Use QWindow::requestUpdate in threaded renderloop.

The default implementation is the same as what we do with the exhaust
delay, but it is now possible for platforms to line it up with vsync
so the GUI thread doesn't spend so much time being blocked.

Change-Id: Ie126f00a1be978608bf2a1db33d80d7f0458590d
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

4 files changed, 18 insertions, 46 deletions

diff --git a/src/quick/items/qquickwindow.cpp b/src/quick/items/qquickwindow.cpp
index 4986996d99..990c339630 100644
--- a/src/quick/items/qquickwindow.cpp
+++ b/src/quick/items/qquickwindow.cpp
@@ -1376,6 +1376,11 @@ bool QQuickWindow::event(QEvent *e)
         if (d->mouseGrabberItem)
             d->mouseGrabberItem->ungrabMouse();
         break;
+    case QEvent::UpdateRequest: {
+        if (d->windowManager)
+            d->windowManager->handleUpdateRequest(this);
+        break;
+    }
     default:
         break;
     }
diff --git a/src/quick/scenegraph/qsgrenderloop_p.h b/src/quick/scenegraph/qsgrenderloop_p.h
index e9b58c60ba..8d3214db60 100644
--- a/src/quick/scenegraph/qsgrenderloop_p.h
+++ b/src/quick/scenegraph/qsgrenderloop_p.h
@@ -64,6 +64,7 @@ public:
 
     virtual void update(QQuickWindow *window) = 0;
     virtual void maybeUpdate(QQuickWindow *window) = 0;
+    virtual void handleUpdateRequest(QQuickWindow *) { }
 
     virtual QAnimationDriver *animationDriver() const = 0;
 
diff --git a/src/quick/scenegraph/qsgthreadedrenderloop.cpp b/src/quick/scenegraph/qsgthreadedrenderloop.cpp
index 29bee67f69..3e0230fe02 100644
--- a/src/quick/scenegraph/qsgthreadedrenderloop.cpp
+++ b/src/quick/scenegraph/qsgthreadedrenderloop.cpp
@@ -105,16 +105,6 @@ QT_BEGIN_NAMESPACE
 
 #define QSG_RT_PAD "                    (RT)"
 
-static int get_env_int(const char *name, int defaultValue)
-{
-    QByteArray content = qgetenv(name);
-
-    bool ok = false;
-    int value = content.toInt(&ok);
-    return ok ? value : defaultValue;
-}
-
-
 static inline int qsgrl_animation_interval() {
     qreal refreshRate = QGuiApplication::primaryScreen()->refreshRate();
     // To work around that some platforms wrongfully return 0 or something
@@ -694,8 +684,6 @@ QSGThreadedRenderLoop::QSGThreadedRenderLoop()
 
     m_animation_driver = sg->createAnimationDriver(this);
 
-    m_exhaust_delay = get_env_int("QML_EXHAUST_DELAY", 5);
-
     connect(m_animation_driver, SIGNAL(started()), this, SLOT(animationStarted()));
     connect(m_animation_driver, SIGNAL(stopped()), this, SLOT(animationStopped()));
 
@@ -709,10 +697,7 @@ QSGRenderContext *QSGThreadedRenderLoop::createRenderContext(QSGContext *sg) con
 
 void QSGThreadedRenderLoop::maybePostPolishRequest(Window *w)
 {
-    if (w->timerId == 0) {
-        qCDebug(QSG_LOG_RENDERLOOP) << "- posting update";
-        w->timerId = startTimer(m_exhaust_delay, Qt::PreciseTimer);
-    }
+    w->window->requestUpdate();
 }
 
 QAnimationDriver *QSGThreadedRenderLoop::animationDriver() const
@@ -862,7 +847,6 @@ void QSGThreadedRenderLoop::handleExposure(QQuickWindow *window)
         win.window = window;
         win.actualWindowFormat = window->format();
         win.thread = new QSGRenderThread(this, QQuickWindowPrivate::get(window)->context);
-        win.timerId = 0;
         win.updateDuringSync = false;
         win.forceRenderPass = true; // also covered by polishAndSync(inExpose=true), but doesn't hurt
         m_windows << win;
@@ -952,6 +936,14 @@ void QSGThreadedRenderLoop::handleObscurity(Window *w)
 }
 
 
+void QSGThreadedRenderLoop::handleUpdateRequest(QQuickWindow *window)
+{
+    qCDebug(QSG_LOG_RENDERLOOP) << "- polish and sync update request";
+    foreach (const Window &w, m_windows)
+        if (w.window == window)
+            polishAndSync(const_cast<Window *>(&w));
+}
+
 void QSGThreadedRenderLoop::maybeUpdate(QQuickWindow *window)
 {
     Window *w = windowFor(m_windows, window);
@@ -1079,8 +1071,6 @@ void QSGThreadedRenderLoop::polishAndSync(Window *w, bool inExpose)
     QQuickWindow *window = w->window;
     if (!w->thread || !w->thread->window) {
         qCDebug(QSG_LOG_RENDERLOOP) << "- not exposed, abort";
-        killTimer(w->timerId);
-        w->timerId = 0;
         return;
     }
 
@@ -1090,8 +1080,6 @@ void QSGThreadedRenderLoop::polishAndSync(Window *w, bool inExpose)
     w = windowFor(m_windows, window);
     if (!w || !w->thread || !w->thread->window) {
         qCDebug(QSG_LOG_RENDERLOOP) << "- removed after event flushing, abort";
-        killTimer(w->timerId);
-        w->timerId = 0;
         return;
     }
 
@@ -1135,9 +1123,6 @@ void QSGThreadedRenderLoop::polishAndSync(Window *w, bool inExpose)
         syncTime = timer.nsecsElapsed();
     Q_QUICK_SG_PROFILE_RECORD(QQuickProfiler::SceneGraphPolishAndSync);
 
-    killTimer(w->timerId);
-    w->timerId = 0;
-
     if (m_animation_timer == 0 && m_animation_driver->isRunning()) {
         qCDebug(QSG_LOG_RENDERLOOP) << "- advancing animations";
         m_animation_driver->advance();
@@ -1160,17 +1145,6 @@ void QSGThreadedRenderLoop::polishAndSync(Window *w, bool inExpose)
     Q_QUICK_SG_PROFILE_END(QQuickProfiler::SceneGraphPolishAndSync);
 }
 
-QSGThreadedRenderLoop::Window *QSGThreadedRenderLoop::windowForTimer(int timerId) const
-{
-    for (int i=0; i<m_windows.size(); ++i) {
-        if (m_windows.at(i).timerId == timerId) {
-            return const_cast<Window *>(&m_windows.at(i));
-            break;
-        }
-    }
-    return 0;
-}
-
 bool QSGThreadedRenderLoop::event(QEvent *e)
 {
     switch ((int) e->type()) {
@@ -1181,15 +1155,8 @@ bool QSGThreadedRenderLoop::event(QEvent *e)
             qCDebug(QSG_LOG_RENDERLOOP) << "- ticking non-visual timer";
             m_animation_driver->advance();
             emit timeToIncubate();
-        } else {
-            qCDebug(QSG_LOG_RENDERLOOP) << "- polish and sync timer";
-            Window *w = windowForTimer(te->timerId());
-            if (w)
-                polishAndSync(w);
-            else
-                killTimer(te->timerId());
+            return true;
         }
-        return true;
     }
 
     default:
diff --git a/src/quick/scenegraph/qsgthreadedrenderloop_p.h b/src/quick/scenegraph/qsgthreadedrenderloop_p.h
index 82f314a6af..b3db56e5f9 100644
--- a/src/quick/scenegraph/qsgthreadedrenderloop_p.h
+++ b/src/quick/scenegraph/qsgthreadedrenderloop_p.h
@@ -60,6 +60,8 @@ public:
 
     void update(QQuickWindow *window);
     void maybeUpdate(QQuickWindow *window);
+    void handleUpdateRequest(QQuickWindow *window);
+
     QSGContext *sceneGraphContext() const;
     QSGRenderContext *createRenderContext(QSGContext *) const;
 
@@ -80,7 +82,6 @@ private:
         QQuickWindow *window;
         QSGRenderThread *thread;
         QSurfaceFormat actualWindowFormat;
-        int timerId;
         uint updateDuringSync : 1;
         uint forceRenderPass : 1;
     };
@@ -89,7 +90,6 @@ private:
 
     void releaseResources(Window *window, bool inDestructor);
     bool checkAndResetForceUpdate(QQuickWindow *window);
-    Window *windowForTimer(int timerId) const;
 
     bool anyoneShowing() const;
     void initialize();
@@ -109,7 +109,6 @@ private:
     QList<Window> m_windows;
 
     int m_animation_timer;
-    int m_exhaust_delay;
 
     bool m_lockedForSync;
 };