It's not hard. Look at gluProject. It will project a 3D point into 2D space
given modelview, projection, and viewport values. From the
The gluProject function maps object coordinates to window coordinates.
const GLdouble modelMatrix,
const GLdouble projMatrix,
const GLint viewport,
objx, objy, objz The object coordinates.
modelMatrix The current modelview matrix (as from a glGetDoublev call).
projMatrix The current projection matrix (as from a glGetDoublev call).
viewport The current viewport (as from a glGetIntegerv call).
winx, winy, winz The computed window coordinates.
The gluProject function transforms the specified object coordinates into window coordinates using modelMatrix, projMatrix, and
viewport. The result is stored in winx, winy, and winz. A return value of GL_TRUE indicates success, and GL_FALSE indicates failure.
> > But I repeat: That's all really * stuff... (Arrrgh... )
> so in conclusion - if I glVertex3f(x,y,z) - there is no GL function which
> returns me xscreen and yscreen ?
> Well it's a cold world And I'm in the middle
> Caught in the in-between I don't belong here
> So I'm writing to you It's wrong here "Letters From Earth"
> Where I'm sending you some Letters from Earth - Ronnie James Dio
Robert A. Schmitt
RESolution Graphics Inc.