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Bug 3100 - SetSwapInterval should now be enabled for ANGLE/EGL (2.0.4rc2)
Summary: SetSwapInterval should now be enabled for ANGLE/EGL (2.0.4rc2)
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: video (show other bugs)
Version: 2.0.3
Hardware: x86 Windows 8
: P2 normal
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-08-24 15:57 UTC by Mark Logan
Modified: 2017-01-09 18:10 UTC (History)
2 users (show)

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Description 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.
Comment 1 Alex Szpakowski 2015-08-29 14:49:51 UTC 
Is there a way to detect the ANGLE version used, so it can be conditionally enabled?

It should also be enabled when ANGLE isn't used (e.g. when using the OpenGL ES 2 / EGL wrapper .dll's from the PowerVR SDK.)
Comment 2 Carles Pagès 2017-01-09 10:05:59 UTC 
Would be nice to get this fixed. Is it really needed to enable it conditionally at this point? The original commit is from more than 3 years ago, and I cannot find any information regarding when the bug was fixed in angle. So even if we checked the angle version (with glGetString(GL_VERSION) for instance), I do not know from which version it would be safe to enable it.
Comment 3 Alex Szpakowski 2017-01-09 17:15:22 UTC 
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.
Comment 4 Sam Lantinga 2017-01-09 18:10:52 UTC 
Okay, thanks guys!
https://hg.libsdl.org/SDL/rev/f3439b0eb486