CompuServe Messages

#VistaPro

    28-Sep-93 21:20:53
Sb: #VistaPro
Fm: Erik Flom 71204,407
To: Clint Woeltjen@VRLI 75300,3706
Clint: PMFJI, but I've noticed a bug in the dithering routines used to generate fractal terrains on the Amiga. I was rendering a top-down view of a wide expanse of terrain (for my RingWorld animation which I never finished. :^(, and I notice the dithering in the left top quadrant is always worse than the other quadrants of the image. The uppper-left quadrant shows markedly less dithering than the other quadrants. This is possibly a result of the error propogation in the dithering algorithm. (With the settings I was using, each polygon was rendered at about 2×2 pixels, with about a 1 pixel overlap. Since the polys are rendered in bands, the overlap didn't cause any problems in any quadrant but the upper-left. In that quadrant, the dithering was noticably different from the remainder of the picture – there was less 'randomness'. It's a pretty weird little bug, and I can see as to how it wouldn't effect many images, but it was annoying nonetheless. I thought you might like to be made aware of the artifacting. (I can't really call it a bug per se. :^) Thanks, Erik Flom