Re: [Mesa3d-dev] Debugging OSmesa16

[Brian P. <br...@va...>]

"J.P. Delport" wrote:
> 
> Hi,
> 
> I've started experimenting with the OSmesa16 library on linux and wrote
> a simple program based on osdemo16 that draws a single smooth shaded
> triangle. I've managed to import the off-screen 16-bit data into Matlab
> to do some checks. The program works fine without
> glEnable(GL_SMOOTH_POLYGON), but with it gives a garbled triangle.

I'll look into this.


> I
> would like to familiarise myself with the OSmesa16 code and trace the
> origin of the error, but I need some pointers on debugging the lib. I'm
> using ddd with gdb and when setting breakpoints e.g. in
> swrast/s_triangle.c gdb complains:
> Error in re-setting breakpoint 1:
> No source file named swrast/s_triangle.c.
> 
> I've tried using the gdb dir command to add source search dirs with no
> success.
> 
> gdb> info shar gives:
> >From        To          Syms Read   Shared Object Library
> 0x40015000  0x4002fe30  Yes         /home/jpdelport/Mesa/lib/libGLU.so.1
> 0x40030000  0x40388fc4  Yes
> /home/jpdelport/Mesa/lib/libOSMesa16.so.1
> 0x4038e000  0x403aa9d8  Yes         /lib/libm.so.6
> 0x403ab000  0x403bd138  Yes         /lib/libpthread.so.0
> 0x403bf000  0x404b385c  Yes         /lib/libc.so.6
> 0x40000000  0x40013ed0  Yes         /lib/ld-linux.so.2
> 
> I compiled (from a CVS checkout on 28/05) libOSMesa16 with: make -f
> Makefile.X11 linux-osmesa16
> and compiled libGLU by going to src-glu and doing: make -f Makefile.X11
> linux-debug
> 
> Any pointers to what I'm doing wrong or how I'm supposed to set up an
> OSmesa debugging session would be appreciated.

First, be sure to recompile the sources with -g and without -O.  Edit
Make-config, look for 'linux-osmesa16'.

If you're debugging a dynamic library you can't set breakpoints in the
library code until execution has begun.  Try setting a breakpoint in
main(), run to that point, then set a breakpoint in the Mesa function
you're interested in.

-Brian