with origin and vectors
+/// expressed in the Cartesian system.
+static IsoCoordSystem make_iso_coord_system(
+    const Tm_Map* const map, const Screen* const screen) {
+  assert(map);
+  assert(screen);
+  const ivec2 o = {screen->width / 2, 0};
+  const ivec2 x = {
+      .x = map->base_tile_width / 2, .y = map->base_tile_height / 2};
+  const ivec2 y = {
+      .x = -map->base_tile_width / 2, .y = map->base_tile_height / 2};
+  return (IsoCoordSystem){o, x, y};
+}
+
+/// Map isometric coordinates to Cartesian coordinates.
+///
+/// For a tile, this gets the screen position of the top diamond-corner of the
+/// tile.
+///
+/// Takes the camera displacement into account.
+static ivec2 iso2cart(
+    const IsoCoordSystem iso_space, ivec2 camera, int iso_x, int iso_y) {
+  const ivec2 vx_offset = ivec2_scale(iso_space.x, iso_x);
+  const ivec2 vy_offset = ivec2_scale(iso_space.y, iso_y);
+  const ivec2 origin_world_space =
+      ivec2_add(iso_space.o, ivec2_add(vx_offset, vy_offset));
+  const ivec2 origin_view_space =
+      ivec2_add(origin_world_space, ivec2_neg(camera));
+  return origin_view_space;
+}
+
 // Method 1.
 // static inline vec2 cart2iso(vec2 cart, int s, int t, int w) {
 //  const double x    = cart.x - (double)(w / 2);
@@ -125,81 +166,67 @@ static inline Pixel* screen_xy_mut(Screen* screen, int x, int y) {
   return (Pixel*)screen_xy_const_ref(screen, x, y);
 }
 
-/// Create the basis for the isometric coordinate system with origin and vectors
-/// expressed in the Cartesian system.
-static CoordSystem make_iso_coord_system(
-    const Tm_Map* const map, const Screen* const screen) {
-  assert(map);
-  assert(screen);
-  const ivec2 o = {screen->width / 2, 0};
-  const ivec2 x = {
-      .x = map->base_tile_width / 2, .y = map->base_tile_height / 2};
-  const ivec2 y = {
-      .x = -map->base_tile_width / 2, .y = map->base_tile_height / 2};
-  return (CoordSystem){o, x, y};
-}
-
 // -----------------------------------------------------------------------------
 // Renderer, world and tile management.
 // -----------------------------------------------------------------------------
 
-IsoGfx* isogfx_new(const IsoGfxDesc* desc) {
+Gfx2d* gfx2d_new(const Gfx2dDesc* desc) {
   assert(desc->screen_width > 0);
   assert(desc->screen_height > 0);
   // Part of our implementation assumes even widths and heights for precision.
   assert((desc->screen_width & 1) == 0);
   assert((desc->screen_height & 1) == 0);
 
-  IsoGfx tmp = {0};
+  Gfx2d tmp = {0};
   if (!memstack_make(&tmp.stack, desc->memory_size, desc->memory)) {
     goto cleanup;
   }
-  IsoGfx* iso =
-      memstack_alloc_aligned(&tmp.stack, sizeof(IsoGfx), alignof(IsoGfx));
-  *iso = tmp;
+  Gfx2d* gfx =
+      memstack_alloc_aligned(&tmp.stack, sizeof(Gfx2d), alignof(Gfx2d));
+  *gfx = tmp;
 
   const size_t screen_size_bytes =
       desc->screen_width * desc->screen_height * sizeof(Pixel);
   Pixel* screen =
-      memstack_alloc_aligned(&iso->stack, screen_size_bytes, alignof(Pixel));
+      memstack_alloc_aligned(&gfx->stack, screen_size_bytes, alignof(Pixel));
 
-  iso->screen = (Screen){.width  = desc->screen_width,
+  gfx->screen = (Screen){.width  = desc->screen_width,
                          .height = desc->screen_height,
                          .pixels = screen};
 
-  iso->last_animation_time = 0.0;
-  iso->watermark           = memstack_watermark(&iso->stack);
+  gfx->last_animation_time = 0.0;
+  gfx->watermark           = memstack_watermark(&gfx->stack);
 
-  return iso;
+  return gfx;
 
 cleanup:
-  isogfx_del(&iso);
+  gfx2d_del(&gfx);
   return nullptr;
 }
 
-void isogfx_clear(IsoGfx* iso) {
-  assert(iso);
-  iso->last_animation_time = 0.0;
-  iso->next_tile           = 0;
-  iso->map                 = nullptr;
-  iso->tileset             = nullptr;
-  iso->head_sprite         = nullptr;
-  // The base of the stack contains the IsoGfx and the screen buffer. Make sure
+void gfx2d_clear(Gfx2d* gfx) {
+  assert(gfx);
+  gfx->last_animation_time = 0.0;
+  gfx->next_tile           = 0;
+  gfx->map                 = nullptr;
+  gfx->tileset             = nullptr;
+  gfx->head_sprite         = nullptr;
+  // The base of the stack contains the Gfx2d and the screen buffer. Make sure
   // we don't clear them.
-  memstack_set_watermark(&iso->stack, iso->watermark);
+  memstack_set_watermark(&gfx->stack, gfx->watermark);
 }
 
-void isogfx_del(IsoGfx** ppIso) {
-  assert(ppIso);
-  IsoGfx* iso = *ppIso;
-  if (iso) {
-    memstack_del(&iso->stack);
-    *ppIso = nullptr;
+void gfx2d_del(Gfx2d** ppGfx) {
+  assert(ppGfx);
+  Gfx2d* gfx = *ppGfx;
+  if (gfx) {
+    memstack_del(&gfx->stack);
+    *ppGfx = nullptr;
   }
 }
 
-void isogfx_make_world(IsoGfx* iso, const WorldDesc* desc) {
-  assert(iso);
+void gfx2d_make_map(Gfx2d* gfx, const MapDesc* desc) {
+  assert(gfx);
   assert(desc);
   assert(desc->tile_width > 0);
   assert(desc->tile_height > 0);
@@ -214,7 +241,7 @@ void isogfx_make_world(IsoGfx* iso, const WorldDesc* desc) {
   assert(desc->num_tiles > 0);
 
   // Handle recreation by destroying the previous world and sprites.
-  isogfx_clear(iso);
+  gfx2d_clear(gfx);
 
   const int    world_size     = desc->world_width * desc->world_height;
   const size_t map_size_bytes = sizeof(Tm_Map) + (world_size * sizeof(Tile));
@@ -229,43 +256,47 @@ void isogfx_make_world(IsoGfx* iso, const WorldDesc* desc) {
                                     (desc->num_tiles * sizeof(Ts_Tile)) +
                                     tile_data_size_bytes;
 
-  iso->map  = memstack_alloc_aligned(&iso->stack, map_size_bytes, 4);
-  *iso->map = (Tm_Map){
+  gfx->map  = memstack_alloc_aligned(&gfx->stack, map_size_bytes, 4);
+  *gfx->map = (Tm_Map){
       .world_width      = desc->world_width,
       .world_height     = desc->world_height,
       .base_tile_width  = desc->tile_width,
       .base_tile_height = desc->tile_height,
       .num_layers       = 1,
+      .flags =
+          (desc->orientation == MapOrthogonal) ? Tm_Orthogonal : Tm_Isometric,
   };
 
-  iso->tileset  = memstack_alloc_aligned(&iso->stack, tileset_size_bytes, 4);
-  *iso->tileset = (Ts_TileSet){
+  gfx->tileset  = memstack_alloc_aligned(&gfx->stack, tileset_size_bytes, 4);
+  *gfx->tileset = (Ts_TileSet){
       .num_tiles = desc->num_tiles,
   };
 
-  iso->iso_space = make_iso_coord_system(iso->map, &iso->screen);
+  gfx->iso_space = make_iso_coord_system(gfx->map, &gfx->screen);
 }
 
-bool isogfx_load_world(IsoGfx* iso, const char* filepath) {
-  assert(iso);
+bool gfx2d_load_map(Gfx2d* gfx, const char* filepath) {
+  assert(gfx);
   assert(filepath);
 
   bool success = false;
 
   // Handle recreation by destroying the previous world and sprites.
-  isogfx_clear(iso);
+  gfx2d_clear(gfx);
 
   // Load the map.
   printf("Load tile map: %s\n", filepath);
   WITH_FILE(filepath, {
     const size_t map_size = get_file_size_f(file);
-    iso->map              = memstack_alloc_aligned(&iso->stack, map_size, 4);
-    success               = read_file_f(file, iso->map);
+    gfx->map              = memstack_alloc_aligned(&gfx->stack, map_size, 4);
+    success               = read_file_f(file, gfx->map);
   });
   if (!success) {
     goto cleanup;
   }
-  Tm_Map* const map = iso->map;
+  Tm_Map* const map = gfx->map;
+
+  printf("Map orientation: %d\n", ((Tm_Flags*)&map->flags)->orientation);
 
   // Load the tile set.
   //
@@ -279,39 +310,39 @@ bool isogfx_load_world(IsoGfx* iso, const char* filepath) {
   printf("Load tile set: %s\n", ts_path_cwd);
   WITH_FILE(ts_path_cwd, {
     const size_t file_size = get_file_size_f(file);
-    iso->tileset           = memstack_alloc_aligned(&iso->stack, file_size, 4);
-    success                = read_file_f(file, iso->tileset);
+    gfx->tileset           = memstack_alloc_aligned(&gfx->stack, file_size, 4);
+    success                = read_file_f(file, gfx->tileset);
   });
   if (!success) {
     // TODO: Log errors using the log library.
     goto cleanup;
   }
-  const Ts_TileSet* const tileset = iso->tileset;
+  const Ts_TileSet* const tileset = gfx->tileset;
   printf("Loaded tile set (%u tiles): %s\n", tileset->num_tiles, ts_path_cwd);
 
   // TODO: These assertions on input data should be library runtime errors.
   assert(ts_validate_tileset(tileset));
   assert(tm_validate_map(map, tileset));
 
-  iso->iso_space = make_iso_coord_system(iso->map, &iso->screen);
+  gfx->iso_space = make_iso_coord_system(gfx->map, &gfx->screen);
 
   success = true;
 
 cleanup:
   if (!success) {
-    isogfx_clear(iso);
+    gfx2d_clear(gfx);
   }
   return success;
 }
 
-int isogfx_world_width(const IsoGfx* iso) {
-  assert(iso);
-  return iso->map->world_width;
+int gfx2d_world_width(const Gfx2d* gfx) {
+  assert(gfx);
+  return gfx->map->world_width;
 }
 
-int isogfx_world_height(const IsoGfx* iso) {
-  assert(iso);
-  return iso->map->world_height;
+int gfx2d_world_height(const Gfx2d* gfx) {
+  assert(gfx);
+  return gfx->map->world_height;
 }
 
 static void make_tile_from_colour(
@@ -339,19 +370,19 @@ static void make_tile_from_colour(
   }
 }
 
-Tile isogfx_make_tile(IsoGfx* iso, const TileDesc* desc) {
-  assert(iso);
+Tile gfx2d_make_tile(Gfx2d* gfx, const TileDesc* desc) {
+  assert(gfx);
   assert(desc);
   // Client must create a world first.
-  assert(iso->map);
-  assert(iso->tileset);
+  assert(gfx->map);
+  assert(gfx->tileset);
   // Currently, procedural tiles must match the base tile size.
-  assert(desc->width == iso->map->base_tile_width);
-  assert(desc->height == iso->map->base_tile_height);
+  assert(desc->width == gfx->map->base_tile_width);
+  assert(desc->height == gfx->map->base_tile_height);
   // Cannot exceed max tiles.
-  assert(iso->next_tile < iso->tileset->num_tiles);
+  assert(gfx->next_tile < gfx->tileset->num_tiles);
 
-  const Tile tile = iso->next_tile++;
+  const Tile tile = gfx->next_tile++;
 
   const size_t tile_size_bytes = desc->width * desc->height * sizeof(Pixel);
 
@@ -360,16 +391,16 @@ Tile isogfx_make_tile(IsoGfx* iso, const TileDesc* desc) {
     assert(desc->width > 0);
     assert(desc->height > 0);
 
-    Ts_Tile* const ts_tile = ts_tileset_get_tile_mut(iso->tileset, tile);
+    Ts_Tile* const ts_tile = ts_tileset_get_tile_mut(gfx->tileset, tile);
 
     *ts_tile = (Ts_Tile){
-        .width  = iso->map->base_tile_width,
-        .height = iso->map->base_tile_height,
+        .width  = gfx->map->base_tile_width,
+        .height = gfx->map->base_tile_height,
         .pixels = tile * tile_size_bytes,
     };
 
     Pixel* const tile_pixels =
-        ts_tileset_get_tile_pixels_mut(iso->tileset, tile);
+        ts_tileset_get_tile_pixels_mut(gfx->tileset, tile);
     make_tile_from_colour(desc->colour, ts_tile, tile_pixels);
     break;
   }
@@ -387,31 +418,31 @@ Tile isogfx_make_tile(IsoGfx* iso, const TileDesc* desc) {
   return tile;
 }
 
-void isogfx_set_tile(IsoGfx* iso, int x, int y, Tile tile) {
-  assert(iso);
+void gfx2d_set_tile(Gfx2d* gfx, int x, int y, Tile tile) {
+  assert(gfx);
 
-  Tm_Layer* const layer    = tm_map_get_layer_mut(iso->map, 0);
-  Tile*           map_tile = tm_layer_get_tile_mut(iso->map, layer, x, y);
+  Tm_Layer* const layer    = tm_map_get_layer_mut(gfx->map, 0);
+  Tile*           map_tile = tm_layer_get_tile_mut(gfx->map, layer, x, y);
 
   *map_tile = tile;
 }
 
-void isogfx_set_tiles(IsoGfx* iso, int x0, int y0, int x1, int y1, Tile tile) {
-  assert(iso);
+void gfx2d_set_tiles(Gfx2d* gfx, int x0, int y0, int x1, int y1, Tile tile) {
+  assert(gfx);
   for (int y = y0; y < y1; ++y) {
     for (int x = x0; x < x1; ++x) {
-      isogfx_set_tile(iso, x, y, tile);
+      gfx2d_set_tile(gfx, x, y, tile);
     }
   }
 }
 
-SpriteSheet isogfx_load_sprite_sheet(IsoGfx* iso, const char* filepath) {
-  assert(iso);
+SpriteSheet gfx2d_load_sprite_sheet(Gfx2d* gfx, const char* filepath) {
+  assert(gfx);
   assert(filepath);
 
   bool         success     = false;
   SpriteSheet  spriteSheet = 0;
-  const size_t watermark   = memstack_watermark(&iso->stack);
+  const size_t watermark   = memstack_watermark(&gfx->stack);
 
   // Load sprite sheet file.
   printf("Load sprite sheet: %s\n", filepath);
@@ -419,7 +450,7 @@ SpriteSheet isogfx_load_sprite_sheet(IsoGfx* iso, const char* filepath) {
   WITH_FILE(filepath, {
     const size_t file_size = get_file_size_f(file);
     ss_sheet =
-        memstack_alloc_aligned(&iso->stack, file_size, alignof(Ss_SpriteSheet));
+        memstack_alloc_aligned(&gfx->stack, file_size, alignof(Ss_SpriteSheet));
     success = read_file_f(file, ss_sheet);
   });
   if (!success) {
@@ -432,63 +463,63 @@ SpriteSheet isogfx_load_sprite_sheet(IsoGfx* iso, const char* filepath) {
 cleanup:
   if (!success) {
     if (ss_sheet) {
-      memstack_set_watermark(&iso->stack, watermark);
+      memstack_set_watermark(&gfx->stack, watermark);
     }
   }
   return spriteSheet;
 }
 
-Sprite isogfx_make_sprite(IsoGfx* iso, SpriteSheet sheet) {
-  assert(iso);
+Sprite gfx2d_make_sprite(Gfx2d* gfx, SpriteSheet sheet) {
+  assert(gfx);
   assert(sheet);
 
   // TODO: Remove memstack_alloc() and replace it with a same-name macro that
   //  calls memstack_alloc_aligned() with sizeof/alignof. No real point in
   //  having unaligned allocations.
   SpriteInstance* sprite = memstack_alloc_aligned(
-      &iso->stack, sizeof(SpriteInstance), alignof(SpriteInstance));
+      &gfx->stack, sizeof(SpriteInstance), alignof(SpriteInstance));
 
   sprite->sheet    = (const Ss_SpriteSheet*)sheet;
-  sprite->next     = iso->head_sprite;
-  iso->head_sprite = sprite;
+  sprite->next     = gfx->head_sprite;
+  gfx->head_sprite = sprite;
 
   return (Sprite)sprite;
 }
 
-void isogfx_set_sprite_position(IsoGfx* iso, Sprite hSprite, int x, int y) {
-  assert(iso);
+void gfx2d_set_sprite_position(Gfx2d* gfx, Sprite hSprite, int x, int y) {
+  assert(gfx);
   SpriteInstance* sprite = (SpriteInstance*)hSprite;
   sprite->position.x     = x;
   sprite->position.y     = y;
 }
 
-void isogfx_set_sprite_animation(IsoGfx* iso, Sprite hSprite, int animation) {
-  assert(iso);
+void gfx2d_set_sprite_animation(Gfx2d* gfx, Sprite hSprite, int animation) {
+  assert(gfx);
   SpriteInstance* sprite = (SpriteInstance*)hSprite;
   sprite->animation      = animation;
 }
 
-void isogfx_update(IsoGfx* iso, double t) {
-  assert(iso);
+void gfx2d_update(Gfx2d* gfx, double t) {
+  assert(gfx);
 
   // If this is the first time update() is called after initialization, just
   // record the starting animation time.
-  if (iso->last_animation_time == 0.0) {
-    iso->last_animation_time = t;
+  if (gfx->last_animation_time == 0.0) {
+    gfx->last_animation_time = t;
     return;
   }
 
-  if ((t - iso->last_animation_time) >= ANIMATION_UPDATE_DELTA) {
+  if ((t - gfx->last_animation_time) >= ANIMATION_UPDATE_DELTA) {
     // TODO: Consider linking animated sprites in a separate list so that we
     //  only walk over those here and not also the static sprites.
-    for (SpriteInstance* sprite = iso->head_sprite; sprite;
+    for (SpriteInstance* sprite = gfx->head_sprite; sprite;
          sprite                 = sprite->next) {
       const Ss_SpriteSheet* sheet = sprite->sheet;
       const Ss_Row* row = ss_get_sprite_sheet_row(sheet, sprite->animation);
       sprite->frame     = (sprite->frame + 1) % row->num_cols;
     }
 
-    iso->last_animation_time = t;
+    gfx->last_animation_time = t;
   }
 }
 
@@ -496,18 +527,6 @@ void isogfx_update(IsoGfx* iso, double t) {
 // Rendering and picking.
 // -----------------------------------------------------------------------------
 
-/// Get the screen position of the top diamond-corner of the tile at world
-/// (x,y).
-static ivec2 GetTileScreenOrigin(
-    const CoordSystem iso_space, ivec2 camera, int world_x, int world_y) {
-  const ivec2 vx_offset = ivec2_scale(iso_space.x, world_x);
-  const ivec2 vy_offset = ivec2_scale(iso_space.y, world_y);
-  const ivec2 screen_origin =
-      ivec2_add(iso_space.o, ivec2_add(vx_offset, vy_offset));
-  const ivec2 origin_view_space = ivec2_add(screen_origin, ivec2_neg(camera));
-  return origin_view_space;
-}
-
 static Pixel alpha_blend(Pixel src, Pixel dst) {
   if ((src.a == 255) || (dst.a == 0)) {
     return src;
@@ -539,6 +558,7 @@ static void draw_rect(
     Screen* screen, ivec2 top_left, int rect_width, int rect_height,
     const Pixel* pixels, const uint8_t* indices) {
   assert(screen);
+  assert(pixels);
 
 #define rect_pixel(X, Y) \
   (indices ? pixels[indices[Y * rect_width + X]] : pixels[Y * rect_width + X])
@@ -566,137 +586,237 @@ static void draw_rect(
   }
 }
 
-/// Draw a tile.
-///
-/// 'screen_origin' is the screen coordinates of the top diamond-corner of the
-/// tile (the base tile for super tiles).
-///     World (0, 0) -> (screen_width / 2, 0).
-static void draw_tile(IsoGfx* iso, ivec2 screen_origin, Tile tile) {
-  assert(iso);
-  assert(iso->tileset);
+/// Draw a tile in an orthogonal map.
+static void draw_tile_ortho(Gfx2d* gfx, Tile tile, int x, int y) {
+  assert(gfx);
+  assert(gfx->tileset);
+  assert(x >= 0);
+  assert(y >= 0);
+  assert(x < gfx->map->world_width);
+  assert(y < gfx->map->world_height);
+
+  const Ts_Tile* pTile  = ts_tileset_get_tile(gfx->tileset, tile);
+  const Pixel*   pixels = ts_tileset_get_tile_pixels(gfx->tileset, tile);
 
-  const Ts_Tile* pTile  = ts_tileset_get_tile(iso->tileset, tile);
-  const Pixel*   pixels = ts_tileset_get_tile_pixels(iso->tileset, tile);
+  const ivec2 screen_origin = map2screen(
+      gfx->camera, gfx->map->base_tile_width, gfx->map->base_tile_height, x, y);
+
+  draw_rect(
+      &gfx->screen, screen_origin, pTile->width, pTile->height, pixels,
+      nullptr);
+}
+
+/// Draw a tile in an isometric map.
+static void draw_tile_iso(Gfx2d* gfx, Tile tile, int iso_x, int iso_y) {
+  assert(gfx);
+  assert(gfx->tileset);
+  assert(iso_x >= 0);
+  assert(iso_y >= 0);
+  assert(iso_x < gfx->map->world_width);
+  assert(iso_y < gfx->map->world_height);
+
+  const Ts_Tile* pTile  = ts_tileset_get_tile(gfx->tileset, tile);
+  const Pixel*   pixels = ts_tileset_get_tile_pixels(gfx->tileset, tile);
+
+  // Compute the screen coordinates of the top diamond-corner of the tile (the
+  // base tile for super tiles).
+  //   World (0, 0) -> (screen_width / 2, 0).
+  const ivec2 screen_origin =
+      iso2cart(gfx->iso_space, gfx->camera, iso_x, iso_y);
 
   // Move from the top diamond-corner to the top-left corner of the tile image.
   // For regular tiles, tile height == base tile height, so the y offset is 0.
   // For super tiles, move as high up as the height of the tile.
   const ivec2 offset = {
-      -(iso->map->base_tile_width / 2),
-      pTile->height - iso->map->base_tile_height};
+      -(gfx->map->base_tile_width / 2),
+      pTile->height - gfx->map->base_tile_height};
   const ivec2 top_left = ivec2_add(screen_origin, offset);
 
   draw_rect(
-      &iso->screen, top_left, pTile->width, pTile->height, pixels, nullptr);
+      &gfx->screen, top_left, pTile->width, pTile->height, pixels, nullptr);
 }
 
-static void draw_world(IsoGfx* iso) {
-  assert(iso);
+static void draw_map_ortho(Gfx2d* gfx) {
+  assert(gfx);
+  assert(gfx->map);
+
+  // TODO: Same TODOs as in draw_map_iso().
+
+  const Tm_Layer* layer = tm_map_get_layer(gfx->map, 0);
 
-  const int W = iso->screen.width;
-  const int H = iso->screen.height;
+  for (int wy = 0; wy < gfx->map->world_height; ++wy) {
+    for (int wx = 0; wx < gfx->map->world_width; ++wx) {
+      const Tile tile = tm_layer_get_tile(gfx->map, layer, wx, wy);
+      draw_tile_ortho(gfx, tile, wx, wy);
+    }
+  }
+}
 
-  memset(iso->screen.pixels, 0, W * H * sizeof(Pixel));
+static void draw_map_iso(Gfx2d* gfx) {
+  assert(gfx);
+  assert(gfx->map);
 
-  const Tm_Layer* layer = tm_map_get_layer(iso->map, 0);
+  // TODO: Support for multiple layers.
+  const Tm_Layer* layer = tm_map_get_layer(gfx->map, 0);
 
   // TODO: Culling.
-  // Ex: map the screen corners to tile space to cull.
-  // Ex: walk in screen space and fetch the tile.
-  // The tile-centric approach might be more cache-friendly since the
-  // screen-centric approach would juggle multiple tiles throughout the scan.
-  for (int wy = 0; wy < iso->map->world_height; ++wy) {
-    for (int wx = 0; wx < iso->map->world_width; ++wx) {
-      const Tile  tile = tm_layer_get_tile(iso->map, layer, wx, wy);
-      const ivec2 screen_origin =
-          GetTileScreenOrigin(iso->iso_space, iso->camera, wx, wy);
-      draw_tile(iso, screen_origin, tile);
+  //  Ex: map the screen corners to tile space to cull.
+  //  Ex: walk in screen space and fetch the tile.
+  //  The tile-centric approach might be more cache-friendly since the
+  //  screen-centric approach would juggle multiple tiles throughout the scan.
+  for (int wy = 0; wy < gfx->map->world_height; ++wy) {
+    for (int wx = 0; wx < gfx->map->world_width; ++wx) {
+      const Tile tile = tm_layer_get_tile(gfx->map, layer, wx, wy);
+      draw_tile_iso(gfx, tile, wx, wy);
     }
   }
 }
 
-static void draw_sprite(
-    IsoGfx* iso, ivec2 origin, const SpriteInstance* sprite,
-    const Ss_SpriteSheet* sheet) {
-  assert(iso);
+static void draw_map(Gfx2d* gfx) {
+  assert(gfx);
+  assert(gfx->map);
+  assert(gfx->screen.pixels);
+
+  const int W = gfx->screen.width;
+  const int H = gfx->screen.height;
+
+  memset(gfx->screen.pixels, 0, W * H * sizeof(Pixel));
+
+  const Tm_Flags* flags = (const Tm_Flags*)&gfx->map->flags;
+  switch (flags->orientation) {
+  case Tm_Orthogonal:
+    draw_map_ortho(gfx);
+    break;
+  case Tm_Isometric:
+    draw_map_iso(gfx);
+    break;
+  }
+}
+
+/// Draw a sprite in an orthogonal/Cartesian coordinate system.
+static void draw_sprite_ortho(
+    Gfx2d* gfx, const SpriteInstance* sprite, const Ss_SpriteSheet* sheet) {
+  assert(gfx);
   assert(sprite);
   assert(sheet);
   assert(sprite->animation >= 0);
   assert(sprite->animation < sheet->num_rows);
   assert(sprite->frame >= 0);
 
+  // Apply an offset similarly to how we offset tiles. The sprite is offset by
+  // -base_tile_width/2 along the x-axis to align the sprite with the leftmost
+  // edge of the tile it is on.
+  const ivec2 screen_origin = map2screen(
+      gfx->camera, gfx->map->base_tile_width, gfx->map->base_tile_height,
+      sprite->position.x, sprite->position.y);
+
   const Ss_Row*  row   = ss_get_sprite_sheet_row(sheet, sprite->animation);
   const uint8_t* frame = ss_get_sprite_sheet_sprite(sheet, row, sprite->frame);
   draw_rect(
-      &iso->screen, origin, sheet->sprite_width, sheet->sprite_height,
+      &gfx->screen, screen_origin, sheet->sprite_width, sheet->sprite_height,
       sheet->palette.colours, frame);
 }
 
-static void draw_sprites(IsoGfx* iso) {
-  assert(iso);
+/// Draw a sprite in an isometric coordinate system.
+static void draw_sprite_iso(
+    Gfx2d* gfx, const SpriteInstance* sprite, const Ss_SpriteSheet* sheet) {
+  assert(gfx);
+  assert(sprite);
+  assert(sheet);
+  assert(sprite->animation >= 0);
+  assert(sprite->animation < sheet->num_rows);
+  assert(sprite->frame >= 0);
+
+  // Apply an offset similarly to how we offset tiles. The sprite is offset by
+  // -base_tile_width/2 along the x-axis to align the sprite with the leftmost
+  // edge of the tile it is on.
+  const ivec2 screen_origin = iso2cart(
+      gfx->iso_space, gfx->camera, sprite->position.x, sprite->position.y);
+  const ivec2 offset   = {-(gfx->map->base_tile_width / 2), 0};
+  const ivec2 top_left = ivec2_add(screen_origin, offset);
+
+  const Ss_Row*  row   = ss_get_sprite_sheet_row(sheet, sprite->animation);
+  const uint8_t* frame = ss_get_sprite_sheet_sprite(sheet, row, sprite->frame);
+  draw_rect(
+      &gfx->screen, top_left, sheet->sprite_width, sheet->sprite_height,
+      sheet->palette.colours, frame);
+}
 
-  for (const SpriteInstance* sprite = iso->head_sprite; sprite;
-       sprite                       = sprite->next) {
-    const Ss_SpriteSheet* sheet = sprite->sheet;
-    assert(sheet);
+static void draw_sprites(Gfx2d* gfx) {
+  assert(gfx);
+  assert(gfx->map);
 
-    const ivec2 screen_origin = GetTileScreenOrigin(
-        iso->iso_space, iso->camera, sprite->position.x, sprite->position.y);
-    draw_sprite(iso, screen_origin, sprite, sheet);
+  const Tm_Flags* flags = (const Tm_Flags*)&gfx->map->flags;
+  switch (flags->orientation) {
+  case Tm_Orthogonal:
+    for (const SpriteInstance* sprite = gfx->head_sprite; sprite;
+         sprite                       = sprite->next) {
+      draw_sprite_ortho(gfx, sprite, sprite->sheet);
+    }
+    break;
+  case Tm_Isometric:
+    for (const SpriteInstance* sprite = gfx->head_sprite; sprite;
+         sprite                       = sprite->next) {
+      draw_sprite_iso(gfx, sprite, sprite->sheet);
+    }
+    break;
   }
 }
 
-void isogfx_set_camera(IsoGfx* iso, int x, int y) {
-  assert(iso);
-  iso->camera = (ivec2){x, y};
+void gfx2d_set_camera(Gfx2d* gfx, int x, int y) {
+  assert(gfx);
+  gfx->camera = (ivec2){x, y};
 }
 
-void isogfx_render(IsoGfx* iso) {
-  assert(iso);
-  draw_world(iso);
-  draw_sprites(iso);
+void gfx2d_render(Gfx2d* gfx) {
+  assert(gfx);
+  draw_map(gfx);
+  draw_sprites(gfx);
 }
 
-void isogfx_draw_tile(IsoGfx* iso, int x, int y, Tile tile) {
-  assert(iso);
-  assert(x >= 0);
-  assert(y >= 0);
-  assert(x < iso->map->world_width);
-  assert(y < iso->map->world_height);
+void gfx2d_draw_tile(Gfx2d* gfx, int x, int y, Tile tile) {
+  assert(gfx);
+  assert(gfx->map);
 
-  const ivec2 screen_origin =
-      GetTileScreenOrigin(iso->iso_space, iso->camera, x, y);
-  draw_tile(iso, screen_origin, tile);
+  const Tm_Flags* flags = (const Tm_Flags*)&gfx->map->flags;
+  switch (flags->orientation) {
+  case Tm_Orthogonal:
+    draw_tile_ortho(gfx, tile, x, y);
+    break;
+  case Tm_Isometric:
+    draw_tile_iso(gfx, tile, x, y);
+    break;
+  }
 }
 
-void isogfx_get_screen_size(const IsoGfx* iso, int* width, int* height) {
-  assert(iso);
+void gfx2d_get_screen_size(const Gfx2d* gfx, int* width, int* height) {
+  assert(gfx);
   assert(width);
   assert(height);
-  *width  = iso->screen.width;
-  *height = iso->screen.height;
+  *width  = gfx->screen.width;
+  *height = gfx->screen.height;
 }
 
-const Pixel* isogfx_get_screen_buffer(const IsoGfx* iso) {
-  assert(iso);
-  return iso->screen.pixels;
+const Pixel* gfx2d_get_screen_buffer(const Gfx2d* gfx) {
+  assert(gfx);
+  return gfx->screen.pixels;
 }
 
-void isogfx_pick_tile(
-    const IsoGfx* iso, double xcart, double ycart, int* xiso, int* yiso) {
-  assert(iso);
+void gfx2d_pick_tile(
+    const Gfx2d* gfx, double xcart, double ycart, int* xiso, int* yiso) {
+  assert(gfx);
   assert(xiso);
   assert(yiso);
 
-  const vec2 camera  = ivec2_to_vec2(iso->camera);
+  const vec2 camera  = ivec2_to_vec2(gfx->camera);
   const vec2 xy_cart = vec2_add(camera, (vec2){xcart, ycart});
 
   const vec2 xy_iso = cart2iso(
-      xy_cart, iso->map->base_tile_width, iso->map->base_tile_height,
-      iso->screen.width);
+      xy_cart, gfx->map->base_tile_width, gfx->map->base_tile_height,
+      gfx->screen.width);
 
-  if ((0 <= xy_iso.x) && (xy_iso.x < iso->map->world_width) &&
-      (0 <= xy_iso.y) && (xy_iso.y < iso->map->world_height)) {
+  if ((0 <= xy_iso.x) && (xy_iso.x < gfx->map->world_width) &&
+      (0 <= xy_iso.y) && (xy_iso.y < gfx->map->world_height)) {
     *xiso = (int)xy_iso.x;
     *yiso = (int)xy_iso.y;
   } else {