Three scene graph examples with docs.

How to make a custom QSGGeometry, how to use QSGSimpleMaterial and how
to use render with raw GL.

Change-Id: I3e5a32b6ae12d7d781c11050ed26a54845e92cca
Reviewed-by: Gunnar Sletta <gunnar.sletta@nokia.com>

5 files changed, 414 insertions, 0 deletions

diff --git a/examples/quick/scenegraph/customgeometry/beziercurve.cpp b/examples/quick/scenegraph/customgeometry/beziercurve.cpp
new file mode 100644
index 0000000000..dde24d09ef
--- /dev/null
+++ b/examples/quick/scenegraph/customgeometry/beziercurve.cpp
@@ -0,0 +1,168 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "beziercurve.h"
+
+#include <QtQuick/qsgnode.h>
+#include <QtQuick/qsgflatcolormaterial.h>
+
+//! [1]
+BezierCurve::BezierCurve(QQuickItem *parent)
+    : QQuickItem(parent)
+    , m_p1(0, 0)
+    , m_p2(1, 0)
+    , m_p3(0, 1)
+    , m_p4(1, 1)
+    , m_segmentCount(32)
+{
+    setFlag(ItemHasContents, true);
+}
+//! [1]
+
+//! [2]
+BezierCurve::~BezierCurve()
+{
+}
+//! [2]
+
+//! [3]
+void BezierCurve::setP1(const QPointF &p)
+{
+    if (p == m_p1)
+        return;
+
+    m_p1 = p;
+    emit p1Changed(p);
+    update();
+}
+//! [3]
+
+void BezierCurve::setP2(const QPointF &p)
+{
+    if (p == m_p2)
+        return;
+
+    m_p2 = p;
+    emit p2Changed(p);
+    update();
+}
+
+void BezierCurve::setP3(const QPointF &p)
+{
+    if (p == m_p3)
+        return;
+
+    m_p3 = p;
+    emit p3Changed(p);
+    update();
+}
+
+void BezierCurve::setP4(const QPointF &p)
+{
+    if (p == m_p4)
+        return;
+
+    m_p4 = p;
+    emit p4Changed(p);
+    update();
+}
+
+void BezierCurve::setSegmentCount(int count)
+{
+    if (m_segmentCount == count)
+        return;
+
+    m_segmentCount = count;
+    emit segmentCountChanged(count);
+    update();
+}
+
+//! [4]
+QSGNode *BezierCurve::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
+{
+    QSGGeometryNode *node = 0;
+    QSGGeometry *geometry = 0;
+
+    if (!oldNode) {
+        node = new QSGGeometryNode;
+//! [4] //! [5]
+        geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), m_segmentCount);
+        geometry->setLineWidth(2);
+        geometry->setDrawingMode(GL_LINE_STRIP);
+        node->setGeometry(geometry);
+        node->setFlag(QSGNode::OwnsGeometry);
+//! [5] //! [6]
+        QSGFlatColorMaterial *material = new QSGFlatColorMaterial;
+        material->setColor(QColor(255, 0, 0));
+        node->setMaterial(material);
+        node->setFlag(QSGNode::OwnsMaterial);
+//! [6] //! [7]
+    } else {
+        node = static_cast<QSGGeometryNode *>(oldNode);
+        geometry = node->geometry();
+        geometry->allocate(m_segmentCount);
+    }
+//! [7]
+
+//! [8]
+    QRectF bounds = boundingRect();
+    QSGGeometry::Point2D *vertices = geometry->vertexDataAsPoint2D();
+    for (int i = 0; i < m_segmentCount; ++i) {
+        qreal t = i / qreal(m_segmentCount - 1);
+        qreal invt = 1 - t;
+
+        QPointF pos = invt * invt * invt * m_p1
+                    + 3 * invt * invt * t * m_p2
+                    + 3 * invt * t * t * m_p3
+                    + t * t * t * m_p4;
+
+        float x = bounds.x() + pos.x() * bounds.width();
+        float y = bounds.y() + pos.y() * bounds.height();
+
+        vertices[i].set(x, y);
+    }
+//! [8]
+
+//! [9]
+    return node;
+}
+//! [9]
+
diff --git a/examples/quick/scenegraph/customgeometry/beziercurve.h b/examples/quick/scenegraph/customgeometry/beziercurve.h
new file mode 100644
index 0000000000..7b750f3142
--- /dev/null
+++ b/examples/quick/scenegraph/customgeometry/beziercurve.h
@@ -0,0 +1,100 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef BEZIERCURVE_H
+#define BEZIERCURVE_H
+
+//! [1]
+#include <QtQuick/QQuickItem>
+
+class BezierCurve : public QQuickItem
+{
+    Q_OBJECT
+
+    Q_PROPERTY(QPointF p1 READ p1 WRITE setP1 NOTIFY p1Changed)
+    Q_PROPERTY(QPointF p2 READ p2 WRITE setP2 NOTIFY p2Changed)
+    Q_PROPERTY(QPointF p3 READ p3 WRITE setP3 NOTIFY p3Changed)
+    Q_PROPERTY(QPointF p4 READ p4 WRITE setP4 NOTIFY p4Changed)
+
+    Q_PROPERTY(int segmentCount READ segmentCount WRITE setSegmentCount NOTIFY segmentCountChanged)
+
+public:
+    BezierCurve(QQuickItem *parent = 0);
+    ~BezierCurve();
+
+//! [2]
+    QSGNode *updatePaintNode(QSGNode *, UpdatePaintNodeData *);
+//! [2]
+
+    QPointF p1() const { return m_p1; }
+    QPointF p2() const { return m_p2; }
+    QPointF p3() const { return m_p3; }
+    QPointF p4() const { return m_p4; }
+
+    int segmentCount() const { return m_segmentCount; }
+
+    void setP1(const QPointF &p);
+    void setP2(const QPointF &p);
+    void setP3(const QPointF &p);
+    void setP4(const QPointF &p);
+
+    void setSegmentCount(int count);
+
+signals:
+    void p1Changed(const QPointF &p);
+    void p2Changed(const QPointF &p);
+    void p3Changed(const QPointF &p);
+    void p4Changed(const QPointF &p);
+
+    void segmentCountChanged(int count);
+
+private:
+    QPointF m_p1;
+    QPointF m_p2;
+    QPointF m_p3;
+    QPointF m_p4;
+
+    int m_segmentCount;
+};
+//! [1]
+
+#endif
+
diff --git a/examples/quick/scenegraph/customgeometry/customgeometry.pro b/examples/quick/scenegraph/customgeometry/customgeometry.pro
new file mode 100644
index 0000000000..8657820493
--- /dev/null
+++ b/examples/quick/scenegraph/customgeometry/customgeometry.pro
@@ -0,0 +1,10 @@
+TARGET = customgeometry
+QT += quick
+
+SOURCES += \
+    main.cpp \
+    beziercurve.cpp
+
+HEADERS += \
+    beziercurve.h
+
diff --git a/examples/quick/scenegraph/customgeometry/main.cpp b/examples/quick/scenegraph/customgeometry/main.cpp
new file mode 100644
index 0000000000..63396f304e
--- /dev/null
+++ b/examples/quick/scenegraph/customgeometry/main.cpp
@@ -0,0 +1,60 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtGui>
+#include <QtQuick>
+
+#include "beziercurve.h"
+
+//! [1]
+int main(int argc, char **argv)
+{
+    QGuiApplication app(argc, argv);
+
+    qmlRegisterType<BezierCurve>("CustomGeometry", 1, 0, "BezierCurve");
+
+    QQuickView view;
+    view.setSource(QUrl("main.qml"));
+    view.show();
+
+    app.exec();
+}
+//! [1]
diff --git a/examples/quick/scenegraph/customgeometry/main.qml b/examples/quick/scenegraph/customgeometry/main.qml
new file mode 100644
index 0000000000..46a11e010e
--- /dev/null
+++ b/examples/quick/scenegraph/customgeometry/main.qml
@@ -0,0 +1,76 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//! [1]
+import QtQuick 2.0
+import CustomGeometry 1.0
+//! [1] //! [2]
+Item {
+    width: 300
+    height: 200
+
+    BezierCurve {
+        id: line
+        anchors.fill: parent
+        anchors.margins: 20
+//! [2] //! [3]
+        property real t
+        SequentialAnimation on t {
+            NumberAnimation { to: 1; duration: 2000; easing.type: Easing.InOutQuad }
+            NumberAnimation { to: 0; duration: 2000; easing.type: Easing.InOutQuad }
+            loops: Animation.Infinite
+        }
+
+        p2: Qt.point(t, 1 - t)
+        p3: Qt.point(1 - t, t)
+    }
+//! [3] //! [4]
+    Text {
+        anchors.bottom: line.bottom
+
+        x: 20
+        width: parent.width - 40
+        wrapMode: Text.WordWrap
+
+        text: "This curve is a custom scene graph item, implemented using GL_LINE_STRIP"
+    }
+}
+//! [4]