drawing circle

Hope my question does not sound too dumb? I looked under various help files and still I could not find the built in function that will draw circle or ellipse. I was hoping to have something of the form glCircle()…
Your help will be appreciated.

OpenGL go no build in functions for drawing primitives (other that points, lines and triangles) at all. If you want primitives other than the one i mentioned, you must look at either the glu-library or GLUT. These are the two most common libraries that uses OpenGL.

Or simple try:
(x, y, z) the center of the circle, r=radius, a=angle
do {
glPoint(x+sin(a)*r, y+sin(a)*r, z);
} while (a<360);

I don’t know about the syntax of glPoint, but in this case it would be (x, y, z);
If you want different circles, try using cos instead of sin or switching the sin’s.
For elipses use something like this:
rx=xradius, ry=yradius
do {
glPoint(x+sin(a)*rx, y+sin(a)*ry, z);
} while (a<360);

another example would be:

dlPoint(x-cos(a)*rx, y+sin(a)*ry, z-sin(-a)*rz);

Feel free to experiment.
Hope that helps - Ls

I’m sorry, but of course you have to increase a by 1 or 0.1 or something like this. And you also could try lines between a and a+0.1, they will even give a circle at the biggest radius, instead of making it a circle of points. Ls