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4>SDL_JoyBallEvent</TITLE
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71><H1
72><A
73NAME="SDLJOYBALLEVENT"
74></A
75>SDL_JoyBallEvent</H1
76><DIV
77CLASS="REFNAMEDIV"
78><A
79NAME="AEN4396"
80></A
81><H2
82>Name</H2
83>SDL_JoyBallEvent&nbsp;--&nbsp;Joystick trackball motion event structure</DIV
84><DIV
85CLASS="REFSECT1"
86><A
87NAME="AEN4399"
88></A
89><H2
90>Structure Definition</H2
91><PRE
92CLASS="PROGRAMLISTING"
93>typedef struct{
94  Uint8 type;
95  Uint8 which;
96  Uint8 ball;
97  Sint16 xrel, yrel;
98} SDL_JoyBallEvent;</PRE
99></DIV
100><DIV
101CLASS="REFSECT1"
102><A
103NAME="AEN4402"
104></A
105><H2
106>Structure Data</H2
107><DIV
108CLASS="INFORMALTABLE"
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110NAME="AEN4404"
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118><TR
119><TD
120ALIGN="LEFT"
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122><TT
123CLASS="STRUCTFIELD"
124><I
125>type</I
126></TT
127></TD
128><TD
129ALIGN="LEFT"
130VALIGN="TOP"
131><TT
132CLASS="LITERAL"
133>SDL_JOYBALLMOTION</TT
134></TD
135></TR
136><TR
137><TD
138ALIGN="LEFT"
139VALIGN="TOP"
140><TT
141CLASS="STRUCTFIELD"
142><I
143>which</I
144></TT
145></TD
146><TD
147ALIGN="LEFT"
148VALIGN="TOP"
149>Joystick device index</TD
150></TR
151><TR
152><TD
153ALIGN="LEFT"
154VALIGN="TOP"
155><TT
156CLASS="STRUCTFIELD"
157><I
158>ball</I
159></TT
160></TD
161><TD
162ALIGN="LEFT"
163VALIGN="TOP"
164>Joystick trackball index</TD
165></TR
166><TR
167><TD
168ALIGN="LEFT"
169VALIGN="TOP"
170><TT
171CLASS="STRUCTFIELD"
172><I
173>xrel</I
174></TT
175>, <TT
176CLASS="STRUCTFIELD"
177><I
178>yrel</I
179></TT
180></TD
181><TD
182ALIGN="LEFT"
183VALIGN="TOP"
184>The relative motion in the X/Y direction</TD
185></TR
186></TBODY
187></TABLE
188><P
189></P
190></DIV
191></DIV
192><DIV
193CLASS="REFSECT1"
194><A
195NAME="AEN4425"
196></A
197><H2
198>Description</H2
199><P
200><SPAN
201CLASS="STRUCTNAME"
202>SDL_JoyBallEvent</SPAN
203> is a member of the <A
204HREF="sdlevent.html"
205><SPAN
206CLASS="STRUCTNAME"
207>SDL_Event</SPAN
208></A
209> union and is used when an event of type <TT
210CLASS="LITERAL"
211>SDL_JOYBALLMOTION</TT
212> is reported.</P
213><P
214>A <TT
215CLASS="LITERAL"
216>SDL_JOYBALLMOTION</TT
217> event occurs when a user moves a trackball on the joystick. The field <TT
218CLASS="STRUCTFIELD"
219><I
220>which</I
221></TT
222> is the index of the joystick that reported the event and <TT
223CLASS="STRUCTFIELD"
224><I
225>ball</I
226></TT
227> is the index of the trackball (for a more detailed explaination see the <A
228HREF="joystick.html"
229>Joystick section</A
230>). Trackballs only return relative motion, this is the change in position on the ball since it was last polled (last cycle of the event loop) and it is stored in <TT
231CLASS="STRUCTFIELD"
232><I
233>xrel</I
234></TT
235> and <TT
236CLASS="STRUCTFIELD"
237><I
238>yrel</I
239></TT
240>.</P
241></DIV
242><DIV
243CLASS="REFSECT1"
244><A
245NAME="AEN4439"
246></A
247><H2
248>See Also</H2
249><P
250><A
251HREF="sdlevent.html"
252><SPAN
253CLASS="STRUCTNAME"
254>SDL_Event</SPAN
255></A
256>,
257<A
258HREF="joystick.html"
259>Joystick Functions</A
260>,
261<A
262HREF="sdljoystickeventstate.html"
263><TT
264CLASS="FUNCTION"
265>SDL_JoystickEventState</TT
266></A
267>,
268<A
269HREF="sdljoystickgetball.html"
270><TT
271CLASS="FUNCTION"
272>SDL_JoystickGetBall</TT
273></A
274></P
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