Added "RemovePassTemplate" method. (#5039)

* Added "RemovePassTemplate" method.

Signed-off-by: garrieta <garrieta@amazon.com>

* RemovePassTemplate only allows to remove PassTemplates
created with the Runtime API. It now asserts if there are Passes
referencing the PassTemplate that should be removed.

Signed-off-by: garrieta <garrieta@amazon.com>

Gems/Atom/RPI/Code/Include/Atom/RPI.Public/Pass/PassLibrary.h

@@ -77,6 +77,16 @@ namespace AZ
             const AZStd::shared_ptr<PassTemplate> GetPassTemplate(const Name& name) const;
             const AZStd::vector<Pass*>& GetPassesForTemplate(const Name& templateName) const;
 
+            //! Removes a PassTemplate by name, only if the following two conditions are met:
+            //! 1- The template was NOT created from an Asset. This means the template will be erasable
+            //!    only if it was created at runtime with C++.
+            //! 2- The are no instantiated Passes referencing such template.
+            //! If the template exists but both conditions are not met then the function will assert.
+            //! If a template with the given name doesn't exist the function does nothing.
+            //! This function should be used judiciously, and under rare circumstances. For example,
+            //! Applications that iteratively create and need to delete templates at runtime.
+            void RemovePassTemplate(const Name& name);
+
             //! Removes a pass from both it's associated template (if it has one) and from the pass name mapping
             void RemovePassFromLibrary(Pass* pass);
 

Gems/Atom/RPI/Code/Include/Atom/RPI.Public/Pass/PassSystem.h

@@ -94,6 +94,7 @@ namespace AZ
             bool HasPassesForTemplateName(const Name& templateName) const override;
             bool AddPassTemplate(const Name& name, const AZStd::shared_ptr<PassTemplate>& passTemplate) override;
             const AZStd::shared_ptr<PassTemplate> GetPassTemplate(const Name& name) const override;
+            void RemovePassTemplate(const Name& name) override;
             void RemovePassFromLibrary(Pass* pass) override;
             void RegisterPass(Pass* pass) override;
             void UnregisterPass(Pass* pass) override;

Gems/Atom/RPI/Code/Include/Atom/RPI.Public/Pass/PassSystemInterface.h

@@ -199,6 +199,9 @@ namespace AZ
             //! Retrieves a PassTemplate from the library
             virtual const AZStd::shared_ptr<PassTemplate> GetPassTemplate(const Name& name) const = 0;
 
+            //! See remarks in PassLibrary.h for the function with this name.
+            virtual void RemovePassTemplate(const Name& name) = 0;
+
             //! Removes all references to the given pass from the pass library
             virtual void RemovePassFromLibrary(Pass* pass) = 0;
                         

Gems/Atom/RPI/Code/Source/RPI.Public/Pass/PassLibrary.cpp

@@ -236,6 +236,19 @@ namespace AZ
             return true;
         }
 
+        void PassLibrary::RemovePassTemplate(const Name& name)
+        {
+            auto itr = m_templateEntries.find(name);
+            if (itr != m_templateEntries.end())
+            {
+                AZ_Assert(itr->second.m_passes.empty(), "Can not delete PassTemplate '%s' because there are %zu Passes referencing it",
+                    name.GetCStr(), itr->second.m_passes.size());
+                AZ_Assert(!itr->second.m_mappingAssetId.IsValid(), "Can not delete PassTemplate '%s' because it was created from an asset",
+                    name.GetCStr());
+                m_templateEntries.erase(itr);
+            }
+        }
+
         void PassLibrary::RemovePassFromLibrary(Pass* pass)
         {
             if (m_isShuttingDown)

Gems/Atom/RPI/Code/Source/RPI.Public/Pass/PassSystem.cpp

@@ -466,6 +466,11 @@ namespace AZ
             return m_passLibrary.GetPassTemplate(name);
         }
 
+        void PassSystem::RemovePassTemplate(const Name& name)
+        {
+            m_passLibrary.RemovePassTemplate(name);
+        }
+
         void PassSystem::RemovePassFromLibrary(Pass* pass)
         {
             m_passLibrary.RemovePassFromLibrary(pass);