Re: XForms: Initialisation of OpenGL

Steve Lamont (spl@szechuan.ucsd.edu)
Fri, 17 Apr 98 05:51:37 PDT

# To subscribers of the xforms list from spl@szechuan.ucsd.edu (Steve Lamont) :

> Either I'm very stupid or I'm just overlooking something:

Probably just overlooking something....

> The application is just a form with as its ONLY object a glcanvas.
> For the canvas an "expose" and a "buttonpress" handler have been defined.
>
> This is the start of the "expose" handler:
>
> FD_gltest *form;
>
> int canvas_expose(FL_OBJECT *ob, Window win, int w, int h,
> XEvent *xev, void *ud)
> {
> GLenum fout;
> static float matrix[16] = { 2.0, 0.0, 0.0, 0.0,
> 0.0, 2.0, 0.0, 0.0,
> 0.0, 0.0, 0.0, 0.0,
> -1.0,-1.0, 0.0, 1.0 };
>
> glViewport(0,0, (GLint)w, (GLint)h);

Try adding a call to fl_activate_glcanvas() before any call to
OpenGL/MesaGL routines. Even if you have only one OpenGL drawing
area, it might be that your GLXContext is getting invalidated for some
reason.

spl
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