1// --- subpixel sprites --- //
 2
 3struct SubpixelSprite {
 4    order: u32,
 5    pad: u32,
 6    bounds: Bounds,
 7    content_mask: Bounds,
 8    color: Hsla,
 9    tile: AtlasTile,
10    transformation: TransformationMatrix,
11}
12@group(1) @binding(0) var<storage, read> b_subpixel_sprites: array<SubpixelSprite>;
13
14struct SubpixelSpriteOutput {
15    @builtin(position) position: vec4<f32>,
16    @location(0) tile_position: vec2<f32>,
17    @location(1) @interpolate(flat) color: vec4<f32>,
18    @location(3) clip_distances: vec4<f32>,
19}
20
21struct SubpixelSpriteFragmentOutput {
22    @location(0) @blend_src(0) foreground: vec4<f32>,
23    @location(0) @blend_src(1) alpha: vec4<f32>,
24}
25
26@vertex
27fn vs_subpixel_sprite(@builtin(vertex_index) vertex_id: u32, @builtin(instance_index) instance_id: u32) -> SubpixelSpriteOutput {
28    let unit_vertex = vec2<f32>(f32(vertex_id & 1u), 0.5 * f32(vertex_id & 2u));
29    let sprite = b_subpixel_sprites[instance_id];
30
31    var out = SubpixelSpriteOutput();
32    out.position = to_device_position_transformed(unit_vertex, sprite.bounds, sprite.transformation);
33    out.tile_position = to_tile_position(unit_vertex, sprite.tile);
34    out.color = hsla_to_rgba(sprite.color);
35    out.clip_distances = distance_from_clip_rect_transformed(unit_vertex, sprite.bounds, sprite.content_mask, sprite.transformation);
36    return out;
37}
38
39@fragment
40fn fs_subpixel_sprite(input: SubpixelSpriteOutput) -> SubpixelSpriteFragmentOutput {
41    let sample = textureSample(t_sprite, s_sprite, input.tile_position).rgb;
42    let alpha_corrected = apply_contrast_and_gamma_correction3(sample, input.color.rgb, gamma_params.subpixel_enhanced_contrast, gamma_params.gamma_ratios);
43
44    // Alpha clip after using the derivatives.
45    if (any(input.clip_distances < vec4<f32>(0.0))) {
46        return SubpixelSpriteFragmentOutput(vec4<f32>(0.0), vec4<f32>(0.0));
47    }
48
49    var out = SubpixelSpriteFragmentOutput();
50    out.foreground = vec4<f32>(input.color.rgb, 1.0);
51    out.alpha = vec4<f32>(input.color.a * alpha_corrected, 1.0);
52    return out;
53}