AppleSGLX Release Notes o OpenGL Support AppleSGLX supports the same version of OpenGL as Leopard (OpenGL 2.1). Many extensions from the OpenGL framework are now builtin. This adds support for GLSL, and a variety of other features. o Thread Support Thread support has been improved since the libGL in XQuartz 2.3.2.1. o GLX 1.4 Support The GLX 1.3 and 1.4 functions should all work with a few exceptions as outlined in this document. o glXMakeContextCurrent (a GLX 1.3 feature) glXMakeContextCurrent should work with the readable drawable. The OpenGL functions: glReadPixels, glCopyPixels, and glCopyColorTable, should use the readable drawable if it's different than the rendering drawable. o glXGetProcAddress (a GLX 1.4 feature and ARB extension) glXGetProcAddress should work and allow getting the address of any extension functions you may need from the X11 libGL, or OpenGL framework libGL. Previous versions of the X11 libGL didn't allow getting the newer OpenGL framework addresses. o GLXPixmaps New support for GLXPixmaps works well with mixed X11 and OpenGL drawing operations. You can create them using glXCreateGLXPixmap or glXCreatePixmap. o GLXPbuffers Support for GLXPbuffers has been added. These are drawables that are not possible to render to with X11, which is allowed by the spec. A GLXPbuffer will never generate a clobber event, however glXSelectEvent and glXGetSelectedEvent should operate normally. Clobber events are not generated due to low-level architectural differences. The contents of your pbuffers will not be clobbered. o Shared Contexts Due to basic low-level architectural differences the usage of shared contexts requires a similar visual or GLXFBConfig be used in the creation of a shared context. It's best if you specify the same visual. This is due to a CGL design difference, and not something that is easily worked around. UPDATE: some changes made seem to help resolve this issue in many cases, so you may be able to use a shared context without this restriction. o Indirect The X server supports indirect fairly well, so OpenGL applications can be run remotely and displayed by XQuartz. This means you can run applications from a remote host on an XQuartz X server. AppleSGLX does not support indirect rendering. Any indirect context created will appear to glXIsDirect as an indirect context, but it does not actually support indirect rendering to a remote X server. AppleSGLX supports GLXPixmaps and GLXPbuffers with direct and indirect contexts, though they are all direct contexts by definition (see above).