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The definitive guide to how the Atari vector system worked was written by Jed Margolin (ex-Atari engineer). It's amazingly detailed but incredibly easy to read
by joezydeco 10y ago
The definitive guide to how the Atari vector system worked was written by Jed Margolin (ex-Atari engineer). It's amazingly detailed but incredibly easy to read:
http://www.jmargolin.com/vgens/vgens.htm http://www.jmargolin.com/vgens/vgens.htm
The secret is very precise (and expensive) DACs. The vector generator actually did all the hard work in Asteroids. The main CPU (a 1.5 MHz 6502) just created vector lists for the AVG to draw.
- acomjean 10y agoLong and very technical. Wow. Really interesting stuff, especially the game specific stuff at the end. 6502 sounds like the Apple // processor. Thanks.
- joezydeco 10y ago6502 was indeed the Apple ][ CPU. Also: Commodore PET/VIC20/64/128, BBC Micro, Nintendo NES, Atari 2600/5200, and Atari 400/800 home computers.
- detaro 10y agoAnother fun detail about the hardware: deterministic random generators with relatively small state. The German computer magazine c't ran a competition for writing Asteroids AIs in 2008, here is the winning entry playing: https://www.youtube.com/watch?v=gZHZd0iN8MM https://www.youtube.com/watch?v=gZHZd0iN8MM Note how it shoots at asteroids that haven't spawned yet, e.g. at 10s, or lines up perfects shots on the splitters of an asteroid at ~28s, before the large one is actually hit. Each time something random happens at the beginning of the game, it narrows down the internal state of the PRNG, and quickly can perfectly predict the game.