Quote:
Originally Posted by Biggles
It's unbelievable Chris, when you think that nowadays even the simplest software seems to need acres of memory. The graphics were still pretty good if I remember right. Some of the tubes looked like the pixels were almost oblong, but maybe this was down to the tube rather than the software? I remember many a happy night playing Galaxians and Space Firebird. The sound effects are still clear in my head.
Alan.
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The pixels vary in size and shape, but almost all of the first generation of raster-based video games used NTSC-like timing but non-interlaced, typically 262 lines or thereabouts of which typically 192 are used for picture information. The CRT was typically turned sideways so the lines were actually columns, and the field scan was actually horizontal. The resolution in the other axis (horizontal in conventional video, vertical in reality) depended on the pixel clock speed, but 6MHz was quite common, giving 256 pixels in an active video period of about 42us.
One of the things I find fascinating about the design of these games is the amount of electronics devoted to creating the video display. There are typically anything between 50 and 200 or more TTL logic ICs, most of which spend their time doing something to do with the graphics. The whole thing is optimised to play only the game it's designed for. Galaxian, for example, couldn't draw a circle or plot a graph. It can only draw aliens! However, it can do it in real-time, to give the smooth movement and quick action that the game needs.
As a budding home computer programmer in the early 80s, it was a source of frustration to me that I couldn't match the graphics performance of the games I saw in the arcades, using a home computer's general-purpose graphics capabilities. Decades later, now I can understand why!
Chris