The algorithm is the same--shadow mapping. What have I changed? Hard to say. Here's what happened: -Since beginning PyOpenGL programming nearly two years ago, I always wanted to make something using shadows. When I first started, I was still unfamiliar with Python, though I had been doing stuff with PyGame for a while. For a month or so, making shadows was way beyond me (I was struggling with gl windows and other random stuff)--which is not to say I didn't try. Naturally, nothing really came of it. -Skipping ahead a year or so, but still about a year ago, I FINALLY got a PyOpenGL shadow demo, but it didn't work because it used PyOpenGL for the matrix multiplication, and that was broken for some reason. -After that was sorted out, I had a working demo, which I refined down to a module about 1/3 the size of the original which could be tacked onto anything. It worked brilliantly--as long as you were using the objects which came with the demo (the purple triangular thing and the green landscape). I tried my objects--a cube and a randomly generated terrain, but they didn't work. -I couldn't figure out why, and for a long time, the project sat, annoying me. This must have been several months. Throughout all this, I had been trying to make shadows in one way or another using various code--the final count is 26 attempts at shadowing! -Yesterday, I tried fixing it again, and within five minutes had isolated the problem to the object texture code. As my objects were being drawn, the texture was disabled via a misplaced glDisable() call. Turns out GL_COLOR_MATERIAL works even if GL_TEXTURE_2D is enabled, so the call wasn't necessary and it was breaking shadows because shadows use a depth texture. Stupid errors like that annoy me. From there, I emailed everyone here and it was only a matter of a few hours to release 'OpenGL Library'.
Ian
