Path: utzoo!utgpu!watmath!clyde!att!rutgers!mit-eddie!husc6!purdue!bouma From: bouma@cs.purdue.EDU (William J. Bouma) Newsgroups: comp.graphics Subject: Re: just a random idea Summary: its been done Keywords: MTV raytracer Message-ID: <5615@medusa.cs.purdue.edu> Date: 6 Dec 88 20:44:27 GMT References: <7980@pasteur.Berkeley.EDU> Organization: Department of Computer Science, Purdue University Lines: 31 In article <7980@pasteur.Berkeley.EDU> seth@miro.Berkeley.EDU (Seth Teller) writes: >I have this idea, see: you take an image (like any bunch of pixels, could even >be a picture) and you kind of paste it on a surface, like wallpaper on a wall. >This way you could make the dullest of polygons look interesting. Like you >could take a Playmate, or a monkey, or something, and put it on a coffee-pot >(well, maybe a coffee-pot is too hard, I'll think of something else). >Waddaya say? > I hacked the MTV tracer to do just this sort of thing a while back. Instead of specifying the color of an object this way: f SkyBlue 1 0 0 0 0 You can say: f function SpherePaintImage /name/of/image/file 1 0 0 0 0 Where SpherePaintImage is a function of the ray intersection with the surface of (in this case) a sphere. All it does is calculate from the intersection point which pixel of the image file corresponds. It returns that as the color for that point on the sphere (instead of SkyBlue). The hack is simple, writing mapping functions is not. I would not want to try writing one that would map onto the coffee-pot. One simple function that gets some use just returns the normal to the surface as the color. Another I use a lot puts grid patterns on polygons. Send playmate and monkey images to: -- Bill|| ...!purdue!bouma