PocketMatrix

There is a site that describes a method to do different types of interpolation with only addition. And it's a site by an ARM programmer too!

I know it's only interpolation, but faster interpolation would mean faster drawing, right?

His site also has an article on fast circle filling, an algorithm which might be adapted for other implicitly defined figures (i.e. defined by a function such as f(x,y)<0).

I actually wrote a Perlin Noise generator a while back using this technique to calculate a high-quality (cubic interp that is) fixed-res Perlin Noise for the PPC. I can post the source and/or binaries somewhere if anyone wants it. It also has a *very* simple script parser (two actually, a C-like one and one that is very similar to FORTH). If you want it, be forewarned, the coding is *very very very* bad.

And if I understand it right, you could probably use it to make a mix between persp-correct texmapping and affine. Just calculate the deltas for a quadratic (or cubic or higher if you want) approximation of the texture co-ords, and use this technique to interpolate. No divs or muls, and it would probably look better than affine.

[edit]Oops, I took a while to post and was beaten to it

You used the secret words, 'perspective correct texture mapping', so now I have to respond.

Doing perspective correct texture mapping by simulating u/z and v/z using a higher order formula may work pretty well, but figuring out that formula will take longer than a couple of divs, making this approach inefficient for all but the largest polygons.

There. I said it.

BTW, I once did a texturemapper that did not just use 16-pixel spans, but 16x16 tiles. Sounds like a good idea, but it looks like crap. OK, back to the bezier topic.

I tried searching on Google Groups and found a couple things that might help:
a) Thick lines can be drawn using scan-conversion of a polygon. There is one topic about this at
b) There is supposedly an article in Graaphic Gems that talks about thick line rendering.
c) There are a whole lot of posts relating to this. You aren't the only one who has no clue how to do it.

Thanks refractor. I've pored over Abrash's books quite a bit, and have most of the chapters of interest (to me) in pdf format.

Dan East