Qt_OpenGL：3D空间中移动图像

//.h

#ifndef GLWIDGET_H
#define GLWIDGET_H

#include <QGLWidget>
#include <QtOpenGL>

class QGLWidget;
class QTimer;

typedef struct Stars{
public:
    int r, g, b;
    GLfloat dist, angle;
}Stars;

class GLWidget : public QGLWidget
{
    Q_OBJECT

public:
    GLWidget(QWidget *parent = 0);
    ~GLWidget();

protected:
    void initializeGL();
    void paintGL();
    void resizeGL(int w, int h);
    void keyPressEvent(QKeyEvent*);
    void timerEvent(QTimerEvent*);

private:
    bool fullscreen;
    GLfloat rotate_angle;
    GLfloat zoom;
    GLfloat title;
    GLfloat spin;
    GLuint loop;
    bool twinkle;
    GLfloat blend;

private:
    void loadTextures();

    GLuint texture[1];

};

#endif // GLWIDGET_H

//.cpp

#include "glwidget.h"
#include <glut.h>
#include <QtGui>
#include <QtCore>

//好吧我承认全部变量不好
GLfloat light_ambient[4] = {0.5,0.5,0.5,1.0};
GLfloat light_diffiuse[4] = {1.0,1.0,1.0,1.0};
GLfloat light_position[4] = {0.0,0.0,2.0,0.0};

static const int num = 50;
static Stars stars[num];

GLWidget::GLWidget(QWidget *parent)
    : QGLWidget(parent)
{
    fullscreen = false;
    rotate_angle = 0.0;
    zoom = -15.0;
    title = 90.0;
    spin = 0.1;
    loop = 0;
    twinkle = false;
    blend = false;

    startTimer(5);
}

void GLWidget::initializeGL(){

    setGeometry(300,150,500,500);
    loadTextures();
    glEnable(GL_TEXTURE_2D);
    glShadeModel(GL_SMOOTH);
    glClearColor(0.0, 0.0, 0.0, 0.5);
    glClearDepth(1.0);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LEQUAL);
    glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);

    glBlendFunc(GL_SRC_ALPHA,GL_ONE);
    glEnable(GL_BLEND);

    //为num个星星对象赋初值
    for(loop = 0; loop < num; ++loop){
        stars[loop].angle = 0.0;
        stars[loop].dist = (float(loop)/num) * 5.0;
        stars[loop].r = rand() % 256;
        stars[loop].g = rand() % 256;
        stars[loop].b = rand() % 256;
    }
}

void GLWidget::paintGL(){

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glBindTexture(GL_TEXTURE_2D, texture[0]);
    for(loop = 0; loop < num; ++loop){
        glLoadIdentity();
        glTranslatef(0.0, 0.0, zoom);  //移向屏幕里面
        glRotatef(title, 1.0, 0.0, 0.0);  //沿x轴旋转title
        glRotatef(stars[loop].angle, 0.0, 1.0, 0.0); //每个星星沿y轴旋转自己的角度
        glTranslatef(stars[loop].dist, 0.0, 0.0);  //平移
        glRotatef(-stars[loop].angle, 0.0, 1.0, 0.0);  //沿y轴反转
        glRotatef(-title, 1.0, 0.0, 0.0);    //沿x轴反转
        if(twinkle){     //如果星星闪烁
            glColor4ub(stars[num-loop-1].r, stars[num-loop-1].g,
                    stars[num-loop-1].b, 255);
            glBegin(GL_QUADS);
                glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f,-1.0f, 0.0f);
                glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f,-1.0f, 0.0f);
                glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, 0.0f);
                glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 0.0f);
            glEnd();
        }
        //如果星星不闪烁
        glRotatef(spin, 0.0f, 0.0f, 1.0f); //沿z轴自转spin
        glColor4ub(stars[loop].r, stars[loop].g, stars[loop].b, 255);
        glBegin(GL_QUADS);
            glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f,-1.0f, 0.0f);
            glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f,-1.0f, 0.0f);
            glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, 0.0f);
            glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 0.0f);
        glEnd();

        spin += 0.01f;
        stars[loop].angle += float(loop)/num;
        stars[loop].dist -= 0.01f; //距离逐渐减小，即越来越靠近屏幕
        if(stars[loop].dist < 0){
            stars[loop].dist += 5.0f;
            stars[loop].r = rand() % 256;
            stars[loop].g = rand() % 256;
            stars[loop].b = rand() % 256;
        }
    }
}

void GLWidget::resizeGL(int w, int h){

    if( 0 == h){
        h = 1;
    }
    glViewport(0, 0, (GLsizei)w, (GLsizei)h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45.0, (GLdouble)w/(GLdouble)h, 0.1, 100.0);
    glColor4f(1.0f, 1.0f, 1.0f, 0.5f);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

void GLWidget::keyPressEvent(QKeyEvent *event){

    switch(event->key()){

        case Qt::Key_T:{
            twinkle = !twinkle;
            updateGL();
            break;
        }
        case Qt::Key_B:{
            blend = !blend;
            if(blend){
                glEnable(GL_BLEND);
                glDisable(GL_DEPTH_TEST);
            }else{
                glDisable(GL_BLEND);
                glEnable(GL_DEPTH_TEST); //色彩混合和深度缓存不能同时开启
            }
            updateGL();
            break;
        }
        case Qt::Key_PageUp:{      //移向屏幕
            zoom -= 0.2;
            updateGL();
            break;
        }
        case Qt::Key_PageDown:{   //移向屏幕外
            zoom += 0.2;
            updateGL();
            break;
        }
        case Qt::Key_Up:{          //加快旋转速度
            title += 0.5;
            updateGL();
            break;
        }
        case Qt::Key_Down:{
            title -= 0.5;
            updateGL();
            break;
        }
        case Qt::Key_F1:{
            fullscreen = !fullscreen;
            if(fullscreen){
                showFullScreen();
            }else{
                setGeometry(300,150,500,500);
                showNormal();
            }
            updateGL();
            break;
        }
        case Qt::Key_Escape:{
            close();
        }
    }
}

void GLWidget::loadTextures(){

    QImage tex, buf;
    if(!buf.load(":Star.bmp")){
        qWarning("Cannot open the image...");
        QImage dummy(128, 128, QImage::Format_RGB32);
        dummy.fill(Qt::green);
        buf = dummy;
    }
    tex = convertToGLFormat(buf);
    glGenTextures(1, &texture[0]);
    glBindTexture(GL_TEXTURE_2D, texture[0]);
    glTexImage2D(GL_TEXTURE_2D, 0, 3, tex.width(), tex.height(), 0, GL_RGBA,
                 GL_UNSIGNED_BYTE, tex.bits());
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
}

void GLWidget::timerEvent(QTimerEvent *){
    updateGL();
}

GLWidget::~GLWidget()
{
}

//main.cpp

#include "glwidget.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    GLWidget w;
    w.show();

    return a.exec();
}

//运行结果截图：

Qt_OpenGL：3D空间中移动图像