Atom/qingtao/atom 16135 (#7334)

* Changes to AttachmentImage related classes to have better support using render target as texture.
- Updated AttachmentImageAsset to support an unique name which can be used as AttachmentId.
- Functions in ImageSystemInterface to find an AttachmentImage by its unique name.
- Added InsertChild function to ParentPass class so it can insert a child pass at any location.
- Change to ImageAttachmentPreviewPass so it can preview cached pass attachment even the source pass was disabled.

Signed-off-by: Qing Tao <55564570+VickyAtAZ@users.noreply.github.com>

Gems/Atom/RPI/Code/Source/RPI.Reflect/Image/AttachmentImageAssetCreator.cpp

@@ -7,6 +7,8 @@
  */
 
 #include <Atom/RPI.Reflect/Image/AttachmentImageAssetCreator.h>
+#include <Atom/RPI.Public/Image/AttachmentImagePool.h>
+#include <Atom/RPI.Public/Image/ImageSystemInterface.h>
 
 #include <AzCore/Asset/AssetManager.h>
 
@@ -47,8 +49,7 @@ namespace AZ
         {
             if (ValidateIsReady())
             {
-                m_asset->m_isClearValueValid = true;
-                m_asset->m_optimizedClearValue = clearValue;
+                m_asset->m_optimizedClearValue = AZStd::make_shared<RHI::ClearValue>(clearValue);
             }
         }
 
@@ -59,12 +60,11 @@ namespace AZ
                 return false;
             }
 
-            // Validate assetId instead of validate AssetData* exist. This is mainly because the Asset<T> 's serializer only need serialize asset id instead of asset data
-            // Instead of create a complete Asset<T>, we could use new Asset(assetId, type, hint) to create a placeholder to save the asset id for serialization.
+            // If the pool wasn't provided, use the system default attachment pool
             if (!m_asset->m_poolAsset.GetId().IsValid())
             {
-                ReportError("You must assign a pool asset before calling End().");
-                return false;
+                Data::Instance<RPI::AttachmentImagePool> pool = RPI::ImageSystemInterface::Get()->GetSystemAttachmentPool();
+                m_asset->m_poolAsset = {pool->GetAssetId(), azrtti_typeid<ResourcePoolAsset>()};
             }
 
             m_asset->SetReady();
@@ -75,5 +75,20 @@ namespace AZ
         {
             m_asset.SetHint(hint);
         }
+
+        void AttachmentImageAssetCreator::SetName(const AZ::Name& uniqueName, bool isUniqueName)
+        {
+            if (uniqueName.IsEmpty())
+            {
+                m_asset->m_isUniqueName = false;
+                AZ_Warning("RPI", false, "Can't set empty string as unique name");
+            }
+            else
+            {
+                m_asset->m_isUniqueName = isUniqueName;
+            }
+            m_asset->m_name = uniqueName;
+
+        }
     }
 }