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!\n");
printf("Trackball Delta- X:%d, Y:%d\n", delta_x, delta_y);