Refactor models and meshes to share more code in a base class

Source/Engine/Content/Assets/ModelBase.h

@@ -4,6 +4,7 @@
 
 #include "../BinaryAsset.h"
 #include "Engine/Core/Collections/Array.h"
+#include "Engine/Graphics/Models/Config.h"
 #include "Engine/Graphics/Models/MaterialSlot.h"
 #include "Engine/Streaming/StreamableResource.h"
 
@@ -26,6 +27,14 @@ struct RenderContextBatch;
 API_CLASS(Abstract, NoSpawn) class FLAXENGINE_API ModelBase : public BinaryAsset, public StreamableResource
 {
     DECLARE_ASSET_HEADER(ModelBase);
+    friend MeshBase;
+    friend class StreamModelLODTask;
+
+protected:
+    bool _initialized = false;
+    int32 _loadedLODs = 0;
+    StreamModelLODTask* _streamingTask = nullptr;
+
 public:
     /// <summary>
     /// The Sign Distant Field (SDF) data for the model.
@@ -106,6 +115,48 @@ public:
         return MaterialSlots.Count();
     }
 
+    /// <summary>
+    /// Gets a value indicating whether this instance is initialized. 
+    /// </summary>
+    FORCE_INLINE bool IsInitialized() const
+    {
+        return _initialized;
+    }
+
+    /// <summary>
+    /// Clamps the index of the LOD to be valid for rendering (only loaded LODs).
+    /// </summary>
+    /// <param name="index">The index.</param>
+    /// <returns>The resident LOD index.</returns>
+    FORCE_INLINE int32 ClampLODIndex(int32 index) const
+    {
+        return Math::Clamp(index, HighestResidentLODIndex(), GetLODsCount() - 1);
+    }
+
+    /// <summary>
+    /// Gets index of the highest resident LOD (it may be equal to LODs.Count if no LOD has been uploaded). Note: LOD=0 is the highest (top quality)
+    /// </summary>
+    FORCE_INLINE int32 HighestResidentLODIndex() const
+    {
+        return GetLODsCount() - _loadedLODs;
+    }
+
+    /// <summary>
+    /// Gets the amount of loaded model LODs.
+    /// </summary>
+    API_PROPERTY() FORCE_INLINE int32 GetLoadedLODs() const
+    {
+        return _loadedLODs;
+    }
+
+    /// <summary>
+    /// Determines whether this model can be rendered.
+    /// </summary>
+    FORCE_INLINE bool CanBeRendered() const
+    {
+        return _loadedLODs > 0;
+    }
+
     /// <summary>
     /// Resizes the material slots collection. Updates meshes that were using removed slots.
     /// </summary>
@@ -127,4 +178,37 @@ public:
     /// Gets the meshes for a particular LOD index.
     /// </summary>
     virtual void GetMeshes(Array<MeshBase*>& meshes, int32 lodIndex = 0) = 0;
+
+public:
+    /// <summary>
+    /// Requests the LOD data asynchronously (creates task that will gather chunk data or null if already here).
+    /// </summary>
+    /// <param name="lodIndex">Index of the LOD.</param>
+    /// <returns>Task that will gather chunk data or null if already here.</returns>
+    ContentLoadTask* RequestLODDataAsync(int32 lodIndex);
+
+    /// <summary>
+    /// Gets the model LOD data (links bytes).
+    /// </summary>
+    /// <param name="lodIndex">Index of the LOD.</param>
+    /// <param name="data">The data (it may be missing if failed to get it).</param>
+    void GetLODData(int32 lodIndex, BytesContainer& data) const;
+
+public:
+    // [BinaryAsset]
+    void CancelStreaming() override;
+#if USE_EDITOR
+    void GetReferences(Array<Guid>& assets, Array<String>& files) const override;
+#endif
+
+    // [StreamableResource]
+    int32 GetCurrentResidency() const override;
+    bool CanBeUpdated() const override;
+    Task* UpdateAllocation(int32 residency) override;
+    Task* CreateStreamingTask(int32 residency) override;
+    void CancelStreamingTasks() override;
+
+protected:
+    // [BinaryAsset]
+    void unload(bool isReloading) override;
 };