kernel ColorQuantization
<   nameSpace : "your namespace";
    vendor : "your vendor";
    version : 1;
    description : "your description";
>
{
    parameter float3 levels
    <
        minValue: float3(0.0,0.0,0.0);
        maxValue: float3(256.0,256.0,256.0);
        defaultValue: float3(6.0,6.0,6.0);
    >;
    
    void evaluatePixel(in image3 source, out pixel3 result)
    {
        pixel3 color = sampleLinear(source,outCoord());
        
        
        result = color - mod(color, float3(1.0,1.0,1.0) / levels);///float3(512.0,512.0,512.0);;
    }
}