Unity shader 初学 玻璃透明效果

Properties
	{
		_BumpMap("BumpMap",2D)="Bump"{}
		_CubeMap("CubeMap",Cube)=""{}

		_Dist("Dist",range(0,100))=0
		_Amount("Amount",range(0,1))=0

	}
	SubShader
	{
		Tags { "Queue"="Transparent" }

		GrabPass
		{
			"_GrabTex1"
		}

		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			
			#include "Lighting.cginc"

			sampler2D _BumpMap;
			float4 _BumpMap_ST;

			sampler2D _GrabTex1;
			float4 _GrabTex1_TexelSize;

			samplerCUBE _CubeMap;

			float _Dist;
			float _Amount;

			struct appdata
			{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
			};

			struct v2f
			{
				float4 vertex : SV_POSITION;
				float2 uv : TEXCOORD0;
				float3 tbn[3] : TEXCOORD1;
				float3 worldPos : TEXCOORD4;
				float4 scrPos : TEXCOORD5;
			};

			v2f vert (appdata_full v)
			{
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.uv = TRANSFORM_TEX(v.texcoord,_BumpMap);
				o.worldPos=mul(unity_ObjectToWorld,v.vertex).xyz;
				o.scrPos=ComputeGrabScreenPos(o.vertex);

				float3 worldNormal=UnityObjectToWorldNormal(v.normal);
				float3 worldTangent=UnityObjectToWorldNormal(v.tangent);
				float3 bitangent=cross(worldTangent,worldNormal);

				o.tbn[0]=worldTangent;
				o.tbn[1]=bitangent;
				o.tbn[2]=worldNormal;

				return o;
			}
			
			fixed4 frag (v2f i) : SV_Target
			{
				fixed3 worldViewDir=normalize(UnityWorldSpaceViewDir(i.worldPos));
				fixed3 bump=UnpackNormal(tex2D(_BumpMap,i.uv.xy));

				
				fixed2 offset=bump*_GrabTex1_TexelSize*_Dist;
				i.scrPos.xy=(offset+i.scrPos.xy)/i.scrPos.w;
				fixed3 refrColor=tex2D(_GrabTex1,i.scrPos.xy).rgb;

				bump=normalize(float3(i.tbn[0]*bump.r+i.tbn[1]*bump.g+i.tbn[2]*bump.b));
				fixed3 reflDir=reflect(-worldViewDir,bump);

				
				fixed3 reflColor=texCUBE(_CubeMap,reflDir).rgb;

				fixed3 color=lerp(reflColor,refrColor,_Amount);
				return fixed4(color,1.0);
			}


			ENDCG
		}
	}