[Mesa3d-users] OSMesa incompatible with other GL output methods?

[Owen K. <Owe...@sc...>]

Hi,

I'm having a problem using OSMesa for off-screen rendering.
Our software is designed to run using glx for output and optionally on
cluster nodes with visual output going to files using OSMesa.

This all works fine as as separate solutions but we want the output type
controlled by a user setting and it seems that if the OSMesa library is
linked but glx used instead it causes the program to segfault on a call
to a non-specific GL function.

I also discovered that the order of linking effects this behaviour, if
-lOSMesa is specified before -lGL on the compile command line then
OSMesa output works but using GL functions through glx will segfault.
If the order is reversed then it works fine through glx and OSMesa
appears to run ok (no error codes are returned) but none of the graphics
commands produce output to the OSMesa buffer and a blank image results.

I've attached a sample program to demonstrate this, it produces opengl
output in a window when run without any command line args, writes to
osmesa and a png file if anything is passed on the command line

If compiled with:
	gcc -o glx glx11.c -lGL -lGLU -lOSMesa -lpng
Runs fine in window but osmesa produces blank output

When compiled with:
	gcc -o glx glx11.c -lOSMesa -lGL -lGLU -lpng
Segfault in window, osmesa produces output correctly

Is there any way to get both working together without recompiling?

Regards,

Owen Kaluza