[PyOpenGL-Users] confused n00b is confused - rendering simple triangles

[Dave C. <dav...@so...>]

I am just getting stated with opengl, and I am working with pyside, 
numpy, and a new constructive solid geometry library called pyPolyCSG.  
My goal is to modify the hellogl.py pyside example found here:
http://qt.gitorious.org/pyside/pyside-examples/blobs/master/examples/opengl/hellogl.py

pyPolyCSG can be found here, if you are interested:
https://github.com/jamesgregson/pyPolyCSG

hellogl.py simply displays the Trolltech logo in a pyside(qt) widget, 
rendered using OpenGL.  Works great.
I gutted the logo construction code and call pyPolyCSG to construct a 
box.  pyPolyCSG returns numpy arrays for vertices and triangles. I 
modified the paintgl() method to paint the mesh -- but clearly I am 
doing something wrong because all I see is a pretty background fill. My 
box is MIA.

I am a total n00b with OpenGL, so I suspect I am missing something very 
basic.

Relevant code:

The Qt widget paintGL callback:

     def paintGL(self):
         # copied from example:
         GL.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT)
         GL.glLoadIdentity()
         GL.glTranslated(0.0, 0.0, -10.0)
         GL.glRotated(self.xRot / 16.0, 1.0, 0.0, 0.0)
         GL.glRotated(self.yRot / 16.0, 0.0, 1.0, 0.0)
         GL.glRotated(self.zRot / 16.0, 0.0, 0.0, 1.0)
         # my code added here:
         v,t = self.object
         v = v/10.0 # Is scaling an issue?
         t = t.astype('uint16')
         colors = numpy.array([1.,0.,0.] * len(v)) # Need some colors?? 
Maybe???
         GL.glVertexPointer(3, GL.GL_FLOAT, 0, v.astype('float32'))
         GL.glColorPointer(3, GL.GL_FLOAT,0, colors.astype('float32'))
         GL.glDrawElements(GL.GL_TRIANGLES, len(t) ,GL.GL_UNSIGNED_SHORT, t)

My geometry construction:

     def makeObject(self):
         self.polyBlock = csg.box(2,4,6) # Call pyPolyCSG to construct a box
         v = self.polyBlock.get_vertices()
         t = self.polyBlock.get_triangles()
         print 'v = '
         print v
         print 't ='
         print t
         return (v,t)

The mesh in numpy arrays:
v =
[[ 0.  0.  0.]
  [ 2.  0.  0.]
  [ 2.  4.  0.]
  [ 0.  4.  0.]
  [ 0.  0.  6.]
  [ 2.  0.  6.]
  [ 2.  4.  6.]
  [ 0.  4.  6.]]
t =
[[4 0 1]
  [4 1 5]
  [6 2 3]
  [6 3 7]
  [0 3 2]
  [0 2 1]
  [7 4 5]
  [7 5 6]
  [5 1 2]
  [5 2 6]
  [7 3 0]
  [7 0 4]]

I'm a total n00b with OpenGL, so don't make too many assumptions about 
what I know :)

Thanks,
   Dave