1 files changed, 46 insertions, 30 deletions

diff --git a/src/quick3d/imports/scene3d/scene3ditem.cpp b/src/quick3d/imports/scene3d/scene3ditem.cpp
index c8c0e0f59..57e6b0e6e 100644
--- a/src/quick3d/imports/scene3d/scene3ditem.cpp
+++ b/src/quick3d/imports/scene3d/scene3ditem.cpp
@@ -5,8 +5,7 @@
 **
 ** This file is part of the Qt3D module of the Qt Toolkit.
 **
-** $QT_BEGIN_LICENSE:COMM$
-**
+** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
@@ -15,25 +14,26 @@
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
-** $QT_END_LICENSE$
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
 **
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
 **
+** $QT_END_LICENSE$
 **
 ****************************************************************************/
 
@@ -200,6 +200,9 @@ private:
     expression that depends on property updates driven by the Qt 3D simulation
     loop (FrameAction) will never reavaluates.
  */
+
+qint8 Scene3DItem::ms_framesNeededToFlushPipeline = 3;
+
 Scene3DItem::Scene3DItem(QQuickItem *parent)
     : QQuickItem(parent)
     , m_entity(nullptr)
@@ -219,6 +222,7 @@ Scene3DItem::Scene3DItem(QQuickItem *parent)
     , m_cameraAspectRatioMode(AutomaticAspectRatio)
     , m_compositingMode(FBO)
     , m_dummySurface(nullptr)
+    , m_framesToRender(ms_framesNeededToFlushPipeline)
 {
     setFlag(QQuickItem::ItemHasContents, true);
     setAcceptedMouseButtons(Qt::MouseButtonMask);
@@ -229,6 +233,11 @@ Scene3DItem::Scene3DItem(QQuickItem *parent)
     // we still won't get ignored by the QtQuick SG when in Underlay mode
     setWidth(1);
     setHeight(1);
+
+    const QByteArray framesToFlushCountEnvVar = qgetenv("QT3D_SCENE3D_FRAMES_FLUSH_COUNT");
+    if (!framesToFlushCountEnvVar.isEmpty()) {
+        ms_framesNeededToFlushPipeline = framesToFlushCountEnvVar.toInt();
+    }
 }
 
 Scene3DItem::~Scene3DItem()
@@ -542,8 +551,13 @@ bool Scene3DItem::needsRender(QRenderAspect *renderAspect)
             || (renderAspectPriv
                 && renderAspectPriv->m_renderer
                 && renderAspectPriv->m_renderer->shouldRender());
-    m_dirty = false;
-    return dirty;
+
+    if (m_dirty) {
+        --m_framesToRender;
+        if (m_framesToRender <= 0)
+            m_dirty = false;
+    }
+    return dirty || m_framesToRender > 0;
 }
 
 // This function is triggered in the context of the Main Thread
@@ -911,15 +925,16 @@ QSGNode *Scene3DItem::updatePaintNode(QSGNode *node, QQuickItem::UpdatePaintNode
         updateWindowSurface();
         managerNode->init();
         // Note: ChangeArbiter is only set after aspect was registered
-
-        // This allows Scene3DItem to know when it needs to re-render as a result of frontend nodes receiving a change.
-        QObject::connect(renderAspectPriv->m_aspectManager->changeArbiter(), &Qt3DCore::QChangeArbiter::receivedChange,
-                         this, [this] { m_dirty = true; }, Qt::DirectConnection);
-
-        // This allows Scene3DItem to know when it needs to re-render as a result of backend nodes receiving a change.
-        // For e.g. nodes being created/destroyed.
-        QObject::connect(renderAspectPriv->m_aspectManager->changeArbiter(), &Qt3DCore::QChangeArbiter::syncedChanges,
-                         this, [this] { m_dirty = true; }, Qt::QueuedConnection);
+        QObject::connect(
+                renderAspectPriv->m_aspectManager->changeArbiter(),
+                &Qt3DCore::QChangeArbiter::receivedChange, this,
+                [this] {
+                    m_dirty = true;
+                    m_framesToRender = ms_framesNeededToFlushPipeline;
+                },
+                Qt::DirectConnection);
+        // Give the window a nudge to trigger an update.
+        QMetaObject::invokeMethod(window(), "requestUpdate", Qt::QueuedConnection);
     }
 
     const bool usesFBO = m_compositingMode == FBO;
@@ -1007,4 +1022,5 @@ void Scene3DItem::mousePressEvent(QMouseEvent *event)
 
 QT_END_NAMESPACE
 
+#include "moc_scene3ditem_p.cpp"
 #include "scene3ditem.moc"