Game Engine Architecture

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off , and the developer is given full control over the character’s move-

ments and actions via a simple heads-up menu. The developer can paint

target points in the game world by simply aiming the camera and can

then instruct the character to walk, run, or sprint to the specifi ed points.

The user can also tell the character to enter or leave nearby cover, fi re its

weapon, and so on.

9.2.1. Debug Drawing API

A debug drawing API generally needs to satisfy the following requirements:

z The API should be simple and easy to use.

z It should support a useful set of primitives , including (but not limited

to):

□ lines,

□ spheres,

□ points (usually represented as small crosses or spheres, because a

single pixel is very diffi cult to see),

Figure 9.4. Manually controlling an NPC’s actions for debugging purposes.

9.2. Debug Drawing Facilities