fix: remove slight offset when cards were rendered

Fixed by updating version of seizer to one that doesn't offset the canvas
projection.

build.zig

@@ -44,6 +44,7 @@ pub fn build(b: *std.Build) void {
         .target = target,
         .optimize = optimize,
     });
+    exe_unit_tests.root_module.addImport("seizer", seizer.module("seizer"));
 
     const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests);
 

build.zig.zon

@@ -16,8 +16,8 @@
     // internet connectivity.
     .dependencies = .{
         .seizer = .{
-            .url = "https://github.com/leroycep/seizer/archive/dd1f9f6c94e91edfd96f0075c5f5d33aa30758f4.tar.gz",
-            .hash = "122009caed9e40d713c847b24c2abf8540299e32fb5e77f73ab2acdf5c27bc3e4c90",
+            .url = "https://github.com/leroycep/seizer/archive/8fdc6335641614c1cd844d1ecd5ad937584a443e.tar.gz",
+            .hash = "1220b6f9d0aba788b55a3e26a34ca9793495fbdb062c463cef1433ff937b96aa77d6",
         },
     },
     .paths = .{

src/assets.zig

@@ -48,9 +48,7 @@ pub const TileSheet = struct {
         this.texture.deinit();
     }
 
-    pub fn renderTile(this: @This(), canvas: *seizer.Canvas, tile_id: u32, pos: [2]f32, options: struct {
-        size: ?[2]f32 = null,
-    }) void {
+    pub fn uvCoordinatesFromTileId(this: @This(), tile_id: u32) seizer.geometry.AABB(f32) {
         const texture_sizef = [2]f32{
             @floatFromInt(this.texture.size[0]),
             @floatFromInt(this.texture.size[1]),
@@ -85,7 +83,7 @@ pub const TileSheet = struct {
             pos_in_tilesf[0] * tile_stridef[0] + tile_offsetf[0],
             pos_in_tilesf[1] * tile_stridef[1] + tile_offsetf[1],
         };
-        const uv = seizer.geometry.AABB(f32){
+        return seizer.geometry.AABB(f32){
             .min = .{
                 pixel_pos[0] / texture_sizef[0],
                 pixel_pos[1] / texture_sizef[1],
@@ -95,14 +93,43 @@ pub const TileSheet = struct {
                 (pixel_pos[1] + tile_sizef[1]) / texture_sizef[1],
             },
         };
+    }
 
-        canvas.rect(pos, options.size orelse tile_sizef, .{
+    pub fn renderTile(this: @This(), canvas: *seizer.Canvas, tile_id: u32, pos: [2]f32, options: struct {
+        size: ?[2]f32 = null,
+    }) void {
+        const uv = this.uvCoordinatesFromTileId(tile_id);
+
+        canvas.rect(pos, options.size orelse [2]f32{ @floatFromInt(this.tile_size[0]), @floatFromInt(this.tile_size[1]) }, .{
             .texture = this.texture.glTexture,
             .uv = uv,
         });
     }
 };
 
+test "tilesheet math is exact" {
+    const tilesheet = TileSheet{
+        .texture = .{
+            .glTexture = undefined,
+            .size = .{ 494, 329 },
+        },
+        .tile_offset = .{ 6, 2 },
+        .tile_size = .{ 20, 29 },
+        .tile_stride = .{ 33, 33 },
+    };
+
+    try std.testing.expectEqualDeep(seizer.geometry.AABB(f32){
+        .min = .{
+            468.0 / 494.0,
+            35.0 / 329.0,
+        },
+        .max = .{
+            (468.0 + 20.0) / 494.0,
+            (35.0 + 29.0) / 329.0,
+        },
+    }, tilesheet.uvCoordinatesFromTileId(29));
+}
+
 /// A texture with a regular grid of sprites
 pub const DeckSprites = struct {
     tilesheet: TileSheet,

src/main.zig

@@ -905,7 +905,7 @@ pub const CardElement = struct {
             .card => |card| render_resources.deck.tilesheet.renderTile(
                 canvas,
                 render_resources.deck.getTileForCard(card),
-                .{ min[0] + mark_offset[0], min[1] + mark_offset[1] },
+                .{ @floor(min[0] + mark_offset[0]), @floor(min[1] + mark_offset[1]) },
                 .{},
             ),
         }
@@ -1196,6 +1196,10 @@ fn glfw_key_callback(window: ?*seizer.backend.glfw.c.GLFWwindow, key: c_int, sca
     }
 }
 
+test {
+    _ = @import("./assets.zig");
+}
+
 const DeckSprites = assets.DeckSprites;
 const Card = assets.Card;