Texture2D Diffuse	: register(t0);
Texture2D Specular	: register(t1);
Texture2D Ambient	: register(t2);

RWTexture2D<float4> Output;

cbuffer Size : register(b0)
{
	int2 Pixels;
}

#define AmbFactor 0.8f;

[numthreads(16, 16, 1)]
void main( uint3 DTid : SV_DispatchThreadID )
{
	float4 Light = Diffuse[DTid.xy] + saturate(Specular[DTid.xy]);
	float4 Amb = float4(Ambient[DTid.xy/2].xyz * Ambient[DTid.xy/2].w, 0);
	float4 GUI;
	uint2 index = DTid.xy/2 + int2(Pixels.x/2,0);
	float3 PostLight = Amb.xyz * AmbFactor;
	PostLight = PostLight + Light.xyz;
	GUI = float4(Ambient[index]);
	PostLight = PostLight * (1 - GUI.w);
	Output[DTid.xy] = float4((GUI.xyz * GUI.w) + PostLight, 1);
}