Hi Dushan, A1: Finding shared edges is more complex than just doing the setup twice.
A2: If you have a 1-bit error and blend (multiply) three transparent surfaces then this results in a 3-bit error which means very bad banding effects (like going from 24-bit to 15-bit color depth). Correct rounding and dithering can correct most of that. A3: LOD is short for Level Of Detail. It is used for mipmapping: Pixels on far away triangles need lower detail textures to avoid aliasing (shimmering) effects. Good luck with your exams! Nicolas -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dusan Colic Sent: maandag 31 januari 2005 5:53 To: [email protected] Subject: [Open-graphics] Few rasterizing questions Just to note that I'm not a programer but just familiar with 3D-2D transformations. Also I've read source and outline you posted. Q1: Do triangles share sides (have same edge)? If it is true then all computation with X and Y coordinates is doubled (minimaly). Why don't we round up X & Y on the start for every vertice that is shared between triangles (eg 100 packed triangles have 300 points but only approx. 100 different ones because they touch each other). Now every triangle is adjacent to next one and there is no progressive summing error. Then we calculate rounded Xd and Yd =Yb. And it's easy to check if Ya=Yb or Yb=Yc for already flat bottomed(top) triangles. Other calculations in render.c can stay the same and we make a very small error. Q2: Is adjusting of A,R,G,B,U,V,LOD,F (after rounding) necesary? Rounding error is about X1-X1f~1/(225) right? I gathered that they have to be enlarged by +0.5, but X1-X1f is so small. Oh and why color information has to be +0.5? Q3: What is LOD? Sorry if I've missed something obvious but my exams are killing me. Best of luck with the project Dushan _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com) _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
