Fix OpenGL VSync

[Anti-Ultimate]

Hopefully this also works on Mac and Linux

The problem was that SwapInterval was always set to null and never changed. Because of that the error message popped up.

[delroth]

@Sonicadvance1 shouldn't GLExtensions be fetching the address of this function?

@dolphin-emu-bot rebuild

[Sonicadvance1]

We grab this extension down in MakeCurrent.
Which this is how it is supposed to be done because Windows regenerates it's function tables each time MakeCurrent is called.
True that GLExtensions should really just be grabbing this function pointer, and when we switch to libepoxy this will be fixed fully there.

[JMC47]

Should this be merged in the meantime? Or should we just wait for the libepoxy?

[Sonicadvance1]

We already grab the function pointer. I don't know why it is NULL on Windows still.
This is an incorrect fix.

[Anti-Ultimate]

Should it be grabbed in ClearCurrent? It isn't grabbed in MakeCurrent as far as I can tell by the code.

[Sonicadvance1]

Must have been an error that it ended up in ClearCurrent, it was supposed to be in MakeCurrent.
ClearCurrent is only called at the very end of OpenGL shutdown.

This is a proper fix
@dolphin-emu-bot rebuild

[BhaaLseN]

Just rebase out those commits. git rebase -i master (replace master with whatever your upstream source is), then remove the two lines from the editor that opens up. The only thing that should remain is "pick a12c98d".
Alternately, create a new branch and git cherry-pick a12c98d1bc, then replace the old one by pushing to your remote branch with the same name as referenced in this PR.

[Anti-Ultimate]

I'd like to do that, but the text file just says noop

[BhaaLseN]

Oh, right, your branch is called master. Try something like origin/master (or whatever your remote is called). HEAD~3 should also work (as its 3 commits back you'd want to edit)

[Anti-Ultimate]

There, done. Goddamnit Git is hard

[BhaaLseN]

Its not (really) hard, you just have to get familiar with it. You (c|sh)ould also fix the commit message (git commit --amend) as it looks a bit...odd.

[Anti-Ultimate]

hold on, that doesn't say anything either.

[Anti-Ultimate]

Okay now

[JMC47]

Can someone check this? vsync hasn't worked in OGL in a good, well, 10 years (more like 1500 builds, but whatev) according to my exaggerated estimates.

[Anti-Ultimate]

I don't want to put any more strain onto the buildbot so here you go:
https://www.dropbox.com/s/wtrybkbf653q9ud/oglvsyncfix.7z

[Sonicadvance1]

@dolphin-emu-bot rebuild

[Nucleoprotein]

I wrote about this issue in ClearCurrent/MakeCurrent a few months ago: https://code.google.com/p/dolphin-emu/issues/detail?id=7169#c10
Thanks for fixing this.

[CrossVR]

Hopefully this also works on Mac and Linux

@Anti-Ultimate As a side note: Since your PR only affected WGL, which is the Windows OpenGL interface, it will not affect any other OS.