rendering: extract default native scene backend

engine/src/Rendering/Internal/RenderPipelineFactory.cpp

@@ -15,32 +15,49 @@ namespace Internal {
 
 namespace {
 
+class DefaultNativePipelineBackendAsset final : public RenderPipelineAsset {
+public:
+    std::unique_ptr<RenderPipeline> CreatePipeline() const override {
+        return Pipelines::Internal::CreateConfiguredBuiltinForwardPipeline();
+    }
+
+    FinalColorSettings GetDefaultFinalColorSettings() const override {
+        return {};
+    }
+};
+
 std::shared_ptr<const RenderPipelineAsset>
-CreateBuiltinForwardPipelineRendererAsset() {
+CreateDefaultNativePipelineBackendAsset() {
     static const std::shared_ptr<const RenderPipelineAsset>
-        s_builtinForwardPipelineAsset =
-            std::make_shared<Pipelines::BuiltinForwardPipelineAsset>();
-    return s_builtinForwardPipelineAsset;
+        s_defaultNativePipelineBackendAsset =
+            std::make_shared<DefaultNativePipelineBackendAsset>();
+    return s_defaultNativePipelineBackendAsset;
 }
 
-std::unique_ptr<SceneDrawBackend> TryCreateSceneDrawBackendFromAsset(
+std::unique_ptr<RenderPipelineBackend> TryCreatePipelineBackendFromAsset(
     const std::shared_ptr<const RenderPipelineAsset>& asset) {
     if (asset == nullptr) {
         return nullptr;
     }
 
-    std::unique_ptr<RenderPipeline> pipeline = asset->CreatePipeline();
-    if (pipeline == nullptr) {
+    return asset->CreatePipeline();
+}
+
+std::unique_ptr<SceneDrawBackend> TryCreateSceneDrawBackendFromAsset(
+    const std::shared_ptr<const RenderPipelineAsset>& asset) {
+    std::unique_ptr<RenderPipelineBackend> pipelineBackend =
+        TryCreatePipelineBackendFromAsset(asset);
+    if (pipelineBackend == nullptr) {
         return nullptr;
     }
 
     SceneDrawBackend* const sceneDrawBackend =
-        dynamic_cast<SceneDrawBackend*>(pipeline.get());
+        dynamic_cast<SceneDrawBackend*>(pipelineBackend.get());
     if (sceneDrawBackend == nullptr) {
         return nullptr;
     }
 
-    (void)pipeline.release();
+    (void)pipelineBackend.release();
     return std::unique_ptr<SceneDrawBackend>(sceneDrawBackend);
 }
 
@@ -56,7 +73,7 @@ std::shared_ptr<const RenderPipelineAsset> CreateFallbackRenderPipelineAsset() {
 
 std::shared_ptr<const RenderPipelineAsset> CreateDefaultPipelineBackendAsset() {
     static const std::shared_ptr<const RenderPipelineAsset> s_defaultAsset =
-        CreateBuiltinForwardPipelineRendererAsset();
+        CreateDefaultNativePipelineBackendAsset();
     return s_defaultAsset;
 }
 
@@ -128,6 +145,39 @@ std::unique_ptr<RenderPipeline> CreateRenderPipelineOrDefault(
     return std::make_unique<Pipelines::ScriptableRenderPipelineHost>();
 }
 
+std::unique_ptr<RenderPipelineBackend> CreatePipelineBackendFromAsset(
+    const std::shared_ptr<const RenderPipelineAsset>& preferredAsset,
+    std::shared_ptr<const RenderPipelineAsset>* outResolvedAsset) {
+    if (std::unique_ptr<RenderPipelineBackend> pipelineBackend =
+            TryCreatePipelineBackendFromAsset(preferredAsset)) {
+        if (outResolvedAsset != nullptr) {
+            *outResolvedAsset = preferredAsset;
+        }
+        return pipelineBackend;
+    }
+
+    const std::shared_ptr<const RenderPipelineAsset> defaultAsset =
+        CreateDefaultPipelineBackendAsset();
+    if (defaultAsset != nullptr &&
+        defaultAsset != preferredAsset) {
+        if (std::unique_ptr<RenderPipelineBackend> pipelineBackend =
+                TryCreatePipelineBackendFromAsset(defaultAsset)) {
+            if (outResolvedAsset != nullptr) {
+                *outResolvedAsset = defaultAsset;
+            }
+            return pipelineBackend;
+        }
+    }
+
+    if (outResolvedAsset != nullptr) {
+        *outResolvedAsset =
+            defaultAsset != nullptr
+                ? defaultAsset
+                : preferredAsset;
+    }
+    return Pipelines::Internal::CreateConfiguredBuiltinForwardPipeline();
+}
+
 std::unique_ptr<SceneDrawBackend> CreateSceneDrawBackendFromAsset(
     const std::shared_ptr<const RenderPipelineAsset>& preferredAsset,
     std::shared_ptr<const RenderPipelineAsset>* outResolvedAsset) {
@@ -146,14 +196,7 @@ std::unique_ptr<SceneDrawBackend> CreateSceneDrawBackendFromAsset(
 }
 
 std::unique_ptr<SceneDrawBackend> CreateDefaultSceneDrawBackend() {
-    if (std::unique_ptr<SceneDrawBackend> sceneDrawBackend =
-            TryCreateSceneDrawBackendFromAsset(
-                CreateDefaultPipelineBackendAsset());
-        sceneDrawBackend != nullptr) {
-        return sceneDrawBackend;
-    }
-
-    return Pipelines::Internal::CreateConfiguredBuiltinForwardPipeline();
+    return Pipelines::Internal::CreateConfiguredBuiltinForwardSceneDrawBackend();
 }
 
 } // namespace Internal