Mercurial > sdl-ios-xcode
annotate docs/html/sdlsetgamma.html @ 968:4675910b0b7b
Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
From: Hannu Savolainen
Subject: Re: SDL uses obsolete OSS features
I did some work on getting OSS to work better with SDL. There have been
some problems with select which should be fixed now.
I'm having some problems in understanding what is the purpose of the
DSP_WaitAudio() routine. I added a return to the very beginning of this
routine and commendted out the define for USE_BLOCKING_WRITES. At least
lbreakout2 seems to work as well as earlier. The latencies are the same.
An ordinary blocking write does exactly the same thing than DSP_WaitAudio
does. So I would recommend using the USE_BLOCKING_WRITES approach and
removing everything from the DSP_WaitAudio routine. Also enabling
USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because
you don't need to handle the partial writes (the do-while loop).
Attached is a patch against SDL-1.2.7. After these changes SDL will use
OSS as it's designed to be used (make it as simple as possible). This code
should work with all OSS implementations because it uses only the very
fundamental features that have been there since the jurassic times.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Fri, 12 Nov 2004 21:39:04 +0000 |
parents | 355632dca928 |
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rev | line source |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >SDL_SetGamma</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="Video" | |
14 HREF="video.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="SDL_SetPalette" | |
17 HREF="sdlsetpalette.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_GetGammaRamp" | |
20 HREF="sdlgetgammaramp.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="sdlsetpalette.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="sdlgetgammaramp.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="SDLSETGAMMA" | |
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74 ></A |
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75 >SDL_SetGamma</H1 |
0 | 76 ><DIV |
77 CLASS="REFNAMEDIV" | |
78 ><A | |
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79 NAME="AEN1569" |
0 | 80 ></A |
81 ><H2 | |
82 >Name</H2 | |
83 >SDL_SetGamma -- Sets the color gamma function for the display</DIV | |
84 ><DIV | |
85 CLASS="REFSYNOPSISDIV" | |
86 ><A | |
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87 NAME="AEN1572" |
0 | 88 ></A |
89 ><H2 | |
90 >Synopsis</H2 | |
91 ><DIV | |
92 CLASS="FUNCSYNOPSIS" | |
93 ><A | |
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94 NAME="AEN1573" |
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 >int <B | |
106 CLASS="FSFUNC" | |
107 >SDL_SetGamma</B | |
108 ></CODE | |
109 >(float redgamma, float greengamma, float bluegamma);</CODE | |
110 ></P | |
111 ><P | |
112 ></P | |
113 ></DIV | |
114 ></DIV | |
115 ><DIV | |
116 CLASS="REFSECT1" | |
117 ><A | |
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118 NAME="AEN1579" |
0 | 119 ></A |
120 ><H2 | |
121 >Description</H2 | |
122 ><P | |
123 >Sets the "gamma function" for the display of each color component. Gamma | |
124 controls the brightness/contrast of colors displayed on the screen. | |
125 A gamma value of <TT | |
126 CLASS="CONSTANT" | |
127 >1.0</TT | |
128 > is identity (i.e., no adjustment | |
129 is made).</P | |
130 ><P | |
131 >This function adjusts the gamma based on the "gamma function" parameter, | |
132 you can directly specify lookup tables for gamma adjustment with | |
133 <A | |
134 HREF="sdlsetgammaramp.html" | |
135 >SDL_SetGammaRamp</A | |
136 >.</P | |
137 ><P | |
138 >Not all display hardware is able to change gamma.</P | |
139 ></DIV | |
140 ><DIV | |
141 CLASS="REFSECT1" | |
142 ><A | |
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143 NAME="AEN1586" |
0 | 144 ></A |
145 ><H2 | |
146 >Return Value</H2 | |
147 ><P | |
148 >Returns -1 on error (or if gamma adjustment is not supported).</P | |
149 ></DIV | |
150 ><DIV | |
151 CLASS="REFSECT1" | |
152 ><A | |
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153 NAME="AEN1589" |
0 | 154 ></A |
155 ><H2 | |
156 >See Also</H2 | |
157 ><P | |
158 ><A | |
159 HREF="sdlgetgammaramp.html" | |
160 >SDL_GetGammaRamp</A | |
161 > | |
162 <A | |
163 HREF="sdlsetgammaramp.html" | |
164 >SDL_SetGammaRamp</A | |
165 ></P | |
166 ></DIV | |
167 ><DIV | |
168 CLASS="NAVFOOTER" | |
169 ><HR | |
170 ALIGN="LEFT" | |
171 WIDTH="100%"><TABLE | |
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172 SUMMARY="Footer navigation table" |
0 | 173 WIDTH="100%" |
174 BORDER="0" | |
175 CELLPADDING="0" | |
176 CELLSPACING="0" | |
177 ><TR | |
178 ><TD | |
179 WIDTH="33%" | |
180 ALIGN="left" | |
181 VALIGN="top" | |
182 ><A | |
183 HREF="sdlsetpalette.html" | |
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184 ACCESSKEY="P" |
0 | 185 >Prev</A |
186 ></TD | |
187 ><TD | |
188 WIDTH="34%" | |
189 ALIGN="center" | |
190 VALIGN="top" | |
191 ><A | |
192 HREF="index.html" | |
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193 ACCESSKEY="H" |
0 | 194 >Home</A |
195 ></TD | |
196 ><TD | |
197 WIDTH="33%" | |
198 ALIGN="right" | |
199 VALIGN="top" | |
200 ><A | |
201 HREF="sdlgetgammaramp.html" | |
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202 ACCESSKEY="N" |
0 | 203 >Next</A |
204 ></TD | |
205 ></TR | |
206 ><TR | |
207 ><TD | |
208 WIDTH="33%" | |
209 ALIGN="left" | |
210 VALIGN="top" | |
211 >SDL_SetPalette</TD | |
212 ><TD | |
213 WIDTH="34%" | |
214 ALIGN="center" | |
215 VALIGN="top" | |
216 ><A | |
217 HREF="video.html" | |
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218 ACCESSKEY="U" |
0 | 219 >Up</A |
220 ></TD | |
221 ><TD | |
222 WIDTH="33%" | |
223 ALIGN="right" | |
224 VALIGN="top" | |
225 >SDL_GetGammaRamp</TD | |
226 ></TR | |
227 ></TABLE | |
228 ></DIV | |
229 ></BODY | |
230 ></HTML | |
231 > |