Mercurial > sdl-ios-xcode
annotate docs/html/sdlkeysym.html @ 773:da0a2ad35bf4
Date: Sun, 4 Jan 2004 23:48:19 +0100
From: Max Horn
Subject: Re: Again Audio CD patch
Am 04.01.2004 um 22:38 schrieb Sam Lantinga:
>
> Okay, I fixed the buffering problems by simply using a 4 second buffer
> instead of a 1 second buffer. However, using your code I can't play an
> entire CD - the playback stops after the first song.
>
Found the problem: FSReadFork returns eofErr when the file is finished.
However, we check its return value for errors, and if anything but
noErr occurs, the reader thread aborts its current iteration. That is
bad, because it aborts before it can ever set the flag which tells that
the file is over (also, any remaining data which FSRead did return is
lost - so you'd not hear about to 4 seconds from the end of the file.
Furthermore, the computed data size was 8 bytes to high (I forgot to
account for the fact that the size of an (A)IFF chunk always contains
the chunk header & size fields, too). This is enough to make it work.
However, the end condition is rather fragile, so I tuned some other
things to be pessimistic (check for <= 0 instead of == 0, when eofErr
is encountered enforce mReadFilePosition == mFileLength). You never
know...
The attached patch fixes the issue for me.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Mon, 05 Jan 2004 00:57:51 +0000 |
parents | e5bc29de3f0a |
children | 355632dca928 |
rev | line source |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >SDL_keysym</TITLE | |
5 ><META | |
6 NAME="GENERATOR" | |
55
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.64 |
0 | 8 "><LINK |
9 REL="HOME" | |
10 TITLE="SDL Library Documentation" | |
11 HREF="index.html"><LINK | |
12 REL="UP" | |
13 TITLE="SDL Event Structures." | |
14 HREF="eventstructures.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="SDL_QuitEvent" | |
17 HREF="sdlquitevent.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDLKey" | |
20 HREF="sdlkey.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 | |
31 WIDTH="100%" | |
32 BORDER="0" | |
33 CELLPADDING="0" | |
34 CELLSPACING="0" | |
35 ><TR | |
36 ><TH | |
37 COLSPAN="3" | |
38 ALIGN="center" | |
39 >SDL Library Documentation</TH | |
40 ></TR | |
41 ><TR | |
42 ><TD | |
43 WIDTH="10%" | |
44 ALIGN="left" | |
45 VALIGN="bottom" | |
46 ><A | |
47 HREF="sdlquitevent.html" | |
48 >Prev</A | |
49 ></TD | |
50 ><TD | |
51 WIDTH="80%" | |
52 ALIGN="center" | |
53 VALIGN="bottom" | |
54 ></TD | |
55 ><TD | |
56 WIDTH="10%" | |
57 ALIGN="right" | |
58 VALIGN="bottom" | |
59 ><A | |
60 HREF="sdlkey.html" | |
61 >Next</A | |
62 ></TD | |
63 ></TR | |
64 ></TABLE | |
65 ><HR | |
66 ALIGN="LEFT" | |
67 WIDTH="100%"></DIV | |
68 ><H1 | |
69 ><A | |
70 NAME="SDLKEYSYM" | |
71 >SDL_keysym</A | |
72 ></H1 | |
73 ><DIV | |
74 CLASS="REFNAMEDIV" | |
75 ><A | |
181
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76 NAME="AEN4275" |
0 | 77 ></A |
78 ><H2 | |
79 >Name</H2 | |
80 >SDL_keysym -- Keysym structure</DIV | |
81 ><DIV | |
82 CLASS="REFSECT1" | |
83 ><A | |
181
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84 NAME="AEN4278" |
0 | 85 ></A |
86 ><H2 | |
87 >Structure Definition</H2 | |
88 ><PRE | |
89 CLASS="PROGRAMLISTING" | |
90 >typedef struct{ | |
91 Uint8 scancode; | |
92 SDLKey sym; | |
93 SDLMod mod; | |
94 Uint16 unicode; | |
95 } SDL_keysym;</PRE | |
96 ></DIV | |
97 ><DIV | |
98 CLASS="REFSECT1" | |
99 ><A | |
181
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100 NAME="AEN4281" |
0 | 101 ></A |
102 ><H2 | |
103 >Structure Data</H2 | |
104 ><DIV | |
105 CLASS="INFORMALTABLE" | |
106 ><A | |
181
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107 NAME="AEN4283" |
0 | 108 ></A |
109 ><P | |
110 ></P | |
111 ><TABLE | |
112 BORDER="0" | |
113 CLASS="CALSTABLE" | |
114 ><TBODY | |
115 ><TR | |
116 ><TD | |
117 ALIGN="LEFT" | |
118 VALIGN="TOP" | |
119 ><TT | |
120 CLASS="STRUCTFIELD" | |
121 ><I | |
122 >scancode</I | |
123 ></TT | |
124 ></TD | |
125 ><TD | |
126 ALIGN="LEFT" | |
127 VALIGN="TOP" | |
128 >Hardware specific scancode</TD | |
129 ></TR | |
130 ><TR | |
131 ><TD | |
132 ALIGN="LEFT" | |
133 VALIGN="TOP" | |
134 ><TT | |
135 CLASS="STRUCTFIELD" | |
136 ><I | |
137 >sym</I | |
138 ></TT | |
139 ></TD | |
140 ><TD | |
141 ALIGN="LEFT" | |
142 VALIGN="TOP" | |
143 >SDL virtual keysym</TD | |
144 ></TR | |
145 ><TR | |
146 ><TD | |
147 ALIGN="LEFT" | |
148 VALIGN="TOP" | |
149 ><TT | |
150 CLASS="STRUCTFIELD" | |
151 ><I | |
152 >mod</I | |
153 ></TT | |
154 ></TD | |
155 ><TD | |
156 ALIGN="LEFT" | |
157 VALIGN="TOP" | |
158 >Current key modifiers</TD | |
159 ></TR | |
160 ><TR | |
161 ><TD | |
162 ALIGN="LEFT" | |
163 VALIGN="TOP" | |
164 ><TT | |
165 CLASS="STRUCTFIELD" | |
166 ><I | |
167 >unicode</I | |
168 ></TT | |
169 ></TD | |
170 ><TD | |
171 ALIGN="LEFT" | |
172 VALIGN="TOP" | |
173 >Translated character</TD | |
174 ></TR | |
175 ></TBODY | |
176 ></TABLE | |
177 ><P | |
178 ></P | |
179 ></DIV | |
180 ></DIV | |
181 ><DIV | |
182 CLASS="REFSECT1" | |
183 ><A | |
181
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184 NAME="AEN4302" |
0 | 185 ></A |
186 ><H2 | |
187 >Description</H2 | |
188 ><P | |
189 >The <SPAN | |
190 CLASS="STRUCTNAME" | |
191 >SDL_keysym</SPAN | |
192 > structure is used by reporting key presses and releases since it is a part of the <A | |
193 HREF="sdlkeyboardevent.html" | |
194 ><SPAN | |
195 CLASS="STRUCTNAME" | |
196 >SDL_KeyboardEvent</SPAN | |
197 ></A | |
198 >.</P | |
199 ><P | |
200 >The <TT | |
201 CLASS="STRUCTFIELD" | |
202 ><I | |
203 >scancode</I | |
204 ></TT | |
205 > field should generally be left alone, it is the hardware dependent scancode returned by the keyboard. The <TT | |
206 CLASS="STRUCTFIELD" | |
207 ><I | |
208 >sym</I | |
209 ></TT | |
210 > field is extremely useful. It is the SDL-defined value of the key (see <A | |
211 HREF="sdlkey.html" | |
212 >SDL Key Syms</A | |
213 >. This field is very useful when you are checking for certain key presses, like so: | |
214 <PRE | |
215 CLASS="PROGRAMLISTING" | |
216 >. | |
217 . | |
218 while(SDL_PollEvent(&event)){ | |
219 switch(event.type){ | |
220 case SDL_KEYDOWN: | |
221 if(event.key.keysym.sym==SDLK_LEFT) | |
222 move_left(); | |
223 break; | |
224 . | |
225 . | |
226 . | |
227 } | |
228 } | |
229 . | |
230 .</PRE | |
231 > | |
232 <TT | |
233 CLASS="STRUCTFIELD" | |
234 ><I | |
235 >mod</I | |
236 ></TT | |
237 > stores the current state of the keyboard modifiers as explained in <A | |
238 HREF="sdlgetmodstate.html" | |
239 ><TT | |
240 CLASS="FUNCTION" | |
241 >SDL_GetModState</TT | |
242 ></A | |
243 >. The <TT | |
244 CLASS="STRUCTFIELD" | |
245 ><I | |
246 >unicode</I | |
247 ></TT | |
248 > is only used when UNICODE translation is enabled with <A | |
249 HREF="sdlenableunicode.html" | |
250 ><TT | |
251 CLASS="FUNCTION" | |
252 >SDL_EnableUNICODE</TT | |
253 ></A | |
254 >. If <TT | |
255 CLASS="STRUCTFIELD" | |
256 ><I | |
257 >unicode</I | |
258 ></TT | |
259 > is non-zero then this a the UNICODE character corresponding to the keypress. If the high 9 bits of the character are 0, then this maps to the equivalent ASCII character: | |
260 <PRE | |
261 CLASS="PROGRAMLISTING" | |
262 >char ch; | |
263 if ( (keysym.unicode & 0xFF80) == 0 ) { | |
264 ch = keysym.unicode & 0x7F; | |
265 } | |
266 else { | |
267 printf("An International Character.\n"); | |
268 }</PRE | |
269 > | |
270 UNICODE translation does have a slight overhead so don't enable it unless its needed.</P | |
271 ></DIV | |
272 ><DIV | |
273 CLASS="REFSECT1" | |
274 ><A | |
181
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275 NAME="AEN4321" |
0 | 276 ></A |
277 ><H2 | |
278 >See Also</H2 | |
279 ><P | |
280 ><A | |
281 HREF="sdlkey.html" | |
282 ><SPAN | |
283 CLASS="STRUCTNAME" | |
284 >SDLKey</SPAN | |
285 ></A | |
286 ></P | |
287 ></DIV | |
288 ><DIV | |
289 CLASS="NAVFOOTER" | |
290 ><HR | |
291 ALIGN="LEFT" | |
292 WIDTH="100%"><TABLE | |
293 WIDTH="100%" | |
294 BORDER="0" | |
295 CELLPADDING="0" | |
296 CELLSPACING="0" | |
297 ><TR | |
298 ><TD | |
299 WIDTH="33%" | |
300 ALIGN="left" | |
301 VALIGN="top" | |
302 ><A | |
303 HREF="sdlquitevent.html" | |
304 >Prev</A | |
305 ></TD | |
306 ><TD | |
307 WIDTH="34%" | |
308 ALIGN="center" | |
309 VALIGN="top" | |
310 ><A | |
311 HREF="index.html" | |
312 >Home</A | |
313 ></TD | |
314 ><TD | |
315 WIDTH="33%" | |
316 ALIGN="right" | |
317 VALIGN="top" | |
318 ><A | |
319 HREF="sdlkey.html" | |
320 >Next</A | |
321 ></TD | |
322 ></TR | |
323 ><TR | |
324 ><TD | |
325 WIDTH="33%" | |
326 ALIGN="left" | |
327 VALIGN="top" | |
328 >SDL_QuitEvent</TD | |
329 ><TD | |
330 WIDTH="34%" | |
331 ALIGN="center" | |
332 VALIGN="top" | |
333 ><A | |
334 HREF="eventstructures.html" | |
335 >Up</A | |
336 ></TD | |
337 ><TD | |
338 WIDTH="33%" | |
339 ALIGN="right" | |
340 VALIGN="top" | |
341 >SDLKey</TD | |
342 ></TR | |
343 ></TABLE | |
344 ></DIV | |
345 ></BODY | |
346 ></HTML | |
347 > |