OpenGL实现3D空间中移动图像

#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

#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()
{
}

#include "glwidget.h"
#include <QApplication>
int main(int argc, char *argv[])
{
 QApplication a(argc, argv);
 GLWidget w;
 w.show();
 return a.exec();
}