Mercurial > sdl-ios-xcode
annotate docs/html/sdljoystickgetaxis.html @ 914:bbf8dcc8aed6
Date: Wed, 23 Jun 2004 17:05:33 -0400
From: Chris Nelson
Subject: [SDL] [Patch] WiseGroup MP-8800 / MP-8866 (PS2 Joystick)
In the current cvs version, SDL doesn't handle these Playstation2
controller => USB adapters correctly, in linux.
It will always assume that the maximum number of joysticks (2 in the
case of the MP-8866, 4 in the case of the 8800) are plugged in. This is
bad not only because it allows SDL to exaggerate the number of logical
joysticks, but primarily because the joystick axes are mapped
incorrectly, all over the place, such that the devices are effectively
unusable unless you have the maximum number of joysticks plugged in.
My changes to src/joystick/linux/SDL_sysjoystick.c build on another's
previous work (which was a special case for this very joystick,
actually), and fix both of these problems, as well as making the current
code a little more general, to allow for others to more easily drop in
code for quirky joysticks such as these.
I've tested this code under 2.6.7 as well as 2.4.24... Both work as
advertised (provided you load the JOYDEV linux code as a module,
otherwise they won't work at all, new code or old, but that's another
issue entirely).
Though this sounds horribly formal, you have my permission to distribute
all of my work on this issue under the LGPL. So there.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Sun, 25 Jul 2004 18:31:50 +0000 |
parents | 355632dca928 |
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rev | line source |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >SDL_JoystickGetAxis</TITLE | |
5 ><META | |
6 NAME="GENERATOR" | |
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ |
0 | 8 "><LINK |
9 REL="HOME" | |
10 TITLE="SDL Library Documentation" | |
11 HREF="index.html"><LINK | |
12 REL="UP" | |
13 TITLE="Joystick" | |
14 HREF="joystick.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="SDL_JoystickUpdate" | |
17 HREF="sdljoystickupdate.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_JoystickGetHat" | |
20 HREF="sdljoystickgethat.html"></HEAD | |
21 ><BODY | |
22 CLASS="REFENTRY" | |
23 BGCOLOR="#FFF8DC" | |
24 TEXT="#000000" | |
25 LINK="#0000ee" | |
26 VLINK="#551a8b" | |
27 ALINK="#ff0000" | |
28 ><DIV | |
29 CLASS="NAVHEADER" | |
30 ><TABLE | |
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31 SUMMARY="Header navigation table" |
0 | 32 WIDTH="100%" |
33 BORDER="0" | |
34 CELLPADDING="0" | |
35 CELLSPACING="0" | |
36 ><TR | |
37 ><TH | |
38 COLSPAN="3" | |
39 ALIGN="center" | |
40 >SDL Library Documentation</TH | |
41 ></TR | |
42 ><TR | |
43 ><TD | |
44 WIDTH="10%" | |
45 ALIGN="left" | |
46 VALIGN="bottom" | |
47 ><A | |
48 HREF="sdljoystickupdate.html" | |
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49 ACCESSKEY="P" |
0 | 50 >Prev</A |
51 ></TD | |
52 ><TD | |
53 WIDTH="80%" | |
54 ALIGN="center" | |
55 VALIGN="bottom" | |
56 ></TD | |
57 ><TD | |
58 WIDTH="10%" | |
59 ALIGN="right" | |
60 VALIGN="bottom" | |
61 ><A | |
62 HREF="sdljoystickgethat.html" | |
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63 ACCESSKEY="N" |
0 | 64 >Next</A |
65 ></TD | |
66 ></TR | |
67 ></TABLE | |
68 ><HR | |
69 ALIGN="LEFT" | |
70 WIDTH="100%"></DIV | |
71 ><H1 | |
72 ><A | |
73 NAME="SDLJOYSTICKGETAXIS" | |
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74 ></A |
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75 >SDL_JoystickGetAxis</H1 |
0 | 76 ><DIV |
77 CLASS="REFNAMEDIV" | |
78 ><A | |
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79 NAME="AEN6320" |
0 | 80 ></A |
81 ><H2 | |
82 >Name</H2 | |
83 >SDL_JoystickGetAxis -- Get the current state of an axis</DIV | |
84 ><DIV | |
85 CLASS="REFSYNOPSISDIV" | |
86 ><A | |
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87 NAME="AEN6323" |
0 | 88 ></A |
89 ><H2 | |
90 >Synopsis</H2 | |
91 ><DIV | |
92 CLASS="FUNCSYNOPSIS" | |
93 ><A | |
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94 NAME="AEN6324" |
0 | 95 ></A |
96 ><P | |
97 ></P | |
98 ><PRE | |
99 CLASS="FUNCSYNOPSISINFO" | |
100 >#include "SDL.h"</PRE | |
101 ><P | |
102 ><CODE | |
103 ><CODE | |
104 CLASS="FUNCDEF" | |
105 >Sint16 <B | |
106 CLASS="FSFUNC" | |
107 >SDL_JoystickGetAxis</B | |
108 ></CODE | |
109 >(SDL_Joystick *joystick, int axis);</CODE | |
110 ></P | |
111 ><P | |
112 ></P | |
113 ></DIV | |
114 ></DIV | |
115 ><DIV | |
116 CLASS="REFSECT1" | |
117 ><A | |
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118 NAME="AEN6330" |
0 | 119 ></A |
120 ><H2 | |
121 >Description</H2 | |
122 ><P | |
123 ><TT | |
124 CLASS="FUNCTION" | |
125 >SDL_JoystickGetAxis</TT | |
126 > returns the current state of the given <TT | |
127 CLASS="PARAMETER" | |
128 ><I | |
129 >axis</I | |
130 ></TT | |
131 > on the given <TT | |
132 CLASS="PARAMETER" | |
133 ><I | |
134 >joystick</I | |
135 ></TT | |
136 >.</P | |
137 ><P | |
138 >On most modern joysticks the X axis is usually represented by <TT | |
139 CLASS="PARAMETER" | |
140 ><I | |
141 >axis</I | |
142 ></TT | |
143 > 0 and the Y axis by <TT | |
144 CLASS="PARAMETER" | |
145 ><I | |
146 >axis</I | |
147 ></TT | |
148 > 1. The value returned by <TT | |
149 CLASS="FUNCTION" | |
150 >SDL_JoystickGetAxis</TT | |
151 > is a signed integer (-32768 to 32768) representing the current position of the <TT | |
152 CLASS="PARAMETER" | |
153 ><I | |
154 >axis</I | |
155 ></TT | |
156 >, it maybe necessary to impose certain tolerances on these values to account for jitter. It is worth noting that some joysticks use axes 2 and 3 for extra buttons.</P | |
157 ></DIV | |
158 ><DIV | |
159 CLASS="REFSECT1" | |
160 ><A | |
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161 NAME="AEN6341" |
0 | 162 ></A |
163 ><H2 | |
164 >Return Value</H2 | |
165 ><P | |
166 >Returns a 16-bit signed integer representing the current position of the <TT | |
167 CLASS="PARAMETER" | |
168 ><I | |
169 >axis</I | |
170 ></TT | |
171 >.</P | |
172 ></DIV | |
173 ><DIV | |
174 CLASS="REFSECT1" | |
175 ><A | |
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176 NAME="AEN6345" |
0 | 177 ></A |
178 ><H2 | |
179 >Examples</H2 | |
180 ><P | |
181 ><PRE | |
182 CLASS="PROGRAMLISTING" | |
183 >Sint16 x_move, y_move; | |
184 SDL_Joystick *joy1; | |
185 . | |
186 . | |
187 x_move=SDL_JoystickGetAxis(joy1, 0); | |
188 y_move=SDL_JoystickGetAxis(joy1, 1);</PRE | |
189 ></P | |
190 ></DIV | |
191 ><DIV | |
192 CLASS="REFSECT1" | |
193 ><A | |
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194 NAME="AEN6349" |
0 | 195 ></A |
196 ><H2 | |
197 >See Also</H2 | |
198 ><P | |
199 ><A | |
200 HREF="sdljoysticknumaxes.html" | |
201 ><TT | |
202 CLASS="FUNCTION" | |
203 >SDL_JoystickNumAxes</TT | |
204 ></A | |
205 ></P | |
206 ></DIV | |
207 ><DIV | |
208 CLASS="NAVFOOTER" | |
209 ><HR | |
210 ALIGN="LEFT" | |
211 WIDTH="100%"><TABLE | |
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212 SUMMARY="Footer navigation table" |
0 | 213 WIDTH="100%" |
214 BORDER="0" | |
215 CELLPADDING="0" | |
216 CELLSPACING="0" | |
217 ><TR | |
218 ><TD | |
219 WIDTH="33%" | |
220 ALIGN="left" | |
221 VALIGN="top" | |
222 ><A | |
223 HREF="sdljoystickupdate.html" | |
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224 ACCESSKEY="P" |
0 | 225 >Prev</A |
226 ></TD | |
227 ><TD | |
228 WIDTH="34%" | |
229 ALIGN="center" | |
230 VALIGN="top" | |
231 ><A | |
232 HREF="index.html" | |
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233 ACCESSKEY="H" |
0 | 234 >Home</A |
235 ></TD | |
236 ><TD | |
237 WIDTH="33%" | |
238 ALIGN="right" | |
239 VALIGN="top" | |
240 ><A | |
241 HREF="sdljoystickgethat.html" | |
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242 ACCESSKEY="N" |
0 | 243 >Next</A |
244 ></TD | |
245 ></TR | |
246 ><TR | |
247 ><TD | |
248 WIDTH="33%" | |
249 ALIGN="left" | |
250 VALIGN="top" | |
251 >SDL_JoystickUpdate</TD | |
252 ><TD | |
253 WIDTH="34%" | |
254 ALIGN="center" | |
255 VALIGN="top" | |
256 ><A | |
257 HREF="joystick.html" | |
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258 ACCESSKEY="U" |
0 | 259 >Up</A |
260 ></TD | |
261 ><TD | |
262 WIDTH="33%" | |
263 ALIGN="right" | |
264 VALIGN="top" | |
265 >SDL_JoystickGetHat</TD | |
266 ></TR | |
267 ></TABLE | |
268 ></DIV | |
269 ></BODY | |
270 ></HTML | |
271 > |