Revamp System Dependencies

[azriel91]

In GitLab by @azriel91 on Jun 20, 2019, 14:59

Ran into this limitation with the current PrefabLoadingSystem. The current system both loads Prefab assets and attaches Components. Given the PrefabLoadingSystem is in the main dispatcher, the following flow is not supported:

1. Load prefab assets
2. Spawn objects (attaches prefab handles) -- in state dispatcher.
3. Process entities with prefab handles (attaches default component values)
4. Amend component values based on game environment -- in state dispatcher.

It would work if either:

• We use one dispatcher, and the PrefabLoadingSystem is in between the Spawn and Rectify systems.
• The PrefabLoadingSystem is split, and the component augmentation part of it is between the Spawn and Rectify systems.

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This may be done in conjunction with using atelier-assets to load assets -- prefabs loading will be part of asset loading, attaching of components will be a separate system.

Related: #181.