Mercurial > sdl-ios-xcode
annotate docs/html/sdlmixaudio.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 |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >SDL_MixAudio</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="Audio" | |
14 HREF="audio.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="SDL_ConvertAudio" | |
17 HREF="sdlconvertaudio.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_LockAudio" | |
20 HREF="sdllockaudio.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="sdlconvertaudio.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="sdllockaudio.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="SDLMIXAUDIO" | |
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74 ></A |
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75 >SDL_MixAudio</H1 |
0 | 76 ><DIV |
77 CLASS="REFNAMEDIV" | |
78 ><A | |
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79 NAME="AEN7107" |
0 | 80 ></A |
81 ><H2 | |
82 >Name</H2 | |
83 >SDL_MixAudio -- Mix audio data</DIV | |
84 ><DIV | |
85 CLASS="REFSYNOPSISDIV" | |
86 ><A | |
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87 NAME="AEN7110" |
0 | 88 ></A |
89 ><H2 | |
90 >Synopsis</H2 | |
91 ><DIV | |
92 CLASS="FUNCSYNOPSIS" | |
93 ><A | |
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94 NAME="AEN7111" |
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 >void <B | |
106 CLASS="FSFUNC" | |
107 >SDL_MixAudio</B | |
108 ></CODE | |
109 >(Uint8 *dst, Uint8 *src, Uint32 len, int volume);</CODE | |
110 ></P | |
111 ><P | |
112 ></P | |
113 ></DIV | |
114 ></DIV | |
115 ><DIV | |
116 CLASS="REFSECT1" | |
117 ><A | |
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118 NAME="AEN7117" |
0 | 119 ></A |
120 ><H2 | |
121 >Description</H2 | |
122 ><P | |
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123 >This function takes two audio buffers of <TT |
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124 CLASS="PARAMETER" |
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125 ><I |
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126 >len</I |
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127 ></TT |
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128 > bytes each |
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129 of the playing audio format and mixes them, performing addition, volume |
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130 adjustment, and overflow clipping. The <TT |
0 | 131 CLASS="PARAMETER" |
132 ><I | |
133 >volume</I | |
134 ></TT | |
55
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135 > ranges |
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136 from 0 to <TT |
0 | 137 CLASS="LITERAL" |
138 >SDL_MIX_MAXVOLUME</TT | |
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139 > and should be set to the maximum |
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140 value for full audio volume. Note this does not change hardware volume. This is |
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141 provided for convenience -- you can mix your own audio data.</P |
181
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142 ><DIV |
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143 CLASS="NOTE" |
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144 ><BLOCKQUOTE |
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145 CLASS="NOTE" |
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146 ><P |
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147 ><B |
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148 >Note: </B |
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149 >Do not use this function for mixing together more than two streams of sample |
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150 data. The output from repeated application of this function may be distorted |
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151 by clipping, because there is no accumulator with greater range than the |
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152 input (not to mention this being an inefficient way of doing it). |
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153 Use mixing functions from SDL_mixer, OpenAL, or write your own mixer instead.</P |
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154 ></BLOCKQUOTE |
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155 ></DIV |
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157 ><DIV | |
158 CLASS="REFSECT1" | |
159 ><A | |
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160 NAME="AEN7125" |
0 | 161 ></A |
162 ><H2 | |
163 >See Also</H2 | |
164 ><P | |
165 ><A | |
166 HREF="sdlopenaudio.html" | |
167 ><TT | |
168 CLASS="FUNCTION" | |
169 >SDL_OpenAudio</TT | |
170 ></A | |
171 ></P | |
172 ></DIV | |
173 ><DIV | |
174 CLASS="NAVFOOTER" | |
175 ><HR | |
176 ALIGN="LEFT" | |
177 WIDTH="100%"><TABLE | |
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178 SUMMARY="Footer navigation table" |
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180 BORDER="0" | |
181 CELLPADDING="0" | |
182 CELLSPACING="0" | |
183 ><TR | |
184 ><TD | |
185 WIDTH="33%" | |
186 ALIGN="left" | |
187 VALIGN="top" | |
188 ><A | |
189 HREF="sdlconvertaudio.html" | |
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190 ACCESSKEY="P" |
0 | 191 >Prev</A |
192 ></TD | |
193 ><TD | |
194 WIDTH="34%" | |
195 ALIGN="center" | |
196 VALIGN="top" | |
197 ><A | |
198 HREF="index.html" | |
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199 ACCESSKEY="H" |
0 | 200 >Home</A |
201 ></TD | |
202 ><TD | |
203 WIDTH="33%" | |
204 ALIGN="right" | |
205 VALIGN="top" | |
206 ><A | |
207 HREF="sdllockaudio.html" | |
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208 ACCESSKEY="N" |
0 | 209 >Next</A |
210 ></TD | |
211 ></TR | |
212 ><TR | |
213 ><TD | |
214 WIDTH="33%" | |
215 ALIGN="left" | |
216 VALIGN="top" | |
217 >SDL_ConvertAudio</TD | |
218 ><TD | |
219 WIDTH="34%" | |
220 ALIGN="center" | |
221 VALIGN="top" | |
222 ><A | |
223 HREF="audio.html" | |
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224 ACCESSKEY="U" |
0 | 225 >Up</A |
226 ></TD | |
227 ><TD | |
228 WIDTH="33%" | |
229 ALIGN="right" | |
230 VALIGN="top" | |
231 >SDL_LockAudio</TD | |
232 ></TR | |
233 ></TABLE | |
234 ></DIV | |
235 ></BODY | |
236 ></HTML | |
237 > |