■Window3
Squeak in Window
The previous tutorial examined how "narrow-phase" collision detection works in N; given two shapes (a dynamic AABB or circle, and a static tile), we learned how to project the dynamic object out of the tile.
This tutorial deals with "broad-phase" collision detection: given a dynamic object in a world full of tiles, how do we know which objects and tiles it should be tested with during the narrow phase? The solution used in N was to split the world into a uniform grid of square "cells"; instead of testing the dynamic object against all the tiles in the world, we only need to test against the tiles contained in the cells which are touching the dynamic object.