Re: [Mesa3d-dev] bugs

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

Brian Paul wrote:
> 
> "Jacob (=Jouk) Jansen" wrote:
> >
> > Hi all,
> >
> > Since some time (around the same time all the software rastering was put
> > in separate directories) I observe the following 2 problems which may or may
> > not be related:
> >    To test I use the program xlockmore (see ftp://ftp.tux.org./pub/tux/bagleyd/xlockmore/
> >
> >  problems :
> >     -in mode moebius a part of the edge is not drawn resulting in a zig-zag
> >       line. Mesa3.4 draws it correct
> 
> This looks like a glPolygonMode() bug.  The interior edges in the quad
> strip shouldn't be rendered.  Keith could probably find this pretty
> quickly.
> 
> >     -Occasional xlock crashes in the GL modes due to invalid floats and
> >      access violation. I have no idea where to look for the error since
> >      normal error messages are not given. So probably a memory leak overwrites
> >      the program.
> 
> Which modes or programs in particular cause this?


I found the problem.

gloss has an FP exception if I run with "setenv MESA_DEBUG FP".

The problem is in the texgen code.  In the template function
for texgen_sphere_map() the VB->tmp_f array is NULL and being
allocated on the spot.  However, its contents are undefined.

Below is a simple patch which just changes the MALLOC to a CALLOC
so the array is initialized to zero.

I know Keith's been changing the vertex buffer code so I'll
wait for him to comment before committing this.

-Brian



*** t_texgen_tmp.h      2000/11/16 21:05:42     1.1
--- t_texgen_tmp.h      2000/12/15 22:57:19
***************
*** 291,297 ****
     GLfloat (*f)[3], *m;
  
     if (!VB->tmp_f) 
!       VB->tmp_f = (GLfloat (*)[3]) MALLOC(VB->Size * sizeof(GLfloat) * 3);
  
     if (!VB->tmp_m) 
        VB->tmp_m = (GLfloat *) MALLOC(VB->Size * sizeof(GLfloat));
--- 291,297 ----
     GLfloat (*f)[3], *m;
  
     if (!VB->tmp_f) 
!       VB->tmp_f = (GLfloat (*)[3]) CALLOC(VB->Size * sizeof(GLfloat) * 3);
  
     if (!VB->tmp_m) 
        VB->tmp_m = (GLfloat *) MALLOC(VB->Size * sizeof(GLfloat));