#pragma kernel VolBlurX VolBlur=VolBlurX 
#pragma kernel VolBlurY VolBlur=VolBlurY VERTICAL_PASS

#define TapSamples 2
//#define SIGMA_FILTER 1


RWTexture3D<float4> Result;
Texture3D<float4> InTex;

static float KernelLUT[3] = {0.38774, 0.24477, 0.06136};

//Gaussian dispubution baked as a LUT. SIGMA = 2 http://dev.theomader.com/gaussian-kernel-calculator/
//static float KernelLUT[5] = { 0.20236, 0.179044, 0.124009, 0.067234, 0.028532 };

//float Gaussian(float radius, float sigma)
//{
//    float v = radius / sigma;
//    return exp(-(v * v));
//}

//float GaussianLUT(int currentKernal) 
//{
//    return KernelLUT[currentKernal];
//}

[numthreads(4,4,4)]
void VolBlur (uint3 id : SV_DispatchThreadID)
{    

    float4 sum = float4(0, 0, 0, 0);

   // [unroll(TapSamples*2 + 1)] //Unroll all potential samples
    for (int i = -TapSamples; i < TapSamples; i++) {

#if VERTICAL_PASS
        int3 ids = uint3(id.x, id.y + i, id.z);
#else
        int3 ids = uint3(id.x + i, id.y, id.z);
#endif
    //    float weight = GaussianLUT( abs(i) );

        sum += InTex[ids].rgba * KernelLUT[abs(i)];
    }
    Result[id.xyz] = sum;
}