Fix default shadow depth bias values and control them based on shadow resolution/quality mix

Source/Engine/GraphicsDevice/Vulkan/GPUDeviceVulkan.cpp

@@ -820,7 +820,7 @@ VkSampler* HelperResourcesVulkan::GetStaticSamplers()
         RenderToolsVulkan::ZeroStruct(createInfo, VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO);
         createInfo.mipLodBias = 0.0f;
         createInfo.minLod = 0.0f;
-        createInfo.maxLod = MAX_float;
+        createInfo.maxLod = 1000.0f;
         createInfo.maxAnisotropy = 1.0f;
         createInfo.anisotropyEnable = VK_FALSE;
         createInfo.borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_BLACK;

Source/Engine/Level/Actors/DirectionalLight.cpp

@@ -10,6 +10,8 @@
 DirectionalLight::DirectionalLight(const SpawnParams& params)
     : LightWithShadow(params)
 {
+    ShadowsDepthBias = 0.002f;
+
     _drawNoCulling = 1;
     Brightness = 8.0f;
 }

Source/Engine/Level/Actors/Light.h

@@ -151,7 +151,7 @@ public:
     /// The depth bias used for shadow map comparison.
     /// </summary>
     API_FIELD(Attributes="EditorOrder(95), EditorDisplay(\"Shadow\", \"Depth Bias\"), Limit(0.0f, 10.0f, 0.0001f)")
-    float ShadowsDepthBias = 0.005f;
+    float ShadowsDepthBias = 0.05f;
 
     /// <summary>
     /// A factor specifying the offset to add to the calculated shadow map depth with respect to the surface normal.

Source/Engine/Level/Actors/PointLight.cpp

@@ -15,8 +15,9 @@ PointLight::PointLight(const SpawnParams& params)
 {
     CastVolumetricShadow = false;
     ShadowsDistance = 2000.0f;
-    ShadowsFadeDistance = 100.0f;
-    ShadowsDepthBias = 0.5f;
+    ShadowsFadeDistance = 500.0f;
+    ShadowsDepthBias = 0.05f;
+
     _direction = Float3::Forward;
     _sphere = BoundingSphere(Vector3::Zero, _radius);
     BoundingBox::FromSphere(_sphere, _box);

Source/Engine/Level/Actors/SpotLight.cpp

@@ -19,8 +19,8 @@ SpotLight::SpotLight(const SpawnParams& params)
 {
     CastVolumetricShadow = false;
     ShadowsDistance = 2000.0f;
-    ShadowsFadeDistance = 100.0f;
-    ShadowsDepthBias = 0.5f;
+    ShadowsFadeDistance = 500.0f;
+    ShadowsDepthBias = 0.05f;
 
     _direction = Vector3::Forward;
     _cosOuterCone = Math::Cos(_outerConeAngle * DegreesToRadians);

Source/Engine/Renderer/ShadowsPass.cpp

@@ -635,9 +635,80 @@ void ShadowsPass::SetupLight(ShadowsCustomBuffer& shadows, RenderContext& render
     atlasLight.Bounds.Center = light.Position + renderContext.View.Origin; // Keep bounds in world-space to properly handle DirtyStaticBounds
     atlasLight.Bounds.Radius = 0.0f;
 
-    // Adjust bias to account for lower shadow quality
-    if (shadows.MaxShadowsQuality == 0)
-        atlasLight.Bias *= 1.5f;
+    // Adjust bias to account for lower shadow quality (mix between different shadow map resolution and filter size) to automatically hide artifacts
+    switch ((Quality)shadows.MaxShadowsQuality)
+    {
+    case Quality::Low:
+        switch (Graphics::ShadowMapsQuality)
+        {
+        case Quality::Low:
+            atlasLight.Bias += 0.003f;
+            break;
+        case Quality::Medium:
+            atlasLight.Bias += 0.001f;
+            break;
+        }
+        break;
+    case Quality::Medium:
+        switch (Graphics::ShadowMapsQuality)
+        {
+        case Quality::Low:
+            atlasLight.Bias += 0.008f;
+            break;
+        case Quality::Medium:
+            atlasLight.Bias += 0.003f;
+            break;
+        case Quality::High:
+            atlasLight.Bias += 0.001f;
+            break;
+        }
+        break;
+    case Quality::High:
+        switch (Graphics::ShadowMapsQuality)
+        {
+        case Quality::Low:
+            atlasLight.Bias += 0.012f;
+            break;
+        case Quality::Medium:
+            atlasLight.Bias += 0.006f;
+            break;
+        case Quality::High:
+            atlasLight.Bias += 0.002f;
+            break;
+        }
+        break;
+    }
+    if (!light.IsDirectionalLight)
+    {
+        switch ((Quality)shadows.MaxShadowsQuality)
+        {
+        case Quality::Medium:
+            switch (Graphics::ShadowMapsQuality)
+            {
+            case Quality::Low:
+                atlasLight.NormalOffsetScale += 25;
+                break;
+            case Quality::Medium:
+                atlasLight.NormalOffsetScale += 10;
+                break;
+            }
+            break;
+        case Quality::High:
+            switch (Graphics::ShadowMapsQuality)
+            {
+            case Quality::Low:
+                atlasLight.NormalOffsetScale += 20;
+                break;
+            case Quality::Medium:
+                atlasLight.NormalOffsetScale +=15;
+                break;
+            case Quality::High:
+                atlasLight.NormalOffsetScale += 5;
+                break;
+            }
+            break;
+        }
+    }
 }
 
 bool ShadowsPass::SetupLight(ShadowsCustomBuffer& shadows, RenderContext& renderContext, RenderContextBatch& renderContextBatch, RenderLocalLightData& light, ShadowAtlasLight& atlasLight)

Source/Shaders/ShadowsSampling.hlsl

@@ -334,6 +334,9 @@ float SampleShadowMapPCSS(Texture2D<float> shadowMap, float2 shadowMapUV, float
 
     // Calculate penumbra size
     float penumbra = max(sceneDepth - avgBlockerDistance, 0.0);
+#if defined(VULKAN)
+    sceneDepth *= lerp(1, 0.985f, saturate(penumbra * 4.0f)); // Fix shadow bias issues on Vulkan
+#endif
     float filterRadius = penumbra * sourceAngle;
     filterRadius = max(filterRadius, minRadius); // Don't use too small filter near blockers to avoid jagged edges