Atom/mriegger/normaloffsetbiasarealight (#4917)

* Adding directional light shadow bias
* Adding normal offset bias for projected shadows

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

Gems/Atom/Feature/Common/Assets/ShaderLib/Atom/Features/Shadow/ProjectedShadow.azsli

@@ -14,6 +14,7 @@
 #include <Atom/RPI/Math.azsli>
 #include "BicubicPcfFilters.azsli"
 #include "Shadow.azsli"
+#include "NormalOffsetShadows.azsli"
 
 // ProjectedShadow calculates shadowed area projected from a light.
 class ProjectedShadow
@@ -123,6 +124,7 @@ float ProjectedShadow::GetThickness(uint shadowIndex, float3 worldPosition)
 
     ProjectedShadow shadow;
     shadow.m_worldPosition = worldPosition;
+    shadow.m_normalVector = 0; // The normal vector is used to reduce acne, this is not an issue when using the shadowmap to determine thickness. 
     shadow.m_shadowIndex = shadowIndex;
     shadow.SetShadowPosition();
     return shadow.GetThickness();
@@ -317,8 +319,13 @@ bool ProjectedShadow::IsShadowed(float3 shadowPosition)
 
 void ProjectedShadow::SetShadowPosition()
 {
+    const float normalBias = ViewSrg::m_projectedShadows[m_shadowIndex].m_normalShadowBias;
+    const float shadowmapSize = ViewSrg::m_projectedFilterParams[m_shadowIndex].m_shadowmapSize;
+    const float3 shadowOffset = ComputeNormalShadowOffset(normalBias, m_normalVector, shadowmapSize);
     const float4x4 depthBiasMatrix = ViewSrg::m_projectedShadows[m_shadowIndex].m_depthBiasMatrix;
-    float4 shadowPositionHomogeneous = mul(depthBiasMatrix, float4(m_worldPosition, 1));
+    
+    float4 shadowPositionHomogeneous = mul(depthBiasMatrix, float4(m_worldPosition + shadowOffset, 1));
+         
     m_shadowPosition = shadowPositionHomogeneous.xyz / shadowPositionHomogeneous.w;
     
     m_bias = ViewSrg::m_projectedShadows[m_shadowIndex].m_bias / shadowPositionHomogeneous.w;

Gems/Atom/Feature/Common/Code/Include/Atom/Feature/CoreLights/DiskLightFeatureProcessorInterface.h

@@ -86,6 +86,8 @@ namespace AZ
             virtual void SetShadowsEnabled(LightHandle handle, bool enabled) = 0;
             //! Sets the shadow bias
             virtual void SetShadowBias(LightHandle handle, float bias) = 0;
+            //! Sets the normal shadow bias
+            virtual void SetNormalShadowBias(LightHandle handle, float bias) = 0;
             //! Sets the shadowmap size (width and height) of the light.
             virtual void SetShadowmapMaxResolution(LightHandle handle, ShadowmapSize shadowmapSize) = 0;
             //! Specifies filter method of shadows.

Gems/Atom/Feature/Common/Code/Include/Atom/Feature/CoreLights/PointLightFeatureProcessorInterface.h

@@ -74,6 +74,8 @@ namespace AZ
             virtual void SetFilteringSampleCount(LightHandle handle, uint16_t count) = 0;
             //! Sets the Esm exponent to use. Higher values produce a steeper falloff in the border areas between light and shadow.
             virtual void SetEsmExponent(LightHandle handle, float exponent) = 0;
+            //! Sets the normal shadow bias. Reduces acne by biasing the shadowmap lookup along the geometric normal.
+            virtual void SetNormalShadowBias(LightHandle handle, float bias) = 0;
             //! Sets all of the the point data for the provided LightHandle.
             virtual void SetPointData(LightHandle handle, const PointLightData& data) = 0;
         };

Gems/Atom/Feature/Common/Code/Source/CoreLights/DiskLightFeatureProcessor.cpp

@@ -313,6 +313,11 @@ namespace AZ
             SetShadowSetting(handle, &ProjectedShadowFeatureProcessor::SetShadowBias, bias);
         }
 
+        void DiskLightFeatureProcessor::SetNormalShadowBias(LightHandle handle, float bias)
+        {
+            SetShadowSetting(handle, &ProjectedShadowFeatureProcessor::SetNormalShadowBias, bias);
+        }
+
         void DiskLightFeatureProcessor::SetShadowmapMaxResolution(LightHandle handle, ShadowmapSize shadowmapSize)
         {
             SetShadowSetting(handle, &ProjectedShadowFeatureProcessor::SetShadowmapMaxResolution, shadowmapSize);

Gems/Atom/Feature/Common/Code/Source/CoreLights/DiskLightFeatureProcessor.h

@@ -51,6 +51,7 @@ namespace AZ
             void SetConeAngles(LightHandle handle, float innerDegrees, float outerDegrees) override;
             void SetShadowsEnabled(LightHandle handle, bool enabled) override;
             void SetShadowBias(LightHandle handle, float bias) override;
+            void SetNormalShadowBias(LightHandle handle, float bias) override;
             void SetShadowmapMaxResolution(LightHandle handle, ShadowmapSize shadowmapSize) override;
             void SetShadowFilterMethod(LightHandle handle, ShadowFilterMethod method) override;
             void SetFilteringSampleCount(LightHandle handle, uint16_t count) override;

Gems/Atom/Feature/Common/Code/Source/CoreLights/PointLightFeatureProcessor.cpp

@@ -302,5 +302,10 @@ namespace AZ
             SetShadowSetting(handle, &ProjectedShadowFeatureProcessor::SetEsmExponent, esmExponent);
         }
 
+        void PointLightFeatureProcessor::SetNormalShadowBias(LightHandle handle, float bias)
+        {
+            SetShadowSetting(handle, &ProjectedShadowFeatureProcessor::SetNormalShadowBias, bias);
+        }
+
     } // namespace Render
 } // namespace AZ

Gems/Atom/Feature/Common/Code/Source/CoreLights/PointLightFeatureProcessor.h

@@ -52,6 +52,7 @@ namespace AZ
             void SetShadowFilterMethod(LightHandle handle, ShadowFilterMethod method) override;
             void SetFilteringSampleCount(LightHandle handle, uint16_t count) override;
             void SetEsmExponent(LightHandle handle, float esmExponent) override;
+            void SetNormalShadowBias(LightHandle handle, float bias) override;
             void SetPointData(LightHandle handle, const PointLightData& data) override;
 
             const Data::Instance<RPI::Buffer>  GetLightBuffer() const;

Gems/Atom/Feature/Common/Code/Source/Shadows/ProjectedShadowFeatureProcessor.cpp

@@ -155,8 +155,9 @@ namespace AZ::Render
     {
         AZ_Assert(id.IsValid(), "Invalid ShadowId passed to ProjectedShadowFeatureProcessor::SetNormalShadowBias().");
 
-        ShadowProperty& shadowProperty = GetShadowPropertyFromShadowId(id);
-        shadowProperty.m_normalShadowBias = normalShadowBias;
+        ShadowData& shadowData = m_shadowData.GetElement<ShadowDataIndex>(id.GetIndex());
+        shadowData.m_normalShadowBias = normalShadowBias;
+        m_deviceBufferNeedsUpdate = true;
     }
 
     void ProjectedShadowFeatureProcessor::SetShadowmapMaxResolution(ShadowId id, ShadowmapSize size)

Gems/Atom/Feature/Common/Code/Source/Shadows/ProjectedShadowFeatureProcessor.h

@@ -68,7 +68,7 @@ namespace AZ::Render
             uint32_t m_filteringSampleCount = 0;
             AZStd::array<float, 2> m_unprojectConstants = { {0, 0} };
             float m_bias;
-            float m_normalShadowBias;
+            float m_normalShadowBias = 0;
             float m_esmExponent = 87.0f;
             float m_padding[3];
         };
@@ -79,7 +79,6 @@ namespace AZ::Render
             ProjectedShadowDescriptor m_desc;
             RPI::ViewPtr m_shadowmapView;
             float m_bias = 0.1f;
-            float m_normalShadowBias = 0.0f;
             ShadowId m_shadowId;
         };
 

Gems/AtomLyIntegration/CommonFeatures/Code/Include/AtomLyIntegration/CommonFeatures/CoreLights/AreaLightBus.h

@@ -132,6 +132,13 @@ namespace AZ
             //! Sets the Esm exponent. Higher values produce a steeper falloff between light and shadow.
             virtual void SetEsmExponent(float exponent) = 0;
 
+            //! Reduces acne by biasing the shadowmap lookup along the geometric normal.
+            //! @return Returns the amount of bias to apply.
+            virtual float GetNormalShadowBias() const = 0;
+
+            //! Reduces acne by biasing the shadowmap lookup along the geometric normal.
+            //! @param normalShadowBias Sets the amount of normal shadow bias to apply.
+            virtual void SetNormalShadowBias(float normalShadowBias) = 0;
         };
 
         //! The EBus for requests to for setting and getting light component properties.

Gems/AtomLyIntegration/CommonFeatures/Code/Include/AtomLyIntegration/CommonFeatures/CoreLights/AreaLightComponentConfig.h

@@ -57,6 +57,7 @@ namespace AZ
             // Shadows (only used for supported shapes)
             bool m_enableShadow = false;
             float m_bias = 0.1f;
+            float m_normalShadowBias = 0.0f;
             ShadowmapSize m_shadowmapMaxSize = ShadowmapSize::Size256;
             ShadowFilterMethod m_shadowFilterMethod = ShadowFilterMethod::None;
             uint16_t m_filteringSampleCount = 12;

Gems/AtomLyIntegration/CommonFeatures/Code/Source/CoreLights/AreaLightComponentConfig.cpp

@@ -34,6 +34,7 @@ namespace AZ
                     // Shadows
                     ->Field("Enable Shadow", &AreaLightComponentConfig::m_enableShadow)
                     ->Field("Shadow Bias", &AreaLightComponentConfig::m_bias)
+                    ->Field("Normal Shadow Bias", &AreaLightComponentConfig::m_normalShadowBias)
                     ->Field("Shadowmap Max Size", &AreaLightComponentConfig::m_shadowmapMaxSize)
                     ->Field("Shadow Filter Method", &AreaLightComponentConfig::m_shadowFilterMethod)
                     ->Field("Filtering Sample Count", &AreaLightComponentConfig::m_filteringSampleCount)

Gems/AtomLyIntegration/CommonFeatures/Code/Source/CoreLights/AreaLightComponentController.cpp

@@ -70,6 +70,8 @@ namespace AZ::Render
                 ->Event("SetEnableShadow", &AreaLightRequestBus::Events::SetEnableShadow)
                 ->Event("GetShadowBias", &AreaLightRequestBus::Events::GetShadowBias)
                 ->Event("SetShadowBias", &AreaLightRequestBus::Events::SetShadowBias)
+                ->Event("GetNormalShadowBias", &AreaLightRequestBus::Events::GetNormalShadowBias)
+                ->Event("SetNormalShadowBias", &AreaLightRequestBus::Events::SetNormalShadowBias)
                 ->Event("GetShadowmapMaxSize", &AreaLightRequestBus::Events::GetShadowmapMaxSize)
                 ->Event("SetShadowmapMaxSize", &AreaLightRequestBus::Events::SetShadowmapMaxSize)
                 ->Event("GetShadowFilterMethod", &AreaLightRequestBus::Events::GetShadowFilterMethod)
@@ -91,6 +93,7 @@ namespace AZ::Render
 
                 ->VirtualProperty("ShadowsEnabled", "GetEnableShadow", "SetEnableShadow")
                 ->VirtualProperty("ShadowBias", "GetShadowBias", "SetShadowBias")
+                ->VirtualProperty("NormalShadowBias", "GetNormalShadowBias", "SetNormalShadowBias")
                 ->VirtualProperty("ShadowmapMaxSize", "GetShadowmapMaxSize", "SetShadowmapMaxSize")
                 ->VirtualProperty("ShadowFilterMethod", "GetShadowFilterMethod", "SetShadowFilterMethod")
                 ->VirtualProperty("FilteringSampleCount", "GetFilteringSampleCount", "SetFilteringSampleCount")
@@ -302,6 +305,7 @@ namespace AZ::Render
             if (m_configuration.m_enableShadow)
             {
                 m_lightShapeDelegate->SetShadowBias(m_configuration.m_bias);
+                m_lightShapeDelegate->SetNormalShadowBias(m_configuration.m_normalShadowBias);
                 m_lightShapeDelegate->SetShadowmapMaxSize(m_configuration.m_shadowmapMaxSize);
                 m_lightShapeDelegate->SetShadowFilterMethod(m_configuration.m_shadowFilterMethod);
                 m_lightShapeDelegate->SetFilteringSampleCount(m_configuration.m_filteringSampleCount);
@@ -474,6 +478,20 @@ namespace AZ::Render
         }
     }
 
+    void AreaLightComponentController::SetNormalShadowBias(float bias)
+    {
+        m_configuration.m_normalShadowBias = bias;
+        if (m_lightShapeDelegate)
+        {
+            m_lightShapeDelegate->SetNormalShadowBias(bias);
+        }
+    }
+
+    float AreaLightComponentController::GetNormalShadowBias() const
+    {
+        return m_configuration.m_normalShadowBias;
+    }
+
     ShadowmapSize AreaLightComponentController::GetShadowmapMaxSize() const
     {
         return m_configuration.m_shadowmapMaxSize;

Gems/AtomLyIntegration/CommonFeatures/Code/Source/CoreLights/AreaLightComponentController.h

@@ -86,6 +86,8 @@ namespace AZ
             void SetFilteringSampleCount(uint32_t count) override;
             float GetEsmExponent() const override;
             void SetEsmExponent(float exponent) override;
+            float GetNormalShadowBias() const override;
+            void SetNormalShadowBias(float bias) override;
 
             void HandleDisplayEntityViewport(
                 const AzFramework::ViewportInfo& viewportInfo,

Gems/AtomLyIntegration/CommonFeatures/Code/Source/CoreLights/DiskLightDelegate.cpp

@@ -138,6 +138,14 @@ namespace AZ::Render
         }
     }
 
+    void DiskLightDelegate::SetNormalShadowBias(float bias)
+    {
+        if (GetShadowsEnabled() && GetLightHandle().IsValid())
+        {
+            GetFeatureProcessor()->SetNormalShadowBias(GetLightHandle(), bias);
+        }
+    }
+
     void DiskLightDelegate::SetShadowmapMaxSize(ShadowmapSize size)
     {
         if (GetShadowsEnabled() && GetLightHandle().IsValid())

Gems/AtomLyIntegration/CommonFeatures/Code/Source/CoreLights/DiskLightDelegate.h

@@ -46,6 +46,7 @@ namespace AZ
             void SetShadowFilterMethod(ShadowFilterMethod method) override;
             void SetFilteringSampleCount(uint32_t count) override;
             void SetEsmExponent(float exponent) override;
+            void SetNormalShadowBias(float bias) override;
 
         private:
 

Gems/AtomLyIntegration/CommonFeatures/Code/Source/CoreLights/EditorAreaLightComponent.cpp

@@ -136,7 +136,7 @@ namespace AZ
                             ->Attribute(Edit::Attributes::Min, 0.0f)
                             ->Attribute(Edit::Attributes::Max, 100.0f)
                             ->Attribute(Edit::Attributes::SoftMin, 0.0f)
-                            ->Attribute(Edit::Attributes::SoftMax, 2.0f)
+                            ->Attribute(Edit::Attributes::SoftMax, 10.0f)
                             ->Attribute(Edit::Attributes::ChangeNotify, Edit::PropertyRefreshLevels::ValuesOnly)
                             ->Attribute(Edit::Attributes::Visibility, &AreaLightComponentConfig::SupportsShadows)
                             ->Attribute(Edit::Attributes::ReadOnly, &AreaLightComponentConfig::ShadowsDisabled)
@@ -171,6 +171,15 @@ namespace AZ
                             ->Attribute(Edit::Attributes::ChangeNotify, Edit::PropertyRefreshLevels::ValuesOnly)
                             ->Attribute(Edit::Attributes::Visibility, &AreaLightComponentConfig::SupportsShadows)
                             ->Attribute(Edit::Attributes::ReadOnly, &AreaLightComponentConfig::IsEsmDisabled)
+                        ->DataElement(
+                            Edit::UIHandlers::Slider, &AreaLightComponentConfig::m_normalShadowBias, "Normal Shadow Bias\n",
+                            "Reduces acne by biasing the shadowmap lookup along the geometric normal.\n"
+                            "If this is 0, no biasing is applied.")
+                            ->Attribute(Edit::Attributes::Min, 0.f)
+                            ->Attribute(Edit::Attributes::Max, 10.0f)
+                            ->Attribute(Edit::Attributes::ChangeNotify, Edit::PropertyRefreshLevels::ValuesOnly)
+                            ->Attribute(Edit::Attributes::Visibility, &AreaLightComponentConfig::SupportsShadows)
+                            ->Attribute(Edit::Attributes::ReadOnly, &AreaLightComponentConfig::ShadowsDisabled)
                                 ;
                 }
             }

Gems/AtomLyIntegration/CommonFeatures/Code/Source/CoreLights/LightDelegateBase.h

@@ -58,6 +58,7 @@ namespace AZ
             void SetShadowFilterMethod([[maybe_unused]] ShadowFilterMethod method) override {};
             void SetFilteringSampleCount([[maybe_unused]] uint32_t count) override {};
             void SetEsmExponent([[maybe_unused]] float esmExponent) override{};
+            void SetNormalShadowBias([[maybe_unused]] float bias) override{};
             
         protected:
             void InitBase(EntityId entityId);

Gems/AtomLyIntegration/CommonFeatures/Code/Source/CoreLights/LightDelegateInterface.h

@@ -79,6 +79,8 @@ namespace AZ
             virtual void SetFilteringSampleCount(uint32_t count) = 0;
             //! Sets the Esm exponent to use. Higher values produce a steeper falloff between light and shadow.
             virtual void SetEsmExponent(float exponent) = 0;
+            //! Sets the normal bias. Reduces acne by biasing the shadowmap lookup along the geometric normal.
+            virtual void SetNormalShadowBias(float bias) = 0;
         };
     } //  namespace Render
 } // namespace AZ

Gems/AtomLyIntegration/CommonFeatures/Code/Source/CoreLights/SphereLightDelegate.cpp

@@ -107,4 +107,13 @@ namespace AZ::Render
             GetFeatureProcessor()->SetEsmExponent(GetLightHandle(), esmExponent);
         }
     }
+
+    void SphereLightDelegate::SetNormalShadowBias(float bias)
+    {
+        if (GetShadowsEnabled() && GetLightHandle().IsValid())
+        {
+            GetFeatureProcessor()->SetNormalShadowBias(GetLightHandle(), bias);
+        }
+    }
+
 } // namespace AZ::Render

Gems/AtomLyIntegration/CommonFeatures/Code/Source/CoreLights/SphereLightDelegate.h

@@ -36,6 +36,7 @@ namespace AZ
             void SetShadowFilterMethod(ShadowFilterMethod method) override;
             void SetFilteringSampleCount(uint32_t count) override;
             void SetEsmExponent(float esmExponent) override;
+            void SetNormalShadowBias(float bias) override;
 
         private: