[[group(0), binding(0)]] var linearSampler : sampler;
[[group(0), binding(1)]] var tex : texture_2d<f32>;
[[group(0), binding(2)]] var bloomTex : texture_2d<f32>;
[[group(0), binding(3)]] var backgroundTex : texture_2d<f32>;

struct VertOutput {
	[[builtin(position)]] Position : vec4<f32>;
	[[location(0)]] uv : vec2<f32>;
};

[[stage(vertex)]] fn vertMain([[builtin(vertex_index)]] index : u32) -> VertOutput {
	var uv = vec2<f32>(f32(index % 2u), f32((index + 1u) % 6u / 3u));
	var position = vec4<f32>(uv * 2.0 - 1.0, 1.0, 1.0);
	return VertOutput(position, uv);
}

[[stage(fragment)]] fn fragMain(input : VertOutput) -> [[location(0)]] vec4<f32> {

	var uv = input.uv;
	uv.y = 1.0 - uv.y;

	var bgColor = textureSample( backgroundTex, linearSampler, uv ).rgb;

	// Combine the texture and bloom, then blow it out to reveal more of the image
	var brightness = min(1.0, textureSample( tex, linearSampler, uv ).r * 2.0);
	brightness = brightness + textureSample( bloomTex, linearSampler, uv ).r;
	brightness = pow(brightness, 1.5);

	return vec4<f32>(bgColor * brightness, 1.0);
}