Apply stronger penalty when luma is distorted

Author: Aikku93

Quantize.c

@@ -15,6 +15,7 @@ static inline void QuantCluster_Train(struct QuantCluster_t *Dst, const struct B
 	struct BGRAf_t Dist = BGRAf_Sub(Data, &Dst->Centroid);
 
 	float DistW  = BGRAf_Len2(&Dist);
+	DistW *= 1.0f + fabsf(Dist.b); //! <- Further penalize distortion by luma distortion
 	float TrainW = 0.001f + DistW; //! <- This will help outliers pop out more often (must not be 0.0!)
 	struct BGRAf_t TrainData = BGRAf_Muli( Data, TrainW);
 	struct BGRAf_t DistData  = BGRAf_Muli(&Dist, DistW);