由例子程序给出的显示列表，展示重定形函数的应用

#include <GL/glut.h>
#include <math.h>
#include <stdlib.h>

const double TWO_PI=6.2831853;
//初始化窗口大小
GLsizei winWidth =400,winHeight=400;
GLuint regHex;
class screenPt
{
            private:
                GLint x,y;//初始化坐标为（0，0）
            public:
                screenPt(){
                    x=y=0;
                }
                void setCoords(GLint xCoord,GLint yCoord){
                    x=xCoord;
                    y=yCoord;
                }
                GLint getx() const{
                    return x;
                }
                GLint gety() const{
                    return y;
                }
};
static void init (void)
{
    screenPt hexVertex,circCtr;
    GLdouble theta;
    GLint k;
  //设置圆心坐标
    circCtr.setCoords(winWidth/2,winHeight/2);

    glClearColor(1.0,1.0,1.0,0.0);/* 显示窗口颜色为白色*/
    //Set up a display list for a red regular hexagon.
    /*Vertices for the hexagon are six equally spaced. 
        points aroud the circumference of a circle.*/

    regHex=glGenLists(1);//get an identifier for the display list
    glNewList(regHex,GL_COMPILE);
        glColor3f(1.0,0.0,0.0);//set fill color for hexagon to red
        glBegin(GL_POLYGON);
            for (k=0;k<6;k++)
            {
                theta=TWO_PI*k/6.0;
                hexVertex.setCoords(circCtr.getx()+150*cos(theta),
                                                        circCtr.gety()+150*sin(theta));
                glVertex2i(hexVertex.getx(),hexVertex.gety());

            }
        glEnd();
    glEndList();
}
void regHexagon()
{
    glClear(GL_COLOR_BUFFER_BIT);
    glCallList(regHex);
    glFlush();
}

void winReshapeFcn(int newWidth,int newHeight)
{
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0.0,(GLdouble)newWidth,0.0,(GLdouble)newHeight);
    glClear(GL_COLOR_BUFFER_BIT);
}

void main( int  argc,char** argv)
{
    glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowPosition(100,100);
    glutInitWindowSize(winWidth,winHeight);
    glutCreateWindow("Reshape-Function & Display-List Example");

    init();
    glutDisplayFunc(regHexagon);
    glutReshapeFunc(winReshapeFcn);

    glutMainLoop();