QOpenGLWidget空白显示不出内容

[yizhou2010]

一个简单程序中，继承与QOpenGLWidget的自定义类，编译没有问题，但是执行的时候一片空白，没有绘制出所需的点，怎么回事啊？继承类代码如下：
.h

#ifndef MYOPENGLWINDOW_H
#define MYOPENGLWINDOW_H
 
#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <gl/GL.h>
class myOpenglWindow : public QOpenGLWidget, protected QOpenGLFunctions
{
    Q_OBJECT
public:
    explicit myOpenglWindow(QWidget *parent = nullptr);
 
protected:
    void initializeGL();
    void resizeGL(int w, int h);
    void paintGL();
signals:
 
public slots:
};
 
#endif // MYOPENGLWINDOW_H

.cpp

#include "myopenglwindow.h"
#include <iostream>
#include "glut.h"
using namespace std;
myOpenglWindow::myOpenglWindow(QWidget *parent) : QOpenGLWidget(parent)
{
 
}
 
void myOpenglWindow::initializeGL()
{
    initializeOpenGLFunctions();
    glClearColor(1.0, 1.0, 1.0,1.0);
    cout<<glGetString(GL_VERSION)<<endl;
}
 
void myOpenglWindow::resizeGL(int w, int h)
{
    glViewport(0, 0, (GLsizei)w, (GLsizei)h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(-1.5,1.5,-1.5,1.5);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}
 
void myOpenglWindow::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
    glPointSize(10.0);
    glColor3d(1.0,0.0,0.0);
    glBegin(GL_POINTS);
    glVertex3d(0.0, 0.0, 0.0);
    glEnd();
}