unity3d：shader贴图局部改色相HSV+mask

//HSV空间转化
					half3 colorHSV = RGB2HSV(col);
					
					colorHSV.y *= _Saturability;
					colorHSV.z += _Lightness;

					half bias = 0.1;
					int maskIdx = (int)(step(bias, mask.b)
						+ step(bias, mask.g) * 2
						+ step(bias, mask.r) * 4);

					//colorHSV.x += GetHue(_listHue[maskIdx]);
					if (maskIdx == 0)
					{
						colorHSV.x += GetHue(_Hue0);
					}
					else if (maskIdx == 1)
					{
						colorHSV.x += GetHue(_Hue1);
					}

//HSV空间转化
					half3 colorRGB = HSV2RGB(colorHSV);
					fixed4 color = fixed4(colorRGB,col.a) * col.a;

					return fixed4(color.rgb,col.a);