Contributor: JASEN BETTS { > If I get inspired, I will add simple perspective transform to these. > There, got inspired. Made mistakes. Foley et al are not very good at > tutoring perspective and I'm kinda ready to be done and post this. > line(round(x1)+200,round(y1)+200, > round(x2)+200,round(y2)+200); try this for perspective (perspecitve is easy to calculate but hard to explain... I worked it out with a pencil and paper using "similar triangles, and a whole heap of other math I never thought I'd need, it took me the best part of 30 minutes but when I saw how simple it really is...) this code gives an approximation of perspective... it's pretty good when K is more than 3 times the size (maximum dimension) of the object K is some constant... (any constant, about 3-10 times the size of the object is good) (K is actually the displacement of the viewpoint down the -Z axis. or something like) K=600 would be a good starting point } line(round(x1/(K+z1)*K)+200,round(y1/(K/z1)*K)+200, round(x2/(K+z2)*K)+200,round(y2/(K/z2)*K)+200); { not computationally efficient but it shows how it works. Here's one that gives "real perspective" } line(round(x1/sqrt(sqr(K+z1)+sqr(x1)+sqr(y1))*K, round(y1/sqrt(sqr(K+y1)+sqr(y1)+sqr(y1))*K, round(x2/sqrt(sqr(K+z2)+sqr(x2)+sqr(y2))*K, round(y2/sqrt(sqr(K+y2)+sqr(y2)+sqr(y2))*K);