author Sam Lantinga <>
Sat, 28 Jun 2003 17:27:33 +0000
changeset 638 b0108e9dea53
parent 433 706de3956894
permissions -rw-r--r--
Date: Sun, 11 May 2003 19:59:06 +0300 From: Pasi K?rkk?inen Subject: [PATCH] fix SDL OpenGL segfault with DRI/Mesa drivers and Glew Hello! The attached patch fixes a bug in SDL which causes SDL to crash in X11_GL_Shutdown() if you are using DRI/Mesa drivers AND glew ( The bug is caused by a namespace collision affecting dlsym() to fetch wrong pointer for glXReleaseBuffersMESA() (uninitialized pointer from glew because the extension is NOT supported by the driver) and then SDL calling it in X11_GL_Shutdown(). SDL should check if the glXReleaseBuffersMESA() is really supported by the driver (from the extensions string) before calling it. Attached patch adds extension string parsing to check if glXReleaseBuffersMESA() is really supported (and this way prevents the segfault). Availability of the extensions should be _always_ checked from the extensions string rather than using dlsym()! Please add it to the next version of SDL. Thanks to gltron and author of glew to help fixing this.

  Using SDL with PicoGUI

- Originally contributed by Micah Dowty <>

PicoGUI is a scalable GUI system with a unique architecture, primarily focused
on scalability to various embedded systems. You can find more information
including a FAQ at

To use the patch:

  1. When compiling, add the "--enable-video-picogui" switch to ./configure

  2. When running your program, ensure that the picogui driver for SDL
     is in use by setting the SDL_VIDEODRIVER environment variable 
     to "picogui".

  3. The program must also be linked to the C client library for PicoGUI
     ( If the program is being compiled with a patched SDL 
     installed this should be done automatically. If you want to use an
     existing binary with PicoGUI, you can set the LD_PRELOAD environment
     variable to the path of your file.


  So far only basic functionality is provided on true color (linear16/24/32)
  devices. Accessing a memory mapped bitmap, updating the display, and handling
  mouse/keyboard input. This functionality has been tested with several
  applications, including mplayer, Xine, sldroids, and Abuse.

TODO list:

  - YUV overlays will be helpful for watching video on set top boxes or other
    embedded devices that have some graphics acceleration hardware

  - Account for rotated bitmap storage in pgserver

  - Support for hiding or changing the cursor

  - The display should be centered when the SDL application is smaller
    than the PicoGUI panel

  - Fullscreen or any other special modes

  - Support for indexed and grayscale modes

  - Probably much more...

--- The End ---