pyopengl-users

Re: [PyOpenGL-Users] freeglut: Unable to create direct context rendering

[Fabrizio P. <pol...@ir...>]

The code

glutInit(sys.argv)
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH | GLUT_ALPHA)
glutInitWindowSize(640, 480)
glutInitWindowPosition(0, 0)
glutCreateWindow("Jeff Molofee's GL Code Tutorial ... NeHe '99")

produces the following error on my system (Debian/Linux Etch i386)

freeglut (./p.py):  ERROR:  Internal error <Visual with necessary 
capabilities not found> in function fgOpenWindow
X Error of failed request:  BadWindow (invalid Window parameter)
   Major opcode of failed request:  4 (X_DestroyWindow)
   Resource id in failed request:  0x0
   Serial number of failed request:  19
   Current serial number in output stream:  22

I have attached the full output of glxinfo and xdpyinfo for more 
information.

F. Pollastri.

Re: [PyOpenGL-Users] freeglut: Unable to create direct context rendering

[Dave P. <de...@bu...>]

On Mon, 25 Sep 2006, Fabrizio Pollastri wrote:
> 
> glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH | GLUT_ALPHA)
>... 
> freeglut (./p.py):  ERROR:  Internal error <Visual with necessary capabilities
> not found> in function fgOpenWindow

You're requesting a window with an alpha channel in the framebuffer, but 
the output of glxinfo indicates that your display doesn't support that 
(all values under "colorbuffer a" are 0).

Generally, you don't actually need alpha in the framebuffer.  It's only 
necessary for things like blending with a GL_DST_ALPHA function, or 
reading back the alpha values of a rendered image.  It's not needed for 
the more common GL_SRC_ALPHA-based blending.

Try removing the "| GL_ALPHA" from your InitDisplayMode command.

--
Dave Pape                                                 Assistant Professor
http://resumbrae.com/                      Media Study, University at Buffalo