Massive Quartz input enhancements from Darrell Walisser. His email: Enclosed is a patch that addresses the following: --Various minor cleanups. Removed dead/obsolete code, made some style cleanups --Mouse Events Now keep track of what button(s) were pressed so we know when to send the mouse up event. This fixes the case where the mouse is dragged outside of the game window and released (in which case we want to send the mouse up event even though the mouse is outside the game window). --Input Grabbing Here is my take on the grabbing situation, which is the basis for the new implementation. There are 3 grab states, ungrabbed (UG), visible (VG), and invisible (IG). Both VG and IG keep the mouse constrained to the window and produce relative motion events. In VG the cursor is visible (duh), in IG it is not. In VG, absolute motion events also work. There are 6 actions that can affect grabbing: 1. Set Fullscreen/Window (F/W). In fullscreen, a visible grab should do nothing. However, a fullscreen visible grab can be treated just like a windowed visible grab, which is what I have done to help simplify things. 2. Cursor hide/show (H/S). If the cursor is hidden when grabbing, the grab is an invisible grab. If the cursor is visible, the grab should just constrain the mouse to the window. 3. Input grab/ungrab(G/U). If grabbed, the cursor should be confined to the window as should the keyboard input. On Mac OS X, the keyboard input is implicitly grabbed by confining the cursor, except for command-tab which can switch away from the application. Should the window come to the foreground if the application is deactivated and grab input is called? This isn't necessary in this implementation because the grab state will be asserted upon activation. Using my notation, these are all the cases that need to be handled (state + action = new state). UG+U = UG UG+G = VG or IG, if cursor is visible or not UG+H = UG UG+S = UG VG+U = UG VG+G = VG VG+H = IG VG+S = VG IG+U = UG IG+G = IG IG+H = IG IG+S = VG The cases that result in the same state can be ignored in the code, which cuts it down to just 5 cases. Another issue is what happens when the app loses/gains input focus from deactivate/activate or iconify/deiconify. I think that if input focus is ever lost (outside of SDL's control), the grab state should be suspended and the cursor should become visible and active again. When regained, the cursor should reappear in its original location and/or grab state. This way, when reactivating the cursor is still in the same position as before so apps shouldn't get confused when the next motion event comes in. This is what I've done in this patch.

--- a/src/video/quartz/SDL_QuartzVideo.h	Fri Dec 20 03:37:28 2002 +0000
+++ b/src/video/quartz/SDL_QuartzVideo.h	Fri Dec 27 20:52:41 2002 +0000
@@ -132,8 +132,12 @@
     SDLKey             keymap[256];        /* Mac OS X to SDL key mapping */
     Uint32             current_mods;       /* current keyboard modifiers, to track modifier state */
     Uint32             last_virtual_button;/* last virtual mouse button pressed */
-    io_connect_t       powerConnection;    /* used with IOKit to detect wake from sleep */
-
+    io_connect_t       power_connection;   /* used with IOKit to detect wake from sleep */
+    Uint8              expect_mouse_up;    /* used to determine when to send mouse up events */
+    Uint8              grab_state;         /* used to manage grab behavior */
+    NSPoint            cursor_loc;         /* saved cursor coords, for activate/deactivate when grabbed */
+    BOOL          	   cursor_visible;     /* tells if cursor was hidden or not */
+    
     ImageDescriptionHandle yuv_idh;
     MatrixRecordPtr        yuv_matrix;
     DecompressorComponent  yuv_codec;
@@ -167,7 +171,11 @@
 #define keymap (this->hidden->keymap)
 #define current_mods (this->hidden->current_mods)
 #define last_virtual_button (this->hidden->last_virtual_button)
-#define powerConnection (this->hidden->powerConnection)
+#define power_connection (this->hidden->power_connection)
+#define expect_mouse_up (this->hidden->expect_mouse_up)
+#define grab_state (this->hidden->grab_state)
+#define cursor_loc (this->hidden->cursor_loc)
+#define cursor_visible (this->hidden->cursor_visible)
 
 #define yuv_idh (this->hidden->yuv_idh)
 #define yuv_matrix (this->hidden->yuv_matrix)
@@ -179,6 +187,22 @@
 #define yuv_height (this->hidden->yuv_height)
 #define yuv_port (this->hidden->yuv_port)
 
+
+/* grab states - the input is in one of these states */
+enum {
+    QZ_UNGRABBED = 0,
+    QZ_VISIBLE_GRAB,
+    QZ_INVISIBLE_GRAB
+};
+
+/* grab actions - these can change the grabbed state */
+enum {
+    QZ_ENABLE_GRAB = 0,
+    QZ_DISABLE_GRAB,
+    QZ_HIDECURSOR,
+    QZ_SHOWCURSOR
+};
+
 /* 
     Obscuring code: maximum number of windows above ours (inclusive)