Game Engine Architecture

742 14. Runtime Gameplay Foundation Systems

freed by simply resett ing the stack pointer to the top of the LSR data block.

At this point, a new level can be loaded in its place. This is illustrated in

Figure 14.11.

While this design is very simple, it has a number of drawbacks. For one

thing, the player only sees the game world in discrete chunks—there is no

way to implement a vast, contiguous, seamless world using this technique.

Another problem is that during the time the level’s resource data is being

loaded, there is no game world in memory. So the player is forced to watch a

two-dimensional loading screen of some sort.

14.4.2. Toward Seamless Loading: Air Locks

The best way to avoid boring level-loading screens is to permit the player

to continue playing the game while the next world chunk and its associated

Figure 14.11. A stack-based memory allocator is extremely well-suited to a one-level-at-a-

time world loading system.