这是我的简单菜单程序。出于测试目的，我打印单词＆＃34; hello＆＃34;每次我选择菜单。但是我不明白为什么我在菜单中选择一个选项后，每次我点击鼠标右键，单词＆＃34;你好＆＃34;再次显示。 我只希望菜单功能执行一次。我怎么能这样做？
#include <windows.h>
#include <GL/glut.h>
static int window;
static int menu_id;
static int submenu1, submenu2, submenu3, submenu4, submenu5, submenu6, submenu7, submenu8;
static int value = 0;
void menu(int num){
if(num == 0){
glutDestroyWindow(window);
exit(0);
}else{
value = num;
}
glutPostRedisplay();
}
void createMenu(void){
submenu1 = glutCreateMenu(menu);
glutAddMenuEntry("red", 1);
glutAddMenuEntry("green", 2);
glutAddMenuEntry("blue", 3);
glutAddMenuEntry("yellow", 4);
glutAddMenuEntry("purple", 5);
glutAddMenuEntry("orange", 6);
glutAddMenuEntry("white", 7);
glutAddMenuEntry("black", 8);
submenu2 = glutCreateMenu(menu);
glutAddMenuEntry("red", 9);
glutAddMenuEntry("green", 10);
glutAddMenuEntry("blue", 11);
glutAddMenuEntry("yellow", 12);
glutAddMenuEntry("purple", 13);
glutAddMenuEntry("orange", 14);
glutAddMenuEntry("white", 15);
glutAddMenuEntry("black", 16);
submenu3 = glutCreateMenu(menu);
glutAddMenuEntry("red", 17);
glutAddMenuEntry("green", 18);
glutAddMenuEntry("blue", 19);
glutAddMenuEntry("yellow", 20);
glutAddMenuEntry("purple", 21);
glutAddMenuEntry("orange", 22);
glutAddMenuEntry("white", 23);
glutAddMenuEntry("black", 24);
submenu4 = glutCreateMenu(menu);
glutAddMenuEntry("red", 25);
glutAddMenuEntry("green", 26);
glutAddMenuEntry("blue", 27);
glutAddMenuEntry("yellow", 28);
glutAddMenuEntry("purple", 29);
glutAddMenuEntry("orange", 30);
glutAddMenuEntry("white", 31);
glutAddMenuEntry("black", 32);
submenu5 = glutCreateMenu(menu);
glutAddMenuEntry("red", 33);
glutAddMenuEntry("green", 34);
glutAddMenuEntry("blue", 35);
glutAddMenuEntry("yellow", 36);
glutAddMenuEntry("purple", 37);
glutAddMenuEntry("orange", 38);
glutAddMenuEntry("white", 39);
glutAddMenuEntry("black", 40);
submenu6 = glutCreateMenu(menu);
glutAddMenuEntry("red", 41);
glutAddMenuEntry("green", 42);
glutAddMenuEntry("blue", 43);
glutAddMenuEntry("yellow", 44);
glutAddMenuEntry("purple", 45);
glutAddMenuEntry("orange", 46);
glutAddMenuEntry("white", 47);
glutAddMenuEntry("black", 48);
submenu7 = glutCreateMenu(menu);
glutAddSubMenu("filled", submenu1);
glutAddSubMenu("outline", submenu2);
submenu8 = glutCreateMenu(menu);
glutAddSubMenu("filled", submenu3);
glutAddSubMenu("outline", submenu4);
menu_id = glutCreateMenu(menu);
glutAddSubMenu("add rectangle", submenu7);
glutAddSubMenu("add ellipse", submenu8);
glutAddSubMenu("add line", submenu5);
glutAddSubMenu("add bezier curve", submenu6);
glutAttachMenu(GLUT_LEFT_BUTTON);
}
void display(void){
glClear(GL_COLOR_BUFFER_BIT);
if(value == 1){
printf("hello\n");
}else if(value == 2){
printf("hello\n");
}else if(value == 3){
printf("hello\n");
}else if(value == 4){
printf("hello\n");
}else if(value == 5){
printf("hello\n");
}else if(value == 6){
printf("hello\n");
}else if(value == 7){
printf("hello\n");
}else if(value == 8){
printf("hello\n");
}else if(value == 9){
printf("hello\n");
}else if(value == 10){
printf("hello\n");
}else if(value == 11){
printf("hello\n");
}else if(value == 12){
printf("hello\n");
}else if(value == 13){
printf("hello\n");
}else if(value == 14){
printf("hello\n");
}else if(value == 15){
printf("hello\n");
}else if(value == 16){
printf("hello\n");
}else if(value == 17){
printf("hello\n");
}else if(value == 18){
printf("hello\n");
}else if(value == 19){
printf("hello\n");
}else if(value == 20){
printf("hello\n");
}else if(value == 21){
printf("hello\n");
}else if(value == 22){
printf("hello\n");
}else if(value == 23){
printf("hello\n");
}else if(value == 24){
printf("hello\n");
}else if(value == 25){
printf("hello\n");
}else if(value == 26){
printf("hello\n");
}else if(value == 27){
printf("hello\n");
}else if(value == 28){
printf("hello\n");
}else if(value == 29){
printf("hello\n");
}else if(value == 30){
printf("hello\n");
}else if(value == 31){
printf("hello\n");
}else if(value == 32){
printf("hello\n");
}else if(value == 33){
printf("hello\n");
}else if(value == 34){
printf("hello\n");
}else if(value == 35){
printf("hello\n");
}else if(value == 36){
printf("hello\n");
}else if(value == 37){
printf("hello\n");
}else if(value == 38){
printf("hello\n");
}else if(value == 39){
printf("hello\n");
}else if(value == 40){
printf("hello\n");
}else if(value == 41){
printf("hello\n");
}else if(value == 42){
printf("hello\n");
}else if(value == 43){
printf("hello\n");
}else if(value == 44){
printf("hello\n");
}else if(value == 45){
printf("hello\n");
}else if(value == 46){
printf("hello\n");
}else if(value == 47){
printf("hello\n");
}else if(value == 48){
printf("hello\n");
}
glFlush();
}
int main(int argc, char *argv[]){
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH);
glutInitWindowSize(640, 480);
glutInitWindowPosition((glutGet(GLUT_SCREEN_WIDTH)-640)/2,
(glutGet(GLUT_SCREEN_HEIGHT)-480)/2);
window = glutCreateWindow("Project 1");
createMenu();
glClearColor(255.0f, 255.0f, 255.0f, 0.0f);
glutDisplayFunc(display);
glutMainLoop();
return EXIT_SUCCESS;
}
答案 0 :(得分：0)
value被设置为一个数字，然后永远不会被设置为0，因此将继续打印“Hello”。如果在printf("hello\n");之后，您放置了value = 0;，那么您的计划可能会有更好的机会。