[10.x.x] HDRP - Update Shader Graph Unlit to use new shared template [Skip CI] (#894)

* Move Unlit to the new sharing template

* Remove comment from unlit template

* Disable code that break raytracing

Author: sebastienlagarde

com.unity.render-pipelines.high-definition/Editor/Material/ShaderGraph/Templates/ShaderPass.template

@@ -24,14 +24,21 @@ Pass
     $splice(PassKeywords)
     $splice(GraphKeywords)
 
+    // --------------------------------------------------
     // Defines
+
+    // Lighting Material only (will not affect unlit)
     $DisableDecals:                     #define _DISABLE_DECALS 1
     $DisableSSR:                        #define _DISABLE_SSR 1
     $DisableSSRTransparent:             #define _DISABLE_SSR_TRANSPARENT 1
+    $BlendMode.PreserveSpecular:        #define _BLENDMODE_PRESERVE_SPECULAR_LIGHTING 1
+
+    // Precomputed velocity is used for alembic
     $AddPrecomputedVelocity:            #define _ADD_PRECOMPUTED_VELOCITY
     $TransparentWritesMotionVec:        #define _TRANSPARENT_WRITES_MOTION_VEC 1
     $DepthOffset:                       #define _DEPTHOFFSET_ON 1
-    $BlendMode.PreserveSpecular:        #define _BLENDMODE_PRESERVE_SPECULAR_LIGHTING 1
+
+    // Attribute
     $AttributesMesh.normalOS:           #define ATTRIBUTES_NEED_NORMAL
     $AttributesMesh.tangentOS:          #define ATTRIBUTES_NEED_TANGENT
     $AttributesMesh.uv0:                #define ATTRIBUTES_NEED_TEXCOORD0
@@ -65,10 +72,12 @@ Pass
         #endif
     #endif
 
+    #ifndef SHADER_UNLIT
     // We need isFontFace when using double sided
     #if defined(_DOUBLESIDED_ON) && !defined(VARYINGS_NEED_CULLFACE)
         #define VARYINGS_NEED_CULLFACE
     #endif
+    #endif
 
     // Translate transparent motion vector define
     #if defined(_TRANSPARENT_WRITES_MOTION_VEC) && defined(_SURFACE_TYPE_TRANSPARENT)
@@ -83,7 +92,7 @@ Pass
     // Includes
     $splice(PreGraphIncludes)
 
-    // Used by SceneSelectionPass
+    // Properties used by SceneSelectionPass
     #ifdef SCENESELECTIONPASS
     int _ObjectId;
     int _PassValue;
@@ -256,6 +265,7 @@ Pass
 
     void GetSurfaceAndBuiltinData(FragInputs fragInputs, float3 V, inout PositionInputs posInput, out SurfaceData surfaceData, out BuiltinData builtinData RAY_TRACING_OPTIONAL_PARAMETERS)
     {
+        #ifndef SHADER_UNLIT
         // Don't dither if displaced tessellation (we're fading out the displacement instead to match the next LOD)
         #if !defined(SHADER_STAGE_RAY_TRACING) && !defined(_TESSELLATION_DISPLACEMENT)
         #ifdef LOD_FADE_CROSSFADE // enable dithering LOD transition if user select CrossFade transition in LOD group
@@ -270,6 +280,7 @@ Pass
         #endif
 
         ApplyDoubleSidedFlipOrMirror(fragInputs, doubleSidedConstants); // Apply double sided flip on the vertex normal
+        #endif // SHADER_UNLIT
 
         SurfaceDescriptionInputs surfaceDescriptionInputs = FragInputsToSurfaceDescriptionInputs(fragInputs, V);
         SurfaceDescription surfaceDescription = SurfaceDescriptionFunction(surfaceDescriptionInputs);
@@ -287,13 +298,29 @@ Pass
         $DepthOffset: ApplyDepthOffsetPositionInput(V, surfaceDescription.DepthOffset, GetViewForwardDir(), GetWorldToHClipMatrix(), posInput);
         #endif
 
+        #ifndef SHADER_UNLIT
         float3 bentNormalWS;
         BuildSurfaceData(fragInputs, surfaceDescription, V, posInput, surfaceData, bentNormalWS);
 
         // Builtin Data
         // For back lighting we use the oposite vertex normal
         InitBuiltinData(posInput, surfaceDescription.Alpha, bentNormalWS, -fragInputs.tangentToWorld[2], fragInputs.texCoord1, fragInputs.texCoord2, builtinData);
 
+        #else
+        BuildSurfaceData(fragInputs, surfaceDescription, V, posInput, surfaceData);
+
+        ZERO_INITIALIZE(BuiltinData, builtinData); // No call to InitBuiltinData as we don't have any lighting
+        builtinData.opacity = surfaceDescription.Alpha;
+
+        #if defined(DEBUG_DISPLAY)
+            // Light Layers are currently not used for the Unlit shader (because it is not lit)
+            // But Unlit objects do cast shadows according to their rendering layer mask, which is what we want to
+            // display in the light layers visualization mode, therefore we need the renderingLayers
+            builtinData.renderingLayers = _EnableLightLayers ? asuint(unity_RenderingLayer.x) : DEFAULT_LIGHT_LAYERS;
+        #endif
+
+        #endif // SHADER_UNLIT
+
         #ifdef _ALPHATEST_ON
             // Used for sharpening by alpha to mask
             $DoAlphaTest:         builtinData.alphaClipTreshold = surfaceDescription.AlphaClipThreshold;
@@ -302,12 +329,28 @@ Pass
             $DoAlphaTestShadow:   builtinData.alphaClipTreshold = surfaceDescription.AlphaClipThresholdShadow;
         #endif
 
-        // override sampleBakedGI:
+        // override sampleBakedGI - not used by Unlit
         $LightingGI: builtinData.bakeDiffuseLighting = surfaceDescription.BakedGI;
         $BackLightingGI: builtinData.backBakeDiffuseLighting = surfaceDescription.BakedBackGI;
 
         $SurfaceDescription.Emission: builtinData.emissiveColor = surfaceDescription.Emission;
 
+        #ifndef SHADER_UNLIT
+        // TODO: need to implement for shader graph raytracing
+        /*
+        // Raytracing specific code to remove Emissive color from the pass to avoid double contribution
+        // To avoid to have double lighting (once from the light source and once from the light itself)
+        #if SHADERPASS == SHADERPASS_RAYTRACING_INDIRECT || SHADERPASS == SHADERPASS_RAYTRACING_GBUFFER
+            builtinData.emissiveColor *= _IncludeIndirectLighting;
+        #elif SHADERPASS == SHADERPASS_RAYTRACING_FORWARD || SHADERPASS == SHADERPASS_PATH_TRACING
+            if (rayCone.spreadAngle < 0.0)
+            {
+                builtinData.emissiveColor *= _IncludeIndirectLighting;
+            }
+        #endif
+        */
+        #endif // SHADER_UNLIT
+
         // Note this will not fully work on transparent surfaces (can check with _SURFACE_TYPE_TRANSPARENT define)
         // We will always overwrite vt feeback with the nearest. So behind transparent surfaces vt will not be resolved
         // This is a limitation of the current MRT approach.
@@ -321,7 +364,12 @@ Pass
         builtinData.distortionBlur = surfaceDescription.DistortionBlur;
         #endif
 
+        #ifndef SHADER_UNLIT
+        // PostInitBuiltinData call ApplyDebugToBuiltinData
         PostInitBuiltinData(V, posInput, surfaceData, builtinData);
+        #else
+        ApplyDebugToBuiltinData(builtinData);
+        #endif
 
         RAY_TRACING_OPTIONAL_ALPHA_TEST_PASS
     }

com.unity.render-pipelines.high-definition/Editor/Material/Unlit/ShaderGraph/HDUnlitPass.template

@@ -18,8 +18,7 @@ sealed partial class HDUnlitSubTarget : SurfaceSubTarget, IRequiresData<HDUnlitD
         public HDUnlitSubTarget() => displayName = "Unlit";
 
         // Templates
-        protected override string templatePath => $"{HDUtils.GetHDRenderPipelinePath()}Editor/Material/Unlit/ShaderGraph/HDUnlitPass.template";
-        protected override string templateMaterialDirectory => $"{HDUtils.GetHDRenderPipelinePath()}Editor/Material/ShaderGraph/Templates";
+        protected override string templateMaterialDirectory => $"{HDUtils.GetHDRenderPipelinePath()}Editor/Material/Unlit/ShaderGraph/";
         protected override ShaderID shaderID => HDShaderUtils.ShaderID.SG_Unlit;
         protected override string renderType => HDRenderTypeTags.HDUnlitShader.ToString();
         protected override string subTargetAssetGuid => "4516595d40fa52047a77940183dc8e74"; // HDUnlitSubTarget

com.unity.render-pipelines.high-definition/Editor/Material/Unlit/ShaderGraph/HDUnlitPass.template.meta

@@ -0,0 +1,42 @@
+void BuildSurfaceData(FragInputs fragInputs, inout SurfaceDescription surfaceDescription, float3 V, PositionInputs posInput, out SurfaceData surfaceData)
+{
+    // setup defaults -- these are used if the graph doesn't output a value
+    ZERO_INITIALIZE(SurfaceData, surfaceData);
+
+    // copy across graph values, if defined
+    $SurfaceDescription.BaseColor: surfaceData.color = surfaceDescription.BaseColor;
+
+    #if defined(DEBUG_DISPLAY)
+    if (_DebugMipMapMode != DEBUGMIPMAPMODE_NONE)
+    {
+        // TODO
+    }
+    #endif
+
+    #if defined(_ENABLE_SHADOW_MATTE) && SHADERPASS == SHADERPASS_FORWARD_UNLIT
+        HDShadowContext shadowContext = InitShadowContext();
+        float shadow;
+        float3 shadow3;
+        // We need to recompute some coordinate not computed by default for shadow matte
+        posInput = GetPositionInput(fragInputs.positionSS.xy, _ScreenSize.zw, fragInputs.positionSS.z, UNITY_MATRIX_I_VP, UNITY_MATRIX_V);
+        float3 upWS = normalize(fragInputs.tangentToWorld[1]);
+        uint renderingLayers = _EnableLightLayers ? asuint(unity_RenderingLayer.x) : DEFAULT_LIGHT_LAYERS;
+        ShadowLoopMin(shadowContext, posInput, upWS, asuint(_ShadowMatteFilter), renderingLayers, shadow3);
+        shadow = dot(shadow3, float3(1.0 / 3.0, 1.0 / 3.0, 1.0 / 3.0));
+
+        float4 shadowColor = (1.0 - shadow) * surfaceDescription.ShadowTint.rgba;
+        float  localAlpha  = saturate(shadowColor.a + surfaceDescription.Alpha);
+
+        // Keep the nested lerp
+        // With no Color (bsdfData.color.rgb, bsdfData.color.a == 0.0f), just use ShadowColor*Color to avoid a ring of "white" around the shadow
+        // And mix color to consider the Color & ShadowColor alpha (from texture or/and color picker)
+        #ifdef _SURFACE_TYPE_TRANSPARENT
+            surfaceData.color = lerp(shadowColor.rgb * surfaceData.color, lerp(lerp(shadowColor.rgb, surfaceData.color, 1.0 - surfaceDescription.ShadowTint.a), surfaceData.color, shadow), surfaceDescription.Alpha);
+        #else
+            surfaceData.color = lerp(lerp(shadowColor.rgb, surfaceData.color, 1.0 - surfaceDescription.ShadowTint.a), surfaceData.color, shadow);
+        #endif
+        localAlpha = ApplyBlendMode(surfaceData.color, localAlpha).a;
+
+        surfaceDescription.Alpha = localAlpha;
+    #endif
+}

com.unity.render-pipelines.high-definition/Editor/Material/Unlit/ShaderGraph/HDUnlitSubTarget.cs

@@ -0,0 +1,9 @@
+// Setup a define to say we are an unlit shader
+#define SHADER_UNLIT
+$EnableShadowMatte: #define _ENABLE_SHADOW_MATTE
+
+// Following Macro are only used by Unlit material
+#if defined(_ENABLE_SHADOW_MATTE) && SHADERPASS == SHADERPASS_FORWARD_UNLIT
+#define LIGHTLOOP_DISABLE_TILE_AND_CLUSTER
+#define HAS_LIGHTLOOP
+#endif