UE4 圆角矩形材质

 https://gist.github.com/CoderJackLiu/dfe206bfec0bb6c694daa5299d50cd79
https://www.bilibili.com/video/BV1Cq4y1A7P1?p=1&vd_source=8fa6b6117b9aadb7a238a8d563f80d0c

//圆角
	float2 UV = uvs;
	float PixelRange = min(min(SizeX/2,SizeY/2),Range);
	//当前绘制的像素
	float2 CurrentP = float2(UV.x*SizeX,UV.y*SizeY);
	//像素坐标参照点
	//float2 MiddleP=float2(0.5*SizeX,0.5*SizeY);
	//左上角圆心像素坐标
	float2 MP1=float2(PixelRange , PixelRange);
	//右上角圆心像素坐标
	float2 MP2=float2(SizeX - PixelRange , PixelRange);
	//左下角圆心像素坐标
	float2 MP3=float2(PixelRange , SizeY - PixelRange);
	//右下角圆心像素坐标
	float2 MP4=float2(SizeX - PixelRange , SizeY - PixelRange);
	if (CurrentP.x<MP1.x&&CurrentP.y<MP1.y)
	{
	/* 左上角 */
	if (length((CurrentP-MP1))<PixelRange)
	{
	/* code */
	return 1;
	}
	return 0;
	}else if (CurrentP.x>MP2.x&&CurrentP.y<MP2.y)
	{
	/* 右上角 */
	if (length((CurrentP-MP2))<PixelRange)
	{
	/* code */
	return 1;
	}
	return 0;
	}else if (CurrentP.x<MP3.x&&CurrentP.y>MP3.y)
	{
	/* 左下角 */
	if (length((CurrentP-MP3))<PixelRange)
	{
	/* code */
	return 1;
	}
	return 0;
	}else if (CurrentP.x>MP4.x&&CurrentP.y>MP4.y)
	{
	/* 右下角 */
	if (length((CurrentP-MP4))<PixelRange)
	{
	/* code */
	return 1;
	}
	return 0;
	}
	return 1;