1 files changed, 27 insertions, 0 deletions
diff --git a/assets/common/shaders/compute/gen_mask.wgsl b/assets/common/shaders/compute/gen_mask.wgsl
new file mode 100644
index 0000000..1ce9f52
--- /dev/null
+++ b/assets/common/shaders/compute/gen_mask.wgsl
@@ -0,0 +1,27 @@
+// This file is part of the 64k demo project.
+// GPU composite shader: Multiply texture A by texture B (masking).
+
+struct MaskParams {
+  width: u32,
+  height: u32,
+}
+
+@group(0) @binding(0) var output_tex: texture_storage_2d<rgba8unorm, write>;
+@group(0) @binding(1) var<uniform> params: MaskParams;
+@group(0) @binding(2) var input_a: texture_2d<f32>;
+@group(0) @binding(3) var input_b: texture_2d<f32>;
+@group(0) @binding(4) var tex_sampler: sampler;
+
+@compute @workgroup_size(8, 8, 1)
+fn main(@builtin(global_invocation_id) id: vec3<u32>) {
+  if (id.x >= params.width || id.y >= params.height) { return; }
+
+  let uv = vec2<f32>(f32(id.x) / f32(params.width),
+                      f32(id.y) / f32(params.height));
+
+  let color_a = textureSampleLevel(input_a, tex_sampler, uv, 0.0);
+  let mask_b = textureSampleLevel(input_b, tex_sampler, uv, 0.0);
+  let masked = color_a * mask_b;
+
+  textureStore(output_tex, id.xy, masked);
+}