Embedded
Games

defining special graphics characters on the TI-99/4a

Existing Tools:
  1. Win994a - the emulator I had the most luck with. Also the most current, and it has the features I needed; loading and saving BASIC files as text back-and-forth on a modern machine (using virtual floppy disks). Without an emulator you're stuck trying to develop on the real machine -- 3 MHz processor, 5 1/4" floppies and all, which is cool in a retro way once the code is working but not when it keeps saying "ERROR 54" for no apparent reason and there's no tab-completion or command history.. ;-}
  2. BASIC Reference - if you don't have the original manual this definitely comes in handy.
New Tools:
  1. 8x8 Pixel Hex Pattern Generator A simple web-based tool I wrote to compose and generate 8x8 pixel graphics characters for game development. It's better than pencil, paper, and a look-up chart but you have to use it a couple-hundred times if you want to draw big stuff.
  2. xbm 2 TI pattern descriptor - the industrial-strength version of Hex Pattern Generator. The goal here was to generate not only character codes but TI BASIC code to define and draw (comparatively) large images on the TI-99/4a screen. The process starts by taking an ordinary image and processing it into a monochrome silhouette saved as an X BitMap. This highly-simplified image file can then be uploaded and processed by my script into special character codes and BASIC code to define and display the image.
Example:

jpeg
monochrome xbm
on TI-99/4a
the characters


Results:
This arrangement enabled our team to complete a game that ran on the real TI-99/4a in TI BASIC. The game had cool looking graphics, but ran way too slow. The next step in the project would be to use the same graphics tools and rewrite the game in TMS 9900 Assembly. Judging from the performance of other games on this machine, our game could run fast enough to play.
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