Windows: Prevent input in one window from stalling another

This dispatches events on a per-window basic instead of globally, using the
same mark trick as before to bound the number of events dispatched.

After the events are dispatched, all the windows are updated if they have an
invalid region.  This ensures that all windows get drawn every iteration if
necessary, since Windows itself does not send WM_PAINT messages if there is
lots of input activity.

1 files changed, 21 insertions, 4 deletions

diff --git a/pugl/detail/win.c b/pugl/detail/win.c
index 080460d..6b7414a 100644
--- a/pugl/detail/win.c
+++ b/pugl/detail/win.c
@@ -735,8 +735,8 @@ puglWaitForEvent(PuglView* PUGL_UNUSED(view))
 }
 #endif
 
-PUGL_API PuglStatus
-puglDispatchEvents(PuglWorld* PUGL_UNUSED(world))
+static PuglStatus
+puglDispatchViewEvents(PuglView* view)
 {
 	/* Windows has no facility to process only currently queued messages, which
 	   causes the event loop to run forever in cases like mouse movement where
@@ -744,11 +744,10 @@ puglDispatchEvents(PuglWorld* PUGL_UNUSED(world))
 	   this, we post a message to ourselves before starting, record its time
 	   when it is received, then break the loop on the first message that was
 	   created afterwards. */
-	PostMessage(NULL, PUGL_LOCAL_MARK_MSG, 0, 0);
 
 	long markTime = 0;
 	MSG  msg;
-	while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) {
+	while (PeekMessage(&msg, view->impl->hwnd, 0, 0, PM_REMOVE)) {
 		if (msg.message == PUGL_LOCAL_MARK_MSG) {
 			markTime = GetMessageTime();
 		} else {
@@ -763,6 +762,24 @@ puglDispatchEvents(PuglWorld* PUGL_UNUSED(world))
 	return PUGL_SUCCESS;
 }
 
+PUGL_API PuglStatus
+puglDispatchEvents(PuglWorld* world)
+{
+	for (size_t i = 0; i < world->numViews; ++i) {
+		PostMessage(world->views[i]->impl->hwnd, PUGL_LOCAL_MARK_MSG, 0, 0);
+	}
+
+	for (size_t i = 0; i < world->numViews; ++i) {
+		puglDispatchViewEvents(world->views[i]);
+	}
+
+	for (size_t i = 0; i < world->numViews; ++i) {
+		UpdateWindow(world->views[i]->impl->hwnd);
+	}
+
+	return PUGL_SUCCESS;
+}
+
 #ifndef PUGL_DISABLE_DEPRECATED
 PuglStatus
 puglProcessEvents(PuglView* view)