DeviceAdded already checks that devices conform to the desired usage
pages. Checking again in DeviceRemoved is unnecessary - if a device
exists, then it has already passed muster.
The functions defined in libdl.dylib are useful in more places than
just AglContext. Moving them to their own class ensures we can access
these from wherever we might need them.
CGL appears to work with both AGL and NSOpenGL contexts, whereas AGL is
limited to AGL contexts. This allows us to be more flexible in terms of
implementation (i.e. we can use Cgl.GetCurrentContext to retrieve a
handle to a context created through SDL, which uses NSOpenGL
internally.)
Instead of modifying the name of an OpenGL symbol on the managed side,
before copying it to the unmanaged side, we perform the modification
directly on the unmanaged side. This reduces the total amount of
allocations in OpenTK by ~30% (673496 bytes in 10750 objects compared
to 930272 bytes in 15243 objects before this modification.)
The IGraphicsMode interface is gradually being removed and the
MacOSFactory will now throw an exception if an instance is requested.
AglContext no longer duplicates MacOSGraphicsMode functionality.
Added IDisposable interface to all classes holding native data that must be freed. OpenTK.Toolkit.Init() now returns an IDisposable instance that can be used to cleanup all native data held by OpenTK. This is useful when re-initializing OpenTK (possibly in a new AppDomain), as is the case in the Example browser.
This is a new platform that can be used then sdl2 is installed on the target system. SDL2 is commercially supported by Valve and provides better support for MacOS compared to our current implementation (Cocoa vs Carbon). It will also help us introduce faster support for new platforms. Existing platforms remain as a fallback and will be automatically used if sdl2 is not installed.
Please note that this is still a work in progress. The new mouse and keyboard API is not supported yet. Due to limitations of sdl2, multiple mice/keyboards are also not supported.
