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The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly uninitialized data structure if loading the library first failed. A later try to use EGL then skipped initialization and assumed it was previously successful because the data structure now already existed. This led to at least one crash in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was dereferenced to make a call to eglBindAPI().
2.0 KiB
Windows
================================================================================ OpenGL ES 2.x support
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.