[2023.3][URP] Fixing decals not affecting grass when using Deferred R…

…endering (UUM-21928)

Fixes UUM-21928 by adding GBuffer passes to the Grass and GrassBillboard shaders.

Packages/com.unity.render-pipelines.universal/Shaders/Terrain/WavingGrass.shader

@@ -16,6 +16,11 @@ Shader "Hidden/TerrainEngine/Details/UniversalPipeline/WavingDoublePass"
 
         Pass
         {
+            Name "ForwardLit"
+            Tags
+            {
+                "LightMode" = "UniversalForward"
+            }
             AlphaToMask On
 
             HLSLPROGRAM
@@ -59,6 +64,54 @@ Shader "Hidden/TerrainEngine/Details/UniversalPipeline/WavingDoublePass"
             ENDHLSL
         }
 
+        Pass
+        {
+            Name "GBuffer"
+            Tags
+            {
+                "LightMode" = "UniversalGBuffer"
+            }
+
+            HLSLPROGRAM
+            #pragma target 4.5
+
+            // Deferred Rendering Path does not support the OpenGL-based graphics API:
+            // Desktop OpenGL, OpenGL ES 3.0, WebGL 2.0.
+            #pragma exclude_renderers gles3 glcore
+
+            // -------------------------------------
+            // Universal Pipeline keywords
+            #pragma multi_compile _ _MAIN_LIGHT_SHADOWS _MAIN_LIGHT_SHADOWS_CASCADE _MAIN_LIGHT_SHADOWS_SCREEN
+            #pragma multi_compile_fragment _ _SHADOWS_SOFT _SHADOWS_SOFT_LOW _SHADOWS_SOFT_MEDIUM _SHADOWS_SOFT_HIGH
+            #pragma multi_compile_fragment _ _LIGHT_COOKIES
+            #pragma multi_compile_fragment _ _RENDER_PASS_ENABLED
+            #pragma multi_compile_fragment _ _GBUFFER_NORMALS_OCT
+            #include_with_pragmas "Packages/com.unity.render-pipelines.core/ShaderLibrary/FoveatedRenderingKeywords.hlsl"
+            #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/ProbeVolumeVariants.hlsl"
+
+            // -------------------------------------
+            // Unity defined keywords
+            #pragma multi_compile _ LIGHTMAP_ON
+            #pragma multi_compile _ SHADOWS_SHADOWMASK
+            #pragma multi_compile _ DIRLIGHTMAP_COMBINED
+            #pragma multi_compile _ LIGHTMAP_SHADOW_MIXING
+
+            //--------------------------------------
+            // GPU Instancing
+            #pragma multi_compile_instancing
+            #pragma instancing_options renderinglayer
+
+            #pragma vertex WavingGrassVert
+            #pragma fragment LitPassFragmentGrass
+            #define _ALPHATEST_ON
+            #define TERRAIN_GBUFFER
+
+            #include "Packages/com.unity.render-pipelines.universal/Shaders/Terrain/WavingGrassInput.hlsl"
+            #include "Packages/com.unity.render-pipelines.universal/Shaders/Terrain/WavingGrassPasses.hlsl"
+
+            ENDHLSL
+        }
+
         Pass
         {
             Name "DepthOnly"

Packages/com.unity.render-pipelines.universal/Shaders/Terrain/WavingGrassBillboard.shader

@@ -16,6 +16,11 @@ Shader "Hidden/TerrainEngine/Details/UniversalPipeline/BillboardWavingDoublePass
 
         Pass
         {
+            Name "ForwardLit"
+            Tags
+            {
+                "LightMode" = "UniversalForward"
+            }
             AlphaToMask On
 
             HLSLPROGRAM
@@ -52,6 +57,48 @@ Shader "Hidden/TerrainEngine/Details/UniversalPipeline/BillboardWavingDoublePass
             ENDHLSL
         }
 
+        Pass
+        {
+            Name "GBuffer"
+            Tags
+            {
+                "LightMode" = "UniversalGBuffer"
+            }
+
+            HLSLPROGRAM
+            #pragma target 4.5
+
+            // Deferred Rendering Path does not support the OpenGL-based graphics API:
+            // Desktop OpenGL, OpenGL ES 3.0, WebGL 2.0.
+            #pragma exclude_renderers gles3 glcore
+
+            // -------------------------------------
+            // Universal Pipeline keywords
+            #pragma multi_compile _ _MAIN_LIGHT_SHADOWS _MAIN_LIGHT_SHADOWS_CASCADE _MAIN_LIGHT_SHADOWS_SCREEN
+            #pragma multi_compile_fragment _ _SHADOWS_SOFT _SHADOWS_SOFT_LOW _SHADOWS_SOFT_MEDIUM _SHADOWS_SOFT_HIGH
+            #pragma multi_compile_fragment _ _RENDER_PASS_ENABLED
+            #pragma multi_compile_fragment _ _GBUFFER_NORMALS_OCT
+            #include_with_pragmas "Packages/com.unity.render-pipelines.core/ShaderLibrary/FoveatedRenderingKeywords.hlsl"
+
+            // -------------------------------------
+            // Unity defined keywords
+            #pragma multi_compile _ SHADOWS_SHADOWMASK
+            #pragma multi_compile _ LIGHTMAP_SHADOW_MIXING
+
+            //--------------------------------------
+            // GPU Instancing
+            #pragma multi_compile_instancing
+
+            #pragma vertex WavingGrassBillboardVert
+            #pragma fragment LitPassFragmentGrass
+            #define _ALPHATEST_ON
+            #define TERRAIN_GBUFFER
+
+            #include "Packages/com.unity.render-pipelines.universal/Shaders/Terrain/WavingGrassInput.hlsl"
+            #include "Packages/com.unity.render-pipelines.universal/Shaders/Terrain/WavingGrassPasses.hlsl"
+            ENDHLSL
+        }
+
         Pass
         {
             Name "DepthOnly"

Packages/com.unity.render-pipelines.universal/Shaders/Terrain/WavingGrassDepthNormalsPass.hlsl

@@ -69,14 +69,13 @@ half4 DepthNormalOnlyFragment(GrassVertexDepthNormalOutput input) : SV_TARGET
 {
     Alpha(SampleAlbedoAlpha(input.uv, TEXTURE2D_ARGS(_MainTex, sampler_MainTex)).a, input.color, _Cutoff);
     #if defined(_GBUFFER_NORMALS_OCT)
-        float3 normalWS = normalize(input.normal);
+        float3 normalWS = NormalizeNormalPerPixel(input.normal);
         float2 octNormalWS = PackNormalOctQuadEncode(normalWS);           // values between [-1, +1], must use fp32 on Nintendo Switch.
         float2 remappedOctNormalWS = saturate(octNormalWS * 0.5 + 0.5);   // values between [ 0,  1]
         half3 packedNormalWS = PackFloat2To888(remappedOctNormalWS);      // values between [ 0,  1]
         return half4(packedNormalWS, 0.0);
     #else
-        half3 normalWS = half3(normalize(cross(ddy(input.viewDirWS), ddx(input.viewDirWS))));
-        return half4(normalWS, 0.0);
+        return half4(NormalizeNormalPerPixel(input.normal), 0.0);
     #endif
 }