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unity-shader-tutorial-grabPass

Posted on Edited on

buildin效果图

urp效果图

GrabPass.shader

GrabPass.shader
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Shader "HHF/Tutorial/GrabPass"
{
    SubShader
    {
        Tags { "Queue"="Transparent" "RenderPipeline" = "UniversalPipeline" }
        Cull Off

        Pass
        {
            HLSLPROGRAM
            // Required to compile gles 2.0 with standard srp library
            #pragma prefer_hlslcc gles
            #pragma exclude_renderers d3d11_9x
            #pragma vertex vert
            #pragma fragment frag
            #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"

            struct appdata
            {
                float4 vertex : POSITION;
            };

            struct v2f
            {
                float4 positionCS : SV_POSITION;
                float4 positionSS : TEXCOORD0;
            };

            CBUFFER_START(UnityPerMaterial)
         
            CBUFFER_END

            // #define REQUIRE_OPAQUE_TEXTURE
            TEXTURE2D(_CameraOpaqueTexture);SAMPLER(sampler_CameraOpaqueTexture);

            v2f vert(appdata v)
            {
                v2f o = (v2f)0;

                o.positionCS = TransformObjectToHClip(v.vertex.xyz);
                o.positionSS = ComputeScreenPos(o.positionCS);
                return o;
            }

            half4 frag(v2f i) : SV_Target
            {
                // 采样抓屏图
                // float2 screenUV = i.positionSS.xy / i.positionSS.w;
                float2 screenUV = i.positionCS.xy / _ScreenParams.xy;
                half4 opaqueTex = SAMPLE_TEXTURE2D(_CameraOpaqueTexture, sampler_CameraOpaqueTexture, screenUV);
                // half3 opaqueTex = SampleSceneColor(screenUV);
                
                return 1 - opaqueTex;
            }

            ENDHLSL
        }
    }

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

        GrabPass { "_GrabPassTexture" }

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

            struct appdata
            {
                float4 vertex : POSITION;
            };

            struct v2f
            {
                float4 positionCS : SV_POSITION;
                float4 positionSS : TEXCOORD0; 
            };

            sampler2D _GrabPassTexture;

            v2f vert(appdata v)
            {
                v2f o = (v2f)0;

                o.positionCS = UnityObjectToClipPos(v.vertex.xyz);
                o.positionSS = ComputeScreenPos(o.positionCS);
                return o;
            }

            half4 frag(v2f i) : SV_Target
            {
                // 采样抓屏图
                // float2 screenUV = i.positionSS.xy / i.positionSS.w;
                float2 screenUV = i.positionCS.xy / _ScreenParams.xy;
                half4 opaqueTex = tex2D(_GrabPassTexture, screenUV);
                
               return 1 - opaqueTex;
            }

            ENDCG
        }
    }
}