brhfl.com

The Atari VCS, better known as the 2600, was an important part of my formative years with technology. It remains a system that I enjoy via emulation, and while recently playing through some games for a future set of posts, I started to think about what exactly made so many of the (particularly lesser-quality) games have such a unique aesthetic to them. The first third-party video game company, Activision, was famously started by ex-Atari employees who wanted credit and believed the system was better suited to original titles than hacked-together arcade ports. They were correct on this point, as pretty much any given Activision game looks better than any given Atari game for the VCS. Imagic, too, was made up of ex-Atari employees, and their games were pretty visually impressive as well. Atari had some better titles toward the end of their run, but for the most part their games and those of most third-parties are visually uninspiring. Yet the things that make them uninspiring are all rather unique to the system:

• Horizontally stretched sprites
• Many copies of the same sprite sharing a horizontal plane
• Simple, horizontally symmetric backgrounds
• Simple, square ‘balls’ in ball games, ‘missiles’ in shooting games

There’s a recurring theme to this aesthetic: lots of things happening in horizontal space. The VCS is made up of three primary chips: the MOS 6507 processor¹, the Television Interface Adaptor (TIA), and the 6532 RAM, I/O, and Timing chip. Of these, we’re primarily concerned with the TIA: it’s the closest thing we have to a video card, and its design is the primary force behind the aesthetic of the console. Before we dive into this, however, we need to know how televisions work. Or, at least how televisions worked in 1977.

Cathode Ray Tubes (CRTs) shoot electrons at a phosphorescent screen, causing it to glow. In a television in 1977, these electrons are focused and moved around the screen via electromagnetism. Well, ‘moved around’ is a sloppy explanation at best, but the signal is created by shooting the focused beams from left to right (that is, horizontally), one line (scan line) at a time, top to bottom. After the bottom line is complete, the beam returns to the upper left and begins again. The analog TV signal contains vertical sync (start up top) information, followed by signals for each line, prefaced by horizontal sync (start to the left) information. This is a gross oversimplification, but it’s accurate enough for the important takeaways: lines are generated horizontally, one at a time, from top to bottom; and synchronization information is built in to the signal. For as antiquated as they seem now, it’s a wonder CRTs ever worked — they are engineering marvels.

The TIA helps a VCS developer manage the above, but it barely helps. The developer needs to keep track of timing and fit their code within the timing requirements of the video signal. Advanced games like some of those lovely Activision titles changed things during the horizontal timing to push the system beyond its intended capabilities — a technique famously known as ‘racing the beam’. But the unique VCS aesthetic of simpler games comes from using that TIA as intended, and the TIA doesn’t know anything beyond what it’s doing to the current horizontal line. This sounds a bit untenable, but it’s worth keeping in mind that the VCS had to find ways to help developers without adding costly RAM beyond the 128 bytes afforded programs.

In the few ways that the TIA does help, it can only help as far as ‘doing stuff horizontally’ is concerned, because it doesn’t know a thing about the previous or next line. It helps by giving the developer a few graphics registers to play with, including a background… or, more accurately, half of a background which is then either repeated or reflected onto the other side of the screen (horizontally symmetric backgrounds). Also included are two player sprites, with the helpful ability to stretch them out to two or four times their width or repeat them two or three times inside that stretched width (horizontally stretched sprites; many copies sharing a horizontal plane). A final convenience exists under the assumption that many games would be of the Pong-like or shooting varieties: single-dot objects (optionally horizontally stretched) that matched the player or background color and offered positioning and collision detection without maintaining a complex graphical object (simple ‘balls’ and ‘missiles’).

Combat, two screenshots of which are simulated above, shows most of these elements, and is very much an archetypal example of the aesthetic I’m referring to. Of the six types of objects (background, two players, two missiles, ball), we see symmetrical, low-resolution backgrounds, player sprites both repeated and stretched, and missiles. Without stretching the limits of the system (racing the beam), this was the sort of thing that you got. With a lot of developers jumping on the home-console bandwagon without trying to live up to the likes of an Activision, this chunky, stretchy, limited-palette² aesthetic truly defines the system, and all for the sake of giving developers the bare minimum assistance in manipulating a signal for a display technology that operates on horizontal lines.