De Re Atari

De Re Atari
Author(s)	Chris Crawford
Country	United States
Language	English
Subject(s)	Atari 8-bit family
Publisher	Atari Program Exchange
Publication date	1982
Pages	250 pp
Followed by	The Art of Computer Game Design

De Re Atari written by Chris Crawford in 1982 contains a detailed description of the advanced features of the Atari 8-bit family of home computers. Atari's own technical documentation only became available to the public some time later, so for a good deal of the time that the machine was popular developers on the platform turned to De Re and Mapping the Atari as crucial development aids.

After some basic introductory information, the book quickly gets "down to business". Individual chapters are devoted to making use of the features of the platform, which included ANTIC and the display list, "graphics indirection" in the form of color support in the GTIA and customized character sets, player-missile graphics, using display list interrupts (the VBI and HBI), smooth scrolling and sound, including a discussion of "volume only sound" which offered higher-resolution volume control for digitized sample playback. Additional chapters covered utilities in the operating system, Atari DOS and Atari BASIC.

How to make use of these features was often not obvious. For instance, Atari's sprite implementation, player-missile graphics, used a register to indicate the X position of sprite on the screen, but required the user to copy the sprite pattern up or down in memory to move it along the Y axis. Likewise, vertical smooth scrolling was quite simple, but horizontal scrolling required a custom display list that created a "virtual screen" as wide as the scrolling playfield. De Re not only talked about these issues, but provided sample implementations and discussed potential alternate implementations.

Crawford had personally made use of many of these features in the seminal wargame Eastern Front (1941) released the previous year. Eastern Front made extensive use of smooth scrolling, custom character graphics and some use of player-missile graphics and basic sound.

The original edition is now out-of-print but available for viewing on a site maintained by Kevin Savetz, the Atari Archives.

External links

• De Re Atari online