Blender:FeatherY

FeatherY.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).r;

//最终Alpha
float EndAlpha=CurrentAlpha;

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

//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(uv.x,clamp(StartUV.y+i/TexSize.y,0,1));
	EndAlpha+=Texture2DSample(Tex,TexSampler,NewUV).r;
}

EndAlpha/=(2*PixelSize+1);

return EndAlpha;