#399 Detaching GLX contexts crashes X

open
nobody
5
2002-01-06
2002-01-06
Joesph Krahn
No

If you try to re-attach glX contexts to different
windows,
one find two server-crashing bugs.

Swapping front/back buffers on a window that does
not currently have an attached context crashes X.

Re-attaching an existing context to another window
and using it crashes X.

This works fine on an SGI.
I get different results with ATI DRI. It does not
crash, but gives strange artifacts.
This also crashes nVidia. Even the new Xig server
gets this wrong (but at least doesn't crash)

Why do it? I want to render to two windows
using the same OpenGL state.

Joe Krahn

Discussion

  • Joesph Krahn
    Joesph Krahn
    2002-01-06

    Source for demop of server-crashing glX context bug.

     
    Attachments
  • Joesph Krahn
    Joesph Krahn
    2002-01-11

    Logged In: YES
    user_id=76454

    It looks like the problem here may just be that an implicit
    glFlush
    is supposed to be done before detaching a context. If you
    add a
    glFlush in front of the glXMakeCurrent commands, the
    problems
    go away.

    However, there is an additional problem which I have not
    verified
    in recent versions of XFree: glXMakeCurrent may allow
    attachment
    of a glX context to a non-matching visual.