Mercurial > sdl-ios-xcode
annotate docs/html/sdlflip.html @ 2042:3908e1f808e1
Fixed bug #292
I might be on crack here.
It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and
right channels of a stereo stream together, and clamps the new mono channel if
it would overflow.
Shouldn't it be dividing by 2 to average the two sample points instead of
clamping? Otherwise the mono sample point's volume doubles in the conversion.
This would also make the conversion faster, as it replaces two branches per
sample frame with a bitwise shift.
--ryan.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 24 Sep 2006 15:56:36 +0000 |
| parents | 355632dca928 |
| children |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_Flip</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_UpdateRects" | |
| 17 HREF="sdlupdaterects.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_SetColors" | |
| 20 HREF="sdlsetcolors.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="sdlupdaterects.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="sdlsetcolors.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="SDLFLIP" | |
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74 ></A |
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75 >SDL_Flip</H1 |
| 0 | 76 ><DIV |
| 77 CLASS="REFNAMEDIV" | |
| 78 ><A | |
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79 NAME="AEN1426" |
| 0 | 80 ></A |
| 81 ><H2 | |
| 82 >Name</H2 | |
| 83 >SDL_Flip -- Swaps screen buffers</DIV | |
| 84 ><DIV | |
| 85 CLASS="REFSYNOPSISDIV" | |
| 86 ><A | |
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87 NAME="AEN1429" |
| 0 | 88 ></A |
| 89 ><H2 | |
| 90 >Synopsis</H2 | |
| 91 ><DIV | |
| 92 CLASS="FUNCSYNOPSIS" | |
| 93 ><A | |
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94 NAME="AEN1430" |
| 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_Flip</B | |
| 108 ></CODE | |
| 109 >(SDL_Surface *screen);</CODE | |
| 110 ></P | |
| 111 ><P | |
| 112 ></P | |
| 113 ></DIV | |
| 114 ></DIV | |
| 115 ><DIV | |
| 116 CLASS="REFSECT1" | |
| 117 ><A | |
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118 NAME="AEN1436" |
| 0 | 119 ></A |
| 120 ><H2 | |
| 121 >Description</H2 | |
| 122 ><P | |
| 123 >On hardware that supports double-buffering, this function sets up a flip | |
| 124 and returns. The hardware will wait for vertical retrace, and then swap | |
| 125 video buffers before the next video surface blit or lock will return. | |
| 126 On hardware that doesn't support double-buffering, this is equivalent | |
| 127 to calling <A | |
| 128 HREF="sdlupdaterect.html" | |
| 129 >SDL_UpdateRect</A | |
| 130 ><TT | |
| 131 CLASS="PARAMETER" | |
| 132 ><I | |
| 133 >(screen, 0, 0, 0, 0)</I | |
| 134 ></TT | |
| 135 ></P | |
| 136 ><P | |
| 137 >The <TT | |
| 138 CLASS="LITERAL" | |
| 139 >SDL_DOUBLEBUF</TT | |
| 140 > flag must have been passed to | |
| 141 <A | |
| 142 HREF="sdlsetvideomode.html" | |
| 143 >SDL_SetVideoMode</A | |
| 144 >, | |
| 145 when | |
| 146 setting the video mode for this function to perform hardware flipping.</P | |
| 147 ></DIV | |
| 148 ><DIV | |
| 149 CLASS="REFSECT1" | |
| 150 ><A | |
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151 NAME="AEN1444" |
| 0 | 152 ></A |
| 153 ><H2 | |
| 154 >Return Value</H2 | |
| 155 ><P | |
| 156 >This function returns <SPAN | |
| 157 CLASS="RETURNVALUE" | |
| 158 >0</SPAN | |
| 159 > if successful, or | |
| 160 <SPAN | |
| 161 CLASS="RETURNVALUE" | |
| 162 >-1</SPAN | |
| 163 > if there was an error.</P | |
| 164 ></DIV | |
| 165 ><DIV | |
| 166 CLASS="REFSECT1" | |
| 167 ><A | |
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168 NAME="AEN1449" |
| 0 | 169 ></A |
| 170 ><H2 | |
| 171 >See Also</H2 | |
| 172 ><P | |
| 173 ><A | |
| 174 HREF="sdlsetvideomode.html" | |
| 175 ><TT | |
| 176 CLASS="FUNCTION" | |
| 177 >SDL_SetVideoMode</TT | |
| 178 ></A | |
| 179 >, | |
| 180 <A | |
| 181 HREF="sdlupdaterect.html" | |
| 182 ><TT | |
| 183 CLASS="FUNCTION" | |
| 184 >SDL_UpdateRect</TT | |
| 185 ></A | |
| 186 >, | |
| 187 <A | |
| 188 HREF="sdlsurface.html" | |
| 189 ><SPAN | |
| 190 CLASS="STRUCTNAME" | |
| 191 >SDL_Surface</SPAN | |
| 192 ></A | |
| 193 ></P | |
| 194 ></DIV | |
| 195 ><DIV | |
| 196 CLASS="NAVFOOTER" | |
| 197 ><HR | |
| 198 ALIGN="LEFT" | |
| 199 WIDTH="100%"><TABLE | |
|
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parents:
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200 SUMMARY="Footer navigation table" |
| 0 | 201 WIDTH="100%" |
| 202 BORDER="0" | |
| 203 CELLPADDING="0" | |
| 204 CELLSPACING="0" | |
| 205 ><TR | |
| 206 ><TD | |
| 207 WIDTH="33%" | |
| 208 ALIGN="left" | |
| 209 VALIGN="top" | |
| 210 ><A | |
| 211 HREF="sdlupdaterects.html" | |
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803
355632dca928
Updated SDL HTML documentation
Sam Lantinga <slouken@libsdl.org>
parents:
181
diff
changeset
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212 ACCESSKEY="P" |
| 0 | 213 >Prev</A |
| 214 ></TD | |
| 215 ><TD | |
| 216 WIDTH="34%" | |
| 217 ALIGN="center" | |
| 218 VALIGN="top" | |
| 219 ><A | |
| 220 HREF="index.html" | |
|
803
355632dca928
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parents:
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221 ACCESSKEY="H" |
| 0 | 222 >Home</A |
| 223 ></TD | |
| 224 ><TD | |
| 225 WIDTH="33%" | |
| 226 ALIGN="right" | |
| 227 VALIGN="top" | |
| 228 ><A | |
| 229 HREF="sdlsetcolors.html" | |
|
803
355632dca928
Updated SDL HTML documentation
Sam Lantinga <slouken@libsdl.org>
parents:
181
diff
changeset
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230 ACCESSKEY="N" |
| 0 | 231 >Next</A |
| 232 ></TD | |
| 233 ></TR | |
| 234 ><TR | |
| 235 ><TD | |
| 236 WIDTH="33%" | |
| 237 ALIGN="left" | |
| 238 VALIGN="top" | |
| 239 >SDL_UpdateRects</TD | |
| 240 ><TD | |
| 241 WIDTH="34%" | |
| 242 ALIGN="center" | |
| 243 VALIGN="top" | |
| 244 ><A | |
| 245 HREF="video.html" | |
|
803
355632dca928
Updated SDL HTML documentation
Sam Lantinga <slouken@libsdl.org>
parents:
181
diff
changeset
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246 ACCESSKEY="U" |
| 0 | 247 >Up</A |
| 248 ></TD | |
| 249 ><TD | |
| 250 WIDTH="33%" | |
| 251 ALIGN="right" | |
| 252 VALIGN="top" | |
| 253 >SDL_SetColors</TD | |
| 254 ></TR | |
| 255 ></TABLE | |
| 256 ></DIV | |
| 257 ></BODY | |
| 258 ></HTML | |
| 259 > |