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annotate docs/html/guidebasicsinit.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 |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >Initializing SDL</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="The Basics" | |
14 HREF="guidethebasics.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="The Basics" | |
17 HREF="guidethebasics.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="Graphics and Video" | |
20 HREF="guidevideo.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="guidethebasics.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 1. The Basics</TD | |
57 ><TD | |
58 WIDTH="10%" | |
59 ALIGN="right" | |
60 VALIGN="bottom" | |
61 ><A | |
62 HREF="guidevideo.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="GUIDEBASICSINIT" | |
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77 ></A |
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78 >Initializing SDL</H1 |
0 | 79 ><P |
80 >SDL is composed of eight subsystems - Audio, CDROM, Event Handling, File I/O, Joystick Handling, Threading, Timers and Video. Before you can use any of these subsystems they must be initialized by calling <A | |
81 HREF="sdlinit.html" | |
82 ><TT | |
83 CLASS="FUNCTION" | |
84 >SDL_Init</TT | |
85 ></A | |
86 > (or <A | |
87 HREF="sdlinitsubsystem.html" | |
88 ><TT | |
89 CLASS="FUNCTION" | |
90 >SDL_InitSubSystem</TT | |
91 ></A | |
181
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92 >). <TT |
0 | 93 CLASS="FUNCTION" |
94 >SDL_Init</TT | |
95 > must be called before any other SDL function. It automatically initializes the Event Handling, File I/O and Threading subsystems and it takes a parameter specifying which other subsystems to initialize. So, to initialize the default subsystems and the Video subsystems you would call: | |
96 <PRE | |
97 CLASS="PROGRAMLISTING" | |
98 > SDL_Init ( SDL_INIT_VIDEO );</PRE | |
99 > | |
100 To initialize the default subsystems, the Video subsystem and the Timers subsystem you would call: | |
101 <PRE | |
102 CLASS="PROGRAMLISTING" | |
103 > SDL_Init ( SDL_INIT_VIDEO | SDL_INIT_TIMER );</PRE | |
104 ></P | |
105 ><P | |
106 ><TT | |
107 CLASS="FUNCTION" | |
108 >SDL_Init</TT | |
109 > is complemented by <A | |
110 HREF="sdlquit.html" | |
111 ><TT | |
112 CLASS="FUNCTION" | |
113 >SDL_Quit</TT | |
114 ></A | |
115 > (and <A | |
116 HREF="sdlquitsubsystem.html" | |
117 ><TT | |
118 CLASS="FUNCTION" | |
119 >SDL_QuitSubSystem</TT | |
120 ></A | |
121 >). <TT | |
122 CLASS="FUNCTION" | |
123 >SDL_Quit</TT | |
124 > shuts down all subsystems, including the default ones. It should always be called before a SDL application exits.</P | |
125 ><P | |
126 >With <TT | |
127 CLASS="FUNCTION" | |
128 >SDL_Init</TT | |
129 > and <TT | |
130 CLASS="FUNCTION" | |
131 >SDL_Quit</TT | |
132 > firmly embedded in your programmers toolkit you can write your first and most basic SDL application. However, we must be prepare to handle errors. Many SDL functions return a value and indicates whether the function has succeeded or failed, <TT | |
133 CLASS="FUNCTION" | |
134 >SDL_Init</TT | |
135 >, for instance, returns -1 if it could not initialize a subsystem. SDL provides a useful facility that allows you to determine exactly what the problem was, every time an error occurs within SDL an error message is stored which can be retrieved using <TT | |
136 CLASS="FUNCTION" | |
137 >SDL_GetError</TT | |
138 >. Use this often, you can never know too much about an error.</P | |
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139 ><DIV |
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140 CLASS="EXAMPLE" |
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141 ><A |
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142 NAME="AEN60" |
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143 ></A |
0 | 144 ><P |
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145 ><B |
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146 >Example 1-1. Initializing SDL</B |
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147 ></P |
0 | 148 ><PRE |
149 CLASS="PROGRAMLISTING" | |
150 >#include "SDL.h" /* All SDL App's need this */ | |
151 #include <stdio.h> | |
152 | |
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153 int main(int argc, char *argv[]) { |
0 | 154 |
155 printf("Initializing SDL.\n"); | |
156 | |
157 /* Initialize defaults, Video and Audio */ | |
158 if((SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO)==-1)) { | |
159 printf("Could not initialize SDL: %s.\n", SDL_GetError()); | |
160 exit(-1); | |
161 } | |
162 | |
163 printf("SDL initialized.\n"); | |
164 | |
165 printf("Quiting SDL.\n"); | |
166 | |
167 /* Shutdown all subsystems */ | |
168 SDL_Quit(); | |
169 | |
170 printf("Quiting....\n"); | |
171 | |
172 exit(0); | |
173 } </PRE | |
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174 ></DIV |
0 | 175 ></DIV |
176 ><DIV | |
177 CLASS="NAVFOOTER" | |
178 ><HR | |
179 ALIGN="LEFT" | |
180 WIDTH="100%"><TABLE | |
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181 SUMMARY="Footer navigation table" |
0 | 182 WIDTH="100%" |
183 BORDER="0" | |
184 CELLPADDING="0" | |
185 CELLSPACING="0" | |
186 ><TR | |
187 ><TD | |
188 WIDTH="33%" | |
189 ALIGN="left" | |
190 VALIGN="top" | |
191 ><A | |
192 HREF="guidethebasics.html" | |
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193 ACCESSKEY="P" |
0 | 194 >Prev</A |
195 ></TD | |
196 ><TD | |
197 WIDTH="34%" | |
198 ALIGN="center" | |
199 VALIGN="top" | |
200 ><A | |
201 HREF="index.html" | |
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202 ACCESSKEY="H" |
0 | 203 >Home</A |
204 ></TD | |
205 ><TD | |
206 WIDTH="33%" | |
207 ALIGN="right" | |
208 VALIGN="top" | |
209 ><A | |
210 HREF="guidevideo.html" | |
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211 ACCESSKEY="N" |
0 | 212 >Next</A |
213 ></TD | |
214 ></TR | |
215 ><TR | |
216 ><TD | |
217 WIDTH="33%" | |
218 ALIGN="left" | |
219 VALIGN="top" | |
220 >The Basics</TD | |
221 ><TD | |
222 WIDTH="34%" | |
223 ALIGN="center" | |
224 VALIGN="top" | |
225 ><A | |
226 HREF="guidethebasics.html" | |
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227 ACCESSKEY="U" |
0 | 228 >Up</A |
229 ></TD | |
230 ><TD | |
231 WIDTH="33%" | |
232 ALIGN="right" | |
233 VALIGN="top" | |
234 >Graphics and Video</TD | |
235 ></TR | |
236 ></TABLE | |
237 ></DIV | |
238 ></BODY | |
239 ></HTML | |
240 > |