Commit a0e878aafb43d7887708c1899ecf044e4fb35093
2015-03-28T00:48:03
Minor input grab clarifications. Clarify that grabbing the mouse only works with one window at a time; this was always true at the system level, though SDL could previously get confused by multiple simultaneous grabs, so now we explicitly break any existing grab before starting a new one and document it as such. Also track the window that is currently grabbed, and provide an API to query for that window. This makes it easy to automate mouse ungrabbing at breakpoints with gdb7's scripting, since the scripts can now know which window to ungrab. In 2.1, we should probably change this API to SDL_GrabInput(win) and SDL_UngrabInput(void), or something.
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diff --git a/include/SDL_video.h b/include/SDL_video.h
index 782fcb0..fe13868 100644
--- a/include/SDL_video.h
+++ b/include/SDL_video.h
@@ -722,6 +722,9 @@ extern DECLSPEC int SDLCALL SDL_UpdateWindowSurfaceRects(SDL_Window * window,
* \param window The window for which the input grab mode should be set.
* \param grabbed This is SDL_TRUE to grab input, and SDL_FALSE to release input.
*
+ * If the caller enables a grab while another window is currently grabbed,
+ * the other window loses its grab in favor of the caller's window.
+ *
* \sa SDL_GetWindowGrab()
*/
extern DECLSPEC void SDLCALL SDL_SetWindowGrab(SDL_Window * window,
@@ -737,6 +740,15 @@ extern DECLSPEC void SDLCALL SDL_SetWindowGrab(SDL_Window * window,
extern DECLSPEC SDL_bool SDLCALL SDL_GetWindowGrab(SDL_Window * window);
/**
+ * \brief Get the window that currently has an input grab enabled.
+ *
+ * \return This returns the window if input is grabbed, and NULL otherwise.
+ *
+ * \sa SDL_SetWindowGrab()
+ */
+extern DECLSPEC SDL_Window * SDLCALL SDL_GetGrabbedWindow(void);
+
+/**
* \brief Set the brightness (gamma correction) for a window.
*
* \return 0 on success, or -1 if setting the brightness isn't supported.
diff --git a/src/dynapi/SDL_dynapi_overrides.h b/src/dynapi/SDL_dynapi_overrides.h
index 8bcde63..dcc6d46 100644
--- a/src/dynapi/SDL_dynapi_overrides.h
+++ b/src/dynapi/SDL_dynapi_overrides.h
@@ -591,3 +591,4 @@
#define SDL_QueueAudio SDL_QueueAudio_REAL
#define SDL_GetQueuedAudioSize SDL_GetQueuedAudioSize_REAL
#define SDL_ClearQueuedAudio SDL_ClearQueuedAudio_REAL
+#define SDL_GetGrabbedWindow SDL_GetGrabbedWindow_REAL
diff --git a/src/dynapi/SDL_dynapi_procs.h b/src/dynapi/SDL_dynapi_procs.h
index c41cdc9..6408e3f 100644
--- a/src/dynapi/SDL_dynapi_procs.h
+++ b/src/dynapi/SDL_dynapi_procs.h
@@ -623,3 +623,4 @@ SDL_DYNAPI_PROC(SDL_bool,SDL_HasAVX2,(void),(),return)
SDL_DYNAPI_PROC(int,SDL_QueueAudio,(SDL_AudioDeviceID a, const void *b, Uint32 c),(a,b,c),return)
SDL_DYNAPI_PROC(Uint32,SDL_GetQueuedAudioSize,(SDL_AudioDeviceID a),(a),return)
SDL_DYNAPI_PROC(void,SDL_ClearQueuedAudio,(SDL_AudioDeviceID a),(a),)
+SDL_DYNAPI_PROC(SDL_Window*,SDL_GetGrabbedWindow,(void),(),return)
diff --git a/src/video/SDL_sysvideo.h b/src/video/SDL_sysvideo.h
index 6966f2b..9b2f7d1 100644
--- a/src/video/SDL_sysvideo.h
+++ b/src/video/SDL_sysvideo.h
@@ -274,6 +274,7 @@ struct SDL_VideoDevice
int num_displays;
SDL_VideoDisplay *displays;
SDL_Window *windows;
+ SDL_Window *grabbed_window;
Uint8 window_magic;
Uint32 next_object_id;
char * clipboard_text;
diff --git a/src/video/SDL_video.c b/src/video/SDL_video.c
index b93c11e..c8cb2fa 100644
--- a/src/video/SDL_video.c
+++ b/src/video/SDL_video.c
@@ -2116,6 +2116,7 @@ void
SDL_UpdateWindowGrab(SDL_Window * window)
{
if (_this->SetWindowGrab) {
+ SDL_Window *grabbed_window;
SDL_bool grabbed;
if ((SDL_GetMouse()->relative_mode || (window->flags & SDL_WINDOW_INPUT_GRABBED)) &&
(window->flags & SDL_WINDOW_INPUT_FOCUS)) {
@@ -2123,6 +2124,19 @@ SDL_UpdateWindowGrab(SDL_Window * window)
} else {
grabbed = SDL_FALSE;
}
+
+ grabbed_window = _this->grabbed_window;
+ if (grabbed) {
+ if (grabbed_window && (grabbed_window != window)) {
+ /* stealing a grab from another window! */
+ grabbed_window->flags &= ~SDL_WINDOW_INPUT_GRABBED;
+ _this->SetWindowGrab(_this, grabbed_window, SDL_FALSE);
+ }
+ _this->grabbed_window = window;
+ } else if (grabbed_window == window) {
+ _this->grabbed_window = NULL; /* ungrabbing. */
+ }
+
_this->SetWindowGrab(_this, window, grabbed);
}
}
@@ -2147,8 +2161,15 @@ SDL_bool
SDL_GetWindowGrab(SDL_Window * window)
{
CHECK_WINDOW_MAGIC(window, SDL_FALSE);
+ SDL_assert(!_this->grabbed_window || ((_this->grabbed_window->flags & SDL_WINDOW_INPUT_GRABBED) != 0));
+ return window == _this->grabbed_window;
+}
- return ((window->flags & SDL_WINDOW_INPUT_GRABBED) != 0);
+SDL_Window *
+SDL_GetGrabbedWindow(void)
+{
+ SDL_assert(!_this->grabbed_window || ((_this->grabbed_window->flags & SDL_WINDOW_INPUT_GRABBED) != 0));
+ return _this->grabbed_window;
}
void