Mercurial > sdl-ios-xcode
annotate docs/html/sdlgetrgba.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_GetRGBA</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="Video" | |
14 HREF="video.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="SDL_GetRGB" | |
17 HREF="sdlgetrgb.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_CreateRGBSurface" | |
20 HREF="sdlcreatergbsurface.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="sdlgetrgb.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="sdlcreatergbsurface.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="SDLGETRGBA" | |
71 >SDL_GetRGBA</A | |
72 ></H1 | |
73 ><DIV | |
74 CLASS="REFNAMEDIV" | |
75 ><A | |
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76 NAME="AEN1363" |
0 | 77 ></A |
78 ><H2 | |
79 >Name</H2 | |
80 >SDL_GetRGBA -- Get RGBA values from a pixel in the specified pixel format.</DIV | |
81 ><DIV | |
82 CLASS="REFSYNOPSISDIV" | |
83 ><A | |
181
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84 NAME="AEN1366" |
0 | 85 ></A |
86 ><H2 | |
87 >Synopsis</H2 | |
88 ><DIV | |
89 CLASS="FUNCSYNOPSIS" | |
90 ><A | |
181
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91 NAME="AEN1367" |
0 | 92 ></A |
93 ><P | |
94 ></P | |
95 ><PRE | |
96 CLASS="FUNCSYNOPSISINFO" | |
97 >#include "SDL.h"</PRE | |
98 ><P | |
99 ><CODE | |
100 ><CODE | |
101 CLASS="FUNCDEF" | |
102 >void <B | |
103 CLASS="FSFUNC" | |
104 >SDL_GetRGBA</B | |
105 ></CODE | |
106 >(Uint32 pixel, SDL_PixelFormat *fmt, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a);</CODE | |
107 ></P | |
108 ><P | |
109 ></P | |
110 ></DIV | |
111 ></DIV | |
112 ><DIV | |
113 CLASS="REFSECT1" | |
114 ><A | |
181
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115 NAME="AEN1373" |
0 | 116 ></A |
117 ><H2 | |
118 >Description</H2 | |
119 ><P | |
120 >Get RGBA component values from a pixel stored in the specified pixel format.</P | |
121 ><P | |
122 >This function uses the entire 8-bit [0..255] range when converting color | |
123 components from pixel formats with less than 8-bits per RGB component | |
124 (e.g., a completely white pixel in 16-bit RGB565 format would return | |
125 [0xff, 0xff, 0xff] not [0xf8, 0xfc, 0xf8]).</P | |
126 ><P | |
127 >If the surface has no alpha component, the alpha will be returned as 0xff | |
128 (100% opaque).</P | |
129 ></DIV | |
130 ><DIV | |
131 CLASS="REFSECT1" | |
132 ><A | |
181
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133 NAME="AEN1378" |
0 | 134 ></A |
135 ><H2 | |
136 >See Also</H2 | |
137 ><P | |
138 ><A | |
139 HREF="sdlgetrgb.html" | |
140 >SDL_GetRGB</A | |
141 >, | |
142 <A | |
143 HREF="sdlmaprgb.html" | |
144 >SDL_MapRGB</A | |
145 >, | |
146 <A | |
147 HREF="sdlmaprgba.html" | |
148 >SDL_MapRGBA</A | |
149 >, | |
150 <A | |
151 HREF="sdlpixelformat.html" | |
152 >SDL_PixelFormat</A | |
153 ></P | |
154 ></DIV | |
155 ><DIV | |
156 CLASS="NAVFOOTER" | |
157 ><HR | |
158 ALIGN="LEFT" | |
159 WIDTH="100%"><TABLE | |
160 WIDTH="100%" | |
161 BORDER="0" | |
162 CELLPADDING="0" | |
163 CELLSPACING="0" | |
164 ><TR | |
165 ><TD | |
166 WIDTH="33%" | |
167 ALIGN="left" | |
168 VALIGN="top" | |
169 ><A | |
170 HREF="sdlgetrgb.html" | |
171 >Prev</A | |
172 ></TD | |
173 ><TD | |
174 WIDTH="34%" | |
175 ALIGN="center" | |
176 VALIGN="top" | |
177 ><A | |
178 HREF="index.html" | |
179 >Home</A | |
180 ></TD | |
181 ><TD | |
182 WIDTH="33%" | |
183 ALIGN="right" | |
184 VALIGN="top" | |
185 ><A | |
186 HREF="sdlcreatergbsurface.html" | |
187 >Next</A | |
188 ></TD | |
189 ></TR | |
190 ><TR | |
191 ><TD | |
192 WIDTH="33%" | |
193 ALIGN="left" | |
194 VALIGN="top" | |
195 >SDL_GetRGB</TD | |
196 ><TD | |
197 WIDTH="34%" | |
198 ALIGN="center" | |
199 VALIGN="top" | |
200 ><A | |
201 HREF="video.html" | |
202 >Up</A | |
203 ></TD | |
204 ><TD | |
205 WIDTH="33%" | |
206 ALIGN="right" | |
207 VALIGN="top" | |
208 >SDL_CreateRGBSurface</TD | |
209 ></TR | |
210 ></TABLE | |
211 ></DIV | |
212 ></BODY | |
213 ></HTML | |
214 > |