Created a pass-through post processing compute pass. The other post-processing passes will be changed over to this kind of thing.

makePassFBO has now been split into makeRenderTarget and makeComputeTarget.

shaders/wgsl/postProcessingPass.wgsl

@@ -0,0 +1,66 @@
+[[block]] struct Config {
+	foo : i32;
+};
+
+// The properties that change over time get their own buffer.
+[[block]] struct Time {
+	seconds : f32;
+	frames : i32;
+};
+
+[[group(0), binding(0)]] var<uniform> config : Config;
+[[group(0), binding(1)]] var<uniform> time : Time;
+
+[[group(0), binding(2)]] var inputTex : texture_2d<f32>;
+[[group(0), binding(3)]] var outputTex : texture_storage_2d<rgba8unorm, write>;
+
+// Shader params
+
+struct ComputeInput {
+	[[builtin(global_invocation_id)]] id : vec3<u32>;
+};
+
+// Constants
+
+let NUM_VERTICES_PER_QUAD : i32 = 6; // 2 * 3
+let PI : f32 = 3.14159265359;
+let TWO_PI : f32 = 6.28318530718;
+let SQRT_2 : f32 = 1.4142135623730951;
+let SQRT_5 : f32 = 2.23606797749979;
+
+// Helper functions for generating randomness, borrowed from elsewhere
+
+fn randomFloat( uv : vec2<f32> ) -> f32 {
+	let a = 12.9898;
+	let b = 78.233;
+	let c = 43758.5453;
+	let dt = dot( uv, vec2<f32>( a, b ) );
+	let sn = dt % PI;
+	return fract(sin(sn) * c);
+}
+
+fn randomVec2( uv : vec2<f32> ) -> vec2<f32> {
+	return fract(vec2<f32>(sin(uv.x * 591.32 + uv.y * 154.077), cos(uv.x * 391.32 + uv.y * 49.077)));
+}
+
+fn wobble(x : f32) -> f32 {
+	return x + 0.3 * sin(SQRT_2 * x) + 0.2 * sin(SQRT_5 * x);
+}
+
+[[stage(compute), workgroup_size(32, 1, 1)]] fn computeMain(input : ComputeInput) {
+
+	// Resolve the invocation ID to a single cell
+	var coord = vec2<i32>(input.id.xy);
+	var screenSize = textureDimensions(inputTex);
+
+	if (coord.x >= screenSize.x) {
+		return;
+	}
+
+	var foo = config.foo;
+	var seconds = time.seconds;
+
+	var inputColor = textureLoad(inputTex, coord, 0);
+	var outputColor = inputColor;
+	textureStore(outputTex, coord, outputColor);
+}