[译]GLUT教程 - 交换菜单

Lighthouse3d.com >> GLUT Tutorial >> Pop-up Menus >> Swapping Menus

GLUT甚至可以在应用程序过程中更改整个菜单.提供了两个函数: glutSetMenu和glutGetMenu.原型如下:

void glutSetMenu(int menu);

menu - 上一个创建菜单的索引值

该函数可以让我们切换菜单,例如在应用程序上下文中切换.

int glutGetMenu(void);

该函数返回当前菜单的索引值.下面我们演示用户按F1时在两个菜单之间切换.

void processSpecialKeys(int c, int x, int y) {
 
    if (!flag) {
        if (c == GLUT_KEY_F1) {
            int x = glutGetMenu();
            if (x == menu1)
                glutSetMenu(menu2);
            else
                glutSetMenu(menu1);
            // don't forget to attach the menu!!!
            glutAttachMenu(GLUT_RIGHT_BUTTON);
        }
    }
}
 
void createGLUTMenus() {
 
    menu2 = glutCreateMenu(processMenuEvents);
    glutAddMenuEntry("Blue",BLUE);
    glutAddMenuEntry("Green",GREEN);
    glutAddMenuEntry("Red",RED);
 
    menu1 = glutCreateMenu(processMenuEvents);
    glutAddMenuEntry("Red",RED);
    glutAddMenuEntry("Green",GREEN);
    glutAddMenuEntry("Blue",BLUE);
    glutAttachMenu(GLUT_RIGHT_BUTTON);
}