The so-called demos (having little in common with program demonstrations) are a particular kind of realtime calculated animation, a phenomenon particularly alive in Europe (one could say, in Finland). Among the many graphical effects and techniques, raytracing is especially suited to the traditional 64k size format, and since Mfx released Transgression in late 1995 a few more raytracing intros have been a part of various programming competitions. The most common realtime raytraced objects we've seen are definitely quadrics, but recently also quartics have been used. Reflections are common, and sometimes you'll see CSG. Raytracing intros can be sometimes disturbing, because of the huge size of filtered pixels (and usually also for that swell north-european techno music, provided you own a Gravis Ultrasound soundcard, for years the standard in demos), but some of them are real technical masterpieces, keeping alive the myth of hacking so misunderstood nowadays.
rtrtdemo.zip - contains all of the demos below:
|Just like antani||Bug2Fix||64k||7/1997|
|I feel like I could||Spinning Kids||64k||9/1997|
|Sviluppo insostenibile||Spinning Kids||64k||12/1998|
|Taint (and old version)||Spinning Kids||64k||3/1999|
|(Independent) Love Bong||Contrast||64k||1/1999|
|Ray of light||Magic and Schatz||4k||4/1999|
|Dallas||Sublogic & Blocc||64k||9/1999|
Other demos with ray tracing parts, too large to include here directly as downloads:
Try, for example, running Gamma2 from Mfx in high resolution mode and discover the real computational power of your processor. Sometimes people don't even believe raytracing can be done at the speed of 10 or more frames per second: i.e. Iflic by Spinning Kids didn't get a good rating at TheItalianGathering'97 because many thought reflections there were just plain environment mapping... likewise the text files accompanying Mfx's Gamma and Gamma2 are a clear example of the same atmosphere around this Finnish demogroup that started endless discussions.
All intros available on this page should run under pure Ms-Dos (reboot Windows 9x with Alt+f4 and the Ms-Dos option), and sometimes configuration switches are available (see the text files included). Also useful (often necessary) for truecolor video modes is a Vesa driver like Scitech's Display Doctor (see http://www.scitechsoft.com) since not all video cards and Vesa programs like each other. Normally to hear the music you'll need a Gravis Ultrasound soundcard (now out of production).
A mailing list specifically for discussing real-time ray tracing now exists; sign up if you are interested. Archives are also available. The FAQ for this group is also available online.
For more information about the demoscene try http://www.scene.org, Scenet, Hugi, the outdated-but-nicely-presented Hornet Archive, (or my links page). There are code tidbits and comments at Thomas Germano's site.
Many thanks to Eric Haines for hosting this page, and all the raytracing coders who made it possible, and those who keep discussing the thing on IRC (yes, one day I might think my intro is ready for release...).
Bonus demo: not part of the distribution, but this one's amazing. A 256 byte program that ray traces: Tube, by Baze/3SC. Click on the image there or download here.