#include "glwidget.h"
#include "ui_glwidget.h"#include <QtGui>
#include <QtCore>
#include <QtOpenGL>GLWidget::GLWidget(QGLWidget *parent) :QGLWidget(parent),ui(new Ui::GLWidget)
{//  setCaption("The Opengl for Qt Framework");ui->setupUi(this);fullscreen = false;rotate_angle = 0.0;
}//这是对虚函数，这里是重写该函数
void GLWidget::initializeGL()
{setGeometry(300, 150, 500, 500);//设置窗口初始位置和大小
    loadTextures();glEnable(GL_TEXTURE_2D);//允许采用2D纹理技术glShadeModel(GL_SMOOTH);//设置阴影平滑模式glClearColor(0.0, 0.0, 0.0, 0);//改变窗口的背景颜色，不过我这里貌似设置后并没有什么效果glClearDepth(1.0);//设置深度缓存glEnable(GL_DEPTH_TEST);//允许深度测试glDepthFunc(GL_LEQUAL);//设置深度测试类型glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);//进行透视校正
}void GLWidget::paintGL()
{//glClear()函数在这里就是对initializeGL()函数中设置的颜色和缓存深度等起作用glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);/*下面开始画立方体,并对其进行纹理映射*/glLoadIdentity();glRotatef(rotate_angle, -0.2f, 0.2f, -0.3f);glBegin(GL_QUADS);//上顶面glTexCoord2f(0.0, 1.0);//将2D的纹理坐标映射到3D的空间物体表面上glVertex3f(-0.3f, 0.3f, -0.3f);glTexCoord2f(0.0, 0.0);glVertex3f(-0.3f, 0.3f, 0.3f);glTexCoord2f(1.0, 0.0);glVertex3f(0.3f, 0.3f, 0.3f);glTexCoord2f(1.0, 1.0);glVertex3f(0.3f, 0.3f, -0.3f);//下顶面glTexCoord2f(0.0, 1.0);glVertex3f(-0.3f, -0.3f, -0.3f);glTexCoord2f(0.0, 0.0);glVertex3f(-0.3f, -0.3f, 0.3f);glTexCoord2f(1.0, 0.0);glVertex3f(0.3f, -0.3f, 0.3f);glTexCoord2f(1.0, 1.0);glVertex3f(0.3f, -0.3f, -0.3f);//正前面glTexCoord2f(0.0, 1.0);glVertex3f(-0.3f, 0.3f, 0.3f);glTexCoord2f(0.0, 0.0);glVertex3f(-0.3f, -0.3f, 0.3f);glTexCoord2f(1.0, 0.0);glVertex3f(0.3f, -0.3f, 0.3f);glTexCoord2f(1.0, 1.0);glVertex3f(0.3f, 0.3f, 0.3f);//右侧面glTexCoord2f(0.0, 1.0);glVertex3f(0.3f, 0.3f, 0.3f);glTexCoord2f(0.0, 0.0);glVertex3f(0.3f, -0.3f, 0.3f);glTexCoord2f(1.0, 0.0);glVertex3f(0.3f, -0.3f, -0.3f);glTexCoord2f(1.0, 1.0);glVertex3f(0.3f, 0.3f, -0.3f);//背后面glTexCoord2f(0.0, 1.0);glVertex3f(-0.3f, 0.3f, -0.3f);glTexCoord2f(0.0, 0.0);glVertex3f(0.3f, 0.3f, -0.3f);glTexCoord2f(1.0, 0.0);glVertex3f(0.3f, -0.3f, -0.3f);glTexCoord2f(1.0, 1.0);glVertex3f(-0.3f, -0.3f, -0.3f);//左侧面glTexCoord2f(0.0, 1.0);glVertex3f(-0.3f, 0.3f, -0.3f);glTexCoord2f(0.0, 0.0);glVertex3f(-0.3f, -0.3f, -0.3f);glTexCoord2f(1.0, 0.0);glVertex3f(-0.3f, -0.3f, 0.3f);glTexCoord2f(1.0, 1.0);glVertex3f(-0.3f, 0.3f, 0.3f);rotate_angle -= 3;glEnd();
}//该程序是设置opengl场景透视图，程序中至少被执行一次(程序启动时).
void GLWidget::resizeGL(int width, int height)
{if(0 == height)height = 1;//防止一条边为0glViewport(0, 0, (GLint)width, (GLint)height);//重置当前视口，本身不是重置窗口的，只不过是这里被Qt给封装好了glMatrixMode(GL_PROJECTION);//选择投影矩阵glLoadIdentity();//重置选择好的投影矩阵// gluPerspective(45.0, (GLfloat)width/(GLfloat)height, 0.1, 100.0);//建立透视投影矩阵glMatrixMode(GL_MODELVIEW);//以下2句和上面出现的解释一样
    glLoadIdentity();}
void GLWidget::keyPressEvent(QKeyEvent *e)
{switch(e->key()){//F1键为全屏和普通屏显示切换键case Qt::Key_F1:fullscreen = !fullscreen;if(fullscreen)showFullScreen();else{setGeometry(300, 150, 500, 500);showNormal();}updateGL();break;//Ese为退出程序键case Qt::Key_Escape:close();}
}/*装载纹理*/
void GLWidget::loadTextures()
{QImage tex, buf;if(!buf.load("../opengl_nehe_05/cherry.jpg")){qWarning("Cannot open the image...");QImage dummy(128, 128, QImage::Format_RGB32);//当没找到所需打开的图片时，创建一副128*128大小，深度为32位的位图
        dummy.fill(Qt::green);buf = dummy;}tex = convertToGLFormat(buf);//将Qt图片的格式buf转换成opengl的图片格式texglGenTextures(1, &texture[0]);//开辟一个纹理内存，内存指向texture[0]glBindTexture(GL_TEXTURE_2D, texture[0]);//将创建的纹理内存指向的内容绑定到纹理对象GL_TEXTURE_2D上，经过这句代码后，以后对//GL_TEXTURE_2D的操作的任何操作都同时对应与它所绑定的纹理对象glTexImage2D(GL_TEXTURE_2D, 0, 3, tex.width(), tex.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, tex.bits());//开始真正创建纹理数据glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);//当所显示的纹理比加载进来的纹理小时，采用GL_LINEAR的方法来处理glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);//当所显示的纹理比加载进来的纹理大时，采用GL_LINEAR的方法来处理
}GLWidget::~GLWidget()
{delete ui;
}