Add LOD Preview debug view mode

Source/Engine/Renderer/Editor/LODPreview.h

@@ -0,0 +1,47 @@
+// Copyright (c) 2012-2021 Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#if USE_EDITOR
+
+#include "Engine/Content/AssetReference.h"
+#include "Engine/Content/Assets/Shader.h"
+#include "Engine/Content/Assets/Texture.h"
+#include "Engine/Graphics/Materials/IMaterial.h"
+
+class GPUPipelineState;
+
+/// <summary>
+/// Rendering Level Of Detail number as colors to debug LOD switches in editor.
+/// </summary>
+class LODPreviewMaterialShader : public IMaterial
+{
+private:
+
+    AssetReference<Shader> _shader;
+    GPUPipelineState* _ps = nullptr;
+    MaterialInfo _info;
+
+public:
+
+    LODPreviewMaterialShader();
+    virtual ~LODPreviewMaterialShader()
+    {
+    }
+
+private:
+
+#if COMPILE_WITH_DEV_ENV
+    void OnShaderReloading(Asset* obj);
+#endif
+
+public:
+
+    // [IMaterial]
+    const MaterialInfo& GetInfo() const override;
+    bool IsReady() const override;
+    DrawPass GetDrawModes() const override;
+    void Bind(BindParameters& params) override;
+};
+
+#endif