jordan%lvvm6.span@SDS.SDSC.EDU (RICH) (01/23/89)
DSEAH%WPI.BITNET@mitvma.mit.edu writes: >Hello! A friend of mine on GEnie heard of a GS program called "The Carousel >of Impossible Physics", which is supposed to be able to refresh a SHR screen >in only 1/30th of a second flicker-free! This sounds like an animation demo that was running at AppleFest SF in September, although the flyer I have doesn't refer to it by that name. The demo showed a picture of a five-sided stepped... I guess carousel is as good a name as any... that rotated with very clean shading and shadow effects while balls bounced down the steps and into tubes which ran back to the top of the steps. This isn't a very good description, I know, but if you saw it you'll remember from this. This particular demo had the images precalculated on Apple's Cray supercomputer and the animation is done by changing only the data that has to be changed from screen to screen. According to the people I asked the computer was just about 100% tied up just displaying those images. The name and address attached to the flyer is: Don Marsh MS 27-B Apple Computer, Inc. 20525 Mariani Ave. Cupertino, CA. 95014 Hope that is of some use... Rich <jordan%lvva.span@sds.sdsc.edu> BIX: richjordan (Rarely there) GEnie: BARRACUDA
keith@Apple.COM (Keith Rollin) (01/23/89)
In article <890123035742.2040121f@Sds.Sdsc.Edu> jordan%lvvm6.span@SDS.SDSC.EDU (RICH) writes: >DSEAH%WPI.BITNET@mitvma.mit.edu writes: >>Hello! A friend of mine on GEnie heard of a GS program called "The Carousel >>of Impossible Physics", which is supposed to be able to refresh a SHR screen >>in only 1/30th of a second flicker-free! > >This sounds like an animation demo that was running at AppleFest SF in >September, although the flyer I have doesn't refer to it by that name. >The demo showed a picture of a five-sided stepped... I guess carousel is as >good a name as any... that rotated with very clean shading and shadow effects >while balls bounced down the steps and into tubes which ran back to the top of >the steps. This isn't a very good description, I know, but if you saw it you'll >remember from this. > >This particular demo had the images precalculated on Apple's Cray supercomputer >and the animation is done by changing only the data that has to be changed from >screen to screen. According to the people I asked the computer was just about >100% tied up just displaying those images. Close, but nothing quit so glamorous. Don generated those images on a "UNIX box" (as he calls it) that he has at home. He used that simply because it had the ray-tracing software that he needed. (OK...so it probably ran faster than a GS as well). The animation was performed by using a technique that kind of makes me not able to sleep at night. First of all, all of the images are stored into memory. Then he turns on low memory shadowing to the SHR screen from bank $01, AND then swaps banks 0 and 1 by using that old AuxStore thing that the Apple //e and //c use. After that, he syncs up with the VBL, sets the stack pointer so that the stack overlays the $2000-$A000 range, and then simply pushes the whole picture onto the stack! By performing the PHA's, he can transfer the whole screen very quickly. Of course, there is a little more to it than this. For one thing, he doesn't push the picture onto the stack all at one time. He does it scanline by scanline, from right to left. He also has some techique of playing with the color tables at the same time; he has some other pictures that show some amazing color quality! > >The name and address attached to the flyer is: > >Don Marsh >MS 27-B >Apple Computer, Inc. >20525 Mariani Ave. >Cupertino, CA. 95014 > >Hope that is of some use... > > Rich > ><jordan%lvva.span@sds.sdsc.edu> >BIX: richjordan (Rarely there) >GEnie: BARRACUDA Keith Rollin --- Apple Computer, Inc. --- Developer Technical Support INTERNET: keith@apple.com UUCP: {decwrl, hoptoad, nsc, sun, amdahl}!apple!keith "You can do what you want to me, but leave my computer alone!"