Documentation work

Related to #1012.

README.md

@@ -138,6 +138,8 @@ information on what to include when reporting a bug.
   for retrieving gamepad input state (#900)
 - Added `glfwRequestWindowAttention` function for requesting attention from the
   user (#732,#988)
+- Added `glfwGetEventTime` function for querying the time of the last input
+  event (#1012)
 - Added `glfwGetKeyScancode` function that allows retrieving platform dependent
   scancodes for keys (#830)
 - Added `glfwSetWindowMaximizeCallback` and `GLFWwindowmaximizefun` for

include/GLFW/glfw3.h

@@ -3366,6 +3366,31 @@ GLFWAPI GLFWwindowmaximizefun glfwSetWindowMaximizeCallback(GLFWwindow* window,
  */
 GLFWAPI GLFWframebuffersizefun glfwSetFramebufferSizeCallback(GLFWwindow* window, GLFWframebuffersizefun cbfun);
 
+/*! @brief Returns the time of the last input event.
+ *
+ *  This function returns the time, in seconds, that the last input event
+ *  occurred.  The time is collected for key, mouse button, scrolling and cursor
+ *  position events including enter and leave.  The function is intended to be
+ *  called from the relevant event callback.
+ *
+ *  @return The time of the input event, in seconds, or zero if an
+ *  [error](@ref error_handling) occurred.
+ *
+ *  @errors Possible errors include @ref GLFW_NOT_INITIALIZED.
+ *
+ *  @remarks The event timestamps provided by most platforms have much lower
+ *  resolution than the GLFW timer.
+ *
+ *  @thread_safety This function must only be called from the main thread.
+ *
+ *  @sa @ref events
+ *
+ *  @since Added in version 3.3.
+ *
+ *  @ingroup window
+ */
+GLFWAPI double glfwGetEventTime(void);
+
 /*! @brief Processes all pending events.
  *
  *  This function processes only those events that are already in the event

src/cocoa_platform.h

@@ -118,6 +118,9 @@ typedef struct _GLFWlibraryNS
     // The window whose disabled cursor mode is active
     _GLFWwindow*        disabledCursorWindow;
 
+    // The time of the last event
+    double              lastEventTime;
+
     struct {
         CFBundleRef     bundle;
         PFN_TISCopyCurrentKeyboardLayoutInputSource CopyCurrentKeyboardLayoutInputSource;

src/cocoa_window.m

@@ -446,6 +446,8 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 
 - (void)mouseDown:(NSEvent *)event
 {
+    _glfw.ns.lastEventTime = [event timestamp];
+
     _glfwInputMouseClick(window,
                          GLFW_MOUSE_BUTTON_LEFT,
                          GLFW_PRESS,
@@ -454,11 +456,15 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 
 - (void)mouseDragged:(NSEvent *)event
 {
+    _glfw.ns.lastEventTime = [event timestamp];
+
     [self mouseMoved:event];
 }
 
 - (void)mouseUp:(NSEvent *)event
 {
+    _glfw.ns.lastEventTime = [event timestamp];
+
     _glfwInputMouseClick(window,
                          GLFW_MOUSE_BUTTON_LEFT,
                          GLFW_RELEASE,
@@ -467,6 +473,8 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 
 - (void)mouseMoved:(NSEvent *)event
 {
+    _glfw.ns.lastEventTime = [event timestamp];
+
     if (window->cursorMode == GLFW_CURSOR_DISABLED)
     {
         const double dx = [event deltaX] - window->ns.cursorWarpDeltaX;
@@ -490,6 +498,8 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 
 - (void)rightMouseDown:(NSEvent *)event
 {
+    _glfw.ns.lastEventTime = [event timestamp];
+
     _glfwInputMouseClick(window,
                          GLFW_MOUSE_BUTTON_RIGHT,
                          GLFW_PRESS,
@@ -498,11 +508,15 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 
 - (void)rightMouseDragged:(NSEvent *)event
 {
+    _glfw.ns.lastEventTime = [event timestamp];
+
     [self mouseMoved:event];
 }
 
 - (void)rightMouseUp:(NSEvent *)event
 {
+    _glfw.ns.lastEventTime = [event timestamp];
+
     _glfwInputMouseClick(window,
                          GLFW_MOUSE_BUTTON_RIGHT,
                          GLFW_RELEASE,
@@ -511,6 +525,8 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 
 - (void)otherMouseDown:(NSEvent *)event
 {
+    _glfw.ns.lastEventTime = [event timestamp];
+
     _glfwInputMouseClick(window,
                          (int) [event buttonNumber],
                          GLFW_PRESS,
@@ -519,11 +535,15 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 
 - (void)otherMouseDragged:(NSEvent *)event
 {
+    _glfw.ns.lastEventTime = [event timestamp];
+
     [self mouseMoved:event];
 }
 
 - (void)otherMouseUp:(NSEvent *)event
 {
+    _glfw.ns.lastEventTime = [event timestamp];
+
     _glfwInputMouseClick(window,
                          (int) [event buttonNumber],
                          GLFW_RELEASE,
@@ -588,6 +608,8 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
     const int key = translateKey([event keyCode]);
     const int mods = translateFlags([event modifierFlags]);
 
+    _glfw.ns.lastEventTime = [event timestamp];
+
     _glfwInputKey(window, key, [event keyCode], GLFW_PRESS, mods);
 
     [self interpretKeyEvents:[NSArray arrayWithObject:event]];
@@ -619,6 +641,9 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 {
     const int key = translateKey([event keyCode]);
     const int mods = translateFlags([event modifierFlags]);
+
+    _glfw.ns.lastEventTime = [event timestamp];
+
     _glfwInputKey(window, key, [event keyCode], GLFW_RELEASE, mods);
 }
 
@@ -1462,6 +1487,12 @@ void _glfwPlatformSetWindowFloating(_GLFWwindow* window, GLFWbool enabled)
         [window->ns.object setLevel:NSNormalWindowLevel];
 }
 
+double _glfwPlatformGetEventTime(void)
+{
+    /* Windows events are stored in seconds */
+    return _glfw.ns.lastEventTime;
+}
+
 void _glfwPlatformPollEvents(void)
 {
     for (;;)

src/internal.h

@@ -685,6 +685,7 @@ void _glfwPlatformSetWindowResizable(_GLFWwindow* window, GLFWbool enabled);
 void _glfwPlatformSetWindowDecorated(_GLFWwindow* window, GLFWbool enabled);
 void _glfwPlatformSetWindowFloating(_GLFWwindow* window, GLFWbool enabled);
 
+double _glfwPlatformGetEventTime(void);
 void _glfwPlatformPollEvents(void);
 void _glfwPlatformWaitEvents(void);
 void _glfwPlatformWaitEventsTimeout(double timeout);

src/mir_platform.h

@@ -114,6 +114,9 @@ typedef struct _GLFWlibraryMir
     // The window whose disabled cursor mode is active
     _GLFWwindow* disabledCursorWindow;
 
+    // The time of the last event
+    int64_t                 lastEventTime;
+
 } _GLFWlibraryMir;
 
 // Mir-specific per-cursor data

src/mir_window.c

@@ -147,6 +147,8 @@ static void handleKeyEvent(const MirKeyboardEvent* key_event, _GLFWwindow* windo
     const long text    = _glfwKeySym2Unicode(key_code);
     const int  plain   = !(mods & (GLFW_MOD_CONTROL | GLFW_MOD_ALT));
 
+    _glfw.mir.lastEventTime = mir_input_event_get_event_time((MirInputEvent *) key_event);
+
     _glfwInputKey(window, toGLFWKeyCode(scan_code), scan_code, pressed, mods);
 
     if (text != -1)
@@ -164,6 +166,8 @@ static void handlePointerButton(_GLFWwindow* window,
     uint32_t newButtonStates        = mir_pointer_event_buttons(pointer_event);
     int publicButton                = GLFW_MOUSE_BUTTON_LEFT;
 
+    _glfw.mir.lastEventTime = mir_input_event_get_event_time((MirEvent *) pointer_event);
+
     // XOR our old button states our new states to figure out what was added or removed
     button = newButtonStates ^ oldButtonStates;
 
@@ -201,6 +205,8 @@ static void handlePointerMotion(_GLFWwindow* window,
     const int hscroll = mir_pointer_event_axis_value(pointer_event, mir_pointer_axis_hscroll);
     const int vscroll = mir_pointer_event_axis_value(pointer_event, mir_pointer_axis_vscroll);
 
+    _glfw.mir.lastEventTime = mir_input_event_get_event_time((MirEvent *) pointer_event);
+
     if (window->cursorMode == GLFW_CURSOR_DISABLED)
     {
         if (_glfw.mir.disabledCursorWindow != window)
@@ -632,6 +638,12 @@ void _glfwPlatformSetWindowFloating(_GLFWwindow* window, GLFWbool enabled)
                     "Mir: Unsupported function %s", __PRETTY_FUNCTION__);
 }
 
+double _glfwPlatformGetEventTime(void)
+{
+    /* Mir events are stored in nanoseconds */
+    return (double) _glfw.mir.lastEventTime / 1000000000.0;
+}
+
 void _glfwPlatformPollEvents(void)
 {
     EventNode* node = NULL;

src/null_window.c

@@ -204,6 +204,11 @@ int _glfwPlatformWindowVisible(_GLFWwindow* window)
     return GLFW_FALSE;
 }
 
+double _glfwPlatformGetEventTime(void)
+{
+    return 0.0;
+}
+
 void _glfwPlatformPollEvents(void)
 {
 }

src/win32_platform.h

@@ -259,6 +259,10 @@ typedef struct _GLFWlibraryWin32
     RAWINPUT*           rawInput;
     int                 rawInputSize;
 
+    // State for accumulating a non-wrapping event time
+    uint32_t            lastTimestamp;
+    uint64_t            eventTime;
+
     struct {
         HINSTANCE                       instance;
         PFN_timeGetTime                 GetTime;

src/win32_window.c

@@ -347,6 +347,14 @@ static int getKeyMods(void)
     return mods;
 }
 
+// Updates the event time with the specified timestamp
+//
+static void updateEventTime(LONG timestamp)
+{
+    _glfw.win32.eventTime += (uint32_t) timestamp - _glfw.win32.lastTimestamp;
+    _glfw.win32.lastTimestamp = timestamp;
+}
+
 // Retrieves and translates modifier keys
 //
 static int getAsyncKeyMods(void)
@@ -595,6 +603,7 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
         case WM_UNICHAR:
         {
             const GLFWbool plain = (uMsg != WM_SYSCHAR);
+            updateEventTime(GetMessageTime());
 
             if (uMsg == WM_UNICHAR && wParam == UNICODE_NOCHAR)
             {
@@ -617,6 +626,7 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
             const int scancode = (lParam >> 16) & 0x1ff;
             const int action = ((lParam >> 31) & 1) ? GLFW_RELEASE : GLFW_PRESS;
             const int mods = getKeyMods();
+            updateEventTime(GetMessageTime());
 
             if (key == _GLFW_KEY_INVALID)
                 break;
@@ -651,6 +661,7 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
         case WM_XBUTTONUP:
         {
             int i, button, action;
+            updateEventTime(GetMessageTime());
 
             if (uMsg == WM_LBUTTONDOWN || uMsg == WM_LBUTTONUP)
                 button = GLFW_MOUSE_BUTTON_LEFT;
@@ -701,6 +712,7 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
         {
             const int x = GET_X_LPARAM(lParam);
             const int y = GET_Y_LPARAM(lParam);
+            updateEventTime(GetMessageTime());
 
             // Disabled cursor motion input is provided by WM_INPUT
             if (window->cursorMode == GLFW_CURSOR_DISABLED)
@@ -779,6 +791,7 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
 
         case WM_MOUSELEAVE:
         {
+            updateEventTime(GetMessageTime());
             window->win32.cursorTracked = GLFW_FALSE;
             _glfwInputCursorEnter(window, GLFW_FALSE);
             return 0;
@@ -786,6 +799,7 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
 
         case WM_MOUSEWHEEL:
         {
+            updateEventTime(GetMessageTime());
             _glfwInputScroll(window, 0.0, (SHORT) HIWORD(wParam) / (double) WHEEL_DELTA);
             return 0;
         }
@@ -793,6 +807,7 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
         case WM_MOUSEHWHEEL:
         {
             // This message is only sent on Windows Vista and later
+            updateEventTime(GetMessageTime());
             // NOTE: The X-axis is inverted for consistency with macOS and X11
             _glfwInputScroll(window, -((SHORT) HIWORD(wParam) / (double) WHEEL_DELTA), 0.0);
             return 0;
@@ -1498,6 +1513,11 @@ void _glfwPlatformSetWindowFloating(_GLFWwindow* window, GLFWbool enabled)
                  SWP_NOACTIVATE | SWP_NOMOVE | SWP_NOSIZE);
 }
 
+double _glfwPlatformGetEventTime(void)
+{
+    return (double) _glfw.win32.eventTime / 1000.0;
+}
+
 void _glfwPlatformPollEvents(void)
 {
     MSG msg;

src/window.c

@@ -956,6 +956,12 @@ GLFWAPI GLFWframebuffersizefun glfwSetFramebufferSizeCallback(GLFWwindow* handle
     return cbfun;
 }
 
+GLFWAPI double glfwGetEventTime(void)
+{
+    _GLFW_REQUIRE_INIT_OR_RETURN(0.0);
+    return _glfwPlatformGetEventTime();
+}
+
 GLFWAPI void glfwPollEvents(void)
 {
     _GLFW_REQUIRE_INIT();

src/wl_init.c

@@ -83,6 +83,7 @@ static void pointerHandleMotion(void* data,
     if (!window)
         return;
 
+    _glfw.wl.lastEventTime = time;
     if (window->cursorMode == GLFW_CURSOR_DISABLED)
         return;
     else
@@ -109,6 +110,7 @@ static void pointerHandleButton(void* data,
     if (!window)
         return;
 
+    _glfw.wl.lastEventTime = time;
     _glfw.wl.pointerSerial = serial;
 
     /* Makes left, right and middle 0, 1 and 2. Overall order follows evdev
@@ -136,6 +138,7 @@ static void pointerHandleAxis(void* data,
     if (!window)
         return;
 
+    _glfw.wl.lastEventTime = time;
     /* Wayland scroll events are in pointer motion coordinate space (think
      * two finger scroll). The factor 10 is commonly used to convert to
      * "scroll step means 1.0. */
@@ -349,6 +352,7 @@ static void keyboardHandleKey(void* data,
     if (!window)
         return;
 
+    _glfw.wl.lastEventTime = time;
     keyCode = toGLFWKeyCode(key);
     action = state == WL_KEYBOARD_KEY_STATE_PRESSED
             ? GLFW_PRESS : GLFW_RELEASE;

src/wl_platform.h

@@ -97,6 +97,7 @@ typedef struct _GLFWwindowWayland
         struct zwp_relative_pointer_v1*    relativePointer;
         struct zwp_locked_pointer_v1*      lockedPointer;
     } pointerLock;
+
 } _GLFWwindowWayland;
 
 // Wayland-specific global data
@@ -138,6 +139,9 @@ typedef struct _GLFWlibraryWayland
     _GLFWwindow*                pointerFocus;
     _GLFWwindow*                keyboardFocus;
 
+    // The time of the last event
+    unsigned int                lastEventTime;
+
 } _GLFWlibraryWayland;
 
 // Wayland-specific per-monitor data

src/wl_window.c

@@ -675,6 +675,11 @@ void _glfwPlatformSetWindowFloating(_GLFWwindow* window, GLFWbool enabled)
                     "Wayland: Window attribute setting not implemented yet");
 }
 
+double _glfwPlatformGetEventTime(void)
+{
+    return (double) _glfw.wl.lastEventTime / 1000.0;
+}
+
 void _glfwPlatformPollEvents(void)
 {
     handleEvents(0);

src/x11_platform.h

@@ -225,6 +225,9 @@ typedef struct _GLFWlibraryX11
     double          restoreCursorPosX, restoreCursorPosY;
     // The window whose disabled cursor mode is active
     _GLFWwindow*    disabledCursorWindow;
+    // State for accumulating a non-wrapping event time
+    Time            lastTimestamp;
+    uint64_t        eventTime;
 
     // Window manager atoms
     Atom            WM_PROTOCOLS;

src/x11_window.c

@@ -1034,6 +1034,14 @@ static unsigned int decodeUTF8(const char** s)
 }
 #endif /*X_HAVE_UTF8_STRING*/
 
+// Updates the event time with the specified timestamp
+//
+static void updateEventTime(Time timestamp)
+{
+    _glfw.x11.eventTime += timestamp - _glfw.x11.lastTimestamp;
+    _glfw.x11.lastTimestamp = timestamp;
+}
+
 // Process the specified X event
 //
 static void processEvent(XEvent *event)
@@ -1076,6 +1084,7 @@ static void processEvent(XEvent *event)
                     const double* values = re->raw_values;
                     double xpos = window->virtualCursorPosX;
                     double ypos = window->virtualCursorPosY;
+                    updateEventTime(re->time);
 
                     if (XIMaskIsSet(re->valuators.mask, 0))
                     {
@@ -1121,6 +1130,7 @@ static void processEvent(XEvent *event)
             const int key = translateKey(keycode);
             const int mods = translateState(event->xkey.state);
             const int plain = !(mods & (GLFW_MOD_CONTROL | GLFW_MOD_ALT));
+            updateEventTime(event->xkey.time);
 
             if (window->x11.ic)
             {
@@ -1214,6 +1224,7 @@ static void processEvent(XEvent *event)
         {
             const int key = translateKey(keycode);
             const int mods = translateState(event->xkey.state);
+            updateEventTime(event->xkey.time);
 
             if (!_glfw.x11.xkb.detectable)
             {
@@ -1254,6 +1265,7 @@ static void processEvent(XEvent *event)
         case ButtonPress:
         {
             const int mods = translateState(event->xbutton.state);
+            updateEventTime(event->xbutton.time);
 
             if (event->xbutton.button == Button1)
                 _glfwInputMouseClick(window, GLFW_MOUSE_BUTTON_LEFT, GLFW_PRESS, mods);
@@ -1288,6 +1300,7 @@ static void processEvent(XEvent *event)
         case ButtonRelease:
         {
             const int mods = translateState(event->xbutton.state);
+            updateEventTime(event->xbutton.time);
 
             if (event->xbutton.button == Button1)
             {
@@ -1325,6 +1338,8 @@ static void processEvent(XEvent *event)
 
         case EnterNotify:
         {
+            updateEventTime(event->xcrossing.time);
+
             // HACK: This is a workaround for WMs (KWM, Fluxbox) that otherwise
             //       ignore the defined cursor for hidden cursor mode
             if (window->cursorMode == GLFW_CURSOR_HIDDEN)
@@ -1336,6 +1351,7 @@ static void processEvent(XEvent *event)
 
         case LeaveNotify:
         {
+            updateEventTime(event->xcrossing.time);
             _glfwInputCursorEnter(window, GLFW_FALSE);
             return;
         }
@@ -1344,6 +1360,7 @@ static void processEvent(XEvent *event)
         {
             const int x = event->xmotion.x;
             const int y = event->xmotion.y;
+            updateEventTime(event->xmotion.time);
 
             if (x != window->x11.warpCursorPosX || y != window->x11.warpCursorPosY)
             {
@@ -2428,6 +2445,11 @@ void _glfwPlatformSetWindowFloating(_GLFWwindow* window, GLFWbool enabled)
     XFlush(_glfw.x11.display);
 }
 
+double _glfwPlatformGetEventTime(void)
+{
+    return (double) _glfw.x11.eventTime / 1000.0;
+}
+
 void _glfwPlatformPollEvents(void)
 {
     _GLFWwindow* window;

tests/events.c

@@ -336,33 +336,35 @@ static void window_maximize_callback(GLFWwindow* window, int maximized)
 static void mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
 {
     Slot* slot = glfwGetWindowUserPointer(window);
-    printf("%08x to %i at %0.3f: Mouse button %i (%s) (with%s) was %s\n",
+    printf("%08x to %i at %0.3f: Mouse button %i (%s) (with%s) was %s at %0.3f\n",
            counter++, slot->number, glfwGetTime(), button,
            get_button_name(button),
            get_mods_name(mods),
-           get_action_name(action));
+           get_action_name(action),
+           glfwGetEventTime());
 }
 
 static void cursor_position_callback(GLFWwindow* window, double x, double y)
 {
     Slot* slot = glfwGetWindowUserPointer(window);
-    printf("%08x to %i at %0.3f: Cursor position: %f %f\n",
+    printf("%08x to %i at %0.3f: Cursor position: %f %f at %0.3f\n",
-           counter++, slot->number, glfwGetTime(), x, y);
+           counter++, slot->number, glfwGetTime(), x, y, glfwGetEventTime());
 }
 
 static void cursor_enter_callback(GLFWwindow* window, int entered)
 {
     Slot* slot = glfwGetWindowUserPointer(window);
-    printf("%08x to %i at %0.3f: Cursor %s window\n",
+    printf("%08x to %i at %0.3f: Cursor %s window at %0.3f\n",
            counter++, slot->number, glfwGetTime(),
-           entered ? "entered" : "left");
+           entered ? "entered" : "left",
+           glfwGetEventTime());
 }
 
 static void scroll_callback(GLFWwindow* window, double x, double y)
 {
     Slot* slot = glfwGetWindowUserPointer(window);
-    printf("%08x to %i at %0.3f: Scroll: %0.3f %0.3f\n",
+    printf("%08x to %i at %0.3f: Scroll: %0.3f %0.3f at %0.3f\n",
-           counter++, slot->number, glfwGetTime(), x, y);
+           counter++, slot->number, glfwGetTime(), x, y, glfwGetEventTime());
 }
 
 static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
@@ -372,20 +374,22 @@ static void key_callback(GLFWwindow* window, int key, int scancode, int action,
 
     if (name)
     {
-        printf("%08x to %i at %0.3f: Key 0x%04x Scancode 0x%04x (%s) (%s) (with%s) was %s\n",
+        printf("%08x to %i at %0.3f: Key 0x%04x Scancode 0x%04x (%s) (%s) (with%s) was %s at %0.3f\n",
                counter++, slot->number, glfwGetTime(), key, scancode,
                get_key_name(key),
                name,
                get_mods_name(mods),
-               get_action_name(action));
+               get_action_name(action),
+               glfwGetEventTime());
     }
     else
     {
-        printf("%08x to %i at %0.3f: Key 0x%04x Scancode 0x%04x (%s) (with%s) was %s\n",
+        printf("%08x to %i at %0.3f: Key 0x%04x Scancode 0x%04x (%s) (with%s) was %s at %0.3f\n",
                counter++, slot->number, glfwGetTime(), key, scancode,
                get_key_name(key),
                get_mods_name(mods),
-               get_action_name(action));
+               get_action_name(action),
+               glfwGetEventTime());
     }
 
     if (action != GLFW_PRESS)