Very cool to see someone actually making a game in their hobby engine!
Regarding the asset prefetching, you mention that they are loaded lazily. Maybe I'm misunderstanding but to me prefetching and lazy loading are the opposite (i.e. you would prefetch during a loading screen in order to avoid loading things on demand since it could affect the game loop). Could you elaborate?
The prefetching works like this: a list of assets is provided, and in each main loop iteration, the engine opens and loads a single one into memory (an unordered map of shared pointers). It would be more effective in a longer game, where as the player moves, the assets are already being prepared for use.
There’s also a mechanism to collect and remove unused assets from memory.
What I really wanted was to load the textures in a separate thread, but 10 years ago, when I tried it, I didn’t get good results. Maybe now things are different.
Regarding the asset prefetching, you mention that they are loaded lazily. Maybe I'm misunderstanding but to me prefetching and lazy loading are the opposite (i.e. you would prefetch during a loading screen in order to avoid loading things on demand since it could affect the game loop). Could you elaborate?