Welcome to the P3DC FAQ Page

This is the Project: 3D Craft (P3DC) Frequently Asked Questions file. This release is : ALPHA-0.9 this file was last updated 21-Aug-1999 by Chuck McManis.

The current list of questions:

There are a bunch of on-line 3D Graphics resources, I have listed some here. And I am also maintaining a reccomended book list for people who want to start building a library of books on 3D graphics.

The current answers:

Q) What is the P3DC Library?

A) This library is my attempt at a 3D engine that is sufficiently flexible for me to "play around" with 3D games programming and 3D experimentation. I've read for years the Graphics GEMs books (highly recommended) and been unable to "try out" the most of the suggested gems because I had no environment I knew well enough to hack around it. I was also somewhat intimidated by the learning curve of Direct3D (and somewhat less so for OpenGL).

Q) Can I use this code in my Commercial Application?

A) Yes. The code is covered under a BSD style license. (it qualifies as "Open Source") See the file license.txt in the distribution.

Q) Would I want to use this code in my Commercial Application?

A) Probably not, these days OpenGL is a much better choice as it runs on a wide variety of platforms and is well supported. My stuff is fine for learning one way that you might approach the problem of building a 3D engine but even I am never satisfied with it (that's why I'm on version 5 and climbing!)

Q) Why did you write this library?

A) So that I could speak intelligently about the issues of writing 3D games.

Long boring version :

I started writing graphics programs in 1982 using a PDP-10 and a Tek 4010 storage scope, and a PDP-11/55 with a COMTAL video frame buffer attached. Fun but the hardware required a air-conditioned machine room.

Then in 1984 I bought an Amiga 1000 and had fun writing programs for it (a lot cheaper but limited colors). Between 1987 and 1995 I didn't write any graphics code. In 1995 I bought an Edge3D board for my PC (used Nvidia NV1 chip) but could never figure out how to program it! (Nvidia was a pain to work with at the time and Direct3D version 1 was a TOTAL joke)

In 1996 I bought a Diamond Multimedia Monster 3d (Voodoo Graphics) based 3D accellerator for my (upgraded) PC. I tried to write a Direct3D (V2) program and between the bugs in D3D the arcane syntax/calls/overhead I gave up in disgust. Then I found the 3Dfx Glide library and when 2.4 was released I decided I'd see if I could write a program to rotate a 3D cube. It took a while but by mid '97 I some code that could rotate a textured cube. Yippee!

Of course this code could not do anything else :-(. So I bought the latest copy of Computer Graphics Principles and Practice, dusted off my old Neumann & Sproul Principles of Interactive Computer Graphics, and dug out my old ACM Siggraph papers and went to work. The result was "Chuck's Graphics Library" which could be used to render flat shaded objects in a 3D world with a fixed field of view camera. I rechristened the project the Generic 3D library (G3D) in late '98 and rebuilt it twice more (versions 2, and 3) and got to the point where cameras were getting flexible and I wanted to do animation.

Then in late '97 and early '98 I rewrote it a fourth time (G3D-4) and got the polygon count up to 50-75K polygons a second on a 200MX Pentium and Monster 3D, added textures and, with the help of my 7 yr old daughter, embarked on making a 3D game. I ran into one roadblock after another and decided I had the wrong architecture still, so I ripped it apart and rewrote it again. That brings us up to the present with version (version 5) which I rechristened again to "Project: 3D Craft" because there were already engines named G3D and that confused people.

Then I took sort of a forced break while the startup I'm in heated up, and now (Aug 99) its back together again and running with textures and a much more flexible model architecture.

Q) How fast is this library?

A) That depends on many things, not the least of which are the speed of the processor and the type of interface. The target for the library is 130K polygons/second on a P5-200 with a Voodoo1 card. That would give me a budget of approximately 3K polygons per frame at 30FPS (We have to allow some time for game AI, sound, etc) But even this number is inaccurate because a scene could have 10K polygons and still work at 30FPS if only 3K of those polygons were "visible" and ended up going down the pipeline to the display.

The short answer is that I've got several game ideas cooking and it should be sufficient for all of them. None of them comes close to the complexity of Unreal :-).

Q) What operating systems does it run on?

A) Windows95 and FreeBSD (Linux would be an easy port). Currently there isn't any Glide support under FreeBSD so it renders to a file. When I can get the Glide libraries to work under FreeBSD there will be a FreeBSD version.

Q) Does it have to use Glide?

A) No. All of the actual "rendering" code goes through a "Graphics Abstraction Layer" (gal) that has to support what Glide supports however P3DC programs never "know" they are talking to Glide, they only know they are rendering graphics. I've written an alternate GAL layer (gal_text) that generates PNG files for example. If you're motivated and want to enhance gal_text.c to do texture mapping that would be pretty cool.

Q) Why didn't you just use OpenGL?

A) Because I learn by building and I had to build a 3D engine to understand it. By using Glide I've got a pretty good device driver abstraction to work with. If you're just writing a game or something and either already know or don't care to know how 3D engines work, I recommend you use OpenGL.

Q) How long did it take you to write P3DC?

A) I've been working on it in my "spare" time for a couple of years now. However the bulk of the time spent on it was late 97 to mid-98. Then I spent the middle of 98 thinking about how to re-write it and in August 1998 embarked on Version 5. Then there was a long pause and I picked it up again in August of 1999.

Q) Do you work on 3D graphics professionally?

A) No, I write and modify operating systems (generally UNIX based) and design Internet appliances.

Q) I've modified P3DC to handle [some feature] can I distribute it?

A) Yes, any code you write you own and you can do whatever you want with it. However you are bound by the P3DC license to include my copyright statement where you put your own copyright statement (manuals, documentation, etc)

Q) Would you consider including my feature in the library?

A) Certainly, the beauty of open source is that anyone and everyone can contribute and make it better. I do retain change control on the final "product", anything can be placed in the "contrib" directory.

Q) What versions of Voodoo card (Glide) does P3DC support?

A) My main development machine now has a Voodoo2 in it, although for a long time I was using a Voodoo Graphics (sst1) in the form of a Diamond Monster 3D. I'm using version 2.x of Glide because it has the most stable support for Voodoo Graphics, I'll probably write a gal_glide3.c layer and then be able to compare the to but I've been leary of doing that given the problems with its support of Voodoo Graphics.

Q) What other hardware are you planning on using?

A) Recently, NVidia released C code that would talk directly to their TNT and TNT2 engines. This seems pretty cool so I may do a gal_tnt.c backend for them as well.


The Glide newsgroup on the 3DFX news server:

The comp.graphics.algorithms news group.

The comp.graphics.algorithms FAQ.


Computer Graphics : Principles and Practice (Systems Programming)
by James D. Foley (Editor), Andries Van Dam (Contributor),
John Hughes (Contributor), van Dam, Feiner, Hughs
Addison-Wesley Pub Co; ISBN: 0201848406

3D Computer Graphics
by Alan Watt
Hardcover - 500 pages 2nd edition (September 1993)
Addison-Wesley Pub Co; ISBN: 0201631865

Graphics Gems
by Andrew S. Glassner (Editor)
Hardcover Reissue edition (June 1993)
Academic Press; ISBN: 0122861663

Graphics Gems II (The Graphics Gems)
by James Arvo (Editor)
Hardcover Reissue edition (October 1994)
Academic Press; ISBN: 0120644819

Graphics Gems Iii/Book and IBM Disk
by David Kirk (Editor)
Hardcover Bk&IBM dsk edition (January 1994)
Academic Press; ISBN: 0124096735

Graphics Gems Iv/Book and IBM Disk (The Graphics Gems Series)
by Paul S. Heckbert (Editor)
Hardcover Book&Disk edition (May 1994)
Ap Professional; ISBN: 0123361559

Graphics Gems V/Book and IBM Version Disk (The Graphics Gems)
by Alan W. Paeth (Editor)
Hardcover - 438 pages Book&Disk edition (May 1995)
Academic Press; ISBN: 0125434553