Modernize the OpenGL examples

Change them to use QOpenGLWidget and QOpenGLTexture.
Advocate also the usage of VBOs.

Hopeless examples, that rely on the fixed pipeline and will
not compile or work in ES and dynamic builds, are moved to
a "legacy" directory. The documentation pages for these are
removed. This long due change avoids the confusion newcomers
experience when trying to get started with Qt 5 and OpenGL.

hellowindow's behavior is changed to open a single window only
by default. The old default behavior, that opened three windows
on platforms that supported both MultipleWindows & ThreadedOpenGL,
can be requested by passing --multiple. --single is removed since it
is the default now. This plays much nicer with drivers that have
issues with threading.

In addition, say hello to hellogl2.

This is the old hellogl example updated to use QOpenGLWidget and
OpenGL 2. It also has a mainwindow with multiple (un)dockable widgets
containing the OpenGL widgets. This helps testing the behavior when
the top-level of the QOpenGLWidget changes and provides a very
important example of how to do proper resource management in this case.
(must use aboutToBeDestroyed() of the context, since the context goes
away and is replaced by a new one on every dock/undock)

As a bonus, the logo is now real 3D, no more orthographic nonsense.

Launch with --multisample to request 4x MSAA.

Launch with --coreprofile to request 3.2 Core. In this particular example
the shaders are present in both versions and there is a VAO so the application
is functional with core profile contexts.

Change-Id: Id780a80cb0708ef164cc172450ed74050f065596
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>

8 files changed, 899 insertions, 0 deletions

diff --git a/examples/opengl/legacy/pbuffers/cube.cpp b/examples/opengl/legacy/pbuffers/cube.cpp
new file mode 100644
index 0000000000..dc1bb23fea
--- /dev/null
+++ b/examples/opengl/legacy/pbuffers/cube.cpp
@@ -0,0 +1,328 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 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 "cube.h"
+#include "glwidget.h"
+
+#include <QtGui/QImage>
+#include <QtCore/QPropertyAnimation>
+
+static const qreal speeds[] = { 3.8f, 4.4f, 5.6f };
+static const qreal amplitudes[] = { 2.0f, 2.5f, 3.0f };
+
+static inline void qSetColor(float colorVec[], QColor c)
+{
+    colorVec[0] = c.redF();
+    colorVec[1] = c.greenF();
+    colorVec[2] = c.blueF();
+    colorVec[3] = c.alphaF();
+}
+
+int Geometry::append(const QVector3D &a, const QVector3D &n, const QVector2D &t)
+{
+    int v = vertices.count();
+    vertices.append(a);
+    normals.append(n);
+    texCoords.append(t);
+    faces.append(v);
+    colors.append(QVector4D(0.6f, 0.6f, 0.6f, 1.0f));
+    return v;
+}
+
+void Geometry::addQuad(const QVector3D &a, const QVector3D &b,
+                           const QVector3D &c, const QVector3D &d,
+                           const QVector<QVector2D> &tex)
+{
+    QVector3D norm = QVector3D::normal(a, b, c);
+    // append first triangle
+    int aref = append(a, norm, tex[0]);
+    append(b, norm, tex[1]);
+    int cref = append(c, norm, tex[2]);
+    // append second triangle
+    faces.append(aref);
+    faces.append(cref);
+    append(d, norm, tex[3]);
+}
+
+void Geometry::loadArrays() const
+{
+    glEnableClientState(GL_VERTEX_ARRAY);
+    glEnableClientState(GL_NORMAL_ARRAY);
+    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+    glEnableClientState(GL_COLOR_ARRAY);
+    glVertexPointer(3, GL_FLOAT, 0, vertices.constData());
+    glNormalPointer(GL_FLOAT, 0, normals.constData());
+    glTexCoordPointer(2, GL_FLOAT, 0, texCoords.constData());
+    glColorPointer(4, GL_FLOAT, 0, colors.constData());
+}
+
+void Geometry::setColors(int start, GLfloat colorArray[4][4])
+{
+    int off = faces[start];
+    for (int i = 0; i < 4; ++i)
+        colors[i + off] = QVector4D(colorArray[i][0],
+                                      colorArray[i][1],
+                                      colorArray[i][2],
+                                      colorArray[i][3]);
+}
+
+Tile::Tile(const QVector3D &loc)
+    : location(loc)
+    , start(0)
+    , count(0)
+    , useFlatColor(false)
+    , geom(0)
+{
+    qSetColor(faceColor, QColor(Qt::darkGray));
+}
+
+void Tile::setColors(GLfloat colorArray[4][4])
+{
+    useFlatColor = true;
+    geom->setColors(start, colorArray);
+}
+
+void Tile::draw() const
+{
+    QMatrix4x4 mat;
+    mat.translate(location);
+    mat.rotate(orientation);
+    glMatrixMode(GL_MODELVIEW);
+    glPushMatrix();
+    glMultMatrixf(mat.constData());
+    glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, faceColor);
+    glDrawElements(GL_TRIANGLES, count, GL_UNSIGNED_SHORT, geom->indices() + start);
+    glPopMatrix();
+}
+
+TileBuilder::TileBuilder(Geometry *g, qreal depth, qreal size)
+    : verts(4)
+    , tex(4)
+    , start(g->count())
+    , count(0)
+    , geom(g)
+{
+    // front face - make a square with bottom-left at origin
+    verts[br].setX(size);
+    verts[tr].setX(size);
+    verts[tr].setY(size);
+    verts[tl].setY(size);
+
+    // these vert numbers are good for the tex-coords
+    for (int i = 0; i < 4; ++i)
+        tex[i] = verts[i].toVector2D();
+
+    // now move verts half cube width across so cube is centered on origin
+    for (int i = 0; i < 4; ++i)
+        verts[i] -= QVector3D(size / 2.0f, size / 2.0f, -depth);
+
+    // add the front face
+    g->addQuad(verts[bl], verts[br], verts[tr], verts[tl], tex);
+
+    count = g->count() - start;
+}
+
+void TileBuilder::initialize(Tile *tile) const
+{
+    tile->start = start;
+    tile->count = count;
+    tile->geom = geom;
+    qSetColor(tile->faceColor, color);
+}
+
+Tile *TileBuilder::newTile(const QVector3D &loc) const
+{
+    Tile *tile = new Tile(loc);
+    initialize(tile);
+    return tile;
+}
+
+Cube::Cube(const QVector3D &loc)
+    : Tile(loc)
+    , rot(0.0f)
+    , r(0)
+    , animGroup(0)
+{
+}
+
+Cube::~Cube()
+{
+}
+
+void Cube::setAltitude(qreal a)
+{
+    if (location.y() != a)
+    {
+        location.setY(a);
+        emit changed();
+    }
+}
+
+void Cube::setRange(qreal r)
+{
+    if (location.x() != r)
+    {
+        location.setX(r);
+        emit changed();
+    }
+}
+
+void Cube::setRotation(qreal r)
+{
+    if (r != rot)
+    {
+        orientation = QQuaternion::fromAxisAndAngle(QVector3D(1.0f, 1.0f, 1.0f), r);
+        emit changed();
+    }
+}
+
+void Cube::removeBounce()
+{
+    delete animGroup;
+    animGroup = 0;
+    delete r;
+    r = 0;
+}
+
+void Cube::startAnimation()
+{
+    if (r)
+    {
+        r->start();
+        r->setCurrentTime(startx);
+    }
+    if (animGroup)
+        animGroup->start();
+    if (rtn)
+        rtn->start();
+}
+
+void Cube::setAnimationPaused(bool paused)
+{
+    if (paused)
+    {
+        if (r)
+            r->pause();
+        if (animGroup)
+            animGroup->pause();
+        if (rtn)
+            rtn->pause();
+    }
+    else
+    {
+        if (r)
+            r->resume();
+        if (animGroup)
+            animGroup->resume();
+        if (rtn)
+            rtn->resume();
+    }
+}
+
+CubeBuilder::CubeBuilder(Geometry *g, qreal depth, qreal size)
+    : TileBuilder(g, depth)
+    , ix(0)
+{
+    for (int i = 0; i < 4; ++i)
+        verts[i].setZ(size / 2.0f);
+    // back face - "extrude" verts down
+    QVector<QVector3D> back(verts);
+    for (int i = 0; i < 4; ++i)
+        back[i].setZ(-size / 2.0f);
+
+    // add the back face
+    g->addQuad(back[br], back[bl], back[tl], back[tr], tex);
+
+    // add the sides
+    g->addQuad(back[bl], back[br], verts[br], verts[bl], tex);
+    g->addQuad(back[br], back[tr], verts[tr], verts[br], tex);
+    g->addQuad(back[tr], back[tl], verts[tl], verts[tr], tex);
+    g->addQuad(back[tl], back[bl], verts[bl], verts[tl], tex);
+
+    count = g->count() - start;
+}
+
+Cube *CubeBuilder::newCube(const QVector3D &loc) const
+{
+    Cube *c = new Cube(loc);
+    initialize(c);
+    qreal d = 4000.0f;
+    qreal d3 = d / 3.0f;
+    // Animate movement from left to right
+    c->r = new QPropertyAnimation(c, "range");
+    c->r->setStartValue(-1.3f);
+    c->r->setEndValue(1.3f);
+    c->startx = ix * d3 * 3.0f;
+    c->r->setDuration(d * 4.0f);
+    c->r->setLoopCount(-1);
+    c->r->setEasingCurve(QEasingCurve(QEasingCurve::CosineCurve));
+
+    c->animGroup = new QSequentialAnimationGroup(c);
+
+    // Animate movement from bottom to top
+    QPropertyAnimation *a_up = new QPropertyAnimation(c, "altitude", c->animGroup);
+    a_up->setEndValue(loc.y());
+    a_up->setStartValue(loc.y() + amplitudes[ix]);
+    a_up->setDuration(d / speeds[ix]);
+    a_up->setLoopCount(1);
+    a_up->setEasingCurve(QEasingCurve(QEasingCurve::InQuad));
+
+    // Animate movement from top to bottom
+    QPropertyAnimation *a_down = new QPropertyAnimation(c, "altitude", c->animGroup);
+    a_down->setEndValue(loc.y() + amplitudes[ix]);
+    a_down->setStartValue(loc.y());
+    a_down->setDuration(d / speeds[ix]);
+    a_down->setLoopCount(1);
+    a_down->setEasingCurve(QEasingCurve(QEasingCurve::OutQuad));
+
+    c->animGroup->addAnimation(a_up);
+    c->animGroup->addAnimation(a_down);
+    c->animGroup->setLoopCount(-1);
+
+    // Animate rotation
+    c->rtn = new QPropertyAnimation(c, "rotation");
+    c->rtn->setStartValue(c->rot);
+    c->rtn->setEndValue(359.0f);
+    c->rtn->setDuration(d * 2.0f);
+    c->rtn->setLoopCount(-1);
+    c->rtn->setDuration(d / 2);
+    ix = (ix + 1) % 3;
+    return c;
+}
diff --git a/examples/opengl/legacy/pbuffers/cube.h b/examples/opengl/legacy/pbuffers/cube.h
new file mode 100644
index 0000000000..05017cb376
--- /dev/null
+++ b/examples/opengl/legacy/pbuffers/cube.h
@@ -0,0 +1,149 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 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 CUBE_H
+#define CUBE_H
+
+#include <QtOpenGL/qgl.h>
+#include <QtCore/qvector.h>
+#include <QtCore/qsequentialanimationgroup.h>
+#include <QtGui/qmatrix4x4.h>
+#include <QtGui/qvector3d.h>
+#include <QtGui/qvector2d.h>
+
+QT_BEGIN_NAMESPACE
+class QPropertyAnimation;
+QT_END_NAMESPACE
+
+class Geometry
+{
+public:
+    void loadArrays() const;
+    void addQuad(const QVector3D &a, const QVector3D &b,
+                 const QVector3D &c, const QVector3D &d,
+                 const QVector<QVector2D> &tex);
+    void setColors(int start, GLfloat colors[4][4]);
+    const GLushort *indices() const { return faces.constData(); }
+    int count() const { return faces.count(); }
+private:
+    QVector<GLushort> faces;
+    QVector<QVector3D> vertices;
+    QVector<QVector3D> normals;
+    QVector<QVector2D> texCoords;
+    QVector<QVector4D> colors;
+    int append(const QVector3D &a, const QVector3D &n, const QVector2D &t);
+    void addTri(const QVector3D &a, const QVector3D &b, const QVector3D &c, const QVector3D &n);
+    friend class Tile;
+};
+
+class Tile
+{
+public:
+    void draw() const;
+    void setColors(GLfloat[4][4]);
+protected:
+    Tile(const QVector3D &loc = QVector3D());
+    QVector3D location;
+    QQuaternion orientation;
+private:
+    int start;
+    int count;
+    bool useFlatColor;
+    GLfloat faceColor[4];
+    Geometry *geom;
+    friend class TileBuilder;
+};
+
+class TileBuilder
+{
+public:
+    enum { bl, br, tr, tl };
+    explicit TileBuilder(Geometry *, qreal depth = 0.0f, qreal size = 1.0f);
+    Tile *newTile(const QVector3D &loc = QVector3D()) const;
+    void setColor(QColor c) { color = c; }
+protected:
+    void initialize(Tile *) const;
+    QVector<QVector3D> verts;
+    QVector<QVector2D> tex;
+    int start;
+    int count;
+    Geometry *geom;
+    QColor color;
+};
+
+class Cube : public QObject, public Tile
+{
+    Q_OBJECT
+    Q_PROPERTY(qreal range READ range WRITE setRange)
+    Q_PROPERTY(qreal altitude READ altitude WRITE setAltitude)
+    Q_PROPERTY(qreal rotation READ rotation WRITE setRotation)
+public:
+    Cube(const QVector3D &loc = QVector3D());
+    ~Cube();
+    qreal range() { return location.x(); }
+    void setRange(qreal r);
+    qreal altitude() { return location.y(); }
+    void setAltitude(qreal a);
+    qreal rotation() { return rot; }
+    void setRotation(qreal r);
+    void removeBounce();
+    void startAnimation();
+    void setAnimationPaused(bool paused);
+signals:
+    void changed();
+private:
+    qreal rot;
+    QPropertyAnimation *r;
+    QPropertyAnimation *rtn;
+    QSequentialAnimationGroup *animGroup;
+    qreal startx;
+    friend class CubeBuilder;
+};
+
+class CubeBuilder : public TileBuilder
+{
+public:
+    explicit CubeBuilder(Geometry *, qreal depth = 0.0f, qreal size = 1.0f);
+    Cube *newCube(const QVector3D &loc = QVector3D()) const;
+private:
+    mutable int ix;
+};
+
+#endif // CUBE_H
diff --git a/examples/opengl/legacy/pbuffers/cubelogo.png b/examples/opengl/legacy/pbuffers/cubelogo.png
new file mode 100644
index 0000000000..3ae0f9ba3f
--- /dev/null
+++ b/examples/opengl/legacy/pbuffers/cubelogo.png
diff --git a/examples/opengl/legacy/pbuffers/glwidget.cpp b/examples/opengl/legacy/pbuffers/glwidget.cpp
new file mode 100644
index 0000000000..b319951ccd
--- /dev/null
+++ b/examples/opengl/legacy/pbuffers/glwidget.cpp
@@ -0,0 +1,246 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 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 "glwidget.h"
+#include <math.h>
+
+#include "cube.h"
+
+#include <QGLPixelBuffer>
+
+#ifndef GL_MULTISAMPLE
+#define GL_MULTISAMPLE  0x809D
+#endif
+
+static GLfloat colorArray[][4] = {
+    {0.243f, 0.423f, 0.125f, 1.0f},
+    {0.176f, 0.31f, 0.09f, 1.0f},
+    {0.4f, 0.69f, 0.212f, 1.0f},
+    {0.317f, 0.553f, 0.161f, 1.0f}
+};
+
+GLWidget::GLWidget(QWidget *parent)
+    : QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
+    , geom(0)
+    , cube(0)
+{
+    // create the pbuffer
+    QGLFormat pbufferFormat = format();
+    pbufferFormat.setSampleBuffers(false);
+    pbuffer = new QGLPixelBuffer(QSize(512, 512), pbufferFormat, this);
+    setWindowTitle(tr("OpenGL pbuffers"));
+    initializeGeometry();
+}
+
+GLWidget::~GLWidget()
+{
+    pbuffer->releaseFromDynamicTexture();
+    glDeleteTextures(1, &dynamicTexture);
+    delete pbuffer;
+
+    qDeleteAll(cubes);
+    qDeleteAll(tiles);
+    delete cube;
+}
+
+void GLWidget::initializeGL()
+{
+    initCommon();
+    glShadeModel(GL_SMOOTH);
+    glEnable(GL_LIGHTING);
+    glEnable(GL_LIGHT0);
+    static GLfloat lightPosition[4] = { 0.5, 5.0, 7.0, 1.0 };
+    glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
+    initPbuffer();
+    cube->startAnimation();
+    connect(cube, SIGNAL(changed()), this, SLOT(update()));
+    for (int i = 0; i < 3; ++i)
+    {
+        cubes[i]->startAnimation();
+        connect(cubes[i], SIGNAL(changed()), this, SLOT(update()));
+    }
+}
+
+void GLWidget::paintGL()
+{
+    pbuffer->makeCurrent();
+    drawPbuffer();
+    // On direct render platforms, drawing onto the pbuffer context above
+    // automatically updates the dynamic texture.  For cases where rendering
+    // directly to a texture is not supported, explicitly copy.
+    if (!hasDynamicTextureUpdate)
+        pbuffer->updateDynamicTexture(dynamicTexture);
+    makeCurrent();
+
+    // Use the pbuffer as a texture to render the scene
+    glBindTexture(GL_TEXTURE_2D, dynamicTexture);
+
+    // set up to render the scene
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+    glLoadIdentity();
+    glTranslatef(0.0f, 0.0f, -10.0f);
+
+    // draw the background
+    glPushMatrix();
+    glScalef(aspect, 1.0f, 1.0f);
+    for (int i = 0; i < tiles.count(); ++i)
+        tiles[i]->draw();
+    glPopMatrix();
+
+    // draw the bouncing cubes
+    for (int i = 0; i < cubes.count(); ++i)
+        cubes[i]->draw();
+}
+
+void GLWidget::initializeGeometry()
+{
+    geom = new Geometry();
+    CubeBuilder cBuilder(geom, 0.5);
+    cBuilder.setColor(QColor(255, 255, 255, 212));
+    // build the 3 bouncing, spinning cubes
+    for (int i = 3; i > 0; --i)
+        cubes.append(cBuilder.newCube(QVector3D((float)(i-1), -1.5f, 5 - i)));
+
+    // build the spinning cube which goes in the dynamic texture
+    cube = cBuilder.newCube();
+    cube->removeBounce();
+
+    // build the background tiles
+    TileBuilder tBuilder(geom);
+    tBuilder.setColor(QColor(Qt::white));
+    for (int c = -2; c <= +2; ++c)
+        for (int r = -2; r <= +2; ++r)
+            tiles.append(tBuilder.newTile(QVector3D(c, r, 0)));
+
+    // graded backdrop for the pbuffer scene
+    TileBuilder bBuilder(geom, 0.0f, 2.0f);
+    bBuilder.setColor(QColor(102, 176, 54, 210));
+    backdrop = bBuilder.newTile(QVector3D(0.0f, 0.0f, -1.5f));
+    backdrop->setColors(colorArray);
+}
+
+void GLWidget::initCommon()
+{
+    qglClearColor(QColor(Qt::darkGray));
+
+    glEnable(GL_DEPTH_TEST);
+    glEnable(GL_CULL_FACE);
+    glEnable(GL_MULTISAMPLE);
+
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glEnable(GL_BLEND);
+
+    glEnable(GL_TEXTURE_2D);
+
+    geom->loadArrays();
+}
+
+void GLWidget::perspectiveProjection()
+{
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+#ifdef QT_OPENGL_ES
+    glFrustumf(-aspect, +aspect, -1.0, +1.0, 4.0, 15.0);
+#else
+    glFrustum(-aspect, +aspect, -1.0, +1.0, 4.0, 15.0);
+#endif
+    glMatrixMode(GL_MODELVIEW);
+}
+
+void GLWidget::orthographicProjection()
+{
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+#ifdef QT_OPENGL_ES
+    glOrthof(-1.0, +1.0, -1.0, +1.0, -90.0, +90.0);
+#else
+    glOrtho(-1.0, +1.0, -1.0, +1.0, -90.0, +90.0);
+#endif
+    glMatrixMode(GL_MODELVIEW);
+}
+
+void GLWidget::resizeGL(int width, int height)
+{
+    glViewport(0, 0, width * devicePixelRatio(), height * devicePixelRatio());
+    aspect = (qreal)width / (qreal)(height ? height : 1);
+    perspectiveProjection();
+}
+
+void GLWidget::drawPbuffer()
+{
+    orthographicProjection();
+
+    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    glDisable(GL_TEXTURE_2D);
+    backdrop->draw();
+    glEnable(GL_TEXTURE_2D);
+
+    glBindTexture(GL_TEXTURE_2D, cubeTexture);
+    glDisable(GL_CULL_FACE);
+    cube->draw();
+    glEnable(GL_CULL_FACE);
+
+    glFlush();
+}
+
+void GLWidget::initPbuffer()
+{
+    pbuffer->makeCurrent();
+
+    cubeTexture = bindTexture(QImage(":res/cubelogo.png"));
+
+    initCommon();
+
+    // generate a texture that has the same size/format as the pbuffer
+    dynamicTexture = pbuffer->generateDynamicTexture();
+
+    // bind the dynamic texture to the pbuffer - this is a no-op under X11
+    hasDynamicTextureUpdate = pbuffer->bindToDynamicTexture(dynamicTexture);
+    makeCurrent();
+}
+
+void GLWidget::setAnimationPaused(bool enable)
+{
+    cube->setAnimationPaused(enable);
+    for (int i = 0; i < 3; ++i)
+        cubes[i]->setAnimationPaused(enable);
+}
diff --git a/examples/opengl/legacy/pbuffers/glwidget.h b/examples/opengl/legacy/pbuffers/glwidget.h
new file mode 100644
index 0000000000..1d23b7772a
--- /dev/null
+++ b/examples/opengl/legacy/pbuffers/glwidget.h
@@ -0,0 +1,89 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 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 GLWIDGET_H
+#define GLWIDGET_H
+
+#include <QGLWidget>
+
+class Geometry;
+class Cube;
+class Tile;
+QT_BEGIN_NAMESPACE
+class QGLPixelBuffer;
+QT_END_NAMESPACE
+
+class GLWidget : public QGLWidget
+{
+public:
+    GLWidget(QWidget *parent = 0);
+    ~GLWidget();
+
+protected:
+    void initializeGL() Q_DECL_OVERRIDE;
+    void paintGL() Q_DECL_OVERRIDE;
+    void resizeGL(int width, int height) Q_DECL_OVERRIDE;
+    void mousePressEvent(QMouseEvent *) Q_DECL_OVERRIDE { setAnimationPaused(true); }
+    void mouseReleaseEvent(QMouseEvent *) Q_DECL_OVERRIDE { setAnimationPaused(false); }
+
+private:
+    void initializeGeometry();
+    void initPbuffer();
+    void initCommon();
+    void perspectiveProjection();
+    void orthographicProjection();
+    void drawPbuffer();
+    void setAnimationPaused(bool enable);
+
+    qreal aspect;
+    GLuint dynamicTexture;
+    GLuint cubeTexture;
+    bool hasDynamicTextureUpdate;
+    QGLPixelBuffer *pbuffer;
+    Geometry *geom;
+    Cube *cube;
+    Tile *backdrop;
+    QList<Cube *> cubes;
+    QList<Tile *> tiles;
+
+};
+//! [3]
+
+#endif
diff --git a/examples/opengl/legacy/pbuffers/main.cpp b/examples/opengl/legacy/pbuffers/main.cpp
new file mode 100644
index 0000000000..8be6640e92
--- /dev/null
+++ b/examples/opengl/legacy/pbuffers/main.cpp
@@ -0,0 +1,65 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 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 <QtWidgets/QApplication>
+#include <QtWidgets/QMessageBox>
+#include <QtOpenGL/QGLPixelBuffer>
+
+#include "glwidget.h"
+
+int main(int argc, char **argv)
+{
+    Q_INIT_RESOURCE(pbuffers);
+
+    QApplication a(argc, argv);
+    GLWidget widget(0);
+    widget.resize(640, 480);
+    widget.makeCurrent();
+
+    if (!QGLFormat::hasOpenGL() || !QGLPixelBuffer::hasOpenGLPbuffers()) {
+        QMessageBox::information(0, "OpenGL pbuffers",
+                                 "This system does not support OpenGL/pbuffers.");
+        return -1;
+    }
+
+    widget.show();
+    return a.exec();
+}
+
diff --git a/examples/opengl/legacy/pbuffers/pbuffers.pro b/examples/opengl/legacy/pbuffers/pbuffers.pro
new file mode 100644
index 0000000000..a349e39f68
--- /dev/null
+++ b/examples/opengl/legacy/pbuffers/pbuffers.pro
@@ -0,0 +1,17 @@
+HEADERS += glwidget.h \
+    cube.h
+SOURCES += glwidget.cpp \
+    main.cpp \
+    cube.cpp
+RESOURCES += pbuffers.qrc
+QT += opengl widgets
+
+# install
+target.path = $$[QT_INSTALL_EXAMPLES]/opengl/pbuffers
+INSTALLS += target
+
+contains(QT_CONFIG, opengles.) {
+    contains(QT_CONFIG, angle): \
+        warning("Qt was built with ANGLE, which provides only OpenGL ES 2.0 on top of DirectX 9.0c")
+    error("This example requires Qt to be configured with -opengl desktop")
+}
diff --git a/examples/opengl/legacy/pbuffers/pbuffers.qrc b/examples/opengl/legacy/pbuffers/pbuffers.qrc
new file mode 100644
index 0000000000..9fc1a56a1a
--- /dev/null
+++ b/examples/opengl/legacy/pbuffers/pbuffers.qrc
@@ -0,0 +1,5 @@
+<!DOCTYPE RCC><RCC version="1.0">
+<qresource prefix="/res">
+   <file>cubelogo.png</file>
+</qresource>
+</RCC>