Add RealtimeSkybox mode to SkyLight for dynamic skylight

Source/Engine/Graphics/Materials/MaterialShaderFeatures.cpp

@@ -60,8 +60,7 @@ void ForwardShadingFeature::Bind(MaterialShader::BindParameters& params, Span<by
     {
         auto& skyLight = cache->SkyLights.First();
         skyLight.SetShaderData(data.SkyLight, false);
-        const auto texture = skyLight.Image ? skyLight.Image->GetTexture() : nullptr;
-        params.GPUContext->BindSR(skyLightShaderRegisterIndex, GET_TEXTURE_VIEW_SAFE(texture));
+        params.GPUContext->BindSR(skyLightShaderRegisterIndex, skyLight.CubemapImageView);
     }
     else
     {

Source/Engine/Level/Actors/SkyLight.cpp

@@ -5,13 +5,17 @@
 #include "Engine/Platform/FileSystem.h"
 #include "Engine/Graphics/RenderView.h"
 #include "Engine/Graphics/RenderTask.h"
+#include "Engine/Graphics/RenderTools.h"
+#include "Engine/Graphics/GPUDevice.h"
+#include "Engine/Graphics/GPUContext.h"
+#include "Engine/Graphics/Textures/GPUTexture.h"
 #include "Engine/Graphics/Textures/TextureData.h"
 #include "Engine/Renderer/RenderList.h"
 #include "Engine/Renderer/ProbesRenderer.h"
+#include "Engine/Renderer/GBufferPass.h"
 #include "Engine/Content/Content.h"
 #include "Engine/Serialization/Serialization.h"
 #include "Engine/ContentImporters/AssetsImportingManager.h"
-#include "Engine/Graphics/RenderTools.h"
 #include "Engine/Level/Scene/Scene.h"
 
 SkyLight::SkyLight(const SpawnParams& params)
@@ -57,10 +61,9 @@ void SkyLight::SetProbeData(TextureData& data)
     // Validate input data
     ASSERT(data.GetArraySize() == 6);
 
-    // Check if was using custom probe
-    if (Mode == Modes::CustomTexture)
+    // Check if wasn't using captured probe
+    if (Mode != Modes::CaptureScene)
     {
-        // Set
         Mode = Modes::CaptureScene;
         _bakedProbe = nullptr;
     }
@@ -122,7 +125,18 @@ void SkyLight::Draw(RenderContext& renderContext)
         data.AdditiveColor = AdditiveColor.ToFloat3() * (AdditiveColor.A * brightness);
         data.IndirectLightingIntensity = IndirectLightingIntensity;
         data.Radius = GetScaledRadius();
-        data.Image = GetSource();
+        if (Mode == Modes::RealtimeSkybox)
+        {
+            if (GPUTextureView* skybox = GBufferPass::Instance()->RenderSkybox(renderContext, GPUDevice::Instance->GetMainContext()))
+            {
+                data.CubemapImageView = skybox;
+            }
+        }
+        else if (CubeTexture* image = GetSource())
+        {
+            data.CubemapImageView = GET_TEXTURE_VIEW_SAFE(image->GetTexture());
+            data.CubemapImageMip = image->StreamingTexture()->TotalMipLevels() - 2.0;
+        }
         data.StaticFlags = GetStaticFlags();
         data.ID = GetID();
         data.ScreenSize = Math::Min(1.0f, Math::Sqrt(RenderTools::ComputeBoundsScreenRadiusSquared(position, (float)_sphere.Radius, renderContext.View)));

Source/Engine/Level/Actors/SkyLight.h

@@ -28,6 +28,11 @@ public:
         /// The custom cube texture will be used as a light source.
         /// </summary>
         CustomTexture = 1,
+
+        /// <summary>
+        /// Realtime skybox will be used as a light source. Uses low-res cubemap generated from the sky/skybox (used by Global Illumination for fallback traces). Offers optimized dynamic ambient lighting.
+        /// </summary>
+        RealtimeSkybox = 2,
     };
 
 private:
@@ -44,13 +49,13 @@ public:
     /// <summary>
     /// Distance from the light at which any geometry should be treated as part of the sky.
     /// </summary>
-    API_FIELD(Attributes="EditorOrder(45), DefaultValue(150000.0f), Limit(0), EditorDisplay(\"Probe\")")
+    API_FIELD(Attributes="EditorOrder(45), Limit(0), EditorDisplay(\"Probe\")")
     float SkyDistanceThreshold = 150000.0f;
 
     /// <summary>
     /// The current light source mode.
     /// </summary>
-    API_FIELD(Attributes="EditorOrder(40), DefaultValue(Modes.CustomTexture), EditorDisplay(\"Probe\")")
+    API_FIELD(Attributes="EditorOrder(40), EditorDisplay(\"Probe\")")
     Modes Mode = Modes::CustomTexture;
 
     /// <summary>

Source/Engine/Renderer/LightPass.cpp

@@ -384,7 +384,7 @@ void LightPass::RenderLights(RenderContextBatch& renderContextBatch, GPUTextureV
         Matrix::Transpose(wvp, perLight.WVP);
 
         // Bind source image
-        context->BindSR(7, light.Image ? light.Image->GetTexture() : nullptr);
+        context->BindSR(7, light.CubemapImageView);
 
         // Calculate lighting
         if (_depthBounds)

Source/Engine/Renderer/RenderList.cpp

@@ -181,7 +181,7 @@ void RenderSkyLightData::SetShaderData(ShaderLightData& data, bool useShadow) co
     data.SpotAngles.X = AdditiveColor.X;
     data.SpotAngles.Y = AdditiveColor.Y;
     data.SourceRadius = AdditiveColor.Z;
-    data.SourceLength = Image ? Image->StreamingTexture()->TotalMipLevels() - 2.0f : 0.0f;
+    data.SourceLength = CubemapImageMip;
     data.Color = Color;
     data.MinRoughness = MIN_ROUGHNESS;
     data.Position = Position;

Source/Engine/Renderer/RenderList.h

@@ -144,7 +144,8 @@ struct RenderSkyLightData : RenderLightData
     Float3 AdditiveColor;
     float Radius;
 
-    CubeTexture* Image;
+    GPUTextureView* CubemapImageView;
+    float CubemapImageMip;
 
     RenderSkyLightData()
     {

Source/Engine/Renderer/VolumetricFogPass.cpp

@@ -483,7 +483,7 @@ void VolumetricFogPass::Render(RenderContext& renderContext)
     }
 
     // Init sky light data
-    GPUTexture* skyLightImage = nullptr;
+    GPUTextureView* skyLightImage = nullptr;
     Platform::MemoryClear(&cache.Data.SkyLight, sizeof(cache.Data.SkyLight));
     if (renderContext.List->SkyLights.HasItems() && !useDDGI)
     {
@@ -493,8 +493,7 @@ void VolumetricFogPass::Render(RenderContext& renderContext)
             cache.Data.SkyLight.MultiplyColor = skyLight.Color;
             cache.Data.SkyLight.AdditiveColor = skyLight.AdditiveColor;
             cache.Data.SkyLight.VolumetricScatteringIntensity = skyLight.VolumetricScatteringIntensity;
-            const auto source = skyLight.Image;
-            skyLightImage = source ? source->GetTexture() : nullptr;
+            skyLightImage = skyLight.CubemapImageView;
         }
     }