Support threading with QQuickRenderControl

Reorganize the rendercontrol example to demonstrate both the single
and multi threaded approaches.

A small helper function is introduced to the QQuickRenderControl API:
The QSGRenderContext has to live on the render thread. Previously there
was no way for applications to move it to the desired thread. This is
now possible.

Pass --threaded to the rendercontrol example to use a separate render thread.

[ChangeLog][QtQuick] QQuickRenderControl can now be used to render the Qt Quick
scene on a dedicated render thread, similarly to how the built-in threaded render
loop operates.

Task-number: QTBUG-42813
Change-Id: I01c3b2ffca8a174d9d2c267a51f2e484ed7b34b3
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>

8 files changed, 938 insertions, 201 deletions

diff --git a/examples/quick/rendercontrol/cuberenderer.cpp b/examples/quick/rendercontrol/cuberenderer.cpp
new file mode 100644
index 0000000000..c385d46533
--- /dev/null
+++ b/examples/quick/rendercontrol/cuberenderer.cpp
@@ -0,0 +1,216 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
+**     of its contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "cuberenderer.h"
+#include <QOpenGLContext>
+#include <QOpenGLFunctions>
+#include <QOpenGLShaderProgram>
+#include <QOpenGLVertexArrayObject>
+#include <QOpenGLBuffer>
+#include <QOpenGLVertexArrayObject>
+#include <QOffscreenSurface>
+#include <QWindow>
+
+CubeRenderer::CubeRenderer()
+    : m_context(0),
+      m_program(0),
+      m_vbo(0)
+{
+}
+
+CubeRenderer::~CubeRenderer()
+{
+    // Use a temporary offscreen surface to do the cleanup.
+    // There may not be a native window surface available anymore at this stage.
+    QScopedPointer<QOffscreenSurface> offscreenSurface(new QOffscreenSurface);
+    offscreenSurface->setFormat(m_context->format());
+    offscreenSurface->create();
+    m_context->makeCurrent(offscreenSurface.data());
+
+    delete m_program;
+    delete m_vbo;
+    delete m_vao;
+
+    m_context->doneCurrent();
+    delete m_context;
+}
+
+void CubeRenderer::init(QWindow *w, QOpenGLContext *share)
+{
+    m_context = new QOpenGLContext;
+    m_context->setShareContext(share);
+    m_context->setFormat(w->requestedFormat());
+    m_context->create();
+    if (!m_context->makeCurrent(w))
+        return;
+
+    QOpenGLFunctions *f = m_context->functions();
+    f->glClearColor(0.0f, 0.1f, 0.25f, 1.0f);
+    f->glViewport(0, 0, w->width() * w->devicePixelRatio(), w->height() * w->devicePixelRatio());
+
+    static const char *vertexShaderSource =
+        "attribute highp vec4 vertex;\n"
+        "attribute lowp vec2 coord;\n"
+        "varying lowp vec2 v_coord;\n"
+        "uniform highp mat4 matrix;\n"
+        "void main() {\n"
+        "   v_coord = coord;\n"
+        "   gl_Position = matrix * vertex;\n"
+        "}\n";
+    static const char *fragmentShaderSource =
+        "varying lowp vec2 v_coord;\n"
+        "uniform sampler2D sampler;\n"
+        "void main() {\n"
+        "   gl_FragColor = vec4(texture2D(sampler, v_coord).rgb, 1.0);\n"
+        "}\n";
+    m_program = new QOpenGLShaderProgram;
+    m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource);
+    m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource);
+    m_program->bindAttributeLocation("vertex", 0);
+    m_program->bindAttributeLocation("coord", 1);
+    m_program->link();
+    m_matrixLoc = m_program->uniformLocation("matrix");
+
+    m_vao = new QOpenGLVertexArrayObject;
+    m_vao->create();
+    QOpenGLVertexArrayObject::Binder vaoBinder(m_vao);
+
+    m_vbo = new QOpenGLBuffer;
+    m_vbo->create();
+    m_vbo->bind();
+
+    GLfloat v[] = {
+        -0.5, 0.5, 0.5, 0.5,-0.5,0.5,-0.5,-0.5,0.5,
+        0.5, -0.5, 0.5, -0.5,0.5,0.5,0.5,0.5,0.5,
+        -0.5, -0.5, -0.5, 0.5,-0.5,-0.5,-0.5,0.5,-0.5,
+        0.5, 0.5, -0.5, -0.5,0.5,-0.5,0.5,-0.5,-0.5,
+
+        0.5, -0.5, -0.5, 0.5,-0.5,0.5,0.5,0.5,-0.5,
+        0.5, 0.5, 0.5, 0.5,0.5,-0.5,0.5,-0.5,0.5,
+        -0.5, 0.5, -0.5, -0.5,-0.5,0.5,-0.5,-0.5,-0.5,
+        -0.5, -0.5, 0.5, -0.5,0.5,-0.5,-0.5,0.5,0.5,
+
+        0.5, 0.5,  -0.5, -0.5, 0.5,  0.5,  -0.5,  0.5,  -0.5,
+        -0.5,  0.5,  0.5,  0.5,  0.5,  -0.5, 0.5, 0.5,  0.5,
+        -0.5,  -0.5, -0.5, -0.5, -0.5, 0.5,  0.5, -0.5, -0.5,
+        0.5, -0.5, 0.5,  0.5,  -0.5, -0.5, -0.5,  -0.5, 0.5
+    };
+    GLfloat texCoords[] = {
+        0.0f,0.0f, 1.0f,1.0f, 1.0f,0.0f,
+        1.0f,1.0f, 0.0f,0.0f, 0.0f,1.0f,
+        1.0f,1.0f, 1.0f,0.0f, 0.0f,1.0f,
+        0.0f,0.0f, 0.0f,1.0f, 1.0f,0.0f,
+
+        1.0f,1.0f, 1.0f,0.0f, 0.0f,1.0f,
+        0.0f,0.0f, 0.0f,1.0f, 1.0f,0.0f,
+        0.0f,0.0f, 1.0f,1.0f, 1.0f,0.0f,
+        1.0f,1.0f, 0.0f,0.0f, 0.0f,1.0f,
+
+        0.0f,1.0f, 1.0f,0.0f, 1.0f,1.0f,
+        1.0f,0.0f, 0.0f,1.0f, 0.0f,0.0f,
+        1.0f,0.0f, 1.0f,1.0f, 0.0f,0.0f,
+        0.0f,1.0f, 0.0f,0.0f, 1.0f,1.0f
+    };
+
+    const int vertexCount = 36;
+    m_vbo->allocate(sizeof(GLfloat) * vertexCount * 5);
+    m_vbo->write(0, v, sizeof(GLfloat) * vertexCount * 3);
+    m_vbo->write(sizeof(GLfloat) * vertexCount * 3, texCoords, sizeof(GLfloat) * vertexCount * 2);
+    m_vbo->release();
+
+    if (m_vao->isCreated())
+        setupVertexAttribs();
+}
+
+void CubeRenderer::resize(int w, int h)
+{
+    m_proj.setToIdentity();
+    m_proj.perspective(45, w / float(h), 0.01f, 100.0f);
+}
+
+void CubeRenderer::setupVertexAttribs()
+{
+    m_vbo->bind();
+    m_program->enableAttributeArray(0);
+    m_program->enableAttributeArray(1);
+    m_context->functions()->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
+    m_context->functions()->glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0,
+                                                  (const void *)(36 * 3 * sizeof(GLfloat)));
+    m_vbo->release();
+}
+
+void CubeRenderer::render(QWindow *w, QOpenGLContext *share, uint texture)
+{
+    if (!m_context)
+        init(w, share);
+
+    if (!m_context->makeCurrent(w))
+        return;
+
+    QOpenGLFunctions *f = m_context->functions();
+    f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    if (texture) {
+        f->glBindTexture(GL_TEXTURE_2D, texture);
+        f->glFrontFace(GL_CW); // because our cube's vertex data is such
+        f->glEnable(GL_CULL_FACE);
+        f->glEnable(GL_DEPTH_TEST);
+
+        m_program->bind();
+        QOpenGLVertexArrayObject::Binder vaoBinder(m_vao);
+        // If VAOs are not supported, set the vertex attributes every time.
+        if (!m_vao->isCreated())
+            setupVertexAttribs();
+
+        static GLfloat angle = 0;
+        QMatrix4x4 m;
+        m.translate(0, 0, -2);
+        m.rotate(90, 0, 0, 1);
+        m.rotate(angle, 0.5, 1, 0);
+        angle += 0.5f;
+
+        m_program->setUniformValue(m_matrixLoc, m_proj * m);
+
+        // Draw the cube.
+        f->glDrawArrays(GL_TRIANGLES, 0, 36);
+    }
+
+    m_context->swapBuffers(w);
+}
diff --git a/examples/quick/rendercontrol/cuberenderer.h b/examples/quick/rendercontrol/cuberenderer.h
new file mode 100644
index 0000000000..8f98376fdf
--- /dev/null
+++ b/examples/quick/rendercontrol/cuberenderer.h
@@ -0,0 +1,73 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
+**     of its contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef CUBERENDERER_H
+#define CUBERENDERER_H
+
+#include <QMatrix4x4>
+
+QT_FORWARD_DECLARE_CLASS(QOpenGLContext)
+QT_FORWARD_DECLARE_CLASS(QOpenGLShaderProgram)
+QT_FORWARD_DECLARE_CLASS(QOpenGLBuffer)
+QT_FORWARD_DECLARE_CLASS(QOpenGLVertexArrayObject)
+QT_FORWARD_DECLARE_CLASS(QWindow)
+
+class CubeRenderer
+{
+public:
+    CubeRenderer();
+    ~CubeRenderer();
+
+    void resize(int w, int h);
+    void render(QWindow *w, QOpenGLContext *share, uint texture);
+
+private:
+    void init(QWindow *w, QOpenGLContext *share);
+    void setupVertexAttribs();
+
+    QOpenGLContext *m_context;
+    QOpenGLShaderProgram *m_program;
+    QOpenGLBuffer *m_vbo;
+    QOpenGLVertexArrayObject *m_vao;
+    int m_matrixLoc;
+    QMatrix4x4 m_proj;
+};
+
+#endif
diff --git a/examples/quick/rendercontrol/main.cpp b/examples/quick/rendercontrol/main.cpp
index d362278ddf..e61eb110aa 100644
--- a/examples/quick/rendercontrol/main.cpp
+++ b/examples/quick/rendercontrol/main.cpp
@@ -39,13 +39,24 @@
 ****************************************************************************/
 
 #include <QGuiApplication>
-#include "window.h"
+#include "window_singlethreaded.h"
+#include "window_multithreaded.h"
 
 int main(int argc, char **argv)
 {
     QGuiApplication app(argc, argv);
-    Window window;
-    window.resize(1024, 768);
-    window.show();
+
+    QScopedPointer<QWindow> window;
+    if (QCoreApplication::arguments().contains(QLatin1String("--threaded"))) {
+        qWarning("Using separate Qt Quick render thread");
+        window.reset(new WindowMultiThreaded);
+    } else {
+        qWarning("Using single-threaded rendering");
+        window.reset(new WindowSingleThreaded);
+    }
+
+    window->resize(1024, 768);
+    window->show();
+
     return app.exec();
 }
diff --git a/examples/quick/rendercontrol/rendercontrol.pro b/examples/quick/rendercontrol/rendercontrol.pro
index ed25a11c1b..3301a773a4 100644
--- a/examples/quick/rendercontrol/rendercontrol.pro
+++ b/examples/quick/rendercontrol/rendercontrol.pro
@@ -2,8 +2,14 @@ TEMPLATE = app
 
 QT += quick qml
 
-SOURCES += main.cpp window.cpp
-HEADERS += window.h
+SOURCES += main.cpp \
+           window_singlethreaded.cpp \
+           window_multithreaded.cpp \
+           cuberenderer.cpp
+
+HEADERS += window_singlethreaded.h \
+           window_multithreaded.h \
+           cuberenderer.h
 
 RESOURCES += rendercontrol.qrc
 
diff --git a/examples/quick/rendercontrol/window_multithreaded.cpp b/examples/quick/rendercontrol/window_multithreaded.cpp
new file mode 100644
index 0000000000..b59b0f59da
--- /dev/null
+++ b/examples/quick/rendercontrol/window_multithreaded.cpp
@@ -0,0 +1,423 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
+**     of its contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "window_multithreaded.h"
+#include "cuberenderer.h"
+#include <QOpenGLContext>
+#include <QOpenGLFunctions>
+#include <QOpenGLFramebufferObject>
+#include <QOpenGLShaderProgram>
+#include <QOpenGLVertexArrayObject>
+#include <QOpenGLBuffer>
+#include <QOpenGLVertexArrayObject>
+#include <QOffscreenSurface>
+#include <QQmlEngine>
+#include <QQmlComponent>
+#include <QQuickItem>
+#include <QQuickWindow>
+#include <QQuickRenderControl>
+#include <QCoreApplication>
+
+/*
+  This implementation runs the Qt Quick scenegraph's sync and render phases on a
+  separate, dedicated thread.  Rendering the cube using our custom OpenGL engine
+  happens on that thread as well.  This is similar to the built-in threaded
+  render loop, but does not support all the features. There is no support for
+  getting Animators running on the render thread for example.
+
+  We choose to use QObject's event mechanism to communicate with the QObject
+  living on the render thread. An alternative would be to subclass QThread and
+  reimplement run() with a custom event handling approach, like
+  QSGThreadedRenderLoop does. That would potentially lead to better results but
+  is also more complex.
+*/
+
+static const QEvent::Type INIT = QEvent::Type(QEvent::User + 1);
+static const QEvent::Type RENDER = QEvent::Type(QEvent::User + 2);
+static const QEvent::Type RESIZE = QEvent::Type(QEvent::User + 3);
+static const QEvent::Type STOP = QEvent::Type(QEvent::User + 4);
+
+static const QEvent::Type UPDATE = QEvent::Type(QEvent::User + 5);
+
+QuickRenderer::QuickRenderer()
+    : m_fbo(0),
+      m_cubeRenderer(0),
+      m_quit(false)
+{
+}
+
+void QuickRenderer::requestInit()
+{
+    QCoreApplication::postEvent(this, new QEvent(INIT));
+}
+
+void QuickRenderer::requestRender()
+{
+    QCoreApplication::postEvent(this, new QEvent(RENDER));
+}
+
+void QuickRenderer::requestResize()
+{
+    QCoreApplication::postEvent(this, new QEvent(RESIZE));
+}
+
+void QuickRenderer::requestStop()
+{
+    QCoreApplication::postEvent(this, new QEvent(STOP));
+}
+
+bool QuickRenderer::event(QEvent *e)
+{
+    QMutexLocker lock(&m_mutex);
+
+    switch (int(e->type())) {
+    case INIT:
+        init();
+        return true;
+    case RENDER:
+        render(&lock);
+        return true;
+    case RESIZE:
+        if (m_cubeRenderer)
+            m_cubeRenderer->resize(m_window->width(), m_window->height());
+        return true;
+    case STOP:
+        cleanup();
+        return true;
+    default:
+        return QObject::event(e);
+    }
+}
+
+void QuickRenderer::init()
+{
+    m_context->makeCurrent(m_surface);
+
+    m_cubeRenderer = new CubeRenderer;
+    m_cubeRenderer->resize(m_window->width(), m_window->height());
+
+    m_renderControl->initialize(m_context);
+}
+
+void QuickRenderer::cleanup()
+{
+    m_context->makeCurrent(m_surface);
+
+    m_renderControl->invalidate();
+
+    delete m_fbo;
+    m_fbo = 0;
+
+    delete m_cubeRenderer;
+    m_cubeRenderer = 0;
+
+    m_context->doneCurrent();
+    m_context->moveToThread(QCoreApplication::instance()->thread());
+
+    m_cond.wakeOne();
+}
+
+void QuickRenderer::ensureFbo()
+{
+    if (m_fbo && m_fbo->size() != m_window->size() * m_window->devicePixelRatio()) {
+        delete m_fbo;
+        m_fbo = 0;
+    }
+
+    if (!m_fbo) {
+        m_fbo = new QOpenGLFramebufferObject(m_window->size() * m_window->devicePixelRatio(),
+                                             QOpenGLFramebufferObject::CombinedDepthStencil);
+        m_quickWindow->setRenderTarget(m_fbo);
+    }
+}
+
+void QuickRenderer::render(QMutexLocker *lock)
+{
+    Q_ASSERT(QThread::currentThread() != m_window->thread());
+
+    if (!m_context->makeCurrent(m_surface)) {
+        qWarning("Failed to make context current on render thread");
+        return;
+    }
+
+    ensureFbo();
+
+    // Synchronization and rendering happens here on the render thread.
+    m_renderControl->sync();
+
+    // The gui thread can now continue.
+    m_cond.wakeOne();
+    lock->unlock();
+
+    // Meanwhile on this thread continue with the actual rendering (into the FBO first).
+    m_renderControl->render();
+
+    // The cube renderer uses its own context, no need to bother with the state here.
+
+    // Get something onto the screen using our custom OpenGL engine.
+    QMutexLocker quitLock(&m_quitMutex);
+    if (!m_quit)
+        m_cubeRenderer->render(m_window, m_context, m_fbo->texture());
+}
+
+void QuickRenderer::aboutToQuit()
+{
+    QMutexLocker lock(&m_quitMutex);
+    m_quit = true;
+}
+
+WindowMultiThreaded::WindowMultiThreaded()
+    : m_rootItem(0),
+      m_quickInitialized(false),
+      m_psrRequested(false)
+{
+    setSurfaceType(QSurface::OpenGLSurface);
+
+    QSurfaceFormat format;
+    // Qt Quick may need a depth and stencil buffer. Always make sure these are available.
+    format.setDepthBufferSize(16);
+    format.setStencilBufferSize(8);
+    setFormat(format);
+
+    m_context = new QOpenGLContext;
+    m_context->setFormat(format);
+    m_context->create();
+
+    m_offscreenSurface = new QOffscreenSurface;
+    // Pass m_context->format(), not format. Format does not specify and color buffer
+    // sizes, while the context, that has just been created, reports a format that has
+    // these values filled in. Pass this to the offscreen surface to make sure it will be
+    // compatible with the context's configuration.
+    m_offscreenSurface->setFormat(m_context->format());
+    m_offscreenSurface->create();
+
+    m_renderControl = new QQuickRenderControl(this);
+
+    // Create a QQuickWindow that is associated with out render control. Note that this
+    // window never gets created or shown, meaning that it will never get an underlying
+    // native (platform) window.
+    m_quickWindow = new QQuickWindow(m_renderControl);
+
+    // Create a QML engine.
+    m_qmlEngine = new QQmlEngine;
+    if (!m_qmlEngine->incubationController())
+        m_qmlEngine->setIncubationController(m_quickWindow->incubationController());
+
+    m_quickRenderer = new QuickRenderer;
+    m_quickRenderer->setContext(m_context);
+
+    // These live on the gui thread. Just give access to them on the render thread.
+    m_quickRenderer->setSurface(m_offscreenSurface);
+    m_quickRenderer->setWindow(this);
+    m_quickRenderer->setQuickWindow(m_quickWindow);
+    m_quickRenderer->setRenderControl(m_renderControl);
+
+    m_quickRendererThread = new QThread;
+
+    // Notify the render control that some scenegraph internals have to live on
+    // m_quickRenderThread.
+    m_renderControl->prepareThread(m_quickRendererThread);
+
+    // The QOpenGLContext and the QObject representing the rendering logic on
+    // the render thread must live on that thread.
+    m_context->moveToThread(m_quickRendererThread);
+    m_quickRenderer->moveToThread(m_quickRendererThread);
+
+    m_quickRendererThread->start();
+
+    // Now hook up the signals. For simplicy we don't differentiate
+    // between renderRequested (only render is needed, no sync) and
+    // sceneChanged (polish and sync is needed too).
+    connect(m_renderControl, &QQuickRenderControl::renderRequested, this, &WindowMultiThreaded::requestUpdate);
+    connect(m_renderControl, &QQuickRenderControl::sceneChanged, this, &WindowMultiThreaded::requestUpdate);
+}
+
+WindowMultiThreaded::~WindowMultiThreaded()
+{
+    // Release resources and move the context ownership back to this thread.
+    m_quickRenderer->mutex()->lock();
+    m_quickRenderer->requestStop();
+    m_quickRenderer->cond()->wait(m_quickRenderer->mutex());
+    m_quickRenderer->mutex()->unlock();
+
+    m_quickRendererThread->quit();
+    m_quickRendererThread->wait();
+
+    delete m_renderControl;
+    delete m_qmlComponent;
+    delete m_quickWindow;
+    delete m_qmlEngine;
+
+    delete m_offscreenSurface;
+    delete m_context;
+}
+
+void WindowMultiThreaded::requestUpdate()
+{
+    if (m_quickInitialized && !m_psrRequested) {
+        m_psrRequested = true;
+        QCoreApplication::postEvent(this, new QEvent(UPDATE));
+    }
+}
+
+bool WindowMultiThreaded::event(QEvent *e)
+{
+    if (e->type() == UPDATE) {
+        polishSyncAndRender();
+        m_psrRequested = false;
+        return true;
+    } else if (e->type() == QEvent::Close) {
+        // Avoid rendering on the render thread when the window is about to
+        // close. Once a QWindow is closed, the underlying platform window will
+        // go away, even though the QWindow instance itself is still
+        // valid. Operations like swapBuffers() are futile and only result in
+        // warnings afterwards. Prevent this.
+        m_quickRenderer->aboutToQuit();
+    }
+    return QWindow::event(e);
+}
+
+void WindowMultiThreaded::polishSyncAndRender()
+{
+    Q_ASSERT(QThread::currentThread() == thread());
+
+    // Polishing happens on the gui thread.
+    m_renderControl->polishItems();
+    // Sync happens on the render thread with the gui thread (this one) blocked.
+    QMutexLocker lock(m_quickRenderer->mutex());
+    m_quickRenderer->requestRender();
+    // Wait until sync is complete.
+    m_quickRenderer->cond()->wait(m_quickRenderer->mutex());
+    // Rendering happens on the render thread without blocking the gui (main)
+    // thread. This is good because the blocking swap (waiting for vsync)
+    // happens on the render thread, not blocking other work.
+}
+
+void WindowMultiThreaded::run()
+{
+    disconnect(m_qmlComponent, SIGNAL(statusChanged(QQmlComponent::Status)), this, SLOT(run()));
+
+    if (m_qmlComponent->isError()) {
+        QList<QQmlError> errorList = m_qmlComponent->errors();
+        foreach (const QQmlError &error, errorList)
+            qWarning() << error.url() << error.line() << error;
+        return;
+    }
+
+    QObject *rootObject = m_qmlComponent->create();
+    if (m_qmlComponent->isError()) {
+        QList<QQmlError> errorList = m_qmlComponent->errors();
+        foreach (const QQmlError &error, errorList)
+            qWarning() << error.url() << error.line() << error;
+        return;
+    }
+
+    m_rootItem = qobject_cast<QQuickItem *>(rootObject);
+    if (!m_rootItem) {
+        qWarning("run: Not a QQuickItem");
+        delete rootObject;
+        return;
+    }
+
+    // The root item is ready. Associate it with the window.
+    m_rootItem->setParentItem(m_quickWindow->contentItem());
+
+    // Update item and rendering related geometries.
+    updateSizes();
+
+    m_quickInitialized = true;
+
+    // Initialize the render thread and perform the first polish/sync/render.
+    m_quickRenderer->requestInit();
+    polishSyncAndRender();
+}
+
+void WindowMultiThreaded::updateSizes()
+{
+    // Behave like SizeRootObjectToView.
+    m_rootItem->setWidth(width());
+    m_rootItem->setHeight(height());
+
+    m_quickWindow->setGeometry(0, 0, width(), height());
+}
+
+void WindowMultiThreaded::startQuick(const QString &filename)
+{
+    m_qmlComponent = new QQmlComponent(m_qmlEngine, QUrl(filename));
+    if (m_qmlComponent->isLoading())
+        connect(m_qmlComponent, &QQmlComponent::statusChanged, this, &WindowMultiThreaded::run);
+    else
+        run();
+}
+
+void WindowMultiThreaded::exposeEvent(QExposeEvent *)
+{
+    if (isExposed()) {
+        if (!m_quickInitialized)
+            startQuick(QStringLiteral("qrc:/rendercontrol/demo.qml"));
+    }
+}
+
+void WindowMultiThreaded::resizeEvent(QResizeEvent *)
+{
+    // If this is a resize after the scene is up and running, recreate the fbo and the
+    // Quick item and scene.
+    if (m_rootItem) {
+        updateSizes();
+        m_quickRenderer->requestResize();
+        polishSyncAndRender();
+    }
+}
+
+void WindowMultiThreaded::mousePressEvent(QMouseEvent *e)
+{
+    // Use the constructor taking localPos and screenPos. That puts localPos into the
+    // event's localPos and windowPos, and screenPos into the event's screenPos. This way
+    // the windowPos in e is ignored and is replaced by localPos. This is necessary
+    // because QQuickWindow thinks of itself as a top-level window always.
+    QMouseEvent mappedEvent(e->type(), e->localPos(), e->screenPos(), e->button(), e->buttons(), e->modifiers());
+    QCoreApplication::sendEvent(m_quickWindow, &mappedEvent);
+}
+
+void WindowMultiThreaded::mouseReleaseEvent(QMouseEvent *e)
+{
+    QMouseEvent mappedEvent(e->type(), e->localPos(), e->screenPos(), e->button(), e->buttons(), e->modifiers());
+    QCoreApplication::sendEvent(m_quickWindow, &mappedEvent);
+}
diff --git a/examples/quick/rendercontrol/window_multithreaded.h b/examples/quick/rendercontrol/window_multithreaded.h
new file mode 100644
index 0000000000..74eab1a963
--- /dev/null
+++ b/examples/quick/rendercontrol/window_multithreaded.h
@@ -0,0 +1,142 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
+**     of its contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef WINDOW_MULTITHREADED_H
+#define WINDOW_MULTITHREADED_H
+
+#include <QWindow>
+#include <QMatrix4x4>
+#include <QThread>
+#include <QWaitCondition>
+#include <QMutex>
+
+QT_FORWARD_DECLARE_CLASS(QOpenGLContext)
+QT_FORWARD_DECLARE_CLASS(QOpenGLFramebufferObject)
+QT_FORWARD_DECLARE_CLASS(QOffscreenSurface)
+QT_FORWARD_DECLARE_CLASS(QQuickRenderControl)
+QT_FORWARD_DECLARE_CLASS(QQuickWindow)
+QT_FORWARD_DECLARE_CLASS(QQmlEngine)
+QT_FORWARD_DECLARE_CLASS(QQmlComponent)
+QT_FORWARD_DECLARE_CLASS(QQuickItem)
+
+class CubeRenderer;
+
+class QuickRenderer : public QObject
+{
+    Q_OBJECT
+
+public:
+    QuickRenderer();
+
+    void requestInit();
+    void requestRender();
+    void requestResize();
+    void requestStop();
+
+    QWaitCondition *cond() { return &m_cond; }
+    QMutex *mutex() { return &m_mutex; }
+
+    void setContext(QOpenGLContext *ctx) { m_context = ctx; }
+    void setSurface(QOffscreenSurface *s) { m_surface = s; }
+    void setWindow(QWindow *w) { m_window = w; }
+    void setQuickWindow(QQuickWindow *w) { m_quickWindow = w; }
+    void setRenderControl(QQuickRenderControl *r) { m_renderControl = r; }
+
+    void aboutToQuit();
+
+private:
+    bool event(QEvent *e) Q_DECL_OVERRIDE;
+    void init();
+    void cleanup();
+    void ensureFbo();
+    void render(QMutexLocker *lock);
+
+    QWaitCondition m_cond;
+    QMutex m_mutex;
+    QOpenGLContext *m_context;
+    QOffscreenSurface *m_surface;
+    QOpenGLFramebufferObject *m_fbo;
+    QWindow *m_window;
+    QQuickWindow *m_quickWindow;
+    QQuickRenderControl *m_renderControl;
+    CubeRenderer *m_cubeRenderer;
+    QMutex m_quitMutex;
+    bool m_quit;
+};
+
+class WindowMultiThreaded : public QWindow
+{
+    Q_OBJECT
+
+public:
+    WindowMultiThreaded();
+    ~WindowMultiThreaded();
+
+protected:
+    void exposeEvent(QExposeEvent *e) Q_DECL_OVERRIDE;
+    void resizeEvent(QResizeEvent *e) Q_DECL_OVERRIDE;
+    void mousePressEvent(QMouseEvent *e) Q_DECL_OVERRIDE;
+    void mouseReleaseEvent(QMouseEvent *e) Q_DECL_OVERRIDE;
+    bool event(QEvent *e) Q_DECL_OVERRIDE;
+
+private slots:
+    void run();
+    void requestUpdate();
+    void polishSyncAndRender();
+
+private:
+    void startQuick(const QString &filename);
+    void updateSizes();
+
+    QuickRenderer *m_quickRenderer;
+    QThread *m_quickRendererThread;
+
+    QOpenGLContext *m_context;
+    QOffscreenSurface *m_offscreenSurface;
+    QQuickRenderControl *m_renderControl;
+    QQuickWindow *m_quickWindow;
+    QQmlEngine *m_qmlEngine;
+    QQmlComponent *m_qmlComponent;
+    QQuickItem *m_rootItem;
+    bool m_quickInitialized;
+    bool m_psrRequested;
+};
+
+#endif
diff --git a/examples/quick/rendercontrol/window.cpp b/examples/quick/rendercontrol/window_singlethreaded.cpp
index 4813936538..993c508c0a 100644
--- a/examples/quick/rendercontrol/window.cpp
+++ b/examples/quick/rendercontrol/window_singlethreaded.cpp
@@ -38,7 +38,8 @@
 **
 ****************************************************************************/
 
-#include "window.h"
+#include "window_singlethreaded.h"
+#include "cuberenderer.h"
 #include <QOpenGLContext>
 #include <QOpenGLFunctions>
 #include <QOpenGLFramebufferObject>
@@ -54,11 +55,9 @@
 #include <QQuickRenderControl>
 #include <QCoreApplication>
 
-Window::Window()
+WindowSingleThreaded::WindowSingleThreaded()
     : m_rootItem(0),
       m_fbo(0),
-      m_program(0),
-      m_vbo(0),
       m_quickInitialized(false),
       m_quickReady(false)
 {
@@ -82,6 +81,8 @@ Window::Window()
     m_offscreenSurface->setFormat(m_context->format());
     m_offscreenSurface->create();
 
+    m_cubeRenderer = new CubeRenderer;
+
     m_renderControl = new QQuickRenderControl(this);
 
     // Create a QQuickWindow that is associated with out render control. Note that this
@@ -98,18 +99,18 @@ Window::Window()
     // a timer with a small interval is used to get better performance.
     m_updateTimer.setSingleShot(true);
     m_updateTimer.setInterval(5);
-    connect(&m_updateTimer, &QTimer::timeout, this, &Window::updateQuick);
+    connect(&m_updateTimer, &QTimer::timeout, this, &WindowSingleThreaded::render);
 
     // Now hook up the signals. For simplicy we don't differentiate between
     // renderRequested (only render is needed, no sync) and sceneChanged (polish and sync
     // is needed too).
-    connect(m_quickWindow, &QQuickWindow::sceneGraphInitialized, this, &Window::createFbo);
-    connect(m_quickWindow, &QQuickWindow::sceneGraphInvalidated, this, &Window::destroyFbo);
-    connect(m_renderControl, &QQuickRenderControl::renderRequested, this, &Window::requestUpdate);
-    connect(m_renderControl, &QQuickRenderControl::sceneChanged, this, &Window::requestUpdate);
+    connect(m_quickWindow, &QQuickWindow::sceneGraphInitialized, this, &WindowSingleThreaded::createFbo);
+    connect(m_quickWindow, &QQuickWindow::sceneGraphInvalidated, this, &WindowSingleThreaded::destroyFbo);
+    connect(m_renderControl, &QQuickRenderControl::renderRequested, this, &WindowSingleThreaded::requestUpdate);
+    connect(m_renderControl, &QQuickRenderControl::sceneChanged, this, &WindowSingleThreaded::requestUpdate);
 }
 
-Window::~Window()
+WindowSingleThreaded::~WindowSingleThreaded()
 {
     // Make sure the context is current while doing cleanup. Note that we use the
     // offscreen surface here because passing 'this' at this point is not safe: the
@@ -125,17 +126,16 @@ Window::~Window()
     delete m_quickWindow;
     delete m_qmlEngine;
     delete m_fbo;
-    delete m_program;
-    delete m_vbo;
-    delete m_vao;
 
     m_context->doneCurrent();
 
     delete m_offscreenSurface;
     delete m_context;
+
+    delete m_cubeRenderer;
 }
 
-void Window::createFbo()
+void WindowSingleThreaded::createFbo()
 {
     // The scene graph has been initialized. It is now time to create an FBO and associate
     // it with the QQuickWindow.
@@ -143,19 +143,41 @@ void Window::createFbo()
     m_quickWindow->setRenderTarget(m_fbo);
 }
 
-void Window::destroyFbo()
+void WindowSingleThreaded::destroyFbo()
 {
     delete m_fbo;
     m_fbo = 0;
 }
 
-void Window::requestUpdate()
+void WindowSingleThreaded::render()
+{
+    if (!m_context->makeCurrent(m_offscreenSurface))
+        return;
+
+    // Polish, synchronize and render the next frame (into our fbo).  In this example
+    // everything happens on the same thread and therefore all three steps are performed
+    // in succession from here. In a threaded setup the render() call would happen on a
+    // separate thread.
+    m_renderControl->polishItems();
+    m_renderControl->sync();
+    m_renderControl->render();
+
+    m_quickWindow->resetOpenGLState();
+    QOpenGLFramebufferObject::bindDefault();
+
+    m_quickReady = true;
+
+    // Get something onto the screen.
+    m_cubeRenderer->render(this, m_context, m_quickReady ? m_fbo->texture() : 0);
+}
+
+void WindowSingleThreaded::requestUpdate()
 {
     if (!m_updateTimer.isActive())
         m_updateTimer.start();
 }
 
-void Window::run()
+void WindowSingleThreaded::run()
 {
     disconnect(m_qmlComponent, SIGNAL(statusChanged(QQmlComponent::Status)), this, SLOT(run()));
 
@@ -190,89 +212,10 @@ void Window::run()
     // Initialize the render control and our OpenGL resources.
     m_context->makeCurrent(m_offscreenSurface);
     m_renderControl->initialize(m_context);
-
-    static const char *vertexShaderSource =
-        "attribute highp vec4 vertex;\n"
-        "attribute lowp vec2 coord;\n"
-        "varying lowp vec2 v_coord;\n"
-        "uniform highp mat4 matrix;\n"
-        "void main() {\n"
-        "   v_coord = coord;\n"
-        "   gl_Position = matrix * vertex;\n"
-        "}\n";
-    static const char *fragmentShaderSource =
-        "varying lowp vec2 v_coord;\n"
-        "uniform sampler2D sampler;\n"
-        "void main() {\n"
-        "   gl_FragColor = vec4(texture2D(sampler, v_coord).rgb, 1.0);\n"
-        "}\n";
-    m_program = new QOpenGLShaderProgram;
-    m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource);
-    m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource);
-    m_program->bindAttributeLocation("vertex", 0);
-    m_program->bindAttributeLocation("coord", 1);
-    m_program->link();
-    m_matrixLoc = m_program->uniformLocation("matrix");
-
-    m_vao = new QOpenGLVertexArrayObject;
-    m_vao->create();
-    m_vao->bind();
-
-    m_vbo = new QOpenGLBuffer;
-    m_vbo->create();
-    m_vbo->bind();
-
-    GLfloat v[] = {
-        -0.5, 0.5, 0.5, 0.5,-0.5,0.5,-0.5,-0.5,0.5,
-        0.5, -0.5, 0.5, -0.5,0.5,0.5,0.5,0.5,0.5,
-        -0.5, -0.5, -0.5, 0.5,-0.5,-0.5,-0.5,0.5,-0.5,
-        0.5, 0.5, -0.5, -0.5,0.5,-0.5,0.5,-0.5,-0.5,
-
-        0.5, -0.5, -0.5, 0.5,-0.5,0.5,0.5,0.5,-0.5,
-        0.5, 0.5, 0.5, 0.5,0.5,-0.5,0.5,-0.5,0.5,
-        -0.5, 0.5, -0.5, -0.5,-0.5,0.5,-0.5,-0.5,-0.5,
-        -0.5, -0.5, 0.5, -0.5,0.5,-0.5,-0.5,0.5,0.5,
-
-        0.5, 0.5,  -0.5, -0.5, 0.5,  0.5,  -0.5,  0.5,  -0.5,
-        -0.5,  0.5,  0.5,  0.5,  0.5,  -0.5, 0.5, 0.5,  0.5,
-        -0.5,  -0.5, -0.5, -0.5, -0.5, 0.5,  0.5, -0.5, -0.5,
-        0.5, -0.5, 0.5,  0.5,  -0.5, -0.5, -0.5,  -0.5, 0.5
-    };
-    GLfloat texCoords[] = {
-        0.0f,0.0f, 1.0f,1.0f, 1.0f,0.0f,
-        1.0f,1.0f, 0.0f,0.0f, 0.0f,1.0f,
-        1.0f,1.0f, 1.0f,0.0f, 0.0f,1.0f,
-        0.0f,0.0f, 0.0f,1.0f, 1.0f,0.0f,
-
-        1.0f,1.0f, 1.0f,0.0f, 0.0f,1.0f,
-        0.0f,0.0f, 0.0f,1.0f, 1.0f,0.0f,
-        0.0f,0.0f, 1.0f,1.0f, 1.0f,0.0f,
-        1.0f,1.0f, 0.0f,0.0f, 0.0f,1.0f,
-
-        0.0f,1.0f, 1.0f,0.0f, 1.0f,1.0f,
-        1.0f,0.0f, 0.0f,1.0f, 0.0f,0.0f,
-        1.0f,0.0f, 1.0f,1.0f, 0.0f,0.0f,
-        0.0f,1.0f, 0.0f,0.0f, 1.0f,1.0f
-    };
-
-    const int vertexCount = 36;
-    m_vbo->allocate(sizeof(GLfloat) * vertexCount * 5);
-    m_vbo->write(0, v, sizeof(GLfloat) * vertexCount * 3);
-    m_vbo->write(sizeof(GLfloat) * vertexCount * 3, texCoords, sizeof(GLfloat) * vertexCount * 2);
-    m_vbo->release();
-
-    if (m_vao->isCreated())
-        setupVertexAttribs();
-
-    // Must unbind before changing the current context. Hence the absence of
-    // QOpenGLVertexArrayObject::Binder here.
-    m_vao->release();
-
-    m_context->doneCurrent();
     m_quickInitialized = true;
 }
 
-void Window::updateSizes()
+void WindowSingleThreaded::updateSizes()
 {
     // Behave like SizeRootObjectToView.
     m_rootItem->setWidth(width());
@@ -280,40 +223,28 @@ void Window::updateSizes()
 
     m_quickWindow->setGeometry(0, 0, width(), height());
 
-    m_proj.setToIdentity();
-    m_proj.perspective(45, width() / float(height()), 0.01f, 100.0f);
-}
-
-void Window::setupVertexAttribs()
-{
-    m_vbo->bind();
-    m_program->enableAttributeArray(0);
-    m_program->enableAttributeArray(1);
-    m_context->functions()->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
-    m_context->functions()->glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0,
-                                                  (const void *)(36 * 3 * sizeof(GLfloat)));
-    m_vbo->release();
+    m_cubeRenderer->resize(width(), height());
 }
 
-void Window::startQuick(const QString &filename)
+void WindowSingleThreaded::startQuick(const QString &filename)
 {
     m_qmlComponent = new QQmlComponent(m_qmlEngine, QUrl(filename));
     if (m_qmlComponent->isLoading())
-        connect(m_qmlComponent, &QQmlComponent::statusChanged, this, &Window::run);
+        connect(m_qmlComponent, &QQmlComponent::statusChanged, this, &WindowSingleThreaded::run);
     else
         run();
 }
 
-void Window::exposeEvent(QExposeEvent *)
+void WindowSingleThreaded::exposeEvent(QExposeEvent *)
 {
     if (isExposed()) {
-        render();
+        m_cubeRenderer->render(this, m_context, m_quickReady ? m_fbo->texture() : 0);
         if (!m_quickInitialized)
             startQuick(QStringLiteral("qrc:/rendercontrol/demo.qml"));
     }
 }
 
-void Window::resizeEvent(QResizeEvent *)
+void WindowSingleThreaded::resizeEvent(QResizeEvent *)
 {
     // If this is a resize after the scene is up and running, recreate the fbo and the
     // Quick item and scene.
@@ -325,71 +256,7 @@ void Window::resizeEvent(QResizeEvent *)
     }
 }
 
-void Window::updateQuick()
-{
-    if (!m_context->makeCurrent(m_offscreenSurface))
-        return;
-
-    // Polish, synchronize and render the next frame (into our fbo).  In this example
-    // everything happens on the same thread and therefore all three steps are performed
-    // in succession from here. In a threaded setup the render() call would happen on a
-    // separate thread.
-    m_renderControl->polishItems();
-    m_renderControl->sync();
-    m_renderControl->render();
-
-    m_quickWindow->resetOpenGLState();
-    QOpenGLFramebufferObject::bindDefault();
-
-    m_quickReady = true;
-
-    // Get something onto the screen.
-    render();
-}
-
-void Window::render()
-{
-    if (!m_context->makeCurrent(this))
-        return;
-
-    QOpenGLFunctions *f = m_context->functions();
-    f->glClearColor(0.0f, 0.1f, 0.25f, 1.0f);
-    f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-
-    if (m_quickReady) {
-        f->glFrontFace(GL_CW); // because our cube's vertex data is such
-        f->glEnable(GL_CULL_FACE);
-        f->glEnable(GL_DEPTH_TEST);
-
-        f->glBindTexture(GL_TEXTURE_2D, m_fbo->texture());
-
-        m_program->bind();
-        QOpenGLVertexArrayObject::Binder vaoBinder(m_vao);
-        // If VAOs are not supported, set the vertex attributes every time.
-        if (!m_vao->isCreated())
-            setupVertexAttribs();
-
-        static GLfloat angle = 0;
-        QMatrix4x4 m;
-        m.translate(0, 0, -2);
-        m.rotate(90, 0, 0, 1);
-        m.rotate(angle, 0.5, 1, 0);
-        angle += 0.5f;
-
-        m_program->setUniformValue(m_matrixLoc, m_proj * m);
-
-        // Draw the cube.
-        f->glDrawArrays(GL_TRIANGLES, 0, 36);
-
-        m_program->release();
-        f->glDisable(GL_DEPTH_TEST);
-        f->glDisable(GL_CULL_FACE);
-    }
-
-    m_context->swapBuffers(this);
-}
-
-void Window::mousePressEvent(QMouseEvent *e)
+void WindowSingleThreaded::mousePressEvent(QMouseEvent *e)
 {
     // Use the constructor taking localPos and screenPos. That puts localPos into the
     // event's localPos and windowPos, and screenPos into the event's screenPos. This way
@@ -399,7 +266,7 @@ void Window::mousePressEvent(QMouseEvent *e)
     QCoreApplication::sendEvent(m_quickWindow, &mappedEvent);
 }
 
-void Window::mouseReleaseEvent(QMouseEvent *e)
+void WindowSingleThreaded::mouseReleaseEvent(QMouseEvent *e)
 {
     QMouseEvent mappedEvent(e->type(), e->localPos(), e->screenPos(), e->button(), e->buttons(), e->modifiers());
     QCoreApplication::sendEvent(m_quickWindow, &mappedEvent);
diff --git a/examples/quick/rendercontrol/window.h b/examples/quick/rendercontrol/window_singlethreaded.h
index 2723aeb011..3ff98423ac 100644
--- a/examples/quick/rendercontrol/window.h
+++ b/examples/quick/rendercontrol/window_singlethreaded.h
@@ -38,15 +38,15 @@
 **
 ****************************************************************************/
 
+#ifndef WINDOW_SINGLETHREADED_H
+#define WINDOW_SINGLETHREADED_H
+
 #include <QWindow>
 #include <QMatrix4x4>
 #include <QTimer>
 
 QT_FORWARD_DECLARE_CLASS(QOpenGLContext)
 QT_FORWARD_DECLARE_CLASS(QOpenGLFramebufferObject)
-QT_FORWARD_DECLARE_CLASS(QOpenGLShaderProgram)
-QT_FORWARD_DECLARE_CLASS(QOpenGLBuffer)
-QT_FORWARD_DECLARE_CLASS(QOpenGLVertexArrayObject)
 QT_FORWARD_DECLARE_CLASS(QOffscreenSurface)
 QT_FORWARD_DECLARE_CLASS(QQuickRenderControl)
 QT_FORWARD_DECLARE_CLASS(QQuickWindow)
@@ -54,13 +54,15 @@ QT_FORWARD_DECLARE_CLASS(QQmlEngine)
 QT_FORWARD_DECLARE_CLASS(QQmlComponent)
 QT_FORWARD_DECLARE_CLASS(QQuickItem)
 
-class Window : public QWindow
+class CubeRenderer;
+
+class WindowSingleThreaded : public QWindow
 {
     Q_OBJECT
 
 public:
-    Window();
-    ~Window();
+    WindowSingleThreaded();
+    ~WindowSingleThreaded();
 
 protected:
     void exposeEvent(QExposeEvent *e) Q_DECL_OVERRIDE;
@@ -69,16 +71,15 @@ protected:
     void mouseReleaseEvent(QMouseEvent *e) Q_DECL_OVERRIDE;
 
 private slots:
-    void render();
-    void updateQuick();
     void run();
+
     void createFbo();
     void destroyFbo();
+    void render();
     void requestUpdate();
 
 private:
     void startQuick(const QString &filename);
-    void setupVertexAttribs();
     void updateSizes();
 
     QOpenGLContext *m_context;
@@ -89,12 +90,10 @@ private:
     QQmlComponent *m_qmlComponent;
     QQuickItem *m_rootItem;
     QOpenGLFramebufferObject *m_fbo;
-    QOpenGLShaderProgram *m_program;
-    QOpenGLBuffer *m_vbo;
-    QOpenGLVertexArrayObject *m_vao;
     bool m_quickInitialized;
     bool m_quickReady;
-    int m_matrixLoc;
-    QMatrix4x4 m_proj;
     QTimer m_updateTimer;
+    CubeRenderer *m_cubeRenderer;
 };
+
+#endif