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| 5131 | clevermous | 1 | |
| 2 | > |
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| 3 | > |
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| 4 | >SDL_LockSurface |
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| 5 | > |
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| 6 | NAME="GENERATOR" |
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| 7 | CONTENT="Modular DocBook HTML Stylesheet Version 1.64 |
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| 8 | "> |
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| 9 | REL="HOME" |
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| 10 | TITLE="SDL Library Documentation" |
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| 11 | HREF="index.html"> |
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| 12 | REL="UP" |
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| 13 | TITLE="Video" |
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| 14 | HREF="video.html"> |
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| 15 | REL="PREVIOUS" |
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| 16 | TITLE="SDL_FreeSurface" |
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| 17 | HREF="sdlfreesurface.html"> |
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| 18 | REL="NEXT" |
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| 19 | TITLE="SDL_UnlockSurface" |
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| 20 | HREF="sdlunlocksurface.html"> |
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| 21 | > |
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| 22 | CLASS="REFENTRY" |
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| 23 | BGCOLOR="#FFF8DC" |
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| 24 | TEXT="#000000" |
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| 25 | LINK="#0000ee" |
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| 26 | VLINK="#551a8b" |
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| 27 | ALINK="#ff0000" |
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| 28 | > |
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| 29 | CLASS="NAVHEADER" |
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| 30 | > |
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| 31 | WIDTH="100%" |
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| 32 | BORDER="0" |
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| 33 | CELLPADDING="0" |
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| 34 | CELLSPACING="0" |
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| 35 | > |
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| 36 | > |
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| 37 | COLSPAN="3" |
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| 38 | ALIGN="center" |
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| 39 | >SDL Library Documentation |
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| 40 | > |
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| 41 | > |
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| 42 | > |
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| 43 | WIDTH="10%" |
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| 44 | ALIGN="left" |
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| 45 | VALIGN="bottom" |
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| 46 | > |
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| 47 | HREF="sdlfreesurface.html" |
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| 48 | >Prev |
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| 49 | > |
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| 50 | > |
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| 51 | WIDTH="80%" |
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| 52 | ALIGN="center" |
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| 53 | VALIGN="bottom" |
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| 54 | > |
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| 55 | > |
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| 56 | WIDTH="10%" |
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| 57 | ALIGN="right" |
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| 58 | VALIGN="bottom" |
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| 59 | > |
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| 60 | HREF="sdlunlocksurface.html" |
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| 61 | >Next |
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| 62 | > |
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| 63 | > |
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| 64 | > |
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| 65 | > |
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| 66 | ALIGN="LEFT" |
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| 67 | WIDTH="100%"> |
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| 68 | > |
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| 69 | > |
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| 70 | NAME="SDLLOCKSURFACE" |
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| 71 | >SDL_LockSurface |
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| 72 | > |
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| 73 | > |
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| 74 | CLASS="REFNAMEDIV" |
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| 75 | > |
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| 76 | NAME="AEN1504" |
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| 77 | > |
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| 78 | > |
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| 79 | >Name |
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| 80 | >SDL_LockSurface -- Lock a surface for directly access. |
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| 81 | > |
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| 82 | CLASS="REFSYNOPSISDIV" |
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| 83 | > |
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| 84 | NAME="AEN1507" |
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| 85 | > |
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| 86 | > |
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| 87 | >Synopsis |
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| 88 | > |
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| 89 | CLASS="FUNCSYNOPSIS" |
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| 90 | > |
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| 91 | NAME="AEN1508" |
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| 92 | > |
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| 93 | > |
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| 94 | > |
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| 95 | > |
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| 96 | CLASS="FUNCSYNOPSISINFO" |
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| 97 | >#include "SDL.h" |
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| 98 | > |
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| 99 | > |
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| 100 | > |
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| 101 | CLASS="FUNCDEF" |
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| 102 | >int |
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| 103 | CLASS="FSFUNC" |
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| 104 | >SDL_LockSurface |
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| 105 | > |
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| 106 | >(SDL_Surface *surface); |
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| 107 | > |
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| 108 | > |
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| 109 | > |
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| 110 | > |
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| 111 | > |
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| 112 | > |
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| 113 | CLASS="REFSECT1" |
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| 114 | > |
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| 115 | NAME="AEN1514" |
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| 116 | > |
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| 117 | > |
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| 118 | >Description |
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| 119 | > |
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| 120 | > |
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| 121 | CLASS="FUNCTION" |
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| 122 | >SDL_LockSurface |
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| 123 | > sets up a surface for directly |
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| 124 | accessing the pixels. Between calls to |
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| 125 | CLASS="FUNCTION" |
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| 126 | >SDL_LockSurface |
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| 127 | > |
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| 128 | and |
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| 129 | CLASS="FUNCTION" |
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| 130 | >SDL_UnlockSurface |
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| 131 | >, you can write to and read from |
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| 132 | |||
| 133 | CLASS="PARAMETER" |
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| 134 | > |
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| 135 | >surface-> |
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| 136 | CLASS="STRUCTFIELD" |
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| 137 | > |
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| 138 | >pixels |
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| 139 | > |
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| 140 | > |
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| 141 | > |
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| 142 | >, using the pixel format stored in |
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| 143 | |||
| 144 | CLASS="PARAMETER" |
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| 145 | > |
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| 146 | >surface-> |
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| 147 | CLASS="STRUCTFIELD" |
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| 148 | > |
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| 149 | >format |
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| 150 | > |
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| 151 | > |
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| 152 | > |
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| 153 | >. Once you are done accessing the |
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| 154 | surface, you should use |
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| 155 | CLASS="FUNCTION" |
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| 156 | >SDL_UnlockSurface |
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| 157 | > to release it. |
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| 158 | > |
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| 159 | >Not all surfaces require locking. |
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| 160 | If |
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| 161 | CLASS="LITERAL" |
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| 162 | >SDL_MUSTLOCK |
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| 163 | >( |
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| 164 | CLASS="PARAMETER" |
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| 165 | > |
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| 166 | >surface |
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| 167 | > |
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| 168 | >) |
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| 169 | evaluates to |
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| 170 | CLASS="RETURNVALUE" |
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| 171 | >0 |
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| 172 | >, then you can read and write to the |
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| 173 | surface at any time, and the pixel format of the surface will not change. |
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| 174 | > |
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| 175 | >No operating system or library calls should be made between lock/unlock |
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| 176 | pairs, as critical system locks may be held during this time. |
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| 177 | > |
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| 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. |
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| 179 | |||
| 180 | CLASS="PROGRAMLISTING" |
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| 181 | > . |
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| 182 | . |
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| 183 | SDL_LockSurface( surface ); |
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| 184 | . |
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| 185 | /* Surface is locked */ |
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| 186 | /* Direct pixel access on surface here */ |
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| 187 | . |
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| 188 | SDL_LockSurface( surface ); |
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| 189 | . |
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| 190 | /* More direct pixel access on surface */ |
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| 191 | . |
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| 192 | SDL_UnlockSurface( surface ); |
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| 193 | /* Surface is still locked */ |
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| 194 | /* Note: Is versions < 1.1.8, the surface would have been */ |
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| 195 | /* no longer locked at this stage */ |
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| 196 | . |
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| 197 | SDL_UnlockSurface( surface ); |
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| 198 | /* Surface is now unlocked */ |
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| 199 | . |
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| 200 | . |
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| 201 | > |
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| 202 | |||
| 203 | > |
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| 204 | > |
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| 205 | CLASS="REFSECT1" |
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| 206 | > |
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| 207 | NAME="AEN1532" |
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| 208 | > |
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| 209 | > |
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| 210 | >Return Value |
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| 211 | > |
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| 212 | > |
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| 213 | CLASS="FUNCTION" |
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| 214 | >SDL_LockSurface |
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| 215 | > returns |
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| 216 | CLASS="RETURNVALUE" |
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| 217 | >0 |
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| 218 | >, |
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| 219 | or |
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| 220 | CLASS="RETURNVALUE" |
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| 221 | >-1 |
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| 222 | > if the surface couldn't be locked. |
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| 223 | > |
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| 224 | > |
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| 225 | CLASS="REFSECT1" |
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| 226 | > |
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| 227 | NAME="AEN1538" |
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| 228 | > |
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| 229 | > |
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| 230 | >See Also |
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| 231 | > |
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| 232 | > |
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| 233 | HREF="sdlunlocksurface.html" |
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| 234 | > |
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| 235 | CLASS="FUNCTION" |
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| 236 | >SDL_UnlockSurface |
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| 237 | > |
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| 238 | > |
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| 239 | > |
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| 240 | > |
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| 241 | CLASS="NAVFOOTER" |
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| 242 | > |
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| 243 | ALIGN="LEFT" |
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| 244 | WIDTH="100%"> |
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| 245 | WIDTH="100%" |
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| 246 | BORDER="0" |
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| 247 | CELLPADDING="0" |
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| 248 | CELLSPACING="0" |
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| 249 | > |
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| 250 | > |
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| 251 | WIDTH="33%" |
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| 252 | ALIGN="left" |
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| 253 | VALIGN="top" |
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| 254 | > |
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| 255 | HREF="sdlfreesurface.html" |
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| 256 | >Prev |
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| 257 | > |
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| 258 | > |
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| 259 | WIDTH="34%" |
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| 260 | ALIGN="center" |
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| 261 | VALIGN="top" |
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| 262 | > |
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| 263 | HREF="index.html" |
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| 264 | >Home |
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| 265 | > |
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| 266 | > |
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| 267 | WIDTH="33%" |
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| 268 | ALIGN="right" |
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| 269 | VALIGN="top" |
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| 270 | > |
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| 271 | HREF="sdlunlocksurface.html" |
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| 272 | >Next |
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| 273 | > |
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| 274 | > |
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| 275 | > |
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| 276 | > |
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| 277 | WIDTH="33%" |
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| 278 | ALIGN="left" |
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| 279 | VALIGN="top" |
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| 280 | >SDL_FreeSurface |
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| 281 | > |
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| 282 | WIDTH="34%" |
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| 283 | ALIGN="center" |
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| 284 | VALIGN="top" |
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| 285 | > |
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| 286 | HREF="video.html" |
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| 287 | >Up |
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| 288 | > |
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| 289 | > |
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| 290 | WIDTH="33%" |
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| 291 | ALIGN="right" |
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| 292 | VALIGN="top" |
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| 293 | >SDL_UnlockSurface |
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| 294 | > |
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| 295 | > |
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| 296 | > |
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| 297 | > |
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| 298 | > |
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| 299 | > |