Allow fixed animation step in QSGGuiThreadRenderLoop

This patch allows to enable the fixed animation step in
QSGGuiThreadRenderLoop if QSG_FIXED_ANIMATION_STEP is set.

Change-Id: I87ff26120283d93e9b8d08286a16990cf6d649ce
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>
Reviewed-by: Aram So <aram.so@lge.com>

2 files changed, 7 insertions, 3 deletions

diff --git a/src/quick/scenegraph/qsgcontext.cpp b/src/quick/scenegraph/qsgcontext.cpp
index 6572ceb2ce..2ba16e7328 100644
--- a/src/quick/scenegraph/qsgcontext.cpp
+++ b/src/quick/scenegraph/qsgcontext.cpp
@@ -136,9 +136,9 @@ public:
     bool distanceFieldAntialiasingDecided;
 };
 
-static bool qsg_useConsistentTiming()
+bool qsg_useConsistentTiming()
 {
-    static int use = -1;
+    int use = -1;
     if (use < 0) {
         use = !qEnvironmentVariableIsEmpty("QSG_FIXED_ANIMATION_STEP") && qgetenv("QSG_FIXED_ANIMATION_STEP") != "no"
             ? 1 : 0;
diff --git a/src/quick/scenegraph/qsgrenderloop.cpp b/src/quick/scenegraph/qsgrenderloop.cpp
index b5f149eff7..cd0f77799b 100644
--- a/src/quick/scenegraph/qsgrenderloop.cpp
+++ b/src/quick/scenegraph/qsgrenderloop.cpp
@@ -67,7 +67,7 @@
 
 QT_BEGIN_NAMESPACE
 
-
+extern bool qsg_useConsistentTiming();
 extern Q_GUI_EXPORT QImage qt_gl_read_framebuffer(const QSize &size, bool alpha_format, bool include_alpha);
 
 /*!
@@ -267,6 +267,10 @@ void QSGRenderLoop::handleContextCreationFailure(QQuickWindow *window,
 QSGGuiThreadRenderLoop::QSGGuiThreadRenderLoop()
     : gl(0)
 {
+    if (qsg_useConsistentTiming()) {
+        QUnifiedTimer::instance(true)->setConsistentTiming(true);
+        qCDebug(QSG_LOG_INFO, "using fixed animation steps");
+    }
     sg = QSGContext::createDefaultContext();
     rc = sg->createRenderContext();
 }