1. Quake Engine

3. THE QUAKE ENGINE IS OLD (relatively) Made in 1996 to power the game of the same name. id’s follow up to the immensely popular “DOOM” Made the transition from DOOM’s psuedo- 3D (2.5D?) to levels and models actually rendered in 3D with polygons

4. Graphics in the 90’s Developers were faced with severe hardware limitations when tasked with making a 3D game that would run well on the average 90’s Home computer. Solution: Pre-processing, getting rid of any and all superfluous polygons, and other loopholes.

5. Binary Space Partitioning Tree The world is divided into convex subspaces. If a node is not inside the viewing frustum, then neither are it’s descendants. The problem is obscured polygons inside the frustum. Painter’s Algorithm: BAD FOR GAMES.

6. Potentially Visible Set Rather than have an algorithm determine what is visible during valuable rendering time, the developers decided to just attach to each leaf in the BSP tree, a list of every other leaf visible from that one. Naturally, this method does not work for moving objects.

7. Moving Objects Moving objects in a BSP tree are a pain to keep track of and there are extra polygons produced when the model is between subspaces. First, the non-moving world is produced with its BSP tree and its Z values are stored in a Z-Buffer. Then the moving objects are drawn using Z-Buffering to determine which are visible

8. Getting Rid of More Things Distant objects are indistinguishable blobs anyway. Why waste rendering time? “Subdivision Rasterization” The difference is not noticeable until close distances so most objects use this method

9. Lighting Smooth shading is bad for large polygons. During pre-processing, lightmaps are made for polygons by casting light from close sources. During runtime, textures are applied to polygons and are lit according to the pre-made maps.

10. Lighting Models Smooth Shading is fine for moving models. The intensity of ambient light is determined by the lightmap on the floor. Constant light vector

12. Sources “Ramblings in Realtime” by Michael Abrash. Images Obtained from Wikipedia, a Google image search, and the aforementioned article.