static const float PI2 = 3.14159265359f * 2;
int CDIndex = 13;
int CSIndex = 24;


Steps = clamp(floor(Steps), 1, 128);
RadialSteps = clamp(floor(RadialSteps), 1, 128);

float stepSize = Radius / Steps;
float radialStepSize = PI2 / RadialSteps;

float result = 0.0f;
float stencil = 0.0f;

for (int i = 1; i <= Steps; ++i)
{
    float currStep = i * stepSize;

    for (int j = 0; j < RadialSteps; ++j)
    {
        float angle = j * radialStepSize;
        float2 coord = float2(cos(angle), sin(angle)) * currStep + ViewportUVToSceneTextureUV(UV,14);
        float sample = SceneTextureLookup(coord, CDIndex, false);
        result += (MaxDistance - clamp(sample, 0, MaxDistance)) / MaxDistance;

        stencil = max(stencil, SceneTextureLookup(coord, CSIndex, false));
    }
}

return float2(result / (RadialSteps * Steps), stencil);