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Submitted by , posted on 08 September 1999
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Image Description, by
this is a screen shot of a software renderer i am making from scratch, it
is an example of the polygon rasterizer scan line interleaving (SLI)
capabilities. this is very cool, easy to do, and can yield 2x or 3x
performance with little visual quality loss. my current texture mapper is
all coded in C and i used no papers, docs, web sites or anything, just
started with algebraic equations and went from there, it actually isn't
that hard once you get into it, the hard part is going to be getting exact
accuracy, what i mean is now when you zoom into two polys that are
adjacently mapped, the texture is off and doesn't line up correctly all the
time at the crease, maybe due to round off errors, but i am almost sure it
is some design error by me, if any body has some general tips for this
problem please tell me about them.
i will be very interested in seeing how SLI will work in an actual game,
but that will be a couple more months before i have good content and engine
to test with. also, i might release the source code in the future, but not
until i get everything completed with the rasterizer.
some specifics about my t mapper so far:
outer loop is all floating point
inner loop is all integer ops, currently 6 adds, 2 shifts, 2 ands, 2
assignments
currently affine mapped, but at huge angles there seems to be NO
distortion, don't know why? but i like it!
y clipping per polygon, and x clipping per scan line
hacked bilinear filtering (this is more ops then in above)
texture can be any size power of 2, width and height can be different
texture is tileable
arbitrary SLI
email me with any questions, comments, or advise!
james bryant
jaybebe@iastate.edu
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