Adding vertexNormal to the Surface structure and using it for shadows (#4617)

* Adding vertex shadow and using it for all shadows
* Fixing small issue with it not being initialized
* Adis recommendations for hair

Signed-off-by: mrieggeramzn <mriegger@amazon.com>

Gems/Atom/Feature/Common/Assets/Materials/Types/EnhancedPBR_ForwardPass.azsl

@@ -185,7 +185,7 @@ PbrLightingOutput ForwardPassPS_Common(VSOutput IN, bool isFrontFace, out float
     float2 normalUv = IN.m_uv[MaterialSrg::m_normalMapUvIndex];
     float3x3 uvMatrix = MaterialSrg::m_normalMapUvIndex == 0 ? MaterialSrg::m_uvMatrix : CreateIdentity3x3(); // By design, only UV0 is allowed to apply transforms.
     float detailLayerNormalFactor = MaterialSrg::m_detail_normal_factor * detailLayerBlendFactor;
-
+    surface.vertexNormal = normalize(IN.m_normal);
     surface.normal = GetDetailedNormalInputWS(
         isFrontFace, IN.m_normal,
         tangents[MaterialSrg::m_normalMapUvIndex],      bitangents[MaterialSrg::m_normalMapUvIndex],      MaterialSrg::m_normalMap,             MaterialSrg::m_sampler, normalUv, MaterialSrg::m_normalFactor,  MaterialSrg::m_flipNormalX,         MaterialSrg::m_flipNormalY,         uvMatrix,                      o_normal_useTexture,

Gems/Atom/Feature/Common/Assets/Materials/Types/Skin.azsl

@@ -237,6 +237,7 @@ PbrLightingOutput SkinPS_Common(VSOutput IN)
         normalMapSample = ApplyNormalWrinkleMap(o_wrinkleLayers_normal_useTexture4, normalMapSample, MaterialSrg::m_wrinkle_normal_texture4, MaterialSrg::m_sampler, normalUv, MaterialSrg::m_flipNormalX, MaterialSrg::m_flipNormalY, IN.m_wrinkleBlendFactors.a);
     }
 
+    surface.vertexNormal = normalize(IN.m_normal);
     if(o_detail_normal_useTexture)
     {
         float3 normalTS = GetTangentSpaceNormal(normalMapSample, uvMatrix, MaterialSrg::m_normalFactor);

Gems/Atom/Feature/Common/Assets/Materials/Types/StandardMultilayerPBR_ForwardPass.azsl

@@ -445,6 +445,7 @@ PbrLightingOutput ForwardPassPS_Common(VSOutput IN, bool isFrontFace, out float
         normalTS = ReorientTangentSpaceNormal(normalTS, lightingInputLayer3.m_normalTS);
     }
     // [GFX TODO][ATOM-14591]: This will only work if the normal maps all use the same UV stream. We would need to add support for having them in different UV streams.
+    surface.vertexNormal = normalize(IN.m_normal);
     surface.normal = normalize(TangentSpaceToWorld(normalTS, IN.m_normal, tangents[MaterialSrg::m_parallaxUvIndex], bitangents[MaterialSrg::m_parallaxUvIndex]));
         
     // ------- Combine Albedo, roughness, specular, roughness ---------

Gems/Atom/Feature/Common/Assets/Materials/Types/StandardPBR_ForwardPass.azsl

@@ -146,7 +146,7 @@ PbrLightingOutput ForwardPassPS_Common(VSOutput IN, bool isFrontFace, out float
 
     float2 normalUv = IN.m_uv[MaterialSrg::m_normalMapUvIndex];
     float3x3 uvMatrix = MaterialSrg::m_normalMapUvIndex == 0 ? MaterialSrg::m_uvMatrix : CreateIdentity3x3(); // By design, only UV0 is allowed to apply transforms.
-
+    surface.vertexNormal = normalize(IN.m_normal);
     surface.normal = GetNormalInputWS(MaterialSrg::m_normalMap, MaterialSrg::m_sampler, normalUv, MaterialSrg::m_flipNormalX, MaterialSrg::m_flipNormalY, isFrontFace, IN.m_normal,
                                        tangents[MaterialSrg::m_normalMapUvIndex], bitangents[MaterialSrg::m_normalMapUvIndex], uvMatrix, o_normal_useTexture, MaterialSrg::m_normalFactor);
 

Gems/Atom/Feature/Common/Assets/ShaderLib/Atom/Features/PBR/Lights/DirectionalLight.azsli

@@ -24,7 +24,7 @@ void ApplyDirectionalLights(Surface surface, inout LightingData lightingData)
         litRatio = DirectionalLightShadow::GetVisibility(
             shadowIndex,
             lightingData.shadowCoords,
-            surface.normal,
+            surface.vertexNormal,
             debugInfo);
             
         if (o_transmission_mode == TransmissionMode::ThickObject)

Gems/Atom/Feature/Common/Assets/ShaderLib/Atom/Features/PBR/Lights/DiskLight.azsli

@@ -86,7 +86,7 @@ void ApplyDiskLight(ViewSrg::DiskLight light, Surface surface, inout LightingDat
                 light.m_position,
                 surface.position,
                 -dirToConeTip,
-                surface.normal);
+                surface.vertexNormal);
              
             // Use backShadowRatio to carry thickness from shadow map for thick mode
             backShadowRatio = 1.0 - litRatio;

Gems/Atom/Feature/Common/Assets/ShaderLib/Atom/Features/PBR/Lights/PointLight.azsli

@@ -83,7 +83,7 @@ void ApplyPointLight(ViewSrg::PointLight light, Surface surface, inout LightingD
                     light.m_position,
                     surface.position,
                     lightDir,
-                    surface.normal);
+                    surface.vertexNormal);
                         
             // Use backShadowRatio to carry thickness from shadow map for thick mode
             backShadowRatio = 1.0 - litRatio;

Gems/Atom/Feature/Common/Assets/ShaderLib/Atom/Features/PBR/Surfaces/EnhancedSurface.azsli

@@ -23,6 +23,7 @@ class Surface
     
     float3 position;            //!< Position in world-space
     float3 normal;              //!< Normal in world-space
+    float3 vertexNormal;        //!< Vertex normal in world-space
     float3 albedo;              //!< Albedo color of the non-metallic material, will be multiplied against the diffuse lighting value
     float3 specularF0;          //!< Fresnel f0 spectral value of the surface
     float roughnessLinear;      //!< Perceptually linear roughness value authored by artists. Must be remapped to roughnessA before use

Gems/Atom/Feature/Common/Assets/ShaderLib/Atom/Features/PBR/Surfaces/SkinSurface.azsli

@@ -22,6 +22,7 @@ class Surface
     
     float3 position;            //!< Position in world-space
     float3 normal;              //!< Normal in world-space
+    float3 vertexNormal;        //!< Vertex normal in world-space
     float3 albedo;              //!< Albedo color of the non-metallic material, will be multiplied against the diffuse lighting value
     float3 specularF0;          //!< Fresnel f0 spectral value of the surface
     float roughnessLinear;      //!< Perceptually linear roughness value authored by artists. Must be remapped to roughnessA before use

Gems/Atom/Feature/Common/Assets/ShaderLib/Atom/Features/PBR/Surfaces/StandardSurface.azsli

@@ -22,6 +22,7 @@ class Surface
     
     float3 position;            //!< Position in world-space
     float3 normal;              //!< Normal in world-space
+    float3 vertexNormal;        //!< Vertex normal in world-space
     float3 albedo;              //!< Albedo color of the non-metallic material, will be multiplied against the diffuse lighting value
     float3 specularF0;          //!< Fresnel f0 spectral value of the surface
     float roughnessLinear;      //!< Perceptually linear roughness value authored by artists. Must be remapped to roughnessA before use

Gems/Atom/TestData/TestData/Materials/Types/AutoBrick_ForwardPass.azsl

@@ -170,6 +170,7 @@ ForwardPassOutput AutoBrick_ForwardPassPS(VSOutput IN)
     // Position, Normal, Roughness
     surface.position = IN.m_worldPosition.xyz;
     surface.normal = normalize(normal);
+    surface.vertexNormal = surfaceNormal;
     surface.roughnessLinear = 1.0f;
     surface.CalculateRoughnessA();
 

Gems/Atom/TestData/TestData/Materials/Types/MinimalPBR_ForwardPass.azsl

@@ -63,6 +63,7 @@ ForwardPassOutput MinimalPBR_MainPassPS(VSOutput IN)
     // Position, Normal, Roughness
     surface.position = IN.m_worldPosition.xyz;
     surface.normal = normalize(IN.m_normal);
+    surface.vertexNormal = normalize(IN.m_normal);
     surface.roughnessLinear = MinimalPBRSrg::m_roughness;
     surface.CalculateRoughnessA();
 

Gems/AtomTressFX/Assets/Shaders/HairLightTypes.azsli

@@ -135,6 +135,7 @@ void SetNormalAndUpdateLightingParams(
 
     float3 projectedNormal = cross(biNormal, tangent);
     surface.normal = normalize(projectedNormal);    // the normalization might be redundunt 
+    surface.vertexNormal = surface.normal; // [To Do] - support proper vertex normals in the hair shader.
 
     // Next is important in order to set NdotV and other PBR settings - needs to be set once per light
     UpdateLightingParameters(lightingData, surface.position, surface.normal, surface.roughnessLinear);
@@ -362,7 +363,7 @@ void ApplyDirectionalLights(Surface surface, inout LightingData lightingData)
         litRatio = DirectionalLightShadow::GetVisibility(
             shadowIndex,
             lightingData.shadowCoords,
-            surface.normal,
+            surface.vertexNormal,
             debugInfo);
     }
 

Gems/AtomTressFX/Assets/Shaders/HairLighting.azsli

@@ -197,6 +197,7 @@ float3 CalculateLighting(
     surface.position = vPositionWS;
     surface.tangent = vTangent;         // Redundant - will be calculated per light
     surface.normal = float3(0, 0, 0);   // Will fail lights that did not initialize properly. 
+    surface.vertexNormal = float3(0,0,0); // [To Do] - vertex normals are not handled yet in the hair shader.
     surface.roughnessLinear = material.m_roughness;
     surface.cuticleTilt = material.m_cuticleTilt;
     surface.thickness = thickness;

Gems/AtomTressFX/Assets/Shaders/HairSurface.azsli

@@ -18,6 +18,7 @@ class Surface
     // ------- BasePbrSurfaceData -------
     float3 position;            //!< Position in world-space
     float3 normal;              //!< Normal in world-space
+    float3 vertexNormal;        //!< Vertex normal in world-space
     float3 albedo;              //!< Albedo color of the non-metallic material, will be multiplied against the diffuse lighting value
     float3 specularF0;          //!< Fresnel f0 spectral value of the surface
     float roughnessLinear;      //!< Perceptually linear roughness value authored by artists. Must be remapped to roughnessA before use

Gems/Terrain/Assets/Shaders/Terrain/TerrainPBR_ForwardPass.azsl

@@ -95,6 +95,7 @@ ForwardPassOutput TerrainPBR_MainPassPS(VSOutput IN)
     detailNormal = ReorientTangentSpaceNormal(macroNormal, detailNormal);
     surface.normal = lerp(detailNormal, macroNormal, detailFactor);
     surface.normal = normalize(surface.normal);
+    surface.vertexNormal = normalize(IN.m_normal);
 
     // ------- Macro Color -------
     float3 macroColor = GetBaseColorInput(TerrainMaterialSrg::m_macroColorMap, TerrainMaterialSrg::m_sampler, origUv, TerrainMaterialSrg::m_baseColor.rgb, o_baseColor_useTexture);