SDL has support for OpenGL ES 2.x under Windows via two alternative
implementations.
The most straightforward method consists in running your app in a system with
a graphic card paired with a relatively recent (as of November of 2013) driver
which supports the WGL_EXT_create_context_es2_profile extension. Vendors known
to ship said extension on Windows currently include nVidia and Intel.
The other method involves using the ANGLE library (https://code.google.com/p/angleproject/)
If an OpenGL ES 2.x context is requested and no WGL_EXT_create_context_es2_profile
extension is found, SDL will try to load the libEGL.dll library provided by
ANGLE.
To obtain the ANGLE binaries, you can either compile from source from
https://chromium.googlesource.com/angle/angle or copy the relevant binaries from
a recent Chrome/Chromium install for Windows. The files you need are:
* libEGL.dll
* libGLESv2.dll
* d3dcompiler_46.dll (supports Windows Vista or later, better shader compiler)
or...
* d3dcompiler_43.dll (supports Windows XP or later)
If you compile ANGLE from source, you can configure it so it does not need the
d3dcompiler_* DLL at all (for details on this, see their documentation).
However, by default SDL will try to preload the d3dcompiler_46.dll to
comply with ANGLE's requirements. If you wish SDL to preload d3dcompiler_43.dll (to
support Windows XP) or to skip this step at all, you can use the
SDL_HINT_VIDEO_WIN_D3DCOMPILER hint (see SDL_hints.h for more details).
Known Bugs:
* SDL_GL_SetSwapInterval is currently a no op when using ANGLE. It appears
that there's a bug in the library which prevents the window contents from
refreshing if this is set to anything other than the default value.
Vulkan Surface Support
==============
Support for creating Vulkan surfaces is configured on by default. To disable it change the value of `SDL_VIDEO_VULKAN_SURFACE` to 0 in `SDL_config_windows`. When it is on you must install a [Vulkan SDK](https://www.lunarg.com/vulkan-sdk/) in order to build libSDL.
