NAME

       SDL_JoystickGetBall - Get relative trackball motion

SYNOPSIS

       #include "SDL.h"

       int SDL_JoystickGetBall(SDL_Joystick *joystick, int ball, int *dx, int *dy);

DESCRIPTION

       Get the ball axis change.

       Trackballs  can  only  return  relative motion since the last call to SDL_JoystickGetBall,
       these motion deltas a placed into dx and dy.

RETURN VALUE

       Returns 0 on success or -1 on failure

EXAMPLES

       int delta_x, delta_y;
       SDL_Joystick *joy;
       .
       .
       .
       SDL_JoystickUpdate();
       if(SDL_JoystickGetBall(joy, 0, &delta_x, &delta_y)==-1)
         printf("TrackBall Read Error!
       ");
       printf("Trackball Delta- X:%d, Y:%d
       ", delta_x, delta_y);

SEE ALSO

       SDL_JoystickNumBalls