ABSTRACT
The first item is important if memory usage is an issue, either because we are working with a memory-limited machine such as a mobile device, or because we want to store a large number of transformations, such as in animation data. In either case, any reduction in representation size means that we have freed-up memory that can be used for more animations, for more animation frames (leading to a smoother result), or for some other aspect of the game. Rotating points and vectors efficiently may seem like an obvious requirement, but one that merits mentioning; not all representations are good at this. Similarly, for some representations concatenation is not possible.
