From 69f38f68879412a9ef157d335d7798917888a261 Mon Sep 17 00:00:00 2001 From: David Robillard Date: Sat, 3 Aug 2019 20:54:08 +0200 Subject: Windows: Prevent event loop from running forever --- pugl/detail/win.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) (limited to 'pugl/detail') diff --git a/pugl/detail/win.c b/pugl/detail/win.c index 65ae4ae..edc8447 100644 --- a/pugl/detail/win.c +++ b/pugl/detail/win.c @@ -45,6 +45,7 @@ #endif #define PUGL_LOCAL_CLOSE_MSG (WM_USER + 50) +#define PUGL_LOCAL_MARK_MSG (WM_USER + 51) #define PUGL_RESIZE_TIMER_ID 9461 #define PUGL_URGENT_TIMER_ID 9462 @@ -689,10 +690,26 @@ puglWaitForEvent(PuglView* PUGL_UNUSED(view)) PUGL_API PuglStatus puglDispatchEvents(PuglWorld* PUGL_UNUSED(world)) { - MSG msg; + /* Windows has no facility to process only currently queued messages, which + causes the event loop to run forever in cases like mouse movement where + the queue is constantly being filled with new messages. To work around + 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)) { - TranslateMessage(&msg); - DispatchMessage(&msg); + if (msg.message == PUGL_LOCAL_MARK_MSG) { + markTime = GetMessageTime(); + } else { + TranslateMessage(&msg); + DispatchMessage(&msg); + if (markTime != 0 && GetMessageTime() > markTime) { + break; + } + } } return PUGL_SUCCESS; -- cgit v1.2.1