Added simple post-processing.

assets/shaders/glsl/post_process.comp

@@ -0,0 +1,19 @@
+#version 460
+
+layout(local_size_x = 16, local_size_y = 16, local_size_x = 1) in;
+
+layout(set = 0, binding = 0, rgba8) uniform readonly image2D u_sourceImage;
+layout(set = 1, binding = 0, rgba8) uniform writeonly image2D u_targetImage;
+
+float luma(vec4 color)
+{
+    return dot(color.rgb, vec3(0.299, 0.587, 0.114));
+}
+
+void main()
+{
+    const ivec2 uv = ivec2(gl_GlobalInvocationID.xy);
+    const vec4 pixel = imageLoad(u_sourceImage, uv);
+    const float lum = luma(pixel);
+    imageStore(u_targetImage, uv, vec4(lum, lum, lum, 1.0));
+}