More fixes for SDL2 window management

[macsforme]

Several additional issues were discovered when validating the fixes for SDL2 window management in #251. This can serve as a repository for fixes for these additional issues as they are completed.

• macOS build confines mouse after being minimized #266 macOS build confines mouse after being minimized
• Saved resolution reset when quitting the game from taskbar/dock #267 Saved resolution reset when quitting the game from taskbar/dock
• Restoring minimized window on macOS 10.15 can result in an offset viewport #268 Restoring minimized window on macOS 10.15 can result in an offset viewport

[blast007]

We'll ignore #267 for now. That's not release critical and overall is a pretty minor bug. We can worry about that one when/if we do further refactoring of our platform code.

[blast007]

The changes in 766a58f are causing Linux and macOS to not confine the mouse to the window. I have a simpler fix that just disables confine to motion box if the window is unmapped and mouseClamp is true. I'll test that solution a bit more.

[blast007]

The alternative fix I have is as follows:

diff --git a/src/bzflag/playing.cxx b/src/bzflag/playing.cxx
index 7c3801d0e..f6850682b 100644
--- a/src/bzflag/playing.cxx
+++ b/src/bzflag/playing.cxx
@@ -1175,6 +1175,8 @@ static void     doEvent(BzfDisplay *disply)
 
         unmapped = true;
         mainWindow->ungrabMouse();
+        if (BZDB.isTrue("mouseClamp"))
+            mainWindow->disableConfineToMotionbox();
         break;
 
     case BzfEvent::KeyUp:

@macsforme Would you prefer I fix this PR to use this, or should I just directly apply that fix and 4735b27 directly to our branch?

[macsforme]

Let me test my fix again and compare it to yours. This was a while ago, but I remember there being at least two parts to the problem (the motion box clamp, and the window clamp).

[blast007]

I'm actually not sure if my alternative fix above actually fixes it. I think when I was testing the issue just decided to stop happening. I will need to test some more.