Pyramid.app
Pyramid grew out of a need to build some simple 3D graphics
primitives for a project I was working on. The functions in
matrix.subproj provide a basic mechanism for defining a 3D
perspective transformation and mapping points from space onto
a viewing plane.
I wrote the pyramid model and viewer as a testbench to get
visual feed back from the matrix routines. Any problems
in the math were *very* obvious as things spun around.
Having completed pyramid, I added the kitchen model for
my wife. Some time ago I had been helping her understand
the basics of perspective, and made various diagrams
based on our kitchen. The crude diagrams didn't help
much, and I decided to do a computer model, which would be
accurate and dynamic. That never happened, of course,
until I realized after writing Pyramid that adding a
kitchen model would be trivial. Watching the lines
converge on the vanishing points along the horizon as the
scene moves really makes the concept come alive.
Though not complicated, it took a while to understand the
math and get it right, and I hadn't seen anything similar
on the net. I'm posting Pyramid and the matrix routines so
that others may have some fun as well.
Acknowledgements:
Thanks to Vince DeMarco for putting his
CircularSlider palette on the net!
Problems:
The hidden line algorithms are primitive. The moon will
occasionally peek through to the foreground.
The kitchen will fold inside out if you look at it from
funny angles. It's really only useful when viewed from
one octant of the coordinate space.
_______________________________________________________
NeXTMail:Peter_Kron@corona.com
Corona Design, Inc.
P.O. Box 51022
Seattle, WA 98115-1022
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These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.