SOFTWARE-DRIVEN GRAPHICS MODES FOR THE ATARI
LAMBERT M. SURHONE, MARIAM T. TENNOE, SUSAN F. HENSSONOW
High Quality Content by WIKIPEDIA articles!
This article describes software driven graphics modes for the Atari 8-bit computers; that is, pseudo-graphics modes whose capabilities are reliant on additional software rather than being supported directly in hardware.
The APAC System, or Any Point, Any Color was a software-driven display mode capable of displaying an image using all 256 of the Atari's possible colors.
By taking 80x192 mode lines that displayed 16 hues, and those that displayed 16 shades, and either interlacing rows of them, quickly alternating between rows of them, or both, a screen displaying 80x96 or 80x192 pixels in 256 colors could be perceived.
APAC was created in early 1987 and later introduced in the magazine A.N.A.L.O.G.
Computing, Issue #60, May 1988 in an article by Tom Tanida.
The source code was written in 6502 assembly language.
