GLX can return valid function pointer to unsupported functions.
We need to check for extension support in addition to the
function pointer.
Fixes crash on OpenSUSE 13.1 in VirtualBox.
When the user requests a GraphicsMode that is not directly supported
by the GPU/drivers, we should relax the requested parameters until
we find a supported mode. An exception should only be thrown when
there is no usable mode.
This makes the X11 backend match the behavior of Windows. The SDL/X11
backend works a little bit differently, in that it falls back to the
a default mode directly if the requested mode is not available. There
is nothing we can do about that.
The _NET_FRAME_EXTENTS atom is implemented differently by
different window managers, when window decorations are hidden
with Motif. Unity returns a 0 size, while Gnome 3 returns the
previous size.
This patch removes that ambiguity: when decorations are hidden,
border size becomes zero. This should work everywhere, unless
some window manager decides to troll us by decorating the window
when we explicitly request no decorations. Sigh...
Windows can now be resized programmatically, even when they have
WindowBorder.Fixed. All resizing logic is now consolidated in the
Bounds property, and ConfigureNotify messages are now handled
correctly depending on their source (StructureNotify or
SubStructureNotify.)
It is now possible to pass a non-realized GraphicsMode to the X11GLContext and X11GLNative constructors. A non-realized GraphicsMode is a GraphicsMode with a null Index (i.e. which has not passed through SelectGraphicsMode()).
According to the Linux OpenGL ABI, glXGetProcAddressARB must be statically exported by libGL. This does *not* hold true for glXGetProcAddress. We must used the ARB version instead.
Furthermore, glx entry points, unlike wgl, do not depend on any specific OpenGL context. This means we can load them in the constructor of the Glx class.
glXGetProcAddress may return a non-null value even if a function is not
supported by the server. We need to check the extension string using
any GLX extensions. Fixes issue http://www.opentk.com/node/3111 "GLX
extension support is not checked correctly".
Furthermore, mode selection is now performed explicitly by the
X11GLContext constructor.
GLX entry points are not bound to a specific context. This means that, unlike WGL, GLX does not require a temporary context in order to load its entry points!
