Light Map

From CacheCalculations. What's a LightMap?

If memory serves, caching to a bitmap (pixel map actually) the result of calculating the illumination from multiple light sources in a 3D renderer.

When building a Quake level, you would run a graphical editor. It would produce a text file as output. You would run "qbsp", which would convert this into a binary file. Then you would run "vis", which would compute potential-visibility lists, so that when the renderer drew from a certain viewpoint, it would consult the visibility lists and consider only those polygons which were potentially visible from that viewpoint. Then you would run "light" and it would produce lightmaps, which specified the brightness on every wall in the level at 16-pixel increments. I believe these things are also used for Quake 2. I don't know about Quake 3. -- EdwardKiser