From: T DOT Harte_ AT _btinternet DOT com (Thomas Harte) Newsgroups: comp.os.msdos.djgpp Subject: Re: 3D hardware acceleration in DJGPP (Was: Re: allegro & 3d?) Date: Fri, 10 Oct 1997 20:47:35 GMT Organization: BT Internet Lines: 47 Message-ID: <343e8ebd.21393626@news.btinternet.com> References: <61llbt$jr3$1 AT news2 DOT xs4all DOT nl> NNTP-Posting-Host: host5-99-52-67.btinternet.com To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Precedence: bulk >Allegro does not make use of any of the hardware accelerated features offered >by any 3D card. Let's just say hardware developers aren't particularly interested in helping what is commercially speaking a minority community. And then, if you are someone like S3, you aren't very interested in helping anyone at all :) At least that's what people have told me! >The 3D part of Allegro is not likely to be extended in the near future, but >even for un-accelerated 3D, it's still a bit slow. It's not that it is so slow, it's that it doesn't do what it could. That is, it perspective corrects every pixel, I have heard people say it only clips on a pixel level, though I doubt that, and as for gouroud shading, I really don't know what's going on there, but it seems to be accurate to more than a fixed point scheme would allow. Maybe it is a brensham style maximum error thing, but I feel a fixed point scheme might be faster. Not that I'm any kind of authority! >You can try using another library such as Lib3D, Plush, Jaw3D, etc, and get it >to draw the image to an Allegro bitmap (you would also have to tell the other >library the height, width, and colourdepth of the bitmap, as it won't be >familiar with Allegro's BITMAP struct). AFAIK, none of these support hardware >accelerated 3D. Just to say here, I am busy making a 3d library specifically for Allegro - no 3d hardware support yet since I don't own any (except an S3 Virge, and I have a toolkit for that downloading now), but if anyone wants to get together on this, just de-spam my e-mail address (the '_'s) and say. It's not going badly, but I'll post an ANNOUNCEment when it gets anywhere decent. Go to http://www.softysoft.home.ml.org and download the gouroud man from the quickies section who I did in a half hour using a 0.1a version of my code if you want. >Are there any libraries out there for Dos/DJGPP that make use of hardware 3D >acceleration, or are there any under development? When I get a 3D card of my >own, I might experiment with writing a DJGPP library for it, and perhaps make >it possible to easily add support for other cards as well as software-rendering >(for when there's no 3D card). Try MESA, it is OpenGL to all extents and purposes and so uses 3DFX if it can. I don't know any URL's or anything. It works with DJGPP, but it is very unspecific and hard to figure out in my opinion. Anyway, if you ever do get 3d accelerator code going, any chance of a look? :) -Thomas