The 3D Story
Your guide to the third dimension.

Precalculated Tables

As the title might say, this is all about doing parts of the calculations in advance. This is not a necesseary modificaton, but a major optimisation.
How do we do it then? We simply decide how accurate our rotations will have to be (my favourite is a tenth of a degree) and then we calculate all sin and cos values with this accuracy and save them in a table. We can then retrieve these values without having to recalculate them.
Why is this necesseary. The simple answer is, it isn't. But (this is a big but) if you want to do texture mapping, shading, morphing, movement, collision detection and any other of the zillions effects that will improve a 3D system , you'll need all the time you can get. This optimisation will save twelve complex calculations for each point in 3D space. To optimize here pays of well.



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Copyright©1997 Johan E. Thelin