It was originally added to work around an input event problem in the code of a specific app which mixed SDL and native UIViews, but that app solved its problems in a better manner since then.
Dzmitry Malyshau
Current code, search paths, and error messages are written to only consider MoltenVK on macOS as a Vulkan Portability implementation. It's not the only implementation available to the users. gfx-portability [1] has been shown to run a number of titles well, including Dota2, Dolphin Emulator, and vkQuake3, often out-performing MoltenVK in frame rate and stability (see Dolphin benchmark [2]).
There is no reason for SDL to be that specific, it's not using any MVK-specific functions other than the WSI initialization ("VK_MVK_macos_surface"). gfx-portability exposes this extension as well, and a more generic WSI extension is in process. It would be good if SDL was written in a more generic way that expect a Vulkan Portability library as opposed to MoltenVK specifically.
[1] https://github.com/gfx-rs/portability
[2] https://gfx-rs.github.io/2019/03/22/dolphin-macos-performance.html
Caleb Cornett
On iOS 12, creating a window with the SDL_WINDOW_FULLSCREEN flag does not dim the home indicator or defer system gestures. The same goes for setting the SDL_HINT_IOS_HIDE_HOME_INDICATOR to "2" -- it has no effect at all.
I've tracked down the source of this misbehavior to a timing issue. The initial `setNeedsUpdate...` calls were happening too early and getting applied to the launch screen by mistake. In the attached patch, I've added a call to those functions right after the launch screen is hidden so that they apply to the main view controller instead. This appears to fix the issue, at least on my iPhone 6s Plus.
SDL_GetWindowDisplayMode was returning an incorrect result on iPhone Plus devices (tested on iOS 12.1/12.2). The problem was that the value returned by UIScreenMode was assumed to be the physical pixels on the display, rather than the scaled retina pixels. The fix is to use the scale returned by UIScreen.scale rather than the nativeScale.
Touch device types include SDL_TOUCH_DEVICE_DIRECT (a touch screen with window-relative coordinates for touches), SDL_TOUCH_DEVICE_INDIRECT_ABSOLUTE (a trackpad-style device with absolute device coordinates), and SDL_TOUCH_DEVICE_INDIRECT_RELATIVE (a trackpad-style device with screen cursor-relative coordinates).
Phone screens are an example of a direct device type. Mac trackpads are the indirect-absolute touch device type. The Apple TV remote is an indirect-relative touch device type.
This variable can be set to the following values:
"0" - The indicator bar is not hidden (default for windowed applications)
"1" - The indicator bar is hidden and is shown when the screen is touched (useful for movie playback applications)
"2" - The indicator bar is dim and the first swipe makes it visible and the second swipe performs the "home" action (default for fullscreen applications)
SDL now builds with gcc 7.2 with the following command line options:
-Wall -pedantic-errors -Wno-deprecated-declarations -Wno-overlength-strings --std=c99
Dominik Reichardt
As discussed in 2012 the iOS onscreen keyboard hides when you hit RETURN (see https://discourse.libsdl.org/t/on-screen-keyboard-change/19216).
IMO this is a bad idea to not be able to influence this behavior and just recently this was fixed for Android by adding the hint SDL_HINT_ANDROID_RETURN_HIDES_IME in changeset 11768 6ce3bb5e38a5.
