KDE4 is iterating over all availiable FB configs. It first tries to get a visual for a given FB config, then, if a visual has a needed depth (24 or 32 bits), it queries the FB config for GLX_BUFFER_SIZE and GLX_ALPHA_SIZE. If buffer_size is 24 or 32, or (visual_depth-alpha_size) is 24 or 32, it queries the FB config for GLX_BIND_TO_TEXTURE_RGBA_EXT support. If the last query shows no support, it queries the FB config for GLX_BIND_TO_TEXTURE_RGB_EXT support. If the latter support is also missing, it gives up.
And the thing that is happening - KDE is unable to find a FB config that has 32 bits buffer size and GLX_BIND_TO_TEXTURE_RGBA_EXT or GLX_BIND_TO_TEXTURE_RGB_EXT support. When I modified the function that gets the depth of a visual (added alpha channel to the sum in glxvisual.cpp for render_type==GLX_RGBA_BIT), it finds the needed FB config (32-bit), but refuses to find a suitable 24-bit FB config. > Visuals are not the same as FB configs in VirtualGL. Visuals are on the > client and FB configs are on the server. Thus, a visual will always > have a 24-bit depth even though the FB config used to create the Pbuffer > may have a 32-bit depth. > > Thus, I don't think that's the cause of the issue. If it's looking for > a visual with GLX_BIND_TO_TEXTURE_RGBA_EXT, then that may be the cause. > How did you determine that it is looking for such a visual? Please be > as verbose as possible. Don't just say "from debugging", as this does > not tell me how you debugged the problem. > > On 4/11/10 6:49 PM, Александр Кириллов wrote: > >> Well, a 32-bit FB config supports rendering alpha channel (24-bit FB >> config has 0 bits for alpha and 32-bit has 8 bits for alpha). >> Yes, glxinfo repots this and also the debugging - the depth field of a >> visual equals 24. >> >>> I'm not sure I understand what you mean about 24-bit vs. 32-bit FB >>> configs. And what do you mean by "VirtualGL tells me that those are >>> 24-bit configs"? Are you running /opt/VirtualGL/bin/glxinfo -c to get >>> this information? >>> >>> On 4/10/10 3:01 PM, Александр Кириллов wrote: >>> >>> >>>> Hello! >>>> >>>> I'm trying to run KDE4 over VNC with TigerVNC and VirtualGL, but it >>>> didn't work out of the box. >>>> I used a debugger and found out that KDE4 cannot find a suitable >>>> GLXFBConfig - 32-bit with GLX_BIND_TO_TEXTURE_RGBA_EXT (or the same with >>>> RGB instead of RGBA) support. >>>> On the host system there are plenty of such GLXFBConfigs, but VirtualGL >>>> tells me that those are 24-bit configs (I've compared them by number). >>>> Can you please suggest me what to do in order to help VirtualGL find a >>>> suitable framebuffer configuration? >>>> >>>> Best regards, >>>> Alexander Kirillov >>>> >>>> >>>> ------------------------------------------------------------------------------ >>>> Download Intel® Parallel Studio Eval >>>> Try the new software tools for yourself. Speed compiling, find bugs >>>> proactively, and fine-tune applications for parallel performance. >>>> See why Intel Parallel Studio got high marks during beta. >>>> http://p.sf.net/sfu/intel-sw-dev >>>> _______________________________________________ >>>> VirtualGL-Users mailing list >>>> [email protected] >>>> https://lists.sourceforge.net/lists/listinfo/virtualgl-users >>>> >>>> >>> ------------------------------------------------------------------------------ >>> Download Intel® Parallel Studio Eval >>> Try the new software tools for yourself. Speed compiling, find bugs >>> proactively, and fine-tune applications for parallel performance. >>> See why Intel Parallel Studio got high marks during beta. >>> http://p.sf.net/sfu/intel-sw-dev >>> _______________________________________________ >>> VirtualGL-Users mailing list >>> [email protected] >>> https://lists.sourceforge.net/lists/listinfo/virtualgl-users >>> >>> >> >> ------------------------------------------------------------------------------ >> Download Intel® Parallel Studio Eval >> Try the new software tools for yourself. Speed compiling, find bugs >> proactively, and fine-tune applications for parallel performance. >> See why Intel Parallel Studio got high marks during beta. >> http://p.sf.net/sfu/intel-sw-dev >> _______________________________________________ >> VirtualGL-Users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/virtualgl-users >> > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > VirtualGL-Users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/virtualgl-users > ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ VirtualGL-Users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/virtualgl-users
