[PyOpenGL-Users] Example of using OpenGL.trackball?

[Rick M. <rm...@sa...>]

Does anyone have an example of using OpenGL.trackball? I'm having a 
hard time getting it to work.

I initialize the trackball:
         self.tb = Trackball()

On mouse movement (I'm doing this under GtkGLExt, so it's called 
ButtonMovement, but the idea is the same) I do:

     def button_motion(self, width, height, event):
         if event.state == gtk.gdk.BUTTON1_MASK:
             self.tb.update(self.beginx,self.beginy,event.x,event.y,
                            width,height)

Finally, in display I do this:
     def display(self, *args):
         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

         glPushMatrix()

         glTranslatef(self.transx,self.transy,self.depth)
         rotmtx = self.tb.matrix
         glMultMatrixf(rotmtx)

         glCallList(1)
         glPopMatrix()
         return

Am I doing something bone-headed here? In the past I've just done the 
rotations by hand, but I wanted to implement a real trackball.

R.

Rick Muller
rm...@sa...