This was the original intent (note SDL_UpdateWindowGrab() in SDL_OnWindowFocusGained() and SDL_OnWindowFocusLost()) and fixes a bug where relative motion unexpectedly stops if the task bar is covering the bottom of the game window and the mouse happens to move over it while relative mode is enabled.
Another alternative would be to confine the mouse when relative mode is enabled, but that generates mouse motion which would need to be ignored, and it's possible for the user moving the mouse to combine with the mouse moving into the confined area so you can't easily tell whether to ignore the mouse motion. See https://github.com/libsdl-org/SDL/issues/4165 for a case where this is problematic.
When possible use native os functions to make a blocking call waiting for
an incoming event. Previous behavior was to continuously poll the event
queue with a small delay between each poll.
The blocking call uses a new optional video driver event,
WaitEventTimeout, if available. It is called only if an window
already shown is available. If present the window is designated
using the variable wakeup_window to receive a wakeup event if
needed.
The WaitEventTimeout function accept a timeout parameter. If
positive the call will wait for an event or return if the timeout
expired without any event. If the timeout is zero it will
implement a polling behavior. If the timeout is negative the
function will block indefinetely waiting for an event.
To let the main thread sees events sent form a different thread
a "wake-up" signal is sent to the main thread if the main thread
is in a blocking state. The wake-up event is sent to the designated
wakeup_window if present.
The wake-up event is sent only if the PushEvent call is coming
from a different thread. Before sending the wake-up event
the ID of the thread making the blocking call is saved using the
variable blocking_thread_id and it is compared to the current
thread's id to decide if the wake-up event should be sent.
Two new optional video device methods are introduced:
WaitEventTimeout
SendWakeupEvent
in addition the mutex
wakeup_lock
which is defined and initialized but only for the drivers supporting the
methods above.
If the methods are not present the system behaves as previously
performing a periodic polling of the events queue.
The blocking call is disabled if a joystick or sensor is detected
and falls back to previous behavior.
Details:
Currently doing 4 system calls per WM_INPUT message, which can cause the thread handling the message loop to be swapped out several times:
* GetProp - to get window data from the window handle
* GetRawInputData - to retrieve the raw input data
* 2 calls to GetMessageExtraInfo - to ignore synthetic mouse events generated for touchscreens
In this change:
* Replaced GetProp by iterating the list of windows maintained by SDL (with a fallback to GetProp). Note that this will affect all messages and not just WM_INPUT
* only calling GetMessageExtraInfo if a touchscreen has been detected
Fix for https://jira.valve.org/browse/CSGO-4855
@saml
On windows, when toggling the state of RelativeMode rapidly, there is a
high chance that SDL_WINDOWEVENT_ENTER / SDL_WINDOWEVENT_LEAVE events
will stop firing indefinitely.
This aims to resolve that shortcoming by ensuring mouse focus state is
correctly updated via WM_MOUSELEAVE events arriving via the windows
event hook.
For keys that are already down when we install the keyboard hook, we need to
allow the WM_KEYUP/WM_SYSKEYUP message to be processed normally. This ensures
that other applications see the key up, which prevents the key from being stuck
down from the perspective of other apps when our grab is released.
This is implemented via a low-level keyboard hook. Unfortunately, this is
rather invasive, but it's how Microsoft recommends that it be done [0].
We want to do as little as possible in the hook, so we only intercept a few
crucial modifier keys there, while leaving other keys to the normal event
processing flow.
We will only install this hook if SDL_HINT_GRAB_KEYBOARD=1, which is not
the default. This will reduce any compatibility concerns to just the SDL
applications that explicitly ask for this behavior.
We also remove the hook when the grab is terminated to ensure that we're
not unnecessarily staying involved in key event processing when it's not
required anymore.
[0]: https://docs.microsoft.com/en-us/windows/win32/dxtecharts/disabling-shortcut-keys-in-games
GetAsyncKeyState() and GetRawInputData() report the state of the physical
buttons without applying the user's primary/secondary mouse button swap
preference. Swap the buttons returned from these functions, so we expose a
consistent view of the buttons to SDL callers. This new behavior also matches
the behavior of macOS and X11 backends.
See the Remarks section of the GetAsyncKeyState() function on MSDN.
We should only perform the VK_LEFT, VK_UP, etc. mapping if none of the other
special mappings apply. This allows the scancode normalization for the number
pad to take place as intended.
- Displays may have been added, removed or changed and all cached monitor
handles are invalidated as a result.
- Display events are handled in three steps:
1. Mark all currently know displays as invalid
2. Enumerate all displays, adding new ones and marking known displays as valid
3. Remove all displays still invalid after enumeration
- Display connect/disconnect events are sent when displays are added or removed
after initial setup
On some systems, GetClipCursor() impacts performance when called frequently, so only call it every once in a while to make sure we haven't lost our capture.
Alex Denisov
When using Win10 on-screen keyboard (tooltip.exe), the left and right cursor keys in it do not produce SDLK_LEFT and SDLK_RIGHT events.
Windows messages generated by the on-screen keyboard, for some reason, have their scancodes set to zeroes. Here is the log from Spy++:
WM_KEYDOWN nVirtKey:VK_LEFT cRepeat:1 ScanCode:00 fExtended:0 fAltDown:0 fRepeat:0 fUp:0
WM_KEYUP nVirtKey:VK_LEFT cRepeat:1 ScanCode:00 fExtended:0 fAltDown:0 fRepeat:1 fUp:1
Regular physical keyboard produces VK_LEFT (ScanCode:4B) and VK_RIGHT (ScanCode:4D) which are interpreted correctly.
With on-screen keyboard, the switch statement in VKeytoScancode() does not check for VK_LEFT and VK_RIGHT, returning SDL_SCANCODE_UNKNOWN, which in turn does not get mapped to anything (because the scan codes are zeroes).
superfury
I notice that, somehow, when locking the mouse into place(using SDL_SetRelativeMouseMode), somehow at least the movement information gets through to both mouse movement and touch movement events?
My app handles both, so when moving a touched finger accross the app(using RDP from an Android device) I see the mouse moving inside the app when it shouldn't(meaning that the touch movement is ignored properly by the app(press-location dependant) but the mouse movement is still performed due to the mouse movement events)?
Windows generates fake raw mouse events for touchscreens for compatibility
with legacy apps that predate touch support in Windows. We already handle
touch events explicitly, so drop the synthetic events to avoid duplicates.
bplu4t2f
When num lock is on, the scancode reported for numpad 5 is SDL_SCANCODE_KP_5, which is correct. However, when num lock is off, windows reports the VK_CLEAR virtual key code, which is incorrectly translated into SDL_SCANCODE_CLEAR inside of the VKeytoScancode(WPARAM vkey) function.
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.
