Qt下使用OpenGL（5）-根据NeHe的教程改写的

#include "nehewidget.h"

#include <gl/GLU.h>
#include <QKeyEvent>

nehewidget::nehewidget(QWidget *parent,bool fs)
: QGLWidget(parent)
{
rtri=0.0;
rquad=0.0;
fullscreen=fs;
setGeometry(50,50,640,480);
//	setCaption("OpenGL window"); //这个函数，不支持了吧？
setWindowTitle("OpenGL Window");
if(fullscreen) showFullScreen();
}

nehewidget::~nehewidget()
{

}

void nehewidget::initializeGL()
{
glShadeModel(GL_SMOOTH);
glClearColor(0,0,0,0);
glClearDepth(1.0);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);
}

void nehewidget::paintGL()
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
//难道是gluPerspective的缘故？参数必须小一些才能看到图形
//而且圆形和屏幕大小有关系，屏幕不对劲，正方形变长方形了……
glTranslatef(-0.5,0.0,0.0);
glRotatef(rtri,0.0,1.0,0.0);
glBegin(GL_TRIANGLES);
glColor3f(1.0,0.0,0.0);
glVertex3f(0.0,0.3,0.0);
glColor3f(0.0,1.0,0.0);
glVertex3f(-0.3,-0.3,0.3);
glColor3f(0.0,0.0,1.0);
glVertex3f(0.3,-0.3,0.3);

glColor3f(1.0,1.0,0.0);
glVertex3f(0.0,0.3,0.0);
glColor3f(0.0,1.0,1.0);
glVertex3f(0.3,-0.3,0.3);
glColor3f(1.0,0.0,1.0);
glVertex3f(0.3,-0.3,-0.3);

glColor3f(0.2,0.7,0.0);
glVertex3f(0.0,0.3,0.0);
glVertex3f(0.3,-0.3,-0.3);
glVertex3f(-0.3,-0.3,-0.3);

glVertex3f(0.0,0.3,0.8);
glVertex3f(-0.3,-0.3,-0.3);
glVertex3f(-0.3,-0.3,0.3);
glEnd();

glBegin(GL_QUADS);
glColor3f(0.5,0.3,0.1);
glVertex3f(-0.3,-0.3,-0.3);
glVertex3f(0.3,-0.3,0.3);
glVertex3f(0.3,-0.3,-0.3);
glVertex3f(-0.3,-0.3,-0.3);
rtri+=3.0;
glLoadIdentity();

//正方形就不作三维了，有兴趣的依葫芦画瓢即可
glTranslatef(0.5,0.0,0.5);
glRotatef(rquad,1.0,0.0,0.0);
glColor3f(0.5,0.5,1.0);
glBegin(GL_QUADS);
glVertex3f(-0.2,0.2,0);
glVertex3f(0.2,0.2,0);
glVertex3f(0.2,-0.2,0);
glVertex3f(-0.2,-0.2,0);
glEnd();
rquad-=5.0;
//下面被注释的一段是另添加的，有兴趣的可以去掉注释运行一下
//用连续的点或三角形来逼近圆，一个空心，一个实心
/*
glTranslatef(-0.5,-0.5,0.0);
GLfloat x,y,angle;
glBegin(GL_POINTS);
for(angle=0;angle<2*3.1415926;angle+=0.001) {
x=0.2*sin(angle);
y=0.2*cos(angle);
glVertex3f(x,y,0.0);
}
glEnd();
glTranslatef(0.5,0.0,0.0);
glBegin(GL_TRIANGLE_FAN);
for(int i=0;i<100;i++) {
float angle=2*3.1415926*i/100;
glVertex3f(0.2*cos(angle),0.2*sin(angle),0);
}
glEnd();
*/
}

void nehewidget::resizeGL(int w,int h)
{
if(h==0) h=1;
glViewport(0,0,(GLint)w,(GLint)h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
//下面这个函数在Qt和OpenGL新版本中都不支持了！先注释掉吧，以后不得不用时再想办法
//	gluPerspective(45.0,(GLfloat)w/(GLfloat)h,0.1,100.0);

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

void nehewidget::keyPressEvent(QKeyEvent *e)
{
switch(e->key()) {
case Qt::Key_F2:
fullscreen=!fullscreen;
if(fullscreen) showFullScreen();
else {
showNormal();
setGeometry(0,0,640,480);
}
updateGL();
break;
case Qt::Key_Escape:
close();
}
}