aBothe
I tried to experiment a bit with SDL2 and OpenGL today and noticed that something caused some weird flickering when resizing my nicely drawn SDL2/OpenGL window:
Just after resizing, the background went black and I had to let my OpenGL code redraw the contents..
However, after some hours spent with googling I found out that in OpenGL examples where this CWBackPixel flag was not used when creating X windows, there was no flickering while resizing the window.
See http://www.sbin.org/doc/Xlib/chapt_04.html @ "The Window Background" for more info.
X11_RestoreWindow() had a call ordering problem that prevented activation, and X11_RaiseWindow() wasn't attempting activation. Windows and OS X both activate in these cases.
CR: saml
SDL provides an SDL_VIDEO_X11_VISUALID environment variable that lets you override
window visuals, but it wasn't being checked for OpenGL windows.
CR: Sam.
If the app is in landscape mode and the user presses the power button, a pause
is followed immediately by a surfaceChanged event because the lock screen
is shown in portrait mode. This triggers a "false" resume.
So, we just pause and resume following the onWindowFocusChanged events.
Also, wait for SDL_APP_WILLENTERBACKGROUND and SDL_APP_DIDENTERBACKGROUND before
blocking the event pump.
