Fixed bug 3107 OSX - Process events in SDLApplication to fix integration with CEF.

John Wordsworth

While attempting to integrate CEF (Browser) into an SDL application, we noticed that there were problems on OS X where approximately 50% of the input events were essentially being lost - even when we were using off-screen rendering in CEF and passing through input events manually.

It appears that this problem has been around for a while (see: http://www.magpcss.org/ceforum/viewtopic.php?f=6&t=11141).

Please consider the following patch that fixes this issue. Instead of processing events directly after calling [NSApp nextEventMatchingMask:...] we now pass these events down to NSApp, for processing by an overloaded sendEvent: method. Chromium also forwards events to NSApp in the same way, which means we don't miss events, even if they were originally dequeued by CEF.

src/video/cocoa/SDL_cocoaevents.m

@@ -36,6 +36,7 @@
 @interface SDLApplication : NSApplication
 
 - (void)terminate:(id)sender;
+- (void)sendEvent:(NSEvent *)theEvent;
 
 @end
 
@@ -47,6 +48,39 @@
     SDL_SendQuit();
 }
 
+// Dispatch events here so that we can handle events caught by
+// nextEventMatchingMask in SDL, as well as events caught by other
+// processes (such as CEF) that are passed down to NSApp.
+- (void)sendEvent:(NSEvent *)theEvent
+{
+    SDL_VideoDevice *_this = SDL_GetVideoDevice();
+    
+    switch ([theEvent type]) {
+        case NSLeftMouseDown:
+        case NSOtherMouseDown:
+        case NSRightMouseDown:
+        case NSLeftMouseUp:
+        case NSOtherMouseUp:
+        case NSRightMouseUp:
+        case NSLeftMouseDragged:
+        case NSRightMouseDragged:
+        case NSOtherMouseDragged: /* usually middle mouse dragged */
+        case NSMouseMoved:
+        case NSScrollWheel:
+            Cocoa_HandleMouseEvent(_this, theEvent);
+            break;
+        case NSKeyDown:
+        case NSKeyUp:
+        case NSFlagsChanged:
+            Cocoa_HandleKeyEvent(_this, theEvent);
+            break;
+        default:
+            break;
+    }
+    
+    [super sendEvent:theEvent];
+}
+
 @end // SDLApplication
 
 /* setAppleMenu disappeared from the headers in 10.4 */
@@ -367,29 +401,7 @@ Cocoa_PumpEvents(_THIS)
             break;
         }
 
-        switch ([event type]) {
+        // Pass events down to SDLApplication to be handled in sendEvent:
-        case NSLeftMouseDown:
-        case NSOtherMouseDown:
-        case NSRightMouseDown:
-        case NSLeftMouseUp:
-        case NSOtherMouseUp:
-        case NSRightMouseUp:
-        case NSLeftMouseDragged:
-        case NSRightMouseDragged:
-        case NSOtherMouseDragged: /* usually middle mouse dragged */
-        case NSMouseMoved:
-        case NSScrollWheel:
-            Cocoa_HandleMouseEvent(_this, event);
-            break;
-        case NSKeyDown:
-        case NSKeyUp:
-        case NSFlagsChanged:
-            Cocoa_HandleKeyEvent(_this, event);
-            break;
-        default:
-            break;
-        }
-        /* Pass through to NSApp to make sure everything stays in sync */
         [NSApp sendEvent:event];
     }
 }}