In the previous chapter, we covered matrices, transformations, and cameras. So far, we have only discussed static scenes, where all interactions are done by moving the camera. With these interactions, a camera transformation is applied to all objects in the 3D scene; we therefore call it a global transform. However, objects in 3D scenes can have actions of their own. For instance, in a car-racing game, each car has its own speed and trajectory. In a first-person shooter game, enemies can hide behind barricades, come to fight, or simply run away. In general, each one of these actions is modeled as a matrix transformation that is attached to the corresponding actor in the scene. These are called local transforms.
In this chapter, you will:
- Learn the difference between global and local transformations.
- Learn about matrix stacks and how to use them to perform animations...
