Unity shader学习之Grab Pass实现玻璃效果

GrabPass可将当前屏幕的图像绘制在一张纹理中，可用来实现玻璃效果。

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shader如下：

// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Custom/Glass"
{Properties{_NormalMap("Normal Map", 2D) = "bump" {}_Distortion("Distortion", Range(0, 100)) = 50}SubShader{Tags{"Queue" = "Transparent""RenderType" = "Transparent"}GrabPass { "_GrabTex" }Pass{CGPROGRAM#pragma vertex vert#pragma fragment frag#include "UnityCG.cginc"sampler2D _GrabTex;float4 _GrabTex_TexelSize;sampler2D _NormalMap;float _Distortion;struct appdata{float4 vertex : POSITION;float2 uv : TEXCOORD0;};struct v2f{float4 pos : SV_POSITION;float2 uv : TEXCOORD0;float4 scrPos : TEXCOORD1;};v2f vert(appdata v){v2f o;o.pos = UnityObjectToClipPos(v.vertex);o.uv = v.uv;o.scrPos = ComputeGrabScreenPos(o.pos);return o;}fixed4 frag(v2f i) : SV_TARGET{float3 bump = UnpackNormal(tex2D(_NormalMap, i.uv));float2 offset = bump.xy * _GrabTex_TexelSize.xy * _Distortion;fixed4 albedo = tex2D(_GrabTex, (i.scrPos.xy + offset) / i.scrPos.w);return albedo;}ENDCG}}
}

效果如下：