[GRASS-dev] Re: [GRASS GIS] #104: saving display to tiff or ppm garbled when NVIZ is not top window

Glynn Clements glynn at gclements.plus.com
Thu Mar 27 13:02:47 EDT 2008

GRASS GIS wrote:

> #104: saving display to tiff or ppm garbled when NVIZ is not top window
> ----------------------+-----------------------------------------------------
>   Reporter:  dylan    |       Owner:  grass-dev at lists.osgeo.org
>       Type:  defect   |      Status:  new                      
>   Priority:  minor    |   Milestone:  6.4.0                    
>  Component:  default  |     Version:  svn-trunk                
> Resolution:           |    Keywords:  NVIZ openGL              
> ----------------------+-----------------------------------------------------
> Comment (by msieczka):
>  Replying to [comment:5 glynn]:
>  > I think I've fixed this; at least, it works on my system.
>  On my system unless I export GRASS_NO_GLX_PIXMAPS=TRUE, NVIZ crashes at
>  saving image as maximum resolution PPM, with the following error:
>  {{{
>  Create PixMap Using GLX 1.1
>  X Error of failed request:  GLXBadContext
>    Major opcode of failed request:  143 (GLX)
>    Minor opcode of failed request:  5 (X_GLXMakeCurrent)
>    Serial number of failed request:  5128
>    Current serial number in output stream:  5128
>  }}}

Odd. The glXMakeCurrent manpage says:

       GLXBadContext is generated if ctx is not a valid GLX context.

But there don't appear to be any errors regarding the
glXCreateContext() call, and both are created using the same
XVisualInfo structure.

>  After exporting GRASS_NO_GLX_PIXMAPS=TRUE all is OK.

Could you debug this?

Once NVIZ is running, get its PID, then:

	$ gdb $GISBASE/etc/nviz2.2/nviz
	> attach <pid>
	> break Create_OS_Ctx
	> cont

Selecting the menu option will re-enter the debugger. Single-step
through the function (with "next"), printing out the values of any
variables as they are assigned.

Glynn Clements <glynn at gclements.plus.com>

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