Shader "Custom/ViewPortTexture"
{
	Properties
	{
		_Mask ("Culling Mask", 2D) = "black" {}
		_MaskLevel ("Mask Alpha", Range(0, 1)) = 0.5
	}
	SubShader
	{
		Tags {"Queue" = "Background"}
		Blend SrcAlpha OneMinusSrcAlpha
		Lighting Off
		ZWrite On
		ZTest Always
		Alphatest LEqual [_MaskLevel]
		Pass
		{
			SetTexture [_Mask] {combine texture}
		}
	}
}
一個用作 Camera Mask 的 Shader. 😀

