How to schedule function in GLUT

Question

I have some function which are calling from main function.Below is code.

int main(int argc, char *argv[])

{

    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);

    glutInitWindowSize (500, 500);

    glutInitWindowPosition (100, 100);

    glutCreateWindow("Game for Gamers");

    glutDisplayFunc(display_func);

    glutKeyboardFunc(keyboard);

    glutSpecialFunc(special);

    glutTimerFunc(50,refreshcheck,0);

    glutIdleFunc (animate);

    glutReshapeFunc (reshape);

    glutMainLoop();


    return 0;

}

Here "refreshcheck" is calling first i want to call "refreshcheck" function after execution of "display_func" function.How will schedule it.I want to call "display_func" execute function first when game loaded in memory before "refreshcheck" function, it is not necessary to call "refreshcheck" after "display_func" when game is running, but for first time this is important.

What is inside refreshcheck? There might be a way to avoid using timers. — Karel Petranek, Apr 07 '11 at 18:16
in this function i have used collision detection check module for each ball and moving objects on plane.display_func is creating objects that's why i want call it. — Ajay_Kumar, Apr 07 '11 at 18:18
I can control with logic but i am looking for some standard use of Glut. — Ajay_Kumar, Apr 07 '11 at 18:18
You should not create the objects in display_func. Create them in another function that you call before entering glutMainLoop. — Karel Petranek, Apr 07 '11 at 18:57

score 1 · Answer 1 · answered Feb 13 '12 at 13:12

You should not be, in general, creating objects inside displayFunc (as dark_charlie correctly pointed out). But that is just bad practice, nothing more.

If you require collision detection, you should make it synchronous to rendering, i.e. call it from your displayFunc (at it's end).

I guess the reason you want to use timer is to have constant step physics. This is usually done the other way, using gettimeofday() (or GetTickCount() on windows) to get the time, and based on the time elapsed between the frames, the physics is called N times. That will get you far better precision than using GLUT timers, as timers are only precise up to 10s of milliseconds, which can be a lot when dealing with fast moving objects, leading to stuttering.

How to schedule function in GLUT

1 Answers1