OpenGL windows don't actually get the WM_WINDOWPOSCHANGED event in the SetWindowPos() call in WIN_SetWindowFullscreen(), so setting the window size to zero never gets reset and we're stuck with a zero sized window.
Instead, just force the resize event in WM_DPICHANGED handling, where we know we need it. If we end up needing to force it in WIN_SetWindowFullscreen(), just set a flag in the window data and respond to that in WM_WINDOWPOSCHANGED, but that's a fairly risky behavior change as suddenly all applications would start getting SDL_WINDOWEVENT_SIZE_CHANGED when going fullscreen, and they may respond to that in expensive and potentially disruptive ways.
For later we'll probably create a DPI changed event and respond to that in the renderer instead of this window size changed hack.
This fixes https://github.com/libsdl-org/SDL/issues/6033 @ericwa
The video core assumes that window->w/h will be updated before returning
from SetWindowFullscreen(). This is needed to generate a resize event
with the correct window size when exiting fullscreen.
The roundtrip allows us to receive the configure callback that informs
us of the new window size before returning.
Fixes#6043
We really only care about DPI changes here, so this both reduces work and also avoids weird cases where viewport state can be corrupted by trivial window events. This doesn't _completely_ get rid of the issue but this is somewhat intentional, since apps will definitely want to do a full reset when changing displays anyhow (otherwise DPI/adapter changes will screw things up, and that's out of our control as long as both window size and drawable size are exposed at the same time.
Note that OpenGL still captures window events because of weird platform-specific issues like macOS and viewport stretching!
Fixes#5949
- This allows looking up the display index for an arbitrary location rather than requiring an active window to do so.
- This change also reimplements the fallback display lookup that found the display with center closest to the window's center to instead find the display rect edge
closest to the window center (this was done in the almost identical display lookup used in SDL_windowsmodes.c, which now uses `SDL_GetPointDisplayIndex`). In
practice this should almost never be hit as it requires the window's center to not be enclosed by any display rect.
