Improvements. You can now call SetDecalMaterial() with any permutation and it works as expected

Signed-off-by: mrieggeramzn <mriegger@amazon.com>

Gems/Atom/Feature/Common/Assets/ShaderLib/Atom/Features/PBR/Decals.azsli

@@ -70,6 +70,8 @@ void ApplyDecal(uint currDecalIndex, inout Surface surface)
 
         float4 baseMap = 0;
         float2 normalMap = 0;
+        // Each texture array handles a size permutation. 
+        // e.g. it could be that tex array 0 handles 256x256 and tex array 1 handles 512x64, etc.
         switch(textureArrayIndex)
         {
             case 0:

Gems/Atom/Feature/Common/Code/Source/Decals/DecalTextureArrayFeatureProcessor.cpp

@@ -301,23 +301,44 @@ namespace AZ
                 return;
             }
 
-            if (material.IsValid())
+            if (GetMaterialUsedByDecal(handle) == material)
+                return;
+
+            const auto decalIndex = handle.GetIndex();
+
+            const bool isValidMaterialBeingUsedCurrently = m_decalData.GetData(decalIndex).m_textureArrayIndex != DecalData::UnusedIndex;
+            if (isValidMaterialBeingUsedCurrently)
             {
-                AZ_Assert(m_decalData.GetData(handle.GetIndex()).m_textureArrayIndex == DecalData::UnusedIndex, "Setting Material on a decal more than once is not currently supported.");
+                RemoveMaterialFromDecal(decalIndex);
+            }
 
-                const auto iter = m_materialToTextureArrayLookupTable.find(material);
-                if (iter != m_materialToTextureArrayLookupTable.end())
-                {
-                    // This material is already loaded and registered with this feature processor
-                    iter->second.m_useCount++;
-                    SetDecalTextureLocation(handle, iter->second.m_location);
-                    return;
-                }
+            if (!material.IsValid())
+                return;
 
-                // Material not loaded so queue it up for loading.
-                QueueMaterialLoadForDecal(material, handle);
+            const auto iter = m_materialToTextureArrayLookupTable.find(material);
+            if (iter != m_materialToTextureArrayLookupTable.end())
+            {
+                // This material is already loaded and registered with this feature processor
+                iter->second.m_useCount++;
+                SetDecalTextureLocation(handle, iter->second.m_location);
                 return;
             }
+
+            // Material not loaded so queue it up for loading.
+            QueueMaterialLoadForDecal(material, handle);
+        }
+
+        void DecalTextureArrayFeatureProcessor::RemoveMaterialFromDecal(const uint16_t decalIndex)
+        {
+            DecalLocation decalLocation;
+            decalLocation.textureArrayIndex = m_decalData.GetData(decalIndex).m_textureArrayIndex;
+            decalLocation.textureIndex = m_decalData.GetData(decalIndex).m_textureIndex;
+            RemoveDecalFromTextureArrays(decalLocation);
+
+            m_decalData.GetData(decalIndex).m_textureArrayIndex = DecalData::UnusedIndex;
+            m_decalData.GetData(decalIndex).m_textureIndex = DecalData::UnusedIndex;
+
+            m_deviceBufferNeedsUpdate = true;
         }
 
         void DecalTextureArrayFeatureProcessor::CacheShaderIndices()

Gems/Atom/Feature/Common/Code/Source/Decals/DecalTextureArrayFeatureProcessor.h

@@ -114,6 +114,7 @@ namespace AZ
             AZStd::optional<DecalLocation> AddMaterialToTextureArrays(const AZ::RPI::MaterialAsset* materialAsset);
 
             int FindTextureArrayWithSize(const RHI::Size& size) const;
+            void RemoveMaterialFromDecal(const uint16_t decalIndex);
             void SetDecalTextureLocation(const DecalHandle& handle, const DecalLocation location);
             void QueueMaterialLoadForDecal(const AZ::Data::AssetId material, const DecalHandle handle);
             bool RemoveDecalFromTextureArrays(const DecalLocation decalLocation);

Gems/AtomLyIntegration/CommonFeatures/Code/Source/Decals/DecalComponentController.cpp

@@ -230,7 +230,7 @@ namespace AZ
         {
             DecalNotificationBus::Event(m_entityId, &DecalNotifications::OnMaterialChanged, m_configuration.m_materialAsset);
 
-            if (m_featureProcessor && m_configuration.m_materialAsset.GetId().IsValid())
+            if (m_featureProcessor)
             {
                 m_featureProcessor->SetDecalMaterial(m_handle, m_configuration.m_materialAsset.GetId());
             }

Gems/AtomLyIntegration/CommonFeatures/Code/Source/Decals/EditorDecalComponent.cpp

@@ -192,7 +192,7 @@ namespace AZ
 
         u32 EditorDecalComponent::OnConfigurationChanged()
         {
-            BaseClass::OnConfigurationChanged();
+            m_controller.ConfigurationChanged();
             return Edit::PropertyRefreshLevels::AttributesAndValues;
         }