Technical Details
Star Raiders uses many techniques that would become common features of Atari 8-bit game programming in the 1980s.
One notable feature of the game was that the main simulation continued running even when the user was interacting with other display. For instance, one might be attacked while examining the Galactic Map. This was unusual for the time, if not unique.
The star field is drawn in a graphics mode that (at full screen coverage) provides 160×96 bitmapped pixels with a palette of four colors. This mode is called "GRAPHICS 7" in Atari BASIC. The use of an indirect palette means that color changes associated with the presence or absence of energy shields, emergency alarms, and the screen flash representing destruction of the ship can be accomplished by simply changing the palette values in memory registers.
Enemy ships, shots, and most other moving objects use Atari's variant of hardware sprites, known as player-missile graphics. The Atari supported only four of these "players" (and four simpler "missiles") but the game sometimes had more moving objects on-screen. In particular, the "radar" display in the lower right of screen was drawn using the background graphics, and updated much more slowly than the sprites. The same was true for the debris particles emitted when an enemy ship is destroyed, and are actually calculated as 3D points. Since the 6502 does not have a native multiply or divide command, the game slows down considerably when several of these particles are active.
The Atari 8-bit family allows different graphics modes and color palettes to be used in different horizontal bands on the screen, by using a simple display list and a type of horizontal blank interrupt. While other games make more extensive use of these techniques, Star Raiders uses them in a relatively simple fashion to combine text displays and graphics; the cockpit display uses a custom character set to display futuristic-looking characters and symbols reminiscent of MICR.
Star Raiders' sounds of engines, shots, explosions, alarms, etc. are synthesized directly using the Atari POKEY sound chip's capabilities. Neubauer was involved in the design of POKEY.
The entire game, code and data, fits into 8K (8192 bytes) of ROM, and requires only 8K of RAM for its working data and display visuals; thus it can run on any Atari 8-bit computer.
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