Add IndirectLightingIntensity to Sky for GI intensity control

Source/Engine/Level/Actors/Sky.cpp

@@ -16,6 +16,9 @@
 #include "Engine/Graphics/Shaders/GPUShader.h"
 #include "Engine/Serialization/Serialization.h"
 #include "Engine/Level/Scene/SceneRendering.h"
+#if USE_EDITOR
+#include "Engine/Renderer/Lightmaps.h"
+#endif
 
 GPU_CB_STRUCT(Data {
     Matrix WVP;
@@ -66,6 +69,10 @@ void Sky::InitConfig(ShaderAtmosphericFogData& config) const
 
     config.AtmosphericFogSunPower = SunPower;
     config.AtmosphericFogDensityOffset = 0.0f;
+#if USE_EDITOR
+    if (IsRunningRadiancePass)
+    config.AtmosphericFogSunPower *= IndirectLightingIntensity;
+#endif
 
     if (SunLight)
     {
@@ -140,6 +147,7 @@ void Sky::Serialize(SerializeStream& stream, const void* otherObj)
     SERIALIZE_MEMBER(Sun, SunLight);
     SERIALIZE(SunDiscScale);
     SERIALIZE(SunPower);
+    SERIALIZE(IndirectLightingIntensity);
 }
 
 void Sky::Deserialize(DeserializeStream& stream, ISerializeModifier* modifier)
@@ -150,6 +158,7 @@ void Sky::Deserialize(DeserializeStream& stream, ISerializeModifier* modifier)
     DESERIALIZE_MEMBER(Sun, SunLight);
     DESERIALIZE(SunDiscScale);
     DESERIALIZE(SunPower);
+    DESERIALIZE(IndirectLightingIntensity);
 }
 
 bool Sky::HasContentLoaded() const
@@ -204,6 +213,11 @@ bool Sky::IsDynamicSky() const
     return !IsStatic() || (SunLight && !SunLight->IsStatic());
 }
 
+float Sky::GetIndirectLightingIntensity() const
+{
+    return IndirectLightingIntensity;
+}
+
 void Sky::ApplySky(GPUContext* context, RenderContext& renderContext, const Matrix& world)
 {
     // Get precomputed cache and bind it to the pipeline

Source/Engine/Level/Actors/Sky.h

@@ -31,21 +31,27 @@ public:
     /// <summary>
     /// Directional light that is used to simulate the sun.
     /// </summary>
-    API_FIELD(Attributes="EditorOrder(10), DefaultValue(null), EditorDisplay(\"Sky\")")
+    API_FIELD(Attributes="EditorOrder(10), EditorDisplay(\"Sky\")")
     ScriptingObjectReference<DirectionalLight> SunLight;
 
     /// <summary>
     /// The sun disc scale.
     /// </summary>
-    API_FIELD(Attributes="EditorOrder(20), DefaultValue(2.0f), EditorDisplay(\"Sky\"), Limit(0, 100, 0.01f)")
+    API_FIELD(Attributes="EditorOrder(20), EditorDisplay(\"Sky\"), Limit(0, 100, 0.01f)")
     float SunDiscScale = 2.0f;
 
     /// <summary>
     /// The sun power.
     /// </summary>
-    API_FIELD(Attributes="EditorOrder(30), DefaultValue(8.0f), EditorDisplay(\"Sky\"), Limit(0, 1000, 0.01f)")
+    API_FIELD(Attributes="EditorOrder(30), EditorDisplay(\"Sky\"), Limit(0, 1000, 0.01f)")
     float SunPower = 8.0f;
 
+    /// <summary>
+    /// Controls how much sky will contribute indirect lighting. When set to 0, there is no GI from the sky. The default value is 1.
+    /// </summary>
+    API_FIELD(Attributes="EditorOrder(40), Limit(0, 100, 0.1f), EditorDisplay(\"Sky\")")
+    float IndirectLightingIntensity = 1.0f;
+
 private:
 #if COMPILE_WITH_DEV_ENV
     void OnShaderReloading(Asset* obj)
@@ -76,6 +82,7 @@ public:
 
     // [ISkyRenderer]
     bool IsDynamicSky() const override;
+    float GetIndirectLightingIntensity() const override;
     void ApplySky(GPUContext* context, RenderContext& renderContext, const Matrix& world) override;
 
 protected:

Source/Engine/Level/Actors/Skybox.cpp

@@ -94,6 +94,11 @@ bool Skybox::IsDynamicSky() const
     return !IsStatic();
 }
 
+float Skybox::GetIndirectLightingIntensity() const
+{
+    return 1.0f;
+}
+
 void Skybox::ApplySky(GPUContext* context, RenderContext& renderContext, const Matrix& world)
 {
     // Prepare mock draw call data

Source/Engine/Level/Actors/Skybox.h

@@ -70,6 +70,7 @@ public:
 
     // [ISkyRenderer]
     bool IsDynamicSky() const override;
+    float GetIndirectLightingIntensity() const override;
     void ApplySky(GPUContext* context, RenderContext& renderContext, const Matrix& world) override;
 
 protected:

Source/Engine/Renderer/DrawCall.h

@@ -40,6 +40,8 @@ public:
     /// </summary>
     virtual bool IsDynamicSky() const = 0;
 
+    virtual float GetIndirectLightingIntensity() const = 0;
+
     /// <summary>
     /// Apply sky material/shader state to the GPU pipeline with custom parameters set (render to GBuffer).
     /// </summary>

Source/Engine/Renderer/GI/DynamicDiffuseGlobalIllumination.cpp

@@ -60,7 +60,7 @@ GPU_CB_STRUCT(Data0 {
     GlobalSurfaceAtlasPass::ConstantsData GlobalSurfaceAtlas;
     ShaderGBufferData GBuffer;
     Float4 RaysRotation;
-    float Padding0;
+    float SkyboxIntensity;
     uint32 ProbesCount;
     float ResetBlend;
     float TemporalTime;
@@ -533,6 +533,7 @@ bool DynamicDiffuseGlobalIlluminationPass::RenderInner(RenderContext& renderCont
         }
         data.TemporalTime = renderContext.List->Setup.UseTemporalAAJitter ? RenderTools::ComputeTemporalTime() : 0.0f;
         data.ViewDir = renderContext.View.Direction;
+        data.SkyboxIntensity = renderContext.List->Sky ? renderContext.List->Sky->GetIndirectLightingIntensity() : 1.0f;
         GBufferPass::SetInputs(renderContext.View, data.GBuffer);
         context->UpdateCB(_cb0, &data);
         context->BindCB(0, _cb0);

Source/Shaders/GI/DDGI.shader

@@ -35,7 +35,7 @@ GlobalSDFData GlobalSDF;
 GlobalSurfaceAtlasData GlobalSurfaceAtlas;
 GBufferData GBuffer;
 float4 RaysRotation;
-float Padding0;
+float SkyboxIntensity;
 uint ProbesCount;
 float ResetBlend;
 float TemporalTime;
@@ -397,7 +397,7 @@ void CS_TraceRays(uint3 DispatchThreadId : SV_DispatchThreadID)
     else
     {
         // Ray hits sky
-        radiance.rgb = Skybox.SampleLevel(SamplerLinearClamp, probeRayDirection, 0).rgb;
+        radiance.rgb = Skybox.SampleLevel(SamplerLinearClamp, probeRayDirection, 0).rgb * SkyboxIntensity;
         radiance.a = 1e27f; // Sky is the limit
     }