[Coco] Scrolling 3D Checkerboard Field

Andrew keeper63 at cox.net
Tue Jul 24 11:31:12 EDT 2007


All -

This is more for my education than for any real purpose:

I have been trying off and on to find a description and/or source code 
(in -any- language) on how to render (and animate) a scrolling 
"checkerboard" field.

Back in the 1980's, I remember that a few 8-bit machines had games which 
used such a effect - one was a soccer-like game set in the "future" 
where you and an opponent (the computer or a second player) went 
head-to-head in "hovercraft". IIRC, it was even split-screen (over/under).

Yet - in all of this time I have never seen anything on how it is done. 
Nor have I ever seen this effect done on a CoCo. The closest was a BASIC 
game Eric Wolf published in the Rainbow called "F-15 Assault" (or 
something like that). It painted a series of horizontal lines out to a 
horizon (thick at the bottom, and gradually getting thinner toward the 
middle - simulating perspective) with mountains. Two-slot palette 
switching animated the "scrolling" field.

However, from what I recall, this wasn't how the checkerboard was done - 
it was a real scrolling system, and could move left/right as well 
(cartesian movement, I suppose). Unless I am completely misremembering 
everything.

Does anyone here have an explanation of this - or could perhaps point me 
to an article or source code showing this effect?

Also - in the same vein - how are "3D" pole-position tracks done? Asking 
both of these questions, I feel like a n00b - I mean, I have no problem 
with the math and difficulties of rendering texture-mapped polys with 3D 
transforms, scaling, rotation, and projection - standard 3D is no 
problem (even on an 8-bit platform - though even wire-frame can be dog 
slow comparatively).

Fake "3D" (aside from ray-casting) on an 8-bit platform - that stumps me 
- and it seems like information is very rare on it because nobody wrote 
down how these effects were done "back-in-the-day" - most likely because 
they were very cool for the time, and thus very profitable. 
Unfortunately, they feel like a bit of game development history which 
has been lost...

Any ideas out there...?

-- Andrew L. Ayers
    Glendale, Arizona



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