Vic-20 Graphics - Overview

When putting together one of my monthly displays (about Branching Fractals in 2017), I started with some early images that I produced using a Commodore Vic-20 computer that I had in 1989. When looking back at those images, and some other images produced using the Vic-20, I realised that there were enough good images to have their own worthwhile presentation. I also want to present these images because I spent a lot of time, artistic understanding, and programming effort in producing them.

I produced an HTML framed display of Vic-20 graphics that was noticed by some good folk at Vic-20 Denial (who all gave encouraging remarks about my images). When I changed my entire website to use a smaller number of pages, that didn't use HTML frames, I decided to convert the Vic-20 Graphics section to include in my new website (because of the comments and links made with those good folk at Vic-20 Denial - thank you good people)!

320 x 352 pixels, produced on a Vic-20 computer, using my own machine code graphics routines, and manual editing of pixels.

(Some background information is presented below the following group of page images.)

Background

I remember my father buying a Commodore Vic-20 computer back in 1981, and plugging it into the family TV to see what it was all about. He had been reading about these 'inexpensive' personal computers ($350 back then was still a lot of money) and with a keen interest in electronics, he wanted to learn how to program one, and thought that it would be good for his children to explore as well. I remember the first time the Vic-20 was turned on, it came up with a display as below, saying "CBM BASIC V2", "3583 BYTES FREE", and "READY.", with a flashing blue block.

The unexpanded Vic-20 greeting screen on startup. Note the number of bytes available for entering and running a program.

Not knowing what to do next, we consulted a manual that came with the computer. The Vic-20 came with a connected data-cassette player that allowed the user to load and save programs. The Vic-20's operating system provided some 'prompts' that helped users to use the computer, like the one shown on the screen capture shown below. The computer seemed to have a 'kind of' personality, or friendliness. At that time, our new computer was mainly used to play commercially developed games, loaded from cartridges or data-cassette tapes.

The unexpanded Vic-20 requesting the user to press play on the data cassette, to load a program.

My real introduction to using personal computers however, happened during my Art Teaching degree in 1988, using on-campus Amiga 500 computers for producing two-dimensional graphics in a paint program, and IBM Clones (probably of the 286 variety) for word processing my assignments on screens that allowed displays of chunky text characters in about 8 different colours.

My father saw that I was getting interested in computing, and he sent me his faithful but no longer required Vic-20 computer to see if I could find it useful.

I found it very useful to have my own computer, even though it didn't have the graphics power of the Amiga 500, or the processing power of the PC clones. I firstly taught myself how to program in BASIC. I found BASIC programming to be fascinating and I enjoyed the use of mathematics and various strategies to achieve some interesting outcomes. I later taught myself some programming in machine code (for amazingly quick processing speeds). Regardless of the programming I was learning, after about 6 months, I started using the Vic-20 for word processing for my course assignments. I now didn't have to rely on booking times in the computer labs to do my word processing. And I was using the Vic-20 to do more and more graphics tasks (my main interest in using computers).

The Vic-20 computer was an 8-bit computer which used a 6502 microprocessor and a 6561 Video Interface Chip (display chip), giving the computer its name. The unexpanded computer came with about 3.5 kilobytes of RAM for programming (miniscule by today's computers' standards) and it had a possible ‘high resolution’ graphics display of 176 pixels wide, by 184 pixels high. The pixels on the Vic-20 computer were not square shaped, but rectangular (approximately twice as wide as they were high), and gave the text and graphics a characteristic look. The computer didn't come with any special graphics routines for plotting pixels, drawing lines, or drawing circles, so I needed to research how to produce such things. I remember being surprised and disappointed by how complex the task of drawing a line on the screen was. One of the things I did was to expand my Vic-20 with some extra RAM. This provided more space for programming, especially for programs involving custom graphics.

On the first page of this presentation, I present some images from the Vic-20 computer running various commercial software, to give an idea of the old computer's general graphics capabilities. The images used in this presentation were taken as screen captures from using WinVICE 2.1 (an excellent Vic-20 emulator, that runs on recent Windows computers).