Fractal Terrain Game on the TI

[+adamantyr]

So, a recent post on a blog about the lamented shutdown of Lucasarts made me remember two very good games by them... Rescue on Fractalus! and Koronis Rift.

 

I played both of these on my brother's Color Computer 3, and they were just excellent! And surprisingly, I hadn't realized that they were originally written for the Atari 800 systems, and later ported to the Apple II and other systems. Which means the basic algorithms used should be very possible on the TI-99/4a! (There WAS an MSX version of Koronis Rift, but it was designed for the MSX2 systems... in fact, the screenshots on MobyGames suggest they were attempting to implement it for the MSX1 and changed their minds.)

 

This has me thinking of a new project... one that actually is considerably different from my CRPG enough to not have cross-contamination. A real-time game with fractal terrain and full bitmap terrain rendering!

 

On the techncial side, I was considering that the best work-around for the color palette limitations with bitmap mode would be to render the display area entirely in 1x4 pixel blocks, alternating between on and off, and then just use the color tables to control pixel placement. This would speed up plotting the display considerably. I'd also limit the view portal to around 32x12 characters (64x96 "pixels"), or 3k of display in color only. That's a reasonable enough buffer space to render the entire scene in CPU memory and then write it sequentially to the VDP.

 

The game would probably NOT procedurally generate the fractal terrain for each "level"... the best algorithms for this involve recursive functions, so outsourcing the data to disk for loading makes the most sense. I need to prototype a few ideas here, but one idea is that the main "map" of points would be in byte coordinates, but the gameplay would be in word coordinates. I think that would generate a sufficiently "big" map. I think if a map consisted of around a thousand points which consumed 3 bytes each, 4-6k per map is manageable. (Objects on the map such as enemies and so forth would be stored in a separate array.)

 

My main complaint is that nobody has ever posted a source code listing for either Rift or Fractalus. I'd be curious to know if they used z-index buffering or other techniques to create the main viewport.

 

Adamantyr

Edited May 3, 2013 by adamantyr