QT Graphics-VIew 3D编程例子- 3D Model Viewer

学习在Graphics-View框架中使用opengl进行3D编程，在网上找了一个不错的例子“3D Model Viewer”，很值得学习。

可以在http://www.oyonale.com/accueil.php?lang=en上下载一些3D模型来测试！

先来一张该例子的截图，看下效果：

该例子使用Graphics-View框架，绘制一个表示太阳的图元（item）；

并在窗口的左上角区域放置了一个2D Widget控制以及说明面板（可以加载不同的3D模型，改变颜色，网格、法向量显示等！）；

通过加载obj模型文件，使用opengl在背景层绘制3D图形，并可以使用鼠标进行控制，但是一次性只能加载一个3D图形。

相关代码如下：

    Model.h - 用于从obj文件中加载3D图形 
 

/****************************************************************************
**
** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information ([email protected])
**
** This file is part of the documentation of Qt. It was originally
** published as part of Qt Quarterly.
**
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License versions 2.0 or 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 GNU General Public Licensing requirements will be met:
** http://www.fsf.org/licensing/licenses/info/GPLv2.html and
** http://www.gnu.org/copyleft/gpl.html.  In addition, as a special
** exception, Nokia gives you certain additional rights. These rights
** are described in the Nokia Qt GPL Exception version 1.3, included in
** the file GPL_EXCEPTION.txt in this package.
**
** Qt for Windows(R) Licensees
** As a special exception, Nokia, as the sole copyright holder for Qt
** Designer, grants users of the Qt/Eclipse Integration plug-in the
** right for the Qt/Eclipse Integration to link to functionality
** provided by Qt Designer and its related libraries.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at [email protected].
**
****************************************************************************/

#ifndef MODEL_H
#define MODEL_H

#include <QString>
#include <QVector>

#include <math.h>

#include "point3d.h"

class Model
{
public :
    Model() {}
    Model( const QString &filePath);

     void render( bool wireframe = false , bool normals = false ) const ;

    QString fileName() const
    {
         return m_fileName;
    }
     int faces() const
    {
         return m_pointIndices.size() / 3 ;
    }
     int edges() const
    {
         return m_edgeIndices.size() / 2 ;
    }
     int points() const
    {
         return m_points.size();
    }

private :
    QString m_fileName;
    QVector<Point3d> m_points;
    QVector<Point3d> m_normals;
    QVector< int > m_edgeIndices;
    QVector< int > m_pointIndices;
};

#endif

OpenGLScene.h - 使用了opengl渲染的场景

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/****************************************************************************
**
** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information ([email protected])
**
** This file is part of the documentation of Qt. It was originally
** published as part of Qt Quarterly.
**
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License versions 2.0 or 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 GNU General Public Licensing requirements will be met:
** http://www.fsf.org/licensing/licenses/info/GPLv2.html and
** http://www.gnu.org/copyleft/gpl.html.  In addition, as a special
** exception, Nokia gives you certain additional rights. These rights
** are described in the Nokia Qt GPL Exception version 1.3, included in
** the file GPL_EXCEPTION.txt in this package.
**
** Qt for Windows(R) Licensees
** As a special exception, Nokia, as the sole copyright holder for Qt
** Designer, grants users of the Qt/Eclipse Integration plug-in the
** right for the Qt/Eclipse Integration to link to functionality
** provided by Qt Designer and its related libraries.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at [email protected].
**
****************************************************************************/

#ifndef OPENGLSCENE_H
#define OPENGLSCENE_H

#include "point3d.h"

#include <QGraphicsScene>
#include <QLabel>
#include <QTime>

#ifndef QT_NO_CONCURRENT
#include <QFutureWatcher>
#endif

class Model;

class OpenGLScene : public QGraphicsScene
{
    Q_OBJECT

public :
    OpenGLScene();

     void drawBackground(QPainter *painter, const QRectF &rect);
     void drawForeground(QPainter *painter, const QRectF &rect);

public slots:
     void enableWireframe( bool enabled);
     void enableNormals( bool enabled);
     void setModelColor();
     void setBackgroundColor();
     void loadModel();
     void loadModel( const QString &filePath);
     void modelLoaded();

protected :
     void mousePressEvent(QGraphicsSceneMouseEvent *event);
     void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);
     void mouseMoveEvent(QGraphicsSceneMouseEvent *event);
     void wheelEvent(QGraphicsSceneWheelEvent * wheelEvent);

private :
    QDialog *createDialog( const QString &windowTitle) const ;

     void setModel(Model *model);

     bool m_wireframeEnabled;
     bool m_normalsEnabled;

    QColor m_modelColor;
    QColor m_backgroundColor;

    Model *m_model;

    QTime m_time;
     int m_lastTime;
     int m_mouseEventTime;

     float m_distance;
    Point3d m_rotation;
    Point3d m_angularMomentum;
    Point3d m_accumulatedMomentum;

    QLabel *m_labels[ 4 ];
    QWidget *m_modelButton;

    QGraphicsRectItem *m_lightItem;

#ifndef QT_NO_CONCURRENT
    QFutureWatcher<Model *> m_modelLoader;
#endif
};

#endif

    Point3d.h - 描述3D点数据的一个类 
 

/****************************************************************************
**
** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information ([email protected])
**
** This file is part of the documentation of Qt. It was originally
** published as part of Qt Quarterly.
**
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License versions 2.0 or 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 GNU General Public Licensing requirements will be met:
** http://www.fsf.org/licensing/licenses/info/GPLv2.html and
** http://www.gnu.org/copyleft/gpl.html.  In addition, as a special
** exception, Nokia gives you certain additional rights. These rights
** are described in the Nokia Qt GPL Exception version 1.3, included in
** the file GPL_EXCEPTION.txt in this package.
**
** Qt for Windows(R) Licensees
** As a special exception, Nokia, as the sole copyright holder for Qt
** Designer, grants users of the Qt/Eclipse Integration plug-in the
** right for the Qt/Eclipse Integration to link to functionality
** provided by Qt Designer and its related libraries.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at [email protected].
**
****************************************************************************/

#ifndef POINT3D_H
#define POINT3D_H

#include "math.h"

#include <qglobal.h>

struct Point3d
{
     float x, y, z;

    Point3d()
        : x( 0 )
        , y( 0 )
        , z( 0 )
    {
    }

    Point3d( float x_, float y_, float z_)
        : x(x_)
        , y(y_)
        , z(z_)
    {
    }

    Point3d operator +( const Point3d &p) const
    {
         return Point3d(* this ) += p;
    }

    Point3d operator -( const Point3d &p) const
    {
         return Point3d(* this ) -= p;
    }

    Point3d operator *( float f) const
    {
         return Point3d(* this ) *= f;
    }

    Point3d & operator +=( const Point3d &p)
    {
        x += p.x;
        y += p.y;
        z += p.z;
         return * this ;
    }

    Point3d & operator -=( const Point3d &p)
    {
        x -= p.x;
        y -= p.y;
        z -= p.z;
         return * this ;
    }

    Point3d & operator *=( float f)
    {
        x *= f;
        y *= f;
        z *= f;
         return * this ;
    }

    Point3d normalize() const
    {
         float r = 1 . / sqrt(x * x + y * y + z * z);
         return Point3d(x * r, y * r, z * r);
    }
     float & operator []( unsigned int index) {
        Q_ASSERT(index < 3 );
         return (&x)[index];
    }

     const float & operator []( unsigned int index) const {
        Q_ASSERT(index < 3 );
         return (&x)[index];
    }
};

inline float dot( const Point3d &a, const Point3d &b)
{
     return a.x * b.x + a.y * b.y + a.z * b.z;
}

inline Point3d cross( const Point3d &a, const Point3d &b)
{
     return Point3d(a.y * b.z - a.z * b.y,
                   a.z * b.x - a.x * b.z,
                   a.x * b.y - a.y * b.x);
}

#endif

主函数调用：

   main.cpp 
 

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#include "openglscene.h"
#include <QApplication>
#include <QObject>
#include <QGLWidget>
#include <QGraphicsView>
#include <QResizeEvent>

class GraphicsView : public QGraphicsView
{
public :
    GraphicsView()
    {
        setWindowTitle(tr( "3D Model Viewer" ));
    }

protected :
     void resizeEvent(QResizeEvent *event) {
         if (scene())
            scene()->setSceneRect(QRect(QPoint( 0 , 0 ), event->size()));
        QGraphicsView::resizeEvent(event);
    }
};

int main( int argc, char **argv)
{
    QApplication app(argc, argv);

    GraphicsView view;
    view.setViewport( new QGLWidget(QGLFormat(QGL::SampleBuffers)));
    view.setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
    view.setScene( new OpenGLScene);
    view.show();

    view.resize( 1024 , 768 );

     return app.exec();
}

其它3D图形欣赏：

QT Graphics-VIew 3D编程例子- 3D Model Viewer

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