[GRASS5] [bug #4246] (grass) NVIZ: segfault in kanimation panel

[Bob Covill]

On Wed, 2006-04-12 at 15:07 +1200, Hamish wrote:
> > I took a quick look at this and I cannot duplicate the error.
> 
> I am using Debian with TclTk 8.4, which is a new thing. See:
>   http://article.gmane.org/gmane.comp.gis.grass.devel/11177
>   http://grass.itc.it/pipermail/grass-commit/2006-March/021104.html
> 
> Maybe a similar issue?
> 
> (I haven't recompiled with tcltk 8.3 yet to check if this is the case,
> obviously it would be a good idea to do so. It works fine with a CVS
> version from February (compiled with tcltk 8.3), so I would guess this 
> is a pretty strong lead)
> 
> 
> > I do get the compiler warning for all of the Tcl_SplitList in src.
> > According to TCL recent documentation arg 4 in Tcl_SplitList should
> > actually be "const char **". If I change 
> > char **listels;
> > in anim_support.c (line ~933)
> > to const char **listels;
> > I do not get the compiler warning.
> 
> If I add "const", the warning goes away for me too. But it still
> segfaults on Load anim file.
> 
> I also notice these warnings:
> 
> <command line>:5:1: warning: "__STDC__" redefined
> In file included from anim_support.c:11:
> interface.h:363: warning: `struct Map_info' declared inside parameter list
> interface.h:363: warning: its scope is only this definition or declaration, which is probably not what you want
> 
> 
> and eight "warning: passing arg 1 of `...' as `float' rather than `double' due to prototype"

I also get these warnings?

>  
> > Also, according to the Tcl_SplitList documentation, the **listels
> > argument should be freed. They recommend using 
> > Tcl_Free((char *) argv);
> > 
> > I am not sure why the free call would be creating a problem. 
> 
> see above links ??

Taking a look at some of the other Tcl_SplitList calls (for example in
draw.c) the char is freed with G_free ((char *) ...). I would expect
these to also segfault if it was a problem with G-free. Try simply
changing 
G_free (listels);
to 
G_free ((char *) listels);

> 
> 
> 
> I've made a number of small cleanups to the kanim code in the last week
> to make things a little easier on the user (also d.nviz, nviz2.2_script).
> Hopefully it will just be smoother and the changes won't be noticed. 
> The Keyframe Animator help page is extended including an example and 
> should be easier to follow.

These all sound great. The extended help is a good idea as the Keyframe
Animator can be quite difficult to learn.

> 
> Also I added an #ifdef to the MPEG code to make it easy to switch to
> using the XVID codec. (compile with gcc -D"USE_XVID") This should really
> be an enviro var or GIS var setting, but for now it's a quick proof of 
> concept hack.

Instead of a compile flag could we try something like ...
codec = avcodec_find_encoder(CODEC_ID_XVID);
if (!codec)
{
	codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);
	if (!codec) {
		fprintf(stderr, "codec not found\n");
		return(-1);
	}
}
This way it tries to load the better quality codec, and if it fails it
will load the old standard mpeg1. I have not tested it to see if it
works. 

> 
> Result of this is that making movies is somewhat easier now. Great 
> synergy with r.in.wms(x2) or r.in.onearth scripts to fetch SRTM and 
> LANDSAT. Process LANDSAT image with Markus's i.landsat.rgb & even 
> better.
> 
> 
> Q: If I make a track with d.nviz the camera looks straight down, not
> forwards along the track. Is this normal/expected?

If the camera is looking down then you need to increase the dist
parameter. The combination of the ht and dist parameters are what
determine the camera look angle. 

> 
> 
> 
> cheers,
> Hamish
> 

Hope this helps.

--
Bob