#include "stdafx.h"#include
     
      #include
      
       #include
       
        const double TWO_PI = 6.2831853;/*Initial display-window size*/GLsizei winWidth = 400, winHeight = 400;GLuint regHex;class screenPt{private:    GLint x, y;public:    /*Default Constructor:initalizes coordinate position to(0,0).*/    screenPt() { x = y = 0; }    void setGoords(GLint xGoord, GLint yGoord) { x = xGoord; y = yGoord; }    GLint getx()const { return x; }    GLint gety()const { return y; }};static void init(void){    screenPt hexVertex, circCtr;    GLdouble theta;    GLint k;    /*Set circle center coordinates.*/    circCtr.setGoords(winWidth / 2, winHeight / 2);    glClearColor(1.0, 1.0, 1.0, 0.0);//Display-window color=white.                                     /*Set up a display list for a red regular hexagon.                                     *Vertice for the hexagon are six equally spaced                                     *points around 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.setGoords(circCtr.getx() + 150 * cos(theta),            circCtr.gety() + 150 * sin(theta));        glVertex2i(hexVertex.getx(), hexVertex.gety());    }    glEnd();    glEndList();}void regHexagon(void){    glClear(GL_COLOR_BUFFER_BIT);        glCallList(regHex);    glFlush();}void winReshapeFcn(GLint newWidth, GLint 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-ListExample");    init();    glutDisplayFunc(regHexagon);    glutReshapeFunc(winReshapeFcn);    glutMainLoop();}