Merge pull request #4734 from aws-lumberyard-dev/Atom/mriegger/directionallightbias

Atom/mriegger/directionallightbias
2021-10-20 15:22:33 -05:00
parent 26f23cc3a5 a114fa5531
commit 2e44d96b05
11 changed files with 74 additions and 24 deletions
@@ -111,16 +111,18 @@ void DirectionalLightShadow::GetShadowCoords(
    float3 worldPosition,
    out float3 shadowCoords[ViewSrg::MaxCascadeCount])
 {
-    const float4x4 depthBiasMatrices[ViewSrg::MaxCascadeCount] = 
-        ViewSrg::m_directionalLightShadows[lightIndex].m_depthBiasMatrices;
    const uint cascadeCount = ViewSrg::m_directionalLightShadows[lightIndex].m_cascadeCount;
-
+    const float shadowBias = ViewSrg::m_directionalLightShadows[lightIndex].m_shadowBias;
+    const float4x4 lightViewToShadowmapMatrices[ViewSrg::MaxCascadeCount] = ViewSrg::m_directionalLightShadows[lightIndex].m_lightViewToShadowmapMatrices;
+    const float4x4 worldToLightViewMatrices[ViewSrg::MaxCascadeCount] = ViewSrg::m_directionalLightShadows[lightIndex].m_worldToLightViewMatrices;
+    
    for (uint index = 0; index < cascadeCount; ++index)
    {
-        const float4x4 depthBiasMatrix = depthBiasMatrices[index];
-        const float4 shadowCoordHomogeneous = mul(depthBiasMatrix, 
-            float4(worldPosition, 1.));
-        shadowCoords[index] = shadowCoordHomogeneous.xyz / shadowCoordHomogeneous.w;
+        float4 lightSpacePos = mul(worldToLightViewMatrices[index], float4(worldPosition, 1.));
+        lightSpacePos.z += shadowBias;
+
+        const float4 clipSpacePos = mul(lightViewToShadowmapMatrices[index], lightSpacePos);                
+        shadowCoords[index] = clipSpacePos.xyz / clipSpacePos.w;
    }
 }

@@ -102,18 +102,19 @@ partial ShaderResourceGroup ViewSrg

    struct DirectionalLightShadow
    {
-        float4x4 m_depthBiasMatrices[MaxCascadeCount];
        float4x4 m_lightViewToShadowmapMatrices[MaxCascadeCount];
        float4x4 m_worldToLightViewMatrices[MaxCascadeCount];
        float m_slopeBiasBase[MaxCascadeCount];
        float m_boundaryScale;
        uint m_shadowmapSize; // width and height of shadowmap
        uint m_cascadeCount;
+        float m_shadowBias; 
        uint m_predictionSampleCount;
        uint m_filteringSampleCount;
        uint m_debugFlags;
        uint m_shadowFilterMethod;
        float m_far_minus_near;
+        float3 m_padding;
    };

    enum ShadowFilterMethod
@@ -157,6 +157,9 @@ namespace AZ
            //! Sets whether the directional shadowmap should use receiver plane bias.
            //! This attempts to reduce shadow acne when using large pcf filters.
            virtual void SetShadowReceiverPlaneBiasEnabled(LightHandle handle, bool enable) = 0;
+
+            //! Reduces acne by applying a small amount of bias along shadow-space z.
+            virtual void SetShadowBias(LightHandle handle, float bias) = 0;
        };
    } // namespace Render
 } // namespace AZ
@@ -589,6 +589,15 @@ namespace AZ
            m_shadowProperties.GetData(handle.GetIndex()).m_isReceiverPlaneBiasEnabled = enable;
        }

+        void DirectionalLightFeatureProcessor::SetShadowBias(LightHandle handle, float bias) 
+        {
+            for (auto& it : m_shadowData) 
+            {
+                it.second.GetData(handle.GetIndex()).m_shadowBias = bias;               
+            }
+            m_shadowBufferNeedsUpdate = true;
+        }
+
        void DirectionalLightFeatureProcessor::OnRenderPipelineAdded(RPI::RenderPipelinePtr pipeline)
        {
            PrepareForChangingRenderPipelineAndCameraView();
@@ -1522,10 +1531,6 @@ namespace AZ

                for (uint16_t cascadeIndex = 0; cascadeIndex < GetCascadeCount(handle); ++cascadeIndex)
                {
-                    const Matrix4x4& worldToLightClipMatrix = property.m_segments.at(cameraView)[cascadeIndex].m_view->GetWorldToClipMatrix();
-                    const Matrix4x4 depthBiasMatrix = Shadow::GetClipToShadowmapTextureMatrix() * worldToLightClipMatrix;
-                    shadowData.m_depthBiasMatrices[cascadeIndex] = depthBiasMatrix;
-
                    const Matrix4x4& lightViewToLightClipMatrix = property.m_segments.at(cameraView)[cascadeIndex].m_view->GetViewToClipMatrix();
                    const Matrix4x4 lightViewToShadowmapMatrix = Shadow::GetClipToShadowmapTextureMatrix() * lightViewToLightClipMatrix;
                    shadowData.m_lightViewToShadowmapMatrices[cascadeIndex] = lightViewToShadowmapMatrix;
@@ -72,12 +72,6 @@ namespace AZ
        // [GFX TODO][ATOM-15172] Look into compacting struct DirectionalLightShadowData
        struct DirectionalLightShadowData
        {
-            AZStd::array<Matrix4x4, Shadow::MaxNumberOfCascades> m_depthBiasMatrices =
-            { {
-                    Matrix4x4::CreateIdentity(),
-                    Matrix4x4::CreateIdentity(),
-                    Matrix4x4::CreateIdentity(),
-                    Matrix4x4::CreateIdentity() } };
            AZStd::array<Matrix4x4, Shadow::MaxNumberOfCascades> m_lightViewToShadowmapMatrices =
            { {
                    Matrix4x4::CreateIdentity(),
@@ -97,11 +91,14 @@ namespace AZ
            float m_boundaryScale = 0.f;
            uint32_t m_shadowmapSize = 1; // width and height of shadowmap
            uint32_t m_cascadeCount = 1;
+            // Reduce acne by applying a small amount of bias to apply along shadow-space z.
+            float m_shadowBias = 0.0f; 
            uint32_t m_predictionSampleCount = 0;
            uint32_t m_filteringSampleCount = 0;
            uint32_t m_debugFlags = 0;
            uint32_t m_shadowFilterMethod = 0; 
            float m_far_minus_near = 0;
+            float m_padding[3];
        };

        class DirectionalLightFeatureProcessor final
@@ -218,6 +215,7 @@ namespace AZ
            void SetShadowFilterMethod(LightHandle handle, ShadowFilterMethod method) override;
            void SetFilteringSampleCount(LightHandle handle, uint16_t count) override;
            void SetShadowReceiverPlaneBiasEnabled(LightHandle handle, bool enable) override;
+            void SetShadowBias(LightHandle handle, float bias) override;

            const Data::Instance<RPI::Buffer> GetLightBuffer() const;
            uint32_t GetLightCount() const;
@@ -168,6 +168,14 @@ namespace AZ
            //! Sets whether the directional shadowmap should use receiver plane bias.
            //! @param enable flag specifying whether to enable the receiver plane bias feature
            virtual void SetShadowReceiverPlaneBiasEnabled(bool enable) = 0;
+
+            //! Shadow bias reduces acne by applying a small amount of offset along shadow-space z.
+            //! @return Returns the amount of bias to apply.
+            virtual float GetShadowBias() const = 0;
+
+            //! Shadow bias reduces acne by applying a small amount of offset along shadow-space z.
+            //! @param Sets the amount of bias to apply.
+            virtual void SetShadowBias(float bias) = 0;
        };
        using DirectionalLightRequestBus = EBus<DirectionalLightRequests>;

@@ -109,6 +109,9 @@ namespace AZ
            //! This uses partial derivatives to reduce shadow acne when using large pcf kernels.
            bool m_receiverPlaneBiasEnabled = true;

+            //! Reduces shadow acne by applying a small amount of offset along shadow-space z.
+            float m_shadowBias = 0.0f;
+
            bool IsSplitManual() const;
            bool IsSplitAutomatic() const;
            bool IsCascadeCorrectionDisabled() const;
@@ -38,7 +38,8 @@ namespace AZ
                    ->Field("IsDebugColoringEnabled", &DirectionalLightComponentConfig::m_isDebugColoringEnabled)
                    ->Field("ShadowFilterMethod", &DirectionalLightComponentConfig::m_shadowFilterMethod)
                    ->Field("PcfFilteringSampleCount", &DirectionalLightComponentConfig::m_filteringSampleCount)
-                    ->Field("ShadowReceiverPlaneBiasEnabled", &DirectionalLightComponentConfig::m_receiverPlaneBiasEnabled);
+                    ->Field("ShadowReceiverPlaneBiasEnabled", &DirectionalLightComponentConfig::m_receiverPlaneBiasEnabled)
+                    ->Field("Shadow Bias", &DirectionalLightComponentConfig::m_shadowBias);
            }
        }

@@ -84,6 +84,8 @@ namespace AZ
                    ->Event("SetFilteringSampleCount", &DirectionalLightRequestBus::Events::SetFilteringSampleCount)
                    ->Event("GetShadowReceiverPlaneBiasEnabled", &DirectionalLightRequestBus::Events::GetShadowReceiverPlaneBiasEnabled)
                    ->Event("SetShadowReceiverPlaneBiasEnabled", &DirectionalLightRequestBus::Events::SetShadowReceiverPlaneBiasEnabled)
+                    ->Event("GetShadowBias", &DirectionalLightRequestBus::Events::GetShadowBias)
+                    ->Event("SetShadowBias", &DirectionalLightRequestBus::Events::SetShadowBias)
                    ->VirtualProperty("Color", "GetColor", "SetColor")
                    ->VirtualProperty("Intensity", "GetIntensity", "SetIntensity")
                    ->VirtualProperty("AngularDiameter", "GetAngularDiameter", "SetAngularDiameter")
@@ -98,7 +100,8 @@ namespace AZ
                    ->VirtualProperty("DebugColoringEnabled", "GetDebugColoringEnabled", "SetDebugColoringEnabled")
                    ->VirtualProperty("ShadowFilterMethod", "GetShadowFilterMethod", "SetShadowFilterMethod")
                    ->VirtualProperty("FilteringSampleCount", "GetFilteringSampleCount", "SetFilteringSampleCount")
-                    ->VirtualProperty("ShadowReceiverPlaneBiasEnabled", "GetShadowReceiverPlaneBiasEnabled", "SetShadowReceiverPlaneBiasEnabled");
+                    ->VirtualProperty("ShadowReceiverPlaneBiasEnabled", "GetShadowReceiverPlaneBiasEnabled", "SetShadowReceiverPlaneBiasEnabled")
+                    ->VirtualProperty("ShadowBias", "GetShadowBias", "SetShadowBias");
                ;
            }
        }
@@ -406,6 +409,20 @@ namespace AZ
            return aznumeric_cast<uint32_t>(m_configuration.m_filteringSampleCount);
        }

+        void DirectionalLightComponentController::SetShadowBias(float bias) 
+        {
+            m_configuration.m_shadowBias = bias;
+            if (m_featureProcessor) 
+            {
+                m_featureProcessor->SetShadowBias(m_lightHandle, bias);
+            }            
+        }
+
+        float DirectionalLightComponentController::GetShadowBias() const 
+        {
+            return m_configuration.m_shadowBias;
+        }
+
        void DirectionalLightComponentController::SetFilteringSampleCount(uint32_t count)
        {
            const uint16_t count16 = GetMin(Shadow::MaxPcfSamplingCount, aznumeric_cast<uint16_t>(count));
@@ -499,6 +516,7 @@ namespace AZ
            SetViewFrustumCorrectionEnabled(m_configuration.m_isCascadeCorrectionEnabled);
            SetDebugColoringEnabled(m_configuration.m_isDebugColoringEnabled);
            SetShadowFilterMethod(m_configuration.m_shadowFilterMethod);
+            SetShadowBias(m_configuration.m_shadowBias);
            SetFilteringSampleCount(m_configuration.m_filteringSampleCount);
            SetShadowReceiverPlaneBiasEnabled(m_configuration.m_receiverPlaneBiasEnabled);

@@ -80,6 +80,8 @@ namespace AZ
            void SetFilteringSampleCount(uint32_t count) override;
            bool GetShadowReceiverPlaneBiasEnabled() const override;
            void SetShadowReceiverPlaneBiasEnabled(bool enable) override;
+            float GetShadowBias() const override;
+            void SetShadowBias(float width) override;

        private:
            friend class EditorDirectionalLightComponent;
@@ -133,8 +133,8 @@ namespace AZ
                            ->EnumAttribute(ShadowFilterMethod::Esm, "ESM")
                            ->EnumAttribute(ShadowFilterMethod::EsmPcf, "ESM+PCF")
                            ->Attribute(Edit::Attributes::ChangeNotify, Edit::PropertyRefreshLevels::ValuesOnly)
-                        ->DataElement(Edit::UIHandlers::Slider, &DirectionalLightComponentConfig::m_filteringSampleCount, "Filtering sample count",
-                            "This is used only when the pixel is predicted as on the boundary. "
+                        ->DataElement(Edit::UIHandlers::Slider, &DirectionalLightComponentConfig::m_filteringSampleCount, "Filtering sample count\n",
+                            "This is used only when the pixel is predicted as on the boundary.\n"
                            "Specific to PCF and ESM+PCF.")
                            ->Attribute(Edit::Attributes::Min, 4)
                            ->Attribute(Edit::Attributes::Max, 64)
@@ -142,10 +142,19 @@ namespace AZ
                            ->Attribute(Edit::Attributes::ReadOnly, &DirectionalLightComponentConfig::IsShadowPcfDisabled)
                        ->DataElement(
                            Edit::UIHandlers::CheckBox, &DirectionalLightComponentConfig::m_receiverPlaneBiasEnabled,
-                            "Shadow Receiver Plane Bias Enable",
+                            "Shadow Receiver Plane Bias Enable\n",
                            "This reduces shadow acne when using large pcf kernels.")
                          ->Attribute(Edit::Attributes::ChangeNotify, Edit::PropertyRefreshLevels::ValuesOnly)
-                          ->Attribute(Edit::Attributes::ReadOnly, &DirectionalLightComponentConfig::IsShadowPcfDisabled);
+                          ->Attribute(Edit::Attributes::ReadOnly, &DirectionalLightComponentConfig::IsShadowPcfDisabled) 
+                         ->DataElement(
+                            Edit::UIHandlers::Slider, &DirectionalLightComponentConfig::m_shadowBias,
+                            "Shadow Bias\n",
+                            "Reduces acne by applying a fixed bias along z in shadow-space.\n"
+                            "If this is 0, no biasing is applied.") 
+                           ->Attribute(Edit::Attributes::Min, 0.f)
+                           ->Attribute(Edit::Attributes::Max, 0.2) 
+                           ->Attribute(Edit::Attributes::ChangeNotify, Edit::PropertyRefreshLevels::ValuesOnly)
+                        ;
                }
            }