Simple Directmedia Layer
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Sam Lantinga b1539c4c49 Fixed bug 4819 - Attempting to create an OpenGL ES context with unachievable MSAA parameters under X11 dooms the program
Solra Bizna

I have written a program that, in the event that the user requests more MSAA samples than their hardware supports, attempts to gracefully fall back to the best MSAA available. This code works with my conventional OpenGL renderer, but if I change nothing about the code except to make it request an OpenGL ES profile instead, Xlib kills the program with an error that looks like:

X Error of failed request:  BadWindow (invalid Window parameter)
  Major opcode of failed request:  4 (X_DestroyWindow)
  Resource id in failed request:  0x5c00008
  Serial number of failed request:  188
  Current serial number in output stream:  193

To trigger the bug, attempt to create a window with the SDL_WINDOW_OPENGL flag, with SDL_GL_CONTEXT_PROFILE_MASK set to SDL_GL_CONTEXT_PROFILE_ES, and with SDL_GL_MULTISAMPLESAMPLES set to any unsupported value. SDL_CreateWindow properly returns NULL, but at this point the program is already doomed. Xlib will shortly terminate the program with an error. Calling SDL_CreateWindow again will immediately trigger this termination.

I have attached a skeletal program that reproduces this bug for me. Replacing SDL_GL_CONTEXT_PROFILE_ES with SDL_GL_CONTEXT_PROFILE_COMPATIBILITY avoids the bug (but, obviously, doesn't create an OpenGL ES context).

As I suspected, the problem was with XDestroyWindow being called twice on the same window. The X11_CreateWindow function in src/video/x11/SDL_x11window.c calls SetupWindowData. If initialization fails after that point, XDestroyWindow gets called on the window by a subsequent call to X11_DestroyWindow. But, later in the same function, iff a GLES context is requested and initializing it fails, X11_XDestroyWindow (which wraps XDestroyWindow) is manually called. Shortly after, the intended call to X11_DestroyWindow occurs, which attempts to destroy the same window again. Boom.

(The above confusing summary involves three separate, similarly-named functions: XDestroyWindow, X11_DestroyWindow, X11_XDestroyWindow)

I have attached a simple patch that removes the redundant X11_XDestroyWindow calls. I've tested that XDestroyWindow still gets called for the windows in question, and that it only gets called once.
2019-11-16 22:35:48 -08:00
acinclude Added missing PKG_CONFIG macros 2019-03-16 17:39:15 -07:00
android-project Fixed bug 4775 - Japanese on Android, remove inputtype PASSWORD (Thanks Tamo!) 2019-10-23 11:25:16 +02:00
android-project-ant Added the old ant Android build project structure 2017-10-28 12:11:25 -07:00
build-scripts Updated SDL development builds to version 2.0.11 2019-09-22 10:37:16 -07:00
cmake hidapi: Add SDL_hidapi.c, allows support for multiple hidapi backends. 2019-07-31 12:20:55 -04:00
debian Updated SDL development builds to version 2.0.11 2019-09-22 10:37:16 -07:00
docs CMake: tabs to spaces in new parts of README-cmake.md 2019-09-23 18:30:22 -04:00
include Added SDL_PIXELFORMAT_BGR444 2019-11-02 22:58:52 +00:00
src Fixed bug 4819 - Attempting to create an OpenGL ES context with unachievable MSAA parameters under X11 dooms the program 2019-11-16 22:35:48 -08:00
test Added SDL_PIXELFORMAT_BGR444 2019-11-02 22:58:52 +00:00
VisualC Fixed the location of controller_type.h in the Visual Studio project 2019-10-22 10:26:49 -07:00
VisualC-WinRT Added display event files to the Visual Studio projects 2018-08-23 02:48:47 -07:00
visualtest test: unify all the command line usage logging. 2019-05-28 17:39:13 -04:00
wayland-protocols wayland: ask xdg-decoration protocol extension to use server-side decorations if possible. 2018-11-04 21:08:40 +01:00
Xcode endpointvolume.h checks not needed since changeset 13078:8ab094a9df6b . 2019-10-01 14:00:02 +03:00
Xcode-iOS fix permissions 2019-08-23 03:01:10 +03:00
.hgignore remove test/aclocal.m4 2019-08-03 12:49:50 +03:00
Android.mk fix permissions 2019-09-05 13:21:02 +03:00
autogen.sh Don't use pushd/popd in autogen.sh; Ubuntu's /bin/sh doesn't support it. 2016-12-26 22:58:58 -05:00
BUGS.txt BUGS.txt: Changed mailing list link to discourse.libsdl.org. 2017-04-01 00:05:25 -04:00
cmake_uninstall.cmake.in Fixed bug 3867 - Can't find install_manifest.txt when running 'uninstall' target 2017-10-12 08:44:45 -07:00
CMakeLists.txt cmake: added support for enabling the ARM SIMD/NEON code. 2019-10-24 23:17:19 -04:00
configure configure: check for build dir when building version res (fix bug #4858) 2019-11-13 10:51:02 +03:00
configure.ac configure: check for build dir when building version res (fix bug #4858) 2019-11-13 10:51:02 +03:00
COPYING.txt Updated copyright for 2019 2019-01-04 22:01:14 -08:00
CREDITS.txt Fixed crash if initialization of EGL failed but was tried again later. 2015-06-21 17:33:46 +02:00
INSTALL.txt More HTTPS doc tweaks. 2017-02-16 16:59:07 -05:00
Makefile.in Add public APIs for creating a Metal view attached to an SDL window. Add SDL_metal.h. 2019-08-05 12:35:32 -03:00
Makefile.minimal Added a dummy sensor driver 2018-08-21 13:29:21 -07:00
Makefile.os2 update version number in Makefile.os2 too 2019-09-22 20:47:00 +03:00
Makefile.pandora Added a dummy sensor driver 2018-08-21 13:29:21 -07:00
Makefile.psp Added a dummy sensor driver 2018-08-21 13:29:21 -07:00
Makefile.wiz Added a dummy sensor driver 2018-08-21 13:29:21 -07:00
README-SDL.txt More HTTPS changes in the documentation. 2017-02-16 16:52:03 -05:00
README.txt readme: correct webpage URL to use HTTPS. 2017-02-16 13:30:34 -05:00
sdl2-config.cmake.in Applied Ubuntu patch bug_822210_fix_sdl2-config.cmake_whitespace.patch 2016-10-07 15:08:37 -07:00
sdl2-config.in Fixed crash if initialization of EGL failed but was tried again later. 2015-06-21 17:33:46 +02:00
sdl2.m4 Fixed bug 4544 - SDL2.m4 SDL2.framework patch made it impossible to fail detection 2019-03-16 18:45:10 -07:00
sdl2.pc.in Fixed crash if initialization of EGL failed but was tried again later. 2015-06-21 17:33:46 +02:00
SDL2.spec.in Fixed bug 4615 - RPM Build fails due to unpackaged files 2019-06-11 19:58:10 -07:00
SDL2Config.cmake Fixed bug 3651 - CMake build does not install CMake package configuration 2017-08-09 19:03:10 -07:00
TODO.txt Fixed crash if initialization of EGL failed but was tried again later. 2015-06-21 17:33:46 +02:00
VisualC.html Fixed two typos in documentation. 2016-01-12 22:23:53 +01:00
WhatsNew.txt Added a helper function SDL_LockTextureToSurface() 2019-09-30 20:58:44 +02:00

                         Simple DirectMedia Layer

                                  (SDL)

                                Version 2.0

---
https://www.libsdl.org/

Simple DirectMedia Layer is a cross-platform development library designed
to provide low level access to audio, keyboard, mouse, joystick, and graphics
hardware via OpenGL and Direct3D. It is used by video playback software,
emulators, and popular games including Valve's award winning catalog
and many Humble Bundle games.

More extensive documentation is available in the docs directory, starting
with README.md

Enjoy!
	Sam Lantinga				(slouken@libsdl.org)