Add Asset system

- Add Abstract Asset class which defines Assets
- Add AssetManager class to keep track of all the Asset
- Add AssetFile class to cache the asset without loading it
- Add UUID class to uniquely identify assets
- Add MetaFile class to load meta asset files

CopiumEngine/src/copium/asset/AssetFile.cpp

@@ -0,0 +1,50 @@
+#include "copium/asset/AssetFile.h"
+
+#include "copium/util/FileSystem.h"
+
+namespace Copium
+{
+  AssetFile::AssetFile(const std::string& path)
+    : path{path}
+  {
+    Load();
+  }
+
+  bool AssetFile::NeedReload() const
+  {
+    return dateModified < FileSystem::DateModified(path);
+  }
+
+  void AssetFile::Load() 
+  {
+    const std::vector<std::pair<std::string, AssetType>> strToType{{"Texture2D", AssetType::Texture2D}};
+    MetaFile metaFile{path};
+    for (auto&& [str, type] : strToType)
+    {
+      if (!metaFile.HasMetaClass(str))
+        continue;
+
+      Load(metaFile, str, type);
+      return;
+    }
+    CP_ABORT("Load : Unknown Asset type");
+  }
+
+  const std::string& AssetFile::GetPath() const
+  {
+    return path;
+  }
+
+  UUID AssetFile::GetUUID() const 
+  {
+    return uuid;
+  }
+
+  void AssetFile::Load(const MetaFile& metaFile, const std::string& className, AssetType assetType)
+  {
+    const MetaFileClass& metaClass = metaFile.GetMetaClass(className);
+    uuid = UUID{metaClass.GetValue("uuid")};
+    type = assetType;
+    dateModified = FileSystem::DateModified(path);
+  }
+}