A Lightmap is a data structure which contains the brightness of surfaces in a game. Lightmaps are precomputed and used for static objects. Quake was the first game to use lightmaps to speed rendering while preventing floors from looking distorted. Before lightmaps were invented game engines used Gouraud shading for the floors and walls which caused shimmering. A binary tree, a simple type of branching linked data structure. ... Brightness is an attribute of visual perception in which a source appears to emit a given amount of light. ... Quake is a first-person shooter computer game that was released by id Software on May 31, 1996. ... Gouraud shading is a method used in computer graphics to simulate the differing effects of light and colour across the surface of an object. ...