Vector4 val = valueRGBA(u, v);
return (val.x+val.y+val.z)*(1.0f/3.0f);
}
protected Vector4 _valueRGBA(float u, float v) {
Vector4 c0 = inputChannels[0].valueRGBA(u, v);
Vector4 c1 = inputChannels[1].valueRGBA(u, v);
Vector4 c2 = inputChannels[2].valueRGBA(u, v);
Vector4 ret = new Vector4();
_function(ret, c0, c1, c2);
return ret;
}