[PLUG] gl graphics fault

[Galen Seitz]

todd.sarratt at attbi.com said:
> I am running an HP Omnibook2100 laptop with debian3.0.  I am trying to
> draw lines on my screen.  I can get vgadrawline() to work no problem.
> But I need to draw a lot of lines and the man pages indicate that
> gl_line is much quicker.  However, anytime I execute a gl_xxx command
> that writes to the screen (gl_setpixel, gl_line, etc).  I get this :

> svgalib: Signal 11: Segmentation fault received.

> The line right before my gl_line statement is

> vga_setpage(0);

> I don't really understand what this does, I haven't found very good
> documentation for it.  I'm just of the impression that it's needed for
> gl_line.  Commenting it out doesn't fix the problem, however... 


Have you looked at the man page (man gl_line) ?  It looks like you might
also need a call to gl_setcontextvga.

galen


from the gl_line man page:

DESCRIPTION
       Draw a line from point (x1, y1) to (x2, y2) inclusively in
       color c.

       You should not assume that the same drawing trajectory  is
       used when you exchange start and end points.

       To  use this program one first sets up a mode with a regu­
       lar vga_setmode call and vga_setpage(0), with  possibly  a
       vga_setlinearaddressing  call.   Then a call to gl_setcon­
       textvga(mode) is made.  This makes the  information  about
       the mode available to gl_line.

       The  pixels  are  placed  directly into video memory using
       inline coded commands.