#pragma section-numbers off
#pragma disable-camelcase
||<tablewidth="100%" style="color: #FF0000;" :> DRAFT||

= SDL_JoystickGetBall =
Use this function to get the ball axis change since the last poll.

<<TableOfContents()>>

== Syntax ==
{{{#!highlight cpp
int SDL_JoystickGetBall(SDL_Joystick* joystick,
                        int           ball,
                        int*          dx,
                        int*          dy)
}}}

== Function Parameters ==
||'''joystick'''||the SDL_Joystick to query||
||'''ball'''||the ball index to query; ball indices start at index 0||
||'''dx'''||the difference in the x axis position since the last poll||
||'''dy'''||the difference in the y axis position since the last poll||

== Return Value ==
Returns 0 on success or a negative error code on failure; call [[SDL_GetError]]() for more information.

== Code Examples ==
{{{#!highlight cpp
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);
}}}

== Remarks ==
Trackballs can only return relative motion since the last call to [[SDL_JoystickGetBall]](), these motion deltas are placed into '''dx''' and '''dy'''.

== Related Functions ==
 .[[SDL_JoystickNumBalls]]

----
[[CategoryAPI]], [[CategoryJoystick]]