No description
1a2a914b33
Matthias 2011-02-23 09:37:51 PST
Please view the attached source file. Using this minimal program (as attached),
it creates an OpenGL 2.0 context with a cleared color buffer. If I set the
OpenGL version to 3.2, the function SDL_GL_CreateContext fails (or more
specifically, glXMakeCurrent fails) with an X11 BadMatch error:
X Error of failed request: BadMatch (invalid parameter attributes)
Major opcode of failed request: 128 (GLX)
Minor opcode of failed request: 5 (X_GLXMakeCurrent)
Serial number of failed request: 153
Current serial number in output stream: 153
Also note that if I do not specify the alpha buffer size, the program works for
OpenGL 2.0 and OpenGL 3.2.
After some further analysis, I believe I have found the problem. The specific
issue is in:
SDL_x11opengl.c::X11_GL_CreateContext.
Note that for OpenGL 3.2 contexts, the GLXFBConfig to use is chosen as the best
match from glXChooseFBConfig. However, opengl attributes originally set with
SDL_GL_SetAttribute are not mapped to GLX attributes and then passed to the
glXChooseFBConfig function. According to the GLX 1.4 specification, if the
attributes are not specified, the function falls back to defaults (which, in
this particular case, prefer alpha channel size == 0).
For testing purposes, I modified the call to glXChooseFBConfig to look
something like this:
int glxAttribs[] =
{
GLX_RED_SIZE,8,
GLX_GREEN_SIZE,8,
GLX_BLUE_SIZE,8,
GLX_ALPHA_SIZE,8,
None
};
if (!glXChooseFBConfig ||
!(framebuffer_config = glXChooseFBConfig(display, DefaultScreen(display),
glxAttribs, &fbcount)))
{
...
}
The best match GLXFBConfig then supports 8 bit alpha channel. The program then
works as intended.
Hope this helps!
|
||
|---|---|---|
| acinclude | ||
| android-project | ||
| build-scripts | ||
| include | ||
| src | ||
| test | ||
| VisualC | ||
| VisualCE | ||
| Xcode | ||
| Xcode-iPhoneOS | ||
| .DISABLED-hgeol | ||
| .hgignore | ||
| .hgtags | ||
| .indent.pro | ||
| aclocal.m4 | ||
| Android.mk | ||
| autogen.sh | ||
| Borland.html | ||
| Borland.zip | ||
| BUGS | ||
| configure | ||
| configure.in | ||
| COPYING | ||
| CREDITS | ||
| INSTALL | ||
| Makefile.ds | ||
| Makefile.in | ||
| Makefile.minimal | ||
| Makefile.pandora | ||
| Makefile.wiz | ||
| NOTES | ||
| README | ||
| README-SDL.txt | ||
| README.android | ||
| README.BeOS | ||
| README.DirectFB | ||
| README.ds | ||
| README.gesture | ||
| README.HG | ||
| README.iphoneos | ||
| README.MacOSX | ||
| README.pandora | ||
| README.Platforms | ||
| README.Porting | ||
| README.touch | ||
| README.Watcom | ||
| README.WinCE | ||
| sdl-config.in | ||
| sdl.m4 | ||
| sdl.pc.in | ||
| SDL.spec.in | ||
| TODO | ||
| UNDER_CONSTRUCTION.txt | ||
| VisualC.html | ||
| Watcom-Win32.zip | ||
| WhatsNew | ||
Simple DirectMedia Layer
(SDL)
Version 1.3
---
http://www.libsdl.org/
This is the Simple DirectMedia Layer, a general API that provides low
level access to audio, keyboard, mouse, joystick, 3D hardware via OpenGL,
and 2D framebuffer across multiple platforms.
The current version supports Windows, Windows CE, Mac OS X, Linux, FreeBSD,
NetBSD, OpenBSD, BSD/OS, Solaris, iOS, and Android. The code contains
support for other operating systems but those are not officially supported.
SDL is written in C, but works with C++ natively, and has bindings to
several other languages, including Ada, C#, Eiffel, Erlang, Euphoria,
Go, Guile, Haskell, Java, Lisp, Lua, ML, Objective C, Pascal, Perl, PHP,
Pike, Pliant, Python, Ruby, and Smalltalk.
This library is distributed under GNU LGPL version 2, which can be
found in the file "COPYING". This license allows you to use SDL
freely in commercial programs as long as you link with the dynamic
library.
The best way to learn how to use SDL is to check out the header files in
the "include" subdirectory and the programs in the "test" subdirectory.
The header files and test programs are well commented and always up to date.
More documentation is available in HTML format in "docs/index.html", and
a documentation wiki is available online at:
http://www.libsdl.org/cgi/docwiki.cgi
The test programs in the "test" subdirectory are in the public domain.
Frequently asked questions are answered online:
http://www.libsdl.org/faq.php
If you need help with the library, or just want to discuss SDL related
issues, you can join the developers mailing list:
http://www.libsdl.org/mailing-list.php
Enjoy!
Sam Lantinga (slouken@libsdl.org)