SCI32: Improve performance when flushing events during video playback

Calling through EventManager::getSciEvent to flush events is
pretty inefficient and created stalls that lead to dropped
frames during the chapter 7 chase in Phantasmagoria 1.

If necessary, performance could be improved further by extending
Common::EventManager to expose SDL_FlushEvents, but this seems to
finish in 0-1ms so should be OK for now.

Refs Trac#9974, Trac#9975.

1 files changed, 7 insertions, 0 deletions

diff --git a/engines/sci/event.cpp b/engines/sci/event.cpp
index 873b6bb48a..b1be46aded 100644
--- a/engines/sci/event.cpp
+++ b/engines/sci/event.cpp
@@ -408,6 +408,13 @@ SciEvent EventManager::getSciEvent(uint32 mask) {
 	return event;
 }
 
+void EventManager::flushEvents() {
+	Common::EventManager *em = g_system->getEventManager();
+	Common::Event event;
+	while (em->pollEvent(event));
+	_events.clear();
+}
+
 #ifdef ENABLE_SCI32
 void EventManager::setHotRectanglesActive(const bool active) {
 	_hotRectanglesActive = active;