BlenderFeatherX

FeatherX.usf

//思路

//1.0 当前像素Alpha值>0
//2.0 横向羽化；
	//2.1 做好uv范围限制
//参数需要
//1.羽化像素个数；
//2.图片像素

//图片尺寸
float2 TexSize=0;
Tex.GetDimensions(TexSize.x, TexSize.y);


//临界Alpha
float InEdgeAlpha=clamp(EdgeAlpha,0,1);
//
float CurrentAlpha=Texture2DSample(Tex,TexSampler,uv).a;

//最终Alpha
float EndAlpha=CurrentAlpha;

//启示UV值
float2 StartUV=float2(clamp(uv.x-PixelSize/TexSize.x,0,1),uv.y);

//当前ALpha如果小于边缘alpha，则返回初始值，不做变化
if (CurrentAlpha<=InEdgeAlpha)
{
	return CurrentAlpha;
}
if (PixelSize<1)
{
	return CurrentAlpha;
}

EndAlpha=CurrentAlpha;
[unroll(17)]for (int i = 1; i < 2*PixelSize+1; i++)
{
	float2 NewUV=float2(clamp(StartUV.x+i/TexSize.x,0,1),uv.y);
	EndAlpha+=Texture2DSample(Tex,TexSampler,NewUV).a;
}

EndAlpha/=(2*PixelSize+1);

return EndAlpha;