Entering the Digitized Era – Part 1 – By Warren Davis

In the beginning, there was the dot. The white dot. Alone in a void of blackness. This was the world of Pong, Computer Space, Breakout and many more. Crude graphics and no color. These were the earliest arcade video games – many implemented solely through hardwired circuitry, no CPU, no software. Some using rasterized graphics, some vector graphics. Some tried to imply color by using cellophane overlays, but let’s face it. They were still black and white.

There’s some debate about which arcade game was the first to introduce colored pixels. Galaxian was probably the first hit game with multi-colored raster graphics (in 1979), even though there were others before it. And Tempest is considered the first game using multi-color vector graphics in 1981. Once we were in the world of color, there was no going back. In this article, I’m going to talk exclusively about rasterized graphics.

In the early days, colors were extremely limited. Systems usually had a color resolution of 2 bytes (or 16 bits) per color. That meant a color consisted of 5 bits of Red, 5 bits of Green and 5 bits of Blue. That translated to 32 shades of each or 32,768 possible colors (32x32x32). If a game system had enough screen memory to allow for 2 bytes per pixel, then every pixel on screen could have any one of those 32,768 colors. We’d call that a “true-color” display. But memory back then was expensive, so to keep costs down, screen memory was generally limited to show only a small subset of the possible colors. This subset was called a “palette”. So instead of storing 2 bytes for each pixel, you stored an index into the palette. For a 16 color palette, that would require only 4 bits, you could fit two color indices into a single byte. That made screen memory 4 times smaller than a “true-color” display would have been.