interpreting glxinfo's output

[andrew rader]

Hi all,

I've been toying with the idea of creating a small compositing window
manager for a while, and I've started looking at the sourcecode of
compiz, xcompmgr, etc and I have a quick question. I'm currently using
a laptop with the intel gm965 chipset (aka X3100) and I've been
bothered by the output of glxinfo regarding the texture_from_pixmap
extension.

My app is using the glXQueryExtensionsString function to check for the
existence of the GLX_EXT_texture_from_pixmap extension, without
success. The output of this function is the following string:

"GLX_ARB_get_proc_address GLX_ARB_multisample GLX_EXT_import_context
GLX_EXT_visual_info GLX_EXT_visual_rating GLX_MESA_copy_sub_buffer
GLX_MESA_swap_control GLX_MESA_swap_frame_usage GLX_OML_swap_method
GLX_SGI_make_current_read GLX_SGI_swap_control GLX_SGI_video_sync
GLX_SGIS_multisample GLX_SGIX_fbconfig GLX_SGIX_visual_select_group "

The above clearly does not contain the texture_from_pixmap extension,
but when I run glxinfo I get the following (snipped for brevity):

name of display: :0.0
display: :0  screen: 0
direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.2
server glx extensions:
   GLX_ARB_multisample, GLX_EXT_import_context, GLX_EXT_texture_from_pixmap,
   GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_copy_sub_buffer,
   GLX_OML_swap_method, GLX_SGI_make_current_read, GLX_SGI_swap_control,
   GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_visual_select_group
client glx vendor string: SGI
client glx version string: 1.4
client glx extensions:
   GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_import_context,
   GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_allocate_memory,
   GLX_MESA_copy_sub_buffer, GLX_MESA_swap_control,
   GLX_MESA_swap_frame_usage, GLX_OML_swap_method, GLX_OML_sync_control,
   GLX_SGI_make_current_read, GLX_SGI_swap_control, GLX_SGI_video_sync,
   GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer,
   GLX_SGIX_visual_select_group, GLX_EXT_texture_from_pixmap
GLX version: 1.2
GLX extensions:
   GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_import_context,
   GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_MESA_copy_sub_buffer,
   GLX_MESA_swap_control, GLX_MESA_swap_frame_usage, GLX_OML_swap_method,
   GLX_SGI_make_current_read, GLX_SGI_swap_control, GLX_SGI_video_sync,
   GLX_SGIS_multisample, GLX_SGIX_fbconfig, GLX_SGIX_visual_select_group
OpenGL vendor string: Tungsten Graphics, Inc
OpenGL renderer string: Mesa DRI Intel(R) 965GM 4.1.3002
OpenGL version string: 1.4 Mesa 7.0.2
OpenGL extensions: <snip>

So my question: what is the difference between "server glx
extensions", "client glx extensions", and "GLX extensions"? It appears
the the first two list "GLX_EXT_texture_from_pixmap" as supported, but
the "GLX extensions" list does not.

Is this a configuration issue? a driver issue? any ideas would be appreciated

-Andy