Repost missed Presents with low priority

Zach Pomerantz committed 10 years ago

Commit 25deaf51 parent 2d4fd781 file · +18 −3Browse files

Showing the changes to interface/src/Application.cpp (1 of 1 file). Show all

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         return false;
     }
+    static bool justPresented = false;
     if ((int)event->type() == (int)Present) {
+        if (justPresented) {
+            justPresented = false;
+            // If presentation is hogging the main thread, repost as low priority to avoid hanging the GUI.
+            // This has the effect of allowing presentation to exceed the paint budget by X times and
+            // only dropping every (1/X) frames, instead of every ceil(X) frames.
+            // (e.g. at a 60FPS target, painting for 17us would fall to 58.82FPS instead of 30FPS).
+            removePostedEvents(this, Present);
+            postEvent(this, new QEvent(static_cast<QEvent::Type>(Present)), Qt::LowEventPriority);
+            return true;
+        }
         idle();
-        removePostedEvents(this, Present); // clear pending presents so we don't clog the pipes
         return true;
     } else if ((int)event->type() == (int)Paint) {
+        justPresented = true;
         paintGL();
         return true;
-    } else if ((int)event->type() == (int)Lambda) {
+    }
+    if ((int)event->type() == (int)Lambda) {
         static_cast<LambdaEvent*>(event)->call();
         return true;
     }
     _renderedFrameIndex = displayPlugin->presentCount();
     // Request a paint ASAP
-    postEvent(this, new QEvent(static_cast<QEvent::Type>(Paint)), Qt::HighEventPriority);
+    postEvent(this, new QEvent(static_cast<QEvent::Type>(Paint)), Qt::HighEventPriority + 1);
     // Update the deadlock watchdog
     updateHeartbeat();