Mercurial > sdl-ios-xcode
annotate docs/html/sdllocksurface.html @ 610:95433459fbd2
Date: Mon, 14 Apr 2003 22:08:27 +0100
From: Patrice Mandin
Subject: [SDL][PATCH] 2 patches for sdl
Here are 2 patches for SDL:
- One is to put the dummy video drivers at the end of the
video drivers list. It gave me problems, when
SDL_VIDEODRIVER is not set, and the dummy driver is used
instead of the platform's driver, just because it is
always available. So the dummy driver must always be at
the end of the list. I suppose picogui and dc video
drivers also don't work.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Tue, 15 Apr 2003 15:46:56 +0000 |
| parents | e5bc29de3f0a |
| children | 355632dca928 |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_LockSurface</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
|
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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_FreeSurface" | |
| 17 HREF="sdlfreesurface.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_UnlockSurface" | |
| 20 HREF="sdlunlocksurface.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="sdlfreesurface.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="sdlunlocksurface.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="SDLLOCKSURFACE" | |
| 71 >SDL_LockSurface</A | |
| 72 ></H1 | |
| 73 ><DIV | |
| 74 CLASS="REFNAMEDIV" | |
| 75 ><A | |
|
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76 NAME="AEN1535" |
| 0 | 77 ></A |
| 78 ><H2 | |
| 79 >Name</H2 | |
| 80 >SDL_LockSurface -- Lock a surface for directly access.</DIV | |
| 81 ><DIV | |
| 82 CLASS="REFSYNOPSISDIV" | |
| 83 ><A | |
|
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84 NAME="AEN1538" |
| 0 | 85 ></A |
| 86 ><H2 | |
| 87 >Synopsis</H2 | |
| 88 ><DIV | |
| 89 CLASS="FUNCSYNOPSIS" | |
| 90 ><A | |
|
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91 NAME="AEN1539" |
| 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 >int <B | |
| 103 CLASS="FSFUNC" | |
| 104 >SDL_LockSurface</B | |
| 105 ></CODE | |
| 106 >(SDL_Surface *surface);</CODE | |
| 107 ></P | |
| 108 ><P | |
| 109 ></P | |
| 110 ></DIV | |
| 111 ></DIV | |
| 112 ><DIV | |
| 113 CLASS="REFSECT1" | |
| 114 ><A | |
|
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115 NAME="AEN1545" |
| 0 | 116 ></A |
| 117 ><H2 | |
| 118 >Description</H2 | |
| 119 ><P | |
| 120 ><TT | |
| 121 CLASS="FUNCTION" | |
| 122 >SDL_LockSurface</TT | |
| 123 > sets up a surface for directly | |
| 124 accessing the pixels. Between calls to <TT | |
| 125 CLASS="FUNCTION" | |
| 126 >SDL_LockSurface</TT | |
| 127 > | |
| 128 and <TT | |
| 129 CLASS="FUNCTION" | |
| 130 >SDL_UnlockSurface</TT | |
| 131 >, you can write to and read from | |
| 132 <TT | |
| 133 CLASS="PARAMETER" | |
| 134 ><I | |
| 135 >surface-><TT | |
| 136 CLASS="STRUCTFIELD" | |
| 137 ><I | |
| 138 >pixels</I | |
| 139 ></TT | |
| 140 ></I | |
| 141 ></TT | |
| 142 >, using the pixel format stored in | |
| 143 <TT | |
| 144 CLASS="PARAMETER" | |
| 145 ><I | |
| 146 >surface-><TT | |
| 147 CLASS="STRUCTFIELD" | |
| 148 ><I | |
| 149 >format</I | |
| 150 ></TT | |
| 151 ></I | |
| 152 ></TT | |
| 153 >. Once you are done accessing the | |
| 154 surface, you should use <TT | |
| 155 CLASS="FUNCTION" | |
| 156 >SDL_UnlockSurface</TT | |
| 157 > to release it.</P | |
| 158 ><P | |
| 159 >Not all surfaces require locking. | |
| 160 If <TT | |
| 161 CLASS="LITERAL" | |
| 162 >SDL_MUSTLOCK</TT | |
| 163 >(<TT | |
| 164 CLASS="PARAMETER" | |
| 165 ><I | |
| 166 >surface</I | |
| 167 ></TT | |
| 168 >) | |
| 169 evaluates to <SPAN | |
| 170 CLASS="RETURNVALUE" | |
| 171 >0</SPAN | |
| 172 >, then you can read and write to the | |
| 173 surface at any time, and the pixel format of the surface will not change. </P | |
| 174 ><P | |
| 175 >No operating system or library calls should be made between lock/unlock | |
| 176 pairs, as critical system locks may be held during this time.</P | |
| 177 ><P | |
| 178 >It should be noted, that since SDL 1.1.8 surface locks are recursive. This means that you can lock a surface multiple times, but each lock must have a match unlock. | |
| 179 <PRE | |
| 180 CLASS="PROGRAMLISTING" | |
| 181 > . | |
| 182 . | |
| 183 SDL_LockSurface( surface ); | |
| 184 . | |
| 185 /* Surface is locked */ | |
| 186 /* Direct pixel access on surface here */ | |
| 187 . | |
| 188 SDL_LockSurface( surface ); | |
| 189 . | |
| 190 /* More direct pixel access on surface */ | |
| 191 . | |
| 192 SDL_UnlockSurface( surface ); | |
| 193 /* Surface is still locked */ | |
| 194 /* Note: Is versions < 1.1.8, the surface would have been */ | |
| 195 /* no longer locked at this stage */ | |
| 196 . | |
| 197 SDL_UnlockSurface( surface ); | |
| 198 /* Surface is now unlocked */ | |
| 199 . | |
| 200 .</PRE | |
|
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201 ></P |
| 0 | 202 ></DIV |
| 203 ><DIV | |
| 204 CLASS="REFSECT1" | |
| 205 ><A | |
|
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206 NAME="AEN1563" |
| 0 | 207 ></A |
| 208 ><H2 | |
| 209 >Return Value</H2 | |
| 210 ><P | |
| 211 ><TT | |
| 212 CLASS="FUNCTION" | |
| 213 >SDL_LockSurface</TT | |
| 214 > returns <SPAN | |
| 215 CLASS="RETURNVALUE" | |
| 216 >0</SPAN | |
| 217 >, | |
| 218 or <SPAN | |
| 219 CLASS="RETURNVALUE" | |
| 220 >-1</SPAN | |
| 221 > if the surface couldn't be locked.</P | |
| 222 ></DIV | |
| 223 ><DIV | |
| 224 CLASS="REFSECT1" | |
| 225 ><A | |
|
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226 NAME="AEN1569" |
| 0 | 227 ></A |
| 228 ><H2 | |
| 229 >See Also</H2 | |
| 230 ><P | |
| 231 ><A | |
| 232 HREF="sdlunlocksurface.html" | |
| 233 ><TT | |
| 234 CLASS="FUNCTION" | |
| 235 >SDL_UnlockSurface</TT | |
| 236 ></A | |
| 237 ></P | |
| 238 ></DIV | |
| 239 ><DIV | |
| 240 CLASS="NAVFOOTER" | |
| 241 ><HR | |
| 242 ALIGN="LEFT" | |
| 243 WIDTH="100%"><TABLE | |
| 244 WIDTH="100%" | |
| 245 BORDER="0" | |
| 246 CELLPADDING="0" | |
| 247 CELLSPACING="0" | |
| 248 ><TR | |
| 249 ><TD | |
| 250 WIDTH="33%" | |
| 251 ALIGN="left" | |
| 252 VALIGN="top" | |
| 253 ><A | |
| 254 HREF="sdlfreesurface.html" | |
| 255 >Prev</A | |
| 256 ></TD | |
| 257 ><TD | |
| 258 WIDTH="34%" | |
| 259 ALIGN="center" | |
| 260 VALIGN="top" | |
| 261 ><A | |
| 262 HREF="index.html" | |
| 263 >Home</A | |
| 264 ></TD | |
| 265 ><TD | |
| 266 WIDTH="33%" | |
| 267 ALIGN="right" | |
| 268 VALIGN="top" | |
| 269 ><A | |
| 270 HREF="sdlunlocksurface.html" | |
| 271 >Next</A | |
| 272 ></TD | |
| 273 ></TR | |
| 274 ><TR | |
| 275 ><TD | |
| 276 WIDTH="33%" | |
| 277 ALIGN="left" | |
| 278 VALIGN="top" | |
| 279 >SDL_FreeSurface</TD | |
| 280 ><TD | |
| 281 WIDTH="34%" | |
| 282 ALIGN="center" | |
| 283 VALIGN="top" | |
| 284 ><A | |
| 285 HREF="video.html" | |
| 286 >Up</A | |
| 287 ></TD | |
| 288 ><TD | |
| 289 WIDTH="33%" | |
| 290 ALIGN="right" | |
| 291 VALIGN="top" | |
| 292 >SDL_UnlockSurface</TD | |
| 293 ></TR | |
| 294 ></TABLE | |
| 295 ></DIV | |
| 296 ></BODY | |
| 297 ></HTML | |
| 298 > |