SDL/WinRT did have support for OpenGL ES 2 via an older version of ANGLE/WinRT,
however its API changed a few months ago, and SDL/WinRT would crash when trying
to use it. It would also occasionally crash when using the older version.
This changeset should make SDL/WinRT work with the latest version, as
available via MS Open Tech's git repository of it at
https://github.com/msopentech/angle
Older versions of ANGLE/WinRT (from either https://github.com/stammen/angleproject
or https://bitbucket.org/DavidLudwig/angleproject) will need to be updated to
MS Open Tech's latest version.
SDL was expected that each SDL_DisplayMode had a driverdata field that was SDL_malloc'ed, and was calling SDL_free on them. This change moves WinRT's driverdata content into a SDL_malloc'ed field.
A port of the ANGLE library (OpenGL ES 2.0 for Direct3D) to WinRT, via https://github.com/stammen/angleproject, is used as a base.
To enable, clone 'angleproject' into the directory one above where SDL/WinRT is, open the file SDL/include/SDL_config_winrt.h, and uncomment the #defines that begin with 'SDL_VIDEO_OPENGL'. From there, apps can create an OpenGL capable SDL_Window via the flag, SDL_WINDOW_OPENGL, and an OpenGL ES 2 context via SDL_GL_CreateContext. The Direct3D 11.1 renderer cannot be used alongside SDL_WINDOW_OPENGL. Only Windows 8/8.1 is supported for now. Shaders may need to be precompiled, in some (all?) cases.
