From beffc6063445bb33c357079701fef8011461ae03 Mon Sep 17 00:00:00 2001
From: Martin Fouilleul <martinfouilleul@gmail.com>
Date: Mon, 15 Aug 2022 23:11:13 +0200
Subject: [PATCH] redraw during live resize operations

---
 src/mp_app.h   |  3 +++
 src/osx_app.mm | 53 +++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/src/mp_app.h b/src/mp_app.h
index ab54328..754951e 100644
--- a/src/mp_app.h
+++ b/src/mp_app.h
@@ -342,6 +342,9 @@ void mp_set_target_fps(u32 fps); // or use wait vblank?
 void mp_pump_events(f64 timeout);
 bool mp_next_event(mp_event* event);
 
+typedef void(*mp_live_resize_callback)(mp_event event, void* data);
+void mp_set_live_resize_callback(mp_live_resize_callback callback, void* data);
+
 //--------------------------------------------------------------------
 // Input state polling
 //--------------------------------------------------------------------
diff --git a/src/osx_app.mm b/src/osx_app.mm
index f9cdcdd..a9893d1 100644
--- a/src/osx_app.mm
+++ b/src/osx_app.mm
@@ -171,6 +171,11 @@ struct mp_app_data
 	mp_input_state inputState;
 	ringbuffer eventQueue;
 
+	mp_live_resize_callback liveResizeCallback;
+	void* liveResizeData;
+
+	CVDisplayLinkRef displayLink;
+
 	mp_frame_stats frameStats;
 
 	NSTimer* frameTimer;
@@ -181,7 +186,6 @@ struct mp_app_data
 	mp_view_data viewPool[MP_APP_MAX_VIEWS];
 	list_info viewFreeList;
 
-
 	TISInputSourceRef kbLayoutInputSource;
 	void* kbLayoutUnicodeData;
 	id kbLayoutListener;
@@ -839,9 +843,26 @@ static void mp_queue_event(mp_event* event)
 	mp_rect viewFrame = {0, 0, contentRect.size.width, contentRect.size.height};
 	mp_view_set_frame(mpWindow->mainView, viewFrame);
 
+
+	if(__mpAppData.liveResizeCallback)
+	{
+		__mpAppData.liveResizeCallback(event, __mpAppData.liveResizeData);
+	}
+
+	//TODO: also ensure we don't overflow the queue during live resize...
 	mp_queue_event(&event);
 }
 
+-(void)windowWillStartLiveResize:(NSNotification *)notification
+{
+	CVDisplayLinkStart(__mpAppData.displayLink);
+}
+
+-(void)windowDidEndLiveResize:(NSNotification *)notification
+{
+	CVDisplayLinkStop(__mpAppData.displayLink);
+}
+
 - (void)windowWillClose:(NSNotification *)notification
 {
 	mpWindow->nsWindow = nil;
@@ -1297,6 +1318,7 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 {
 }
 
+
 @end //@implementation MPNativeView
 
 /*
@@ -1326,6 +1348,25 @@ f64 mp_get_elapsed_seconds()
 }
 */
 
+CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink,
+                             const CVTimeStamp *inNow,
+                             const CVTimeStamp *inOutputTime,
+                             CVOptionFlags flagsIn,
+                             CVOptionFlags *flagsOut,
+                             void *displayLinkContext)
+{
+	if(__mpAppData.liveResizeCallback)
+	{
+		mp_event event = {};
+		event.type = MP_EVENT_FRAME;
+
+		__mpAppData.liveResizeCallback(event, __mpAppData.liveResizeData);
+	}
+
+	return(0);
+}
+
+
 //***************************************************************
 //			public API
 //***************************************************************
@@ -1367,6 +1408,10 @@ void mp_init()
 		LOG_MESSAGE("run application\n");
 		[NSApp run];
 
+		CGDirectDisplayID displayID = CGMainDisplayID();
+		CVDisplayLinkCreateWithCGDisplay(displayID, &__mpAppData.displayLink);
+		CVDisplayLinkSetOutputCallback(__mpAppData.displayLink, DisplayLinkCallback, 0);
+
 		[NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
 		[NSApp activateIgnoringOtherApps:YES];
 
@@ -1993,6 +2038,12 @@ void mp_end_frame()
 // Events handling
 //--------------------------------------------------------------------
 
+void mp_set_live_resize_callback(mp_live_resize_callback callback, void* data)
+{
+	__mpAppData.liveResizeCallback = callback;
+	__mpAppData.liveResizeData = data;
+}
+
 void mp_pump_events(f64 timeout)
 {
 	__mpAppData.inputState.frameCounter++;