From 17d7532c796eced679e7e234c4e6dc7546045c22 Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Thu, 4 Sep 2025 19:02:21 -0700
Subject: Add support for ortho sprite rendering. Now tested.

---
 src/gfx2d.c | 45 +++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 41 insertions(+), 4 deletions(-)

diff --git a/src/gfx2d.c b/src/gfx2d.c
index 6630c95..698e32c 100644
--- a/src/gfx2d.c
+++ b/src/gfx2d.c
@@ -690,7 +690,32 @@ static void draw_map(IsoGfx* iso) {
   }
 }
 
-static void draw_sprite(
+/// Draw a sprite in an orthogonal/Cartesian coordinate system.
+static void draw_sprite_ortho(
+    IsoGfx* iso, const SpriteInstance* sprite, const Ss_SpriteSheet* sheet) {
+  assert(iso);
+  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(
+      iso->camera, iso->map->base_tile_width, iso->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, screen_origin, sheet->sprite_width, sheet->sprite_height,
+      sheet->palette.colours, frame);
+}
+
+/// Draw a sprite in an isometric coordinate system.
+static void draw_sprite_iso(
     IsoGfx* iso, const SpriteInstance* sprite, const Ss_SpriteSheet* sheet) {
   assert(iso);
   assert(sprite);
@@ -716,10 +741,22 @@ static void draw_sprite(
 
 static void draw_sprites(IsoGfx* iso) {
   assert(iso);
+  assert(iso->map);
 
-  for (const SpriteInstance* sprite = iso->head_sprite; sprite;
-       sprite                       = sprite->next) {
-    draw_sprite(iso, sprite, sprite->sheet);
+  const Tm_Flags* flags = (const Tm_Flags*)&iso->map->flags;
+  switch (flags->orientation) {
+  case Tm_Orthogonal:
+    for (const SpriteInstance* sprite = iso->head_sprite; sprite;
+         sprite                       = sprite->next) {
+      draw_sprite_ortho(iso, sprite, sprite->sheet);
+    }
+    break;
+  case Tm_Isometric:
+    for (const SpriteInstance* sprite = iso->head_sprite; sprite;
+         sprite                       = sprite->next) {
+      draw_sprite_iso(iso, sprite, sprite->sheet);
+    }
+    break;
   }
 }
 
-- 
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