sampler RT : register(s0);

float4 Posterize_ps (float2 iTexCoord : TEXCOORD0) : COLOR
{

	float nColors = 8;
	float gamma = 0.6;

	float4 texCol = tex2D(RT, iTexCoord);
	float3 tc = texCol.xyz;
	tc = pow(tc, gamma);
	tc = tc * nColors;
	tc = floor(tc);
	tc = tc / nColors;
	tc = pow(tc,1.0/gamma);
	return float4(tc,texCol.w);
}