This lets the user to correctly detect current vsync state by reading SDL_RendererInfo.
Also fixes SetVSync's return value check (it may be positive for error too).
(cherry picked from commit d78072fcd46943288a6007cd6f4ab1f98f446b1d)
Most of these are probably harmless, but the changes to SDL_immdevice.c and SDL_pixels.c appear to have fixed genuine bugs.
SDL_audiocvt.c: By separating the calculation of the divisor, I got rid of the suspicion that dividing a double by an integer led to loss of precision.
SDL_immdevice.c: Added a missing test, one that could have otherwise led to dereferencing a null pointer.
SDL_events.c, SDL_gamecontroller.c, SDL_joystick.c, SDL_malloc.c, SDL_video.c: Made it clear the return values weren't used.
SDL_hidapi_shield.c: The size is zero, so nothing bad would have happened, but the SDL_memset() was still being given an address outside of the array's range.
SDL_dinputjoystick.c: Initialize local data, just in case IDirectInputDevice8_GetProperty() isn't guaranteed to write to it.
SDL_render_sw.c: drawstate.viewport could be null (as seen on line 691).
SDL.c: SDL_MostSignificantBitIndex32() could return -1, though I don't know if you want to cope with that (what I did) or SDL_assert() that it can't happen.
SDL_hints.c: Replaced boolean tests on pointer values with comparisons to NULL.
SDL_pixels.c: Looks like the switch is genuinely missing a break!
SDL_rect_impl.h: The MacOS static checker pointed out issues with the X comparisons that were handled by assertions; I added assertions for the Y comparisons.
SDL_yuv.c, SDL_windowskeyboard.c, SDL_windowswindow.c: Checked error-result returns.
It turns out that we can safely create a Metal view on an existing window, and that avoids issues with the window being recreated with the wrong orientation in iOS 16.
Fixes https://github.com/libsdl-org/SDL/issues/6289
This kicks in if the platform doesn't support vsync directly, or if the present fails for some reason (e.g. minimized on some platforms)
Fixes https://github.com/libsdl-org/SDL/issues/5134
There is supposedly an OpenGL ES2 target that does not support precision specifiers. However, the existing logic to detect this is currently broken in two ways:
1) There's a typo of the `#ifdef` as `#if`.
2) Checking for `GL_FRAGMENT_PRECISION_HIGH` can not be the correct way to detect this platform. Other targets, including some desktops, will also not have this defined (for various reasons).
Because some of the shader code is missing precision specifiers, and because a default is ONLY provided if `GL_FRAGMENT_PRECISION_HIGH` is set, these other targets break.
Instead of 'hard-coding' the prologue string into shaders in the C source, use our ability to provide a list of strings to `glShaderSource` instead, leaving the determination to run-time.
This commit closes https://github.com/libsdl-org/SDL/pull/6182