Mercurial > sdl-ios-xcode
annotate docs/html/joystick.html @ 1544:ab1e4c41ab71
Fixed bug #33
Mike Frysinger wrote:
> with libsdl-1.2.9, some games (like bomberclone) started
> segfaulting in Gentoo
[...snip...]
> the last change in the last hunk:
[...snip...]
> if i change the statement to read:
> (table[which].blit_features & GetBlitFeatures()) == GetBlitFeatures()
> bomberclone no longer segfaults on my box
Alex Volkov wrote:
> The test "(table[which].blit_features & GetBlitFeatures()) ==
> table[which].blit_features)" is correct, and the previous
> "(table[which].cpu_mmx == SDL_HasMMX())" was actually broken.
I think there is potentially a slightly different cause of the above problem.
During the introduction of the Altivec code, the blit_table struct field
'alpha' got changed from a straightforward enum to a bitmask, which makes
perfect sense by itself. However, now the table driven blitter selection code
in SDL_CalculateBlitN() can choose the wrong blitters when searching for a
NO_ALPHA blitter because of the following code:
int a_need = 0;
...
(a_need & table[which].alpha) == a_need &&
When searching through the normal_blit_2[] table, a SET_ALPHA blitter (like
Blit_RGB565_ARGB8888) can now be selected instead of a NO_ALPHA one, causing
alpha channel bits to appear in a non-alpha destination surface. I suppose this
could theoretically be an indirect cause of the segfault mentioned above.
I *think* this can be fixed by changing to
int a_need = NO_ALPHA;
author | Sam Lantinga <slouken@libsdl.org> |
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date | Wed, 15 Mar 2006 15:47:49 +0000 |
parents | 355632dca928 |
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rev | line source |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >Joystick</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="SDL Reference" | |
14 HREF="reference.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="SDL_JoystickEventState" | |
17 HREF="sdljoystickeventstate.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_NumJoysticks" | |
20 HREF="sdlnumjoysticks.html"><META | |
21 NAME="KEYWORD" | |
22 CONTENT="joystick"><META | |
23 NAME="KEYWORD" | |
24 CONTENT="function"></HEAD | |
25 ><BODY | |
26 CLASS="CHAPTER" | |
27 BGCOLOR="#FFF8DC" | |
28 TEXT="#000000" | |
29 LINK="#0000ee" | |
30 VLINK="#551a8b" | |
31 ALINK="#ff0000" | |
32 ><DIV | |
33 CLASS="NAVHEADER" | |
34 ><TABLE | |
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35 SUMMARY="Header navigation table" |
0 | 36 WIDTH="100%" |
37 BORDER="0" | |
38 CELLPADDING="0" | |
39 CELLSPACING="0" | |
40 ><TR | |
41 ><TH | |
42 COLSPAN="3" | |
43 ALIGN="center" | |
44 >SDL Library Documentation</TH | |
45 ></TR | |
46 ><TR | |
47 ><TD | |
48 WIDTH="10%" | |
49 ALIGN="left" | |
50 VALIGN="bottom" | |
51 ><A | |
52 HREF="sdljoystickeventstate.html" | |
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53 ACCESSKEY="P" |
0 | 54 >Prev</A |
55 ></TD | |
56 ><TD | |
57 WIDTH="80%" | |
58 ALIGN="center" | |
59 VALIGN="bottom" | |
60 ></TD | |
61 ><TD | |
62 WIDTH="10%" | |
63 ALIGN="right" | |
64 VALIGN="bottom" | |
65 ><A | |
66 HREF="sdlnumjoysticks.html" | |
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67 ACCESSKEY="N" |
0 | 68 >Next</A |
69 ></TD | |
70 ></TR | |
71 ></TABLE | |
72 ><HR | |
73 ALIGN="LEFT" | |
74 WIDTH="100%"></DIV | |
75 ><DIV | |
76 CLASS="CHAPTER" | |
77 ><H1 | |
78 ><A | |
79 NAME="JOYSTICK" | |
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80 ></A |
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81 >Chapter 9. Joystick</H1 |
0 | 82 ><DIV |
83 CLASS="TOC" | |
84 ><DL | |
85 ><DT | |
86 ><B | |
87 >Table of Contents</B | |
88 ></DT | |
89 ><DT | |
90 ><A | |
91 HREF="sdlnumjoysticks.html" | |
92 >SDL_NumJoysticks</A | |
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93 > -- Count available joysticks.</DT |
0 | 94 ><DT |
95 ><A | |
96 HREF="sdljoystickname.html" | |
97 >SDL_JoystickName</A | |
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98 > -- Get joystick name.</DT |
0 | 99 ><DT |
100 ><A | |
101 HREF="sdljoystickopen.html" | |
102 >SDL_JoystickOpen</A | |
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103 > -- Opens a joystick for use.</DT |
0 | 104 ><DT |
105 ><A | |
106 HREF="sdljoystickopened.html" | |
107 >SDL_JoystickOpened</A | |
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108 > -- Determine if a joystick has been opened</DT |
0 | 109 ><DT |
110 ><A | |
111 HREF="sdljoystickindex.html" | |
112 >SDL_JoystickIndex</A | |
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113 > -- Get the index of an SDL_Joystick.</DT |
0 | 114 ><DT |
115 ><A | |
116 HREF="sdljoysticknumaxes.html" | |
117 >SDL_JoystickNumAxes</A | |
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118 > -- Get the number of joystick axes</DT |
0 | 119 ><DT |
120 ><A | |
121 HREF="sdljoysticknumballs.html" | |
122 >SDL_JoystickNumBalls</A | |
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123 > -- Get the number of joystick trackballs</DT |
0 | 124 ><DT |
125 ><A | |
126 HREF="sdljoysticknumhats.html" | |
127 >SDL_JoystickNumHats</A | |
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128 > -- Get the number of joystick hats</DT |
0 | 129 ><DT |
130 ><A | |
131 HREF="sdljoysticknumbuttons.html" | |
132 >SDL_JoystickNumButtons</A | |
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133 > -- Get the number of joysitck buttons</DT |
0 | 134 ><DT |
135 ><A | |
136 HREF="sdljoystickupdate.html" | |
137 >SDL_JoystickUpdate</A | |
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138 > -- Updates the state of all joysticks</DT |
0 | 139 ><DT |
140 ><A | |
141 HREF="sdljoystickgetaxis.html" | |
142 >SDL_JoystickGetAxis</A | |
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143 > -- Get the current state of an axis</DT |
0 | 144 ><DT |
145 ><A | |
146 HREF="sdljoystickgethat.html" | |
147 >SDL_JoystickGetHat</A | |
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148 > -- Get the current state of a joystick hat</DT |
0 | 149 ><DT |
150 ><A | |
151 HREF="sdljoystickgetbutton.html" | |
152 >SDL_JoystickGetButton</A | |
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153 > -- Get the current state of a given button on a given joystick</DT |
0 | 154 ><DT |
155 ><A | |
156 HREF="sdljoystickgetball.html" | |
157 >SDL_JoystickGetBall</A | |
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158 > -- Get relative trackball motion</DT |
0 | 159 ><DT |
160 ><A | |
161 HREF="sdljoystickclose.html" | |
162 >SDL_JoystickClose</A | |
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163 > -- Closes a previously opened joystick</DT |
0 | 164 ></DL |
165 ></DIV | |
166 ><P | |
167 >Joysticks, and other similar input devices, have a very strong role in game playing and SDL provides comprehensive support for them. Axes, Buttons, POV Hats and trackballs are all supported.</P | |
168 ><P | |
169 >Joystick support is initialized by passed the <TT | |
170 CLASS="LITERAL" | |
171 >SDL_INIT_JOYSTICK</TT | |
172 > flag to <A | |
173 HREF="sdlinit.html" | |
174 ><TT | |
175 CLASS="FUNCTION" | |
176 >SDL_Init</TT | |
177 ></A | |
178 >. Once initilized joysticks must be opened using <A | |
179 HREF="sdljoystickopen.html" | |
180 ><TT | |
181 CLASS="FUNCTION" | |
182 >SDL_JoystickOpen</TT | |
183 ></A | |
184 >.</P | |
185 ><P | |
186 >While using the functions describe in this secton may seem like the best way to access and read from joysticks, in most cases they aren't. Ideally joysticks should be read using the <A | |
187 HREF="event.html" | |
188 >event</A | |
189 > system. To enable this, you must set the joystick event processing state with <A | |
190 HREF="sdljoystickeventstate.html" | |
191 ><TT | |
192 CLASS="FUNCTION" | |
193 >SDL_JoystickEventState</TT | |
194 ></A | |
195 >. Joysticks must be <A | |
196 HREF="sdljoystickopen.html" | |
197 >opened</A | |
198 > before they can be used of course.</P | |
199 ><DIV | |
200 CLASS="NOTE" | |
201 ><BLOCKQUOTE | |
202 CLASS="NOTE" | |
203 ><P | |
204 ><B | |
205 >Note: </B | |
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206 >If you are <SPAN |
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207 CLASS="emphasis" |
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208 ><I |
0 | 209 CLASS="EMPHASIS" |
210 >not</I | |
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211 ></SPAN |
0 | 212 > handling the joystick via the event queue then you must explicitly request a joystick update by calling <A |
213 HREF="sdljoystickupdate.html" | |
214 ><TT | |
215 CLASS="FUNCTION" | |
216 >SDL_JoystickUpdate</TT | |
217 ></A | |
218 >.</P | |
219 ></BLOCKQUOTE | |
220 ></DIV | |
221 ><DIV | |
222 CLASS="NOTE" | |
223 ><BLOCKQUOTE | |
224 CLASS="NOTE" | |
225 ><P | |
226 ><B | |
227 >Note: </B | |
228 >Force Feedback is not yet support. Sam (slouken@libsdl.org) is soliciting suggestions from people with force-feedback experience on the best wat to desgin the API.</P | |
229 ></BLOCKQUOTE | |
230 ></DIV | |
231 ></DIV | |
232 ><DIV | |
233 CLASS="NAVFOOTER" | |
234 ><HR | |
235 ALIGN="LEFT" | |
236 WIDTH="100%"><TABLE | |
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237 SUMMARY="Footer navigation table" |
0 | 238 WIDTH="100%" |
239 BORDER="0" | |
240 CELLPADDING="0" | |
241 CELLSPACING="0" | |
242 ><TR | |
243 ><TD | |
244 WIDTH="33%" | |
245 ALIGN="left" | |
246 VALIGN="top" | |
247 ><A | |
248 HREF="sdljoystickeventstate.html" | |
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249 ACCESSKEY="P" |
0 | 250 >Prev</A |
251 ></TD | |
252 ><TD | |
253 WIDTH="34%" | |
254 ALIGN="center" | |
255 VALIGN="top" | |
256 ><A | |
257 HREF="index.html" | |
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258 ACCESSKEY="H" |
0 | 259 >Home</A |
260 ></TD | |
261 ><TD | |
262 WIDTH="33%" | |
263 ALIGN="right" | |
264 VALIGN="top" | |
265 ><A | |
266 HREF="sdlnumjoysticks.html" | |
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267 ACCESSKEY="N" |
0 | 268 >Next</A |
269 ></TD | |
270 ></TR | |
271 ><TR | |
272 ><TD | |
273 WIDTH="33%" | |
274 ALIGN="left" | |
275 VALIGN="top" | |
276 >SDL_JoystickEventState</TD | |
277 ><TD | |
278 WIDTH="34%" | |
279 ALIGN="center" | |
280 VALIGN="top" | |
281 ><A | |
282 HREF="reference.html" | |
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283 ACCESSKEY="U" |
0 | 284 >Up</A |
285 ></TD | |
286 ><TD | |
287 WIDTH="33%" | |
288 ALIGN="right" | |
289 VALIGN="top" | |
290 >SDL_NumJoysticks</TD | |
291 ></TR | |
292 ></TABLE | |
293 ></DIV | |
294 ></BODY | |
295 ></HTML | |
296 > |