Runtime target textures seem to need to be the same format as the canvas current texture. Requires additional investigation.

Created a computeToTexture shader to experiment with writing directly to textures as a means of performing post processing.

shaders/wgsl/computeToTexture.wgsl

@@ -0,0 +1,23 @@
+[[block]] struct Time {
+	seconds : f32;
+	frames : i32;
+};
+
+[[group(0), binding(0)]] var textureSampler : sampler;
+[[group(0), binding(1)]] var inputTex : texture_2d<f32>;
+[[group(0), binding(2)]] var outputTex : texture_storage_2d<rgba8unorm, write>;
+
+// Compute shader
+
+[[stage(compute), workgroup_size(32, 1, 1)]] fn computeMain([[builtin(global_invocation_id)]] id : vec3<u32>) {
+	var row = i32(id.y);
+	var column = i32(id.x);
+
+	if (column >= i32(textureDimensions(inputTex).x)) {
+		return;
+	}
+
+	var color = textureSampleLevel(inputTex, textureSampler, vec2<f32>(f32(column), f32(row)), 0.0);
+	color.g = color.r;
+	textureStore(outputTex, vec2<i32>(column, row), color);
+}

shaders/wgsl/renderToCanvas.wgsl

@@ -13,5 +13,5 @@ struct VertOutput {
 }
 
 [[stage(fragment)]] fn fragMain(input : VertOutput) -> [[location(0)]] vec4<f32> {
-	return textureSample(inputTexture, inputSampler, input.uv);
+	return textureSample(inputTexture, inputSampler, vec2<f32>(input.uv.x, 1.0 - input.uv.y));
 }