mesa3d-dev

[Mesa3d-dev] Segmentation Fault in shade_rastpos

[Allen B. <ba...@lo...>]

Hi,

I'm getting a segmentation fault in the Mesa function shade_rastpos()
when lighting is turned on and if no other drawing precedes a call to
RasterPos2i(). Attached is a sample program which demonstrates the
problem. I'm using Mesa 3.5.1 on RedHat 7.1/i386.

BTW, GL_RASTER_POSITION_UNCLIPPED_IBM works great! Thank you.

Thanks,
Allen

[Mesa3d-dev] Segmentation Fault in shade_rastpos

[Allen B. <ba...@lo...>]

Hi,

I'm getting a segmentation fault in the Mesa function shade_rastpos()
when lighting is turned on and if no other drawing precedes a call to
RasterPos2i(). Attached is a sample program which demonstrates the
problem. I'm using Mesa 3.5.1 on RedHat 7.1/i386.

Thanks,
Allen

Re: [Mesa3d-dev] Segmentation Fault in shade_rastpos

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

Allen Barnett wrote:
> 
> Hi,
> 
> I'm getting a segmentation fault in the Mesa function shade_rastpos()
> when lighting is turned on and if no other drawing precedes a call to
> RasterPos2i(). Attached is a sample program which demonstrates the
> problem. I'm using Mesa 3.5.1 on RedHat 7.1/i386.

Hmmm, your test program runs fine here.  Can you get a stack trace
with your debugger?


> BTW, GL_RASTER_POSITION_UNCLIPPED_IBM works great! Thank you.

You're welcome!

-Brain

Re: [Mesa3d-dev] Segmentation Fault in shade_rastpos

[Allen B. <ba...@lo...>]

Brian Paul wrote:
> 
> Allen Barnett wrote:
> >
> > Hi,
> >
> > I'm getting a segmentation fault in the Mesa function shade_rastpos()
> > when lighting is turned on and if no other drawing precedes a call to
> > RasterPos2i(). Attached is a sample program which demonstrates the
> > problem. I'm using Mesa 3.5.1 on RedHat 7.1/i386.
> 
> Hmmm, your test program runs fine here.  Can you get a stack trace
> with your debugger?

Sorry, I pressed the send button before I reverted the attached code to
its failure mode in my original message. Did you test it with the quad
drawing commented out as below?

> void display ( void )
> {
> #if 0
>  glBegin( GL_QUADS );
>  glVertex2i( 0, 0 );
>  glVertex2i( 50, 0 );
>  glVertex2i( 50, 50 );
>  glVertex2i( 0, 50 );
>  glEnd();
> #endif
> 
>  glRasterPos2i( 0, 0 );
> }

The output from the debugger is below.

And another question(s): How do you debug Mesa with GDB? I guess I don't
understand how to get it to compile without optimization (a ./configure
option?) and if I have to build and link with a static archive library
instead of a shared object? Any tips would be helpful.

Thanks,
Allen

GNU gdb 5.0rh-5 Red Hat Linux 7.1
Copyright 2001 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you
are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
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details.
This GDB was configured as "i386-redhat-linux"...
(gdb) r
Starting program: /home/allen/lignumCAD/OGLFT/try7
[New Thread 1024 (LWP 25135)]
 
Program received signal SIGFPE, Arithmetic exception.
[Switching to Thread 1024 (LWP 25135)]
0x4023916b in _mesa_test_os_sse_exception_support ()
   from /usr/local/lib/libGL.so.1
(gdb) c
Continuing.
Brian Paul Mesa X11 1.2 Mesa 3.5
 
Program received signal SIGSEGV, Segmentation fault.
0x40119526 in shade_rastpos (ctx=0xbffff928, vertex=0x403b3177,
normal=0x1,
    Rcolor=0xbffff954, Rspec=0xbffff95c, Rindex=0x804869e) at
rastpos.c:228
228                 GET_SHINE_TAB_ENTRY( ctx->_ShineTable[0], n_dot_h,
spec_coef );
(gdb) where
#0  0x40119526 in shade_rastpos (ctx=0xbffff928, vertex=0x403b3177,
    normal=0x1, Rcolor=0xbffff954, Rspec=0xbffff95c, Rindex=0x804869e)
    at rastpos.c:228
#1  0x00000007 in ?? ()
#2  0x4002b763 in processWindowWorkList (window=0xbfffff27)
    at glut_event.c:1297
#3  0x403b3177 in __libc_start_main (main=0x8048998 <main>, argc=1,
    ubp_av=0xbffff954, init=0x8048688 <_init>, fini=0x8048ab0 <_fini>,
    rtld_fini=0x4000e184 <_dl_fini>, stack_end=0xbffff94c)
    at ../sysdeps/generic/libc-start.c:129
(gdb) l
223                    n_dot_h *= n_dot_h;
224                    n_dot_h /= LEN_SQUARED_3FV( h );
225                    shininess *= .5;
226                 }
227
228                 GET_SHINE_TAB_ENTRY( ctx->_ShineTable[0], n_dot_h,
spec_coef );
229
230                 if (spec_coef > 1.0e-10) {
231                    if
(ctx->Light.Model.ColorControl==GL_SEPARATE_SPECULAR_COLOR) {
232                       ACC_SCALE_SCALAR_3V( specularContrib,
spec_coef,

Re: [Mesa3d-dev] Segmentation Fault in shade_rastpos

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

Allen Barnett wrote:
> 
> Brian Paul wrote:
> >
> > Allen Barnett wrote:
> > >
> > > Hi,
> > >
> > > I'm getting a segmentation fault in the Mesa function shade_rastpos()
> > > when lighting is turned on and if no other drawing precedes a call to
> > > RasterPos2i(). Attached is a sample program which demonstrates the
> > > problem. I'm using Mesa 3.5.1 on RedHat 7.1/i386.
> >
> > Hmmm, your test program runs fine here.  Can you get a stack trace
> > with your debugger?
> 
> Sorry, I pressed the send button before I reverted the attached code to
> its failure mode in my original message. Did you test it with the quad
> drawing commented out as below?
> 
> > void display ( void )
> > {
> > #if 0
> >  glBegin( GL_QUADS );
> >  glVertex2i( 0, 0 );
> >  glVertex2i( 50, 0 );
> >  glVertex2i( 50, 50 );
> >  glVertex2i( 0, 50 );
> >  glEnd();
> > #endif
> >
> >  glRasterPos2i( 0, 0 );
> > }
> 
> The output from the debugger is below.

I've checked in a fix for this problem.  Here's the diff:

diff -r1.28 rastpos.c
133a134,136
>    if (!ctx->_ShineTable[0] || !ctx->_ShineTable[1])
>       _mesa_validate_all_lighting_tables( ctx );
> 


> And another question(s): How do you debug Mesa with GDB? I guess I don't
> understand how to get it to compile without optimization (a ./configure
> option?) and if I have to build and link with a static archive library
> instead of a shared object? Any tips would be helpful.

I always use the old-style Makefiles when debugging/developing.  Try this:

cd src
make -f Makefile.X11 clean
make -f Makefile.X11 linux-debug

When running with gdb and using a shared libGL.so, you can't set breakpoints
in the Mesa code until the program has begun executing.  To work around that,
first set a breakpoint in main(), then run.  When gdb stops in main() you
can then set breakpoints elsewhere in Mesa.

-Brian

Re: [Mesa3d-dev] Segmentation Fault in shade_rastpos

[Sven M. H. <pe...@gm...>]

On Thu, Jul 05, 2001 at 09:43:52AM -0600, Brian Paul wrote:
> Allen Barnett wrote:
> >
> > And another question(s): How do you debug Mesa with GDB? I guess I don't
> > understand how to get it to compile without optimization (a ./configure
> > option?) and if I have to build and link with a static archive library
> > instead of a shared object? Any tips would be helpful.
> 
> I always use the old-style Makefiles when debugging/developing.  Try this:
> 
> cd src
> make -f Makefile.X11 clean
> make -f Makefile.X11 linux-debug

Try:
    $ configure --enable-debug
That should add -O0 to CFLAGS if you're using GCC. If you're using a different
compiler, tell me which flag you need for debugging code, and I'll add it.

-Sven

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