source: data/branches/Shader_HS18/programs/Cg/BrightBloom2_ps20.cg @ 12206

//-------------------------------
//BrightBloom_ps20.cg
// High-pass filter for obtaining lumminance
// We use an aproximation formula that is pretty fast:
//   f(x) = ( -3 * ( x - 1 )^2 + 1 ) * 2
//   Color += f(Color)
//-------------------------------

float4 main(float2 texCoord: TEXCOORD0,
                uniform sampler RT: register(s0)
                ) : COLOR {
        float4 tex = tex2D(RT,   texCoord);

        tex -= 1;
        float4 bright4= -6 * tex * tex + 2; //float4 bright4= ( -3 * tex * tex + 1 ) * 2;
        float bright = dot( bright4, float4( 0.333333, 0.333333, 0.333333, 0) );
        tex += bright + 0.6;

        return tex;
}