[Fwd: [PyOpenGL-Users] glVertexArrayd slows performance]

[Douglas T. <dt...@sk...>]

Sorry, I should have mentioned that the positions
are changing every frame. Thanks,

Doug


-------- Original Message --------
Subject: 	[PyOpenGL-Users] glVertexArrayd slows performance
Date: 	Sat, 04 Feb 2006 16:46:50 -0800
From: 	Douglas Taylor <dt...@sk...>
To: 	pyo...@li...



Hi,

I've been trying to improve a dot drawing routine
and I tried the vertex array method but it slows
performance by a factor of 2. My testing machine
runs Mac OSX 10.3.9 and has PyOpenGL version 2.0.2.01 .
I tried allocating the xyData array 2 ways and both have
the same performance

1) xyData = RandomArray.uniform(0.0,1.0, (NUM_POINTS,2))

2)  xyData = Numeric.zeros( (NUM_POINTS,2), 'd')

and the code looks as

       if use_vertex_array == False:
           glColor4f(1.0, 0.0, 0.0,1.0);
           glBegin(GL_POINTS);
           for i in range(NUM_POINTS):
              glVertex3f(xstart[i],ystart[i],zstart[i]);
           glEnd()
       else:
       # Pass a pointer to the start of the point-coordinate array:
           glColor4f(0.0, 1.0, 0.0,1.0);
           xyData[:,0] = xstart
           xyData[:,1] = ystart
           glVertexPointerd(xyData);
           glEnableClientState(GL_VERTEX_ARRAY);
           glDrawArrays(GL_POINTS, 0, len(xstart));
           glDisableClientState(GL_VERTEX_ARRAY);

By timing parts of the code it spends most of it's time in
           glVertexPointerd(xyData);
the call to glDrawArrays(GL_POINTS, 0, len(xstart)); is quite fast.
Am I doing something wrong here? Any help would be
greatly appreciated. Thanks,

Doug Taylor





-------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc. Do you grep through log files
for problems?  Stop!  Download the new AJAX search engine that makes
searching your log files as easy as surfing the  web.  DOWNLOAD SPLUNK!
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=103432&bid=230486&dat=121642
_______________________________________________
PyOpenGL Homepage
http://pyopengl.sourceforge.net
_______________________________________________
PyOpenGL-Users mailing list
PyO...@li...
https://lists.sourceforge.net/lists/listinfo/pyopengl-users