Mercurial > sdl-ios-xcode
annotate docs/html/guideaudioexamples.html @ 1629:ef4a796e7f24
Fixed bug #55
From Christian Walther:
When writing my patch for #12, I ended up doing all sorts of changes to the way
application/window activating/deactivating is handled in the Quartz backend,
resulting in the attached patch. It does make the code a bit cleaner IMHO, but
as it might be regarded as a case of "if it ain't broken, don't fix it" I'd
like to hear other people's opinion about it. Please shout if some change
strikes you as unnecessary or wrong, and I'll explain the reasons behind it. As
far as I tested it, it does not introduce any new bugs, but I may well have
missed some.
- The most fundamental change (that triggered most of the others) is irrelevant
for the usual single-window SDL applications, it only affects the people who
are crazy enough to display other Cocoa windows alongside the SDL window (I'm
actually doing this currently, although the additional window only displays
debugging info and won't be present in the final product): Before, some things
were done on the application becoming active, some on the window becoming key,
and some on the window becoming main. Conceptually, all these actions belong to
the window becoming key, so that's what I implemented. However, since in a
single-window application these three events always happen together, the
previous implementation "ain't broken".
- This slightly changed the meaning of the SDL_APPMOUSEFOCUS flag from
SDL_GetAppState(): Before, it meant "window is main and mouse is inside window
(or mode is fullscreen)". Now, it means "window is key and mouse is inside
window (or mode is fullscreen)". It makes more sense to me that way. (See
http://developer.apple.com/documentation/Cocoa/Conceptual/WinPanel/Concepts/ChangingMainKeyWindow.html
for a discussion of what key and main windows are.) The other two flags are
unchanged: SDL_APPACTIVE = application is not hidden and window is not
minimized, SDL_APPINPUTFOCUS = window is key (or mode is fullscreen).
- As a side effect, the reorganization fixes the following two issues (and
maybe others) (but they could also be fixed in less invasive ways):
* A regression that was introduced in revision 1.42 of SDL_QuartzVideo.m
(http://libsdl.org/cgi/cvsweb.cgi/SDL12/src/video/quartz/SDL_QuartzVideo.m.diff?r1=1.41&r2=1.42)
(from half-desirable to undesirable behavior):
Situation: While in windowed mode, hide the cursor using
SDL_ShowCursor(SDL_DISABLE), move the mouse outside of the window so that the
cursor becomes visible again, and SDL_SetVideoMode() to a fullscreen mode.
What happened before revision 1.42: The cursor is visible, but becomes
invisible as soon as the mouse is moved (half-desirable).
What happens in revision 1.42 and after (including current CVS): The cursor is
visible and stays visible (undesirable).
What happens after my patch: The cursor is invisible from the beginning
(desirable).
* When the cursor is hidden and grabbed, switch away from the application using
cmd-tab (which ungrabs and makes the cursor visible), move the cursor outside
of the SDL window, then cmd-tab back to the application. In 1.2.8 and in the
current CVS, the cursor is re-grabbed, but it stays visible (immovable in the
middle of the window). With my patch, the cursor is correctly re-grabbed and
hidden. (For some reason, it still doesn't work correctly if you switch back to
the application using the dock instead of cmd-tab. I haven't been able to
figure out why. I can step over [NSCursor hide] being called in the debugger,
but it seems to have no effect.)
- The patch includes my patch for #12 (it was easier to obtain using cvs diff
that way). If you apply both of them, you will end up with 6 duplicate lines in
SDL_QuartzEvents.m.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Thu, 13 Apr 2006 14:17:48 +0000 |
parents | 355632dca928 |
children |
rev | line source |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >Audio Examples</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="Examples" | |
14 HREF="guideexamples.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="Event Examples" | |
17 HREF="guideeventexamples.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="CDROM Examples" | |
20 HREF="guidecdromexamples.html"></HEAD | |
21 ><BODY | |
22 CLASS="SECT1" | |
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="guideeventexamples.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 >Chapter 4. Examples</TD | |
57 ><TD | |
58 WIDTH="10%" | |
59 ALIGN="right" | |
60 VALIGN="bottom" | |
61 ><A | |
62 HREF="guidecdromexamples.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 ><DIV | |
72 CLASS="SECT1" | |
73 ><H1 | |
74 CLASS="SECT1" | |
75 ><A | |
76 NAME="GUIDEAUDIOEXAMPLES" | |
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77 ></A |
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78 >Audio Examples</H1 |
0 | 79 ><P |
80 ></P | |
81 ><DIV | |
82 CLASS="SECT2" | |
83 ><H2 | |
84 CLASS="SECT2" | |
85 ><A | |
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86 NAME="AEN382" |
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87 ></A |
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88 >Opening the audio device</H2 |
0 | 89 ><P |
90 ><PRE | |
91 CLASS="PROGRAMLISTING" | |
92 > SDL_AudioSpec wanted; | |
93 extern void fill_audio(void *udata, Uint8 *stream, int len); | |
94 | |
95 /* Set the audio format */ | |
96 wanted.freq = 22050; | |
97 wanted.format = AUDIO_S16; | |
98 wanted.channels = 2; /* 1 = mono, 2 = stereo */ | |
99 wanted.samples = 1024; /* Good low-latency value for callback */ | |
100 wanted.callback = fill_audio; | |
101 wanted.userdata = NULL; | |
102 | |
103 /* Open the audio device, forcing the desired format */ | |
104 if ( SDL_OpenAudio(&wanted, NULL) < 0 ) { | |
105 fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError()); | |
106 return(-1); | |
107 } | |
108 return(0);</PRE | |
109 ></P | |
110 ></DIV | |
111 ><DIV | |
112 CLASS="SECT2" | |
113 ><H2 | |
114 CLASS="SECT2" | |
115 ><A | |
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116 NAME="AEN386" |
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117 ></A |
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118 >Playing audio</H2 |
0 | 119 ><P |
120 ><PRE | |
121 CLASS="PROGRAMLISTING" | |
122 > static Uint8 *audio_chunk; | |
123 static Uint32 audio_len; | |
124 static Uint8 *audio_pos; | |
125 | |
126 /* The audio function callback takes the following parameters: | |
127 stream: A pointer to the audio buffer to be filled | |
128 len: The length (in bytes) of the audio buffer | |
129 */ | |
130 void fill_audio(void *udata, Uint8 *stream, int len) | |
131 { | |
132 /* Only play if we have data left */ | |
133 if ( audio_len == 0 ) | |
134 return; | |
135 | |
136 /* Mix as much data as possible */ | |
137 len = ( len > audio_len ? audio_len : len ); | |
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138 SDL_MixAudio(stream, audio_pos, len, SDL_MIX_MAXVOLUME); |
0 | 139 audio_pos += len; |
140 audio_len -= len; | |
141 } | |
142 | |
143 /* Load the audio data ... */ | |
144 | |
145 ;;;;; | |
146 | |
147 audio_pos = audio_chunk; | |
148 | |
149 /* Let the callback function play the audio chunk */ | |
150 SDL_PauseAudio(0); | |
151 | |
152 /* Do some processing */ | |
153 | |
154 ;;;;; | |
155 | |
156 /* Wait for sound to complete */ | |
157 while ( audio_len > 0 ) { | |
158 SDL_Delay(100); /* Sleep 1/10 second */ | |
159 } | |
160 SDL_CloseAudio();</PRE | |
161 ></P | |
162 ></DIV | |
163 ></DIV | |
164 ><DIV | |
165 CLASS="NAVFOOTER" | |
166 ><HR | |
167 ALIGN="LEFT" | |
168 WIDTH="100%"><TABLE | |
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169 SUMMARY="Footer navigation table" |
0 | 170 WIDTH="100%" |
171 BORDER="0" | |
172 CELLPADDING="0" | |
173 CELLSPACING="0" | |
174 ><TR | |
175 ><TD | |
176 WIDTH="33%" | |
177 ALIGN="left" | |
178 VALIGN="top" | |
179 ><A | |
180 HREF="guideeventexamples.html" | |
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181 ACCESSKEY="P" |
0 | 182 >Prev</A |
183 ></TD | |
184 ><TD | |
185 WIDTH="34%" | |
186 ALIGN="center" | |
187 VALIGN="top" | |
188 ><A | |
189 HREF="index.html" | |
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190 ACCESSKEY="H" |
0 | 191 >Home</A |
192 ></TD | |
193 ><TD | |
194 WIDTH="33%" | |
195 ALIGN="right" | |
196 VALIGN="top" | |
197 ><A | |
198 HREF="guidecdromexamples.html" | |
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199 ACCESSKEY="N" |
0 | 200 >Next</A |
201 ></TD | |
202 ></TR | |
203 ><TR | |
204 ><TD | |
205 WIDTH="33%" | |
206 ALIGN="left" | |
207 VALIGN="top" | |
208 >Event Examples</TD | |
209 ><TD | |
210 WIDTH="34%" | |
211 ALIGN="center" | |
212 VALIGN="top" | |
213 ><A | |
214 HREF="guideexamples.html" | |
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215 ACCESSKEY="U" |
0 | 216 >Up</A |
217 ></TD | |
218 ><TD | |
219 WIDTH="33%" | |
220 ALIGN="right" | |
221 VALIGN="top" | |
222 >CDROM Examples</TD | |
223 ></TR | |
224 ></TABLE | |
225 ></DIV | |
226 ></BODY | |
227 ></HTML | |
228 > |