NeHe 系列教程之一： 创建一个OpenGL 窗口

英文教程地址：　lesson01

在Qt的实现中， 我们主要依赖QGLWidget类， 我们主要重载三个重要方法 ：

    void initializeGL();
    void resizeGL(int w, int h);
    void paintGL();

下面给出实现代码，本课代码框架也是后续课程代码的基础，一些通用代码仅在此课中展示。

首先，声明创建OpenGL窗口类，它继承于QGLWidget， 代码如下：

#ifndef MYGLWIDGET_H
#define MYGLWIDGET_H#include <QGLWidget>class QTimer;
class QKeyEvent;class MyGLWidget : public QGLWidget
{Q_OBJECT
public:explicit MyGLWidget(QWidget *parent = 0);protected:void initializeGL();void resizeGL(int w, int h);void paintGL();void keyPressEvent(QKeyEvent *);void closeEvent(QCloseEvent *);private:QTimer *timer;bool fullscreen;  //窗口是否全屏显示
};#endif // MYGLWIDGET_H

该类主要声明了三个重载方法，并重载了按键和关闭窗口事件响应方法。

窗口类的实现代码如下：

#include "myglwidget.h"
#include <QTimer>
#include <QKeyEvent>
#include <QMessageBox>
#include <QApplication>
#include <QDebug>MyGLWidget::MyGLWidget(QWidget *parent) :QGLWidget(parent), fullscreen(false)
{setWindowTitle(tr("nehe----lesson01"));timer = new QTimer(this);connect(timer, SIGNAL(timeout()), this, SLOT(updateGL())); //不停刷新窗口timer->start(10);
}void MyGLWidget::initializeGL()
{glShadeModel(GL_SMOOTH);   // Enables Smooth ShadingglClearColor(0.0f, 0.0f, 0.0f, 0.0f);  // Black BackgroundglClearDepth(1.0f);             // Depth Buffer SetupglEnable(GL_DEPTH_TEST);        // Enables Depth TestingglDepthFunc(GL_LEQUAL);        // The Type Of Depth Test To DoglHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // Really Nice Perspective Calculations
}void MyGLWidget::resizeGL(int width, int height)
{if (height==0) {    // Prevent A Divide By Zero Byheight=1;    // Making Height Equal One}glViewport(0, 0, width, height);    // Reset The Current ViewportglMatrixMode(GL_PROJECTION);       // Select The Projection MatrixglLoadIdentity();                  // Reset The Projection Matrix// Calculate The Aspect Ratio Of The WindowgluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);glMatrixMode(GL_MODELVIEW);      // Select The Modelview MatrixglLoadIdentity();                // Reset The Modelview Matrix
}void MyGLWidget::paintGL()
{glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);  // Clear The Screen And The Depth BufferglLoadIdentity();       // Reset The Current Modelview MatrixqDebug("NeHe--Lesson1");
}void MyGLWidget::keyPressEvent(QKeyEvent *e)
{switch (e->key()) {case Qt::Key_F:  //F 键进行全屏切换fullscreen = !fullscreen;if (fullscreen) {showFullScreen();} else {resize(640, 480);showNormal();}break;case Qt::Key_Escape:   //退出确认QMessageBox::StandardButton reply;reply = QMessageBox::question(NULL, "NeHe","Do you want to exit?",QMessageBox::Yes | QMessageBox::No,QMessageBox::Yes);if (reply == QMessageBox::Yes) {qApp->quit();}break;default:QGLWidget::keyPressEvent(e);break;}
}
//点击窗口关闭按键时确认退出
void MyGLWidget::closeEvent(QCloseEvent *e)
{QMessageBox::StandardButton reply;reply = QMessageBox::question(this, "NeHe","Do you want to exit?",QMessageBox::Yes | QMessageBox::No,QMessageBox::No);if (reply == QMessageBox::Yes) {e->accept();} else {e->ignore();}
}

main函数中的代码如下所示：

#include <QApplication>
#include "myglwidget.h"int main(int argc, char *argv[])
{QApplication app(argc, argv);MyGLWidget win;win.show();return app.exec();
}

运行效果如下所示：