Mark Logan 2015-08-24 15:57:50 UTC
In SDL_windowsopengles.c, WIN_GLES_SetSwapInterval is as follows:
WIN_GLES_SetSwapInterval(_THIS, int interval)
{
/* FIXME: This should call SDL_EGL_SetSwapInterval, but ANGLE has a bug that prevents this
* from working if we do (the window contents freeze and don't swap properly). So, we ignore
* the request for now.
*/
SDL_Log("WARNING: Ignoring SDL_GL_SetSwapInterval call due to ANGLE bug");
return 0;
}
With a recent version of ANGLE (early July) calling SDL_EGL_SetSwapInterval with a D3D11 backend appears to work just fine. I am working on testing this with D3D9.
--
Alex Szpakowski
I found the bug, it was fixed in 2013. https://bugs.chromium.org/p/angleproject/issues/detail?id=481
In my opinion it should be safe to unconditionally use SetSwapInterval now. Anyone who encounters the bug should update their ANGLE to a version less than 3 years old, especially since they'd be using a SDL version that's 3+ years newer than their ANGLE version.
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().
