code：
#include <GL/glut.h>
#include <stdlib.h>
int hh,ww,xx,yy;
void display(){
glClear (GL_COLOR_BUFFER_BIT);
glRectf (-1.0, -1.0, 1.0, 1.0);
glutSwapBuffers ();
}
void myinit (void){
glClearColor (0.0, 0.0, 0.0, 1.0);
glColor3f (1.0, 1.0, 1.0);
glShadeModel (GL_FLAT);
}
void mymenu(int value){
if (value == 1){
glClear(GL_COLOR_BUFFER_BIT);
glutSwapBuffers();
}
if (value == 2){
exit(0);
}
}
/* Main Loop
* Open window with initial window size, title bar,
* RGBA display mode, and handle input events.
*/
int main(int argc, char** argv){
glutInit(&argc,argv);
glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);
glutInitWindowPosition(310,0);
glutCreateWindow("double buffered");
myinit ();
glutDisplayFunc(display);//注册显示回调函数
glutCreateMenu(mymenu);//注册菜单回调函数
glutAddMenuEntry("Clear Screen",1);//添加菜单项
glutAddMenuEntry("Exit",2);
glutAttachMenu(GLUT_RIGHT_BUTTON);//把当前菜单注册到指定的鼠标键
glutMainLoop();
}
