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annotate docs/html/time.html @ 1982:3b4ce57c6215
First shot at new audio data types (int32 and float32).
Notable changes:
- Converters between types are autogenerated. Instead of making multiple
passes over the data with seperate filters for endianess, size, signedness,
etc, converting between data types is always one specialized filter. This
simplifies SDL_BuildAudioCVT(), which otherwise had a million edge cases
with the new types, and makes the actually conversions more CPU cache
friendly. Left a stub for adding specific optimized versions of these
routines (SSE/MMX/Altivec, assembler, etc)
- Autogenerated converters are built by SDL/src/audio/sdlgenaudiocvt.pl. This
does not need to be run unless tweaking the code, and thus doesn't need
integration into the build system.
- Went through all the drivers and tried to weed out all the "Uint16"
references that are better specified with the new SDL_AudioFormat typedef.
- Cleaned out a bunch of hardcoded bitwise magic numbers and replaced them
with new SDL_AUDIO_* macros.
- Added initial float32 and int32 support code. Theoretically, existing
drivers will push these through converters to get the data they want to
feed to the hardware.
Still TODO:
- Optimize and debug new converters.
- Update the CoreAudio backend to accept float32 data directly.
- Other backends, too?
- SDL_LoadWAV() needs to be updated to support int32 and float32 .wav files
(both of which exist and can be generated by 'sox' for testing purposes).
- Update the mixer to handle new datatypes.
- Optionally update SDL_sound and SDL_mixer, etc.
author | Ryan C. Gordon <icculus@icculus.org> |
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date | Thu, 24 Aug 2006 12:10:46 +0000 |
parents | 355632dca928 |
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rev | line source |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >Time</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_CondWaitTimeout" | |
17 HREF="sdlcondwaittimeout.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_GetTicks" | |
20 HREF="sdlgetticks.html"><META | |
21 NAME="KEYWORD" | |
22 CONTENT="time"><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="sdlcondwaittimeout.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="sdlgetticks.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="TIME" | |
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80 ></A |
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81 >Chapter 13. Time</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="sdlgetticks.html" | |
92 >SDL_GetTicks</A | |
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93 > -- Get the number of milliseconds since the SDL library initialization.</DT |
0 | 94 ><DT |
95 ><A | |
96 HREF="sdldelay.html" | |
97 >SDL_Delay</A | |
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98 > -- Wait a specified number of milliseconds before returning.</DT |
0 | 99 ><DT |
100 ><A | |
101 HREF="sdladdtimer.html" | |
102 >SDL_AddTimer</A | |
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103 > -- Add a timer which will call a callback after the specified number of milliseconds has |
0 | 104 elapsed.</DT |
105 ><DT | |
106 ><A | |
107 HREF="sdlremovetimer.html" | |
108 >SDL_RemoveTimer</A | |
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109 > -- Remove a timer which was added with |
0 | 110 <A |
111 HREF="sdladdtimer.html" | |
112 >SDL_AddTimer</A | |
113 >.</DT | |
114 ><DT | |
115 ><A | |
116 HREF="sdlsettimer.html" | |
117 >SDL_SetTimer</A | |
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118 > -- Set a callback to run after the specified number of milliseconds has |
0 | 119 elapsed.</DT |
120 ></DL | |
121 ></DIV | |
122 ><P | |
123 >SDL provides several cross-platform functions for dealing with time. | |
124 It provides a way to get the current time, a way to wait a little while, | |
125 and a simple timer mechanism. These functions give you two ways of moving an | |
126 object every x milliseconds: | |
127 | |
128 <P | |
129 ></P | |
130 ><UL | |
131 ><LI | |
132 ><P | |
133 >Use a timer callback function. This may have the bad effect that it runs in a seperate thread or uses alarm signals, but it's easier to implement.</P | |
134 ></LI | |
135 ><LI | |
136 ><P | |
137 >Or you can get the number of milliseconds passed, and move the object if, for example, 30 ms passed.</P | |
138 ></LI | |
139 ></UL | |
140 > </P | |
141 ></DIV | |
142 ><DIV | |
143 CLASS="NAVFOOTER" | |
144 ><HR | |
145 ALIGN="LEFT" | |
146 WIDTH="100%"><TABLE | |
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147 SUMMARY="Footer navigation table" |
0 | 148 WIDTH="100%" |
149 BORDER="0" | |
150 CELLPADDING="0" | |
151 CELLSPACING="0" | |
152 ><TR | |
153 ><TD | |
154 WIDTH="33%" | |
155 ALIGN="left" | |
156 VALIGN="top" | |
157 ><A | |
158 HREF="sdlcondwaittimeout.html" | |
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159 ACCESSKEY="P" |
0 | 160 >Prev</A |
161 ></TD | |
162 ><TD | |
163 WIDTH="34%" | |
164 ALIGN="center" | |
165 VALIGN="top" | |
166 ><A | |
167 HREF="index.html" | |
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168 ACCESSKEY="H" |
0 | 169 >Home</A |
170 ></TD | |
171 ><TD | |
172 WIDTH="33%" | |
173 ALIGN="right" | |
174 VALIGN="top" | |
175 ><A | |
176 HREF="sdlgetticks.html" | |
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177 ACCESSKEY="N" |
0 | 178 >Next</A |
179 ></TD | |
180 ></TR | |
181 ><TR | |
182 ><TD | |
183 WIDTH="33%" | |
184 ALIGN="left" | |
185 VALIGN="top" | |
186 >SDL_CondWaitTimeout</TD | |
187 ><TD | |
188 WIDTH="34%" | |
189 ALIGN="center" | |
190 VALIGN="top" | |
191 ><A | |
192 HREF="reference.html" | |
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193 ACCESSKEY="U" |
0 | 194 >Up</A |
195 ></TD | |
196 ><TD | |
197 WIDTH="33%" | |
198 ALIGN="right" | |
199 VALIGN="top" | |
200 >SDL_GetTicks</TD | |
201 ></TR | |
202 ></TABLE | |
203 ></DIV | |
204 ></BODY | |
205 ></HTML | |
206 > |