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
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/****************************************************************************
** ** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies). ** Contact: Qt Software Information (qt-info@nokia.com) ** ** 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 qt-sales@nokia.com. ** ****************************************************************************/ #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 (qt-info@nokia.com) ** ** 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 qt-sales@nokia.com. ** ****************************************************************************/ #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
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/****************************************************************************
** ** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies). ** Contact: Qt Software Information (qt-info@nokia.com) ** ** 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 qt-sales@nokia.com. ** ****************************************************************************/ #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：
