Quake 3 Source Code Review

An anonymous reader writes "id Software has a history of releasing the source code for their older games under the GPL. Coder Fabien Sanglard has been taking it upon himself to go through each of these releases, analyze the source code, and post a detailed write-up about it. He's now completed a review of the Quake 3 source code, diving into the details of idTech3. It's an interesting read — he says he was impressed in particular by the 'virtual machines system and the associated toolchain that altogether account for 30% of the code released. Under this perspective idTech3 is a mini operating system providing system calls to three processes.'"

Comments

Re:I'm a dumbass-

[parlancex]

Q3 engine's curved surfaces are actually quadratic bezier spline patches (9 control points per patch). The patches had to be designed with special tools in an editor and were tessellated at runtime to an appropriate detail level based on the computer's graphics settings. The engine did not support any kind of collision detection with these surfaces so they had to be enveloped in invisible brushes to appease the BSP system for collision and culling.

While they were interesting at the time the reasons nobody really does this anymore are probably:

• The special tools required to design curved surfaces need to be supported by the artist's tools and entire game toolchain, creating more work for artists and tool programmers
• Quadratic bezier patches are one of the simplest types of curved surface but can still be difficult to work with. Certain shapes are hard to construct properly with them.
• Lastly I'd say they've been kind of superseded by smooth / detail surfaces available through subdivision algorithms which can work on conventional geometry and conventional tools, and is supported on modern cards in hardware