Merge pull request #1711 from aws-lumberyard-dev/Atom/dmcdiar/ATOM-15921

[ATOM-15921] ReflectionProbe cubemaps bake with incorrect exposure value

Gems/Atom/Feature/Common/Code/Source/ReflectionProbe/ReflectionProbe.cpp

@@ -96,16 +96,29 @@ namespace AZ
 
         void ReflectionProbe::Simulate(uint32_t probeIndex)
         {
-            if (m_buildingCubeMap && m_environmentCubeMapPass->IsFinished())
+            if (m_buildingCubeMap)
             {
-                // all faces of the cubemap have been rendered, invoke the callback
-                m_callback(m_environmentCubeMapPass->GetTextureData(), m_environmentCubeMapPass->GetTextureFormat());
-
-                // remove the pipeline
-                m_scene->RemoveRenderPipeline(m_environmentCubeMapPipelineId);
-                m_environmentCubeMapPass = nullptr;
-
-                m_buildingCubeMap = false;
+                Data::Instance<RPI::ShaderResourceGroup> sceneSrg = m_scene->GetShaderResourceGroup();
+
+                if (m_environmentCubeMapPass->IsFinished())
+                {
+                    // all faces of the cubemap have been rendered, invoke the callback
+                    m_callback(m_environmentCubeMapPass->GetTextureData(), m_environmentCubeMapPass->GetTextureFormat());
+
+                    // remove the pipeline
+                    m_scene->RemoveRenderPipeline(m_environmentCubeMapPipelineId);
+                    m_environmentCubeMapPass = nullptr;
+
+                    // restore exposure
+                    sceneSrg->SetConstant(m_iblExposureConstantIndex, m_previousExposure);
+
+                    m_buildingCubeMap = false;
+                }
+                else
+                {
+                    // set exposure to 0.0 while baking the cubemap
+                    sceneSrg->SetConstant(m_iblExposureConstantIndex, 0.0f);
+                }
             }
 
             // track if we need to update culling based on changes to the draw packets or Srg
@@ -283,6 +296,10 @@ namespace AZ
             const RPI::Ptr<RPI::ParentPass>& rootPass = environmentCubeMapPipeline->GetRootPass();
             rootPass->AddChild(m_environmentCubeMapPass);
 
+            // store the current IBL exposure value
+            Data::Instance<RPI::ShaderResourceGroup> sceneSrg = m_scene->GetShaderResourceGroup();
+            m_previousExposure = sceneSrg->GetConstant<float>(m_iblExposureConstantIndex);
+
             m_scene->AddRenderPipeline(environmentCubeMapPipeline);
         }
 

Gems/Atom/Feature/Common/Code/Source/ReflectionProbe/ReflectionProbe.h

@@ -163,6 +163,8 @@ namespace AZ
             RPI::Ptr<RPI::EnvironmentCubeMapPass> m_environmentCubeMapPass = nullptr;
             RPI::RenderPipelineId m_environmentCubeMapPipelineId;
             BuildCubeMapCallback m_callback;
+            RHI::ShaderInputNameIndex m_iblExposureConstantIndex = "m_iblExposure";
+            float m_previousExposure = 0.0f;
             bool m_buildingCubeMap = false;
         };