Creates a new TerrainManager.
The scene where chunks will be added/removed.
The manager configuration.
Initializes the manager and generates the initial grid of chunks. Also ensures default biome textures are loaded if missing.
Updates the terrain grid based on a focus point (e.g. player position). Triggers rebuilding of the grid if the focus point moves to a new chunk.
The current focus position.
Manages dynamic loading and unloading of terrain chunks to create an "infinite" terrain feel. Chunks are loaded around a specific focus point (usually the player).