Mercurial > sdl-ios-xcode
annotate docs/html/sdlgetrgba.html @ 1240:3b8a43c428bb
From Bug #36:
There are a couple of issues with the selection of Altivec alpha-blitting
routines in CalculateAlphaBlit() in src/video/SDL_Blit_A.c.
1) There's no check for the presence of Altivec when checking if the
Blit32to565PixelAlphaAltivec() routine can be selected.
2) Altivec cannot be used in video memory, and there's no check if the
destination surface is a hardware surface. (Alpha-blitting to a hardware
surface with GPU support is a bad idea, but somebody's bound to do it anyway.)
Patch to fix these attached.
| author | Ryan C. Gordon <icculus@icculus.org> |
|---|---|
| date | Sun, 08 Jan 2006 21:18:15 +0000 |
| parents | 355632dca928 |
| children |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_GetRGBA</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_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 | |
|
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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="sdlgetrgb.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="sdlcreatergbsurface.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="SDLGETRGBA" | |
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74 ></A |
|
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75 >SDL_GetRGBA</H1 |
| 0 | 76 ><DIV |
| 77 CLASS="REFNAMEDIV" | |
| 78 ><A | |
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79 NAME="AEN1747" |
| 0 | 80 ></A |
| 81 ><H2 | |
| 82 >Name</H2 | |
| 83 >SDL_GetRGBA -- Get RGBA values from a pixel in the specified pixel format.</DIV | |
| 84 ><DIV | |
| 85 CLASS="REFSYNOPSISDIV" | |
| 86 ><A | |
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87 NAME="AEN1750" |
| 0 | 88 ></A |
| 89 ><H2 | |
| 90 >Synopsis</H2 | |
| 91 ><DIV | |
| 92 CLASS="FUNCSYNOPSIS" | |
| 93 ><A | |
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94 NAME="AEN1751" |
| 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 >void <B | |
| 106 CLASS="FSFUNC" | |
| 107 >SDL_GetRGBA</B | |
| 108 ></CODE | |
| 109 >(Uint32 pixel, SDL_PixelFormat *fmt, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a);</CODE | |
| 110 ></P | |
| 111 ><P | |
| 112 ></P | |
| 113 ></DIV | |
| 114 ></DIV | |
| 115 ><DIV | |
| 116 CLASS="REFSECT1" | |
| 117 ><A | |
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118 NAME="AEN1757" |
| 0 | 119 ></A |
| 120 ><H2 | |
| 121 >Description</H2 | |
| 122 ><P | |
| 123 >Get RGBA component values from a pixel stored in the specified pixel format.</P | |
| 124 ><P | |
| 125 >This function uses the entire 8-bit [0..255] range when converting color | |
| 126 components from pixel formats with less than 8-bits per RGB component | |
| 127 (e.g., a completely white pixel in 16-bit RGB565 format would return | |
| 128 [0xff, 0xff, 0xff] not [0xf8, 0xfc, 0xf8]).</P | |
| 129 ><P | |
| 130 >If the surface has no alpha component, the alpha will be returned as 0xff | |
| 131 (100% opaque).</P | |
| 132 ></DIV | |
| 133 ><DIV | |
| 134 CLASS="REFSECT1" | |
| 135 ><A | |
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parents:
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136 NAME="AEN1762" |
| 0 | 137 ></A |
| 138 ><H2 | |
| 139 >See Also</H2 | |
| 140 ><P | |
| 141 ><A | |
| 142 HREF="sdlgetrgb.html" | |
| 143 >SDL_GetRGB</A | |
| 144 >, | |
| 145 <A | |
| 146 HREF="sdlmaprgb.html" | |
| 147 >SDL_MapRGB</A | |
| 148 >, | |
| 149 <A | |
| 150 HREF="sdlmaprgba.html" | |
| 151 >SDL_MapRGBA</A | |
| 152 >, | |
| 153 <A | |
| 154 HREF="sdlpixelformat.html" | |
| 155 >SDL_PixelFormat</A | |
| 156 ></P | |
| 157 ></DIV | |
| 158 ><DIV | |
| 159 CLASS="NAVFOOTER" | |
| 160 ><HR | |
| 161 ALIGN="LEFT" | |
| 162 WIDTH="100%"><TABLE | |
|
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parents:
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163 SUMMARY="Footer navigation table" |
| 0 | 164 WIDTH="100%" |
| 165 BORDER="0" | |
| 166 CELLPADDING="0" | |
| 167 CELLSPACING="0" | |
| 168 ><TR | |
| 169 ><TD | |
| 170 WIDTH="33%" | |
| 171 ALIGN="left" | |
| 172 VALIGN="top" | |
| 173 ><A | |
| 174 HREF="sdlgetrgb.html" | |
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803
355632dca928
Updated SDL HTML documentation
Sam Lantinga <slouken@libsdl.org>
parents:
181
diff
changeset
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175 ACCESSKEY="P" |
| 0 | 176 >Prev</A |
| 177 ></TD | |
| 178 ><TD | |
| 179 WIDTH="34%" | |
| 180 ALIGN="center" | |
| 181 VALIGN="top" | |
| 182 ><A | |
| 183 HREF="index.html" | |
|
803
355632dca928
Updated SDL HTML documentation
Sam Lantinga <slouken@libsdl.org>
parents:
181
diff
changeset
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184 ACCESSKEY="H" |
| 0 | 185 >Home</A |
| 186 ></TD | |
| 187 ><TD | |
| 188 WIDTH="33%" | |
| 189 ALIGN="right" | |
| 190 VALIGN="top" | |
| 191 ><A | |
| 192 HREF="sdlcreatergbsurface.html" | |
|
803
355632dca928
Updated SDL HTML documentation
Sam Lantinga <slouken@libsdl.org>
parents:
181
diff
changeset
|
193 ACCESSKEY="N" |
| 0 | 194 >Next</A |
| 195 ></TD | |
| 196 ></TR | |
| 197 ><TR | |
| 198 ><TD | |
| 199 WIDTH="33%" | |
| 200 ALIGN="left" | |
| 201 VALIGN="top" | |
| 202 >SDL_GetRGB</TD | |
| 203 ><TD | |
| 204 WIDTH="34%" | |
| 205 ALIGN="center" | |
| 206 VALIGN="top" | |
| 207 ><A | |
| 208 HREF="video.html" | |
|
803
355632dca928
Updated SDL HTML documentation
Sam Lantinga <slouken@libsdl.org>
parents:
181
diff
changeset
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209 ACCESSKEY="U" |
| 0 | 210 >Up</A |
| 211 ></TD | |
| 212 ><TD | |
| 213 WIDTH="33%" | |
| 214 ALIGN="right" | |
| 215 VALIGN="top" | |
| 216 >SDL_CreateRGBSurface</TD | |
| 217 ></TR | |
| 218 ></TABLE | |
| 219 ></DIV | |
| 220 ></BODY | |
| 221 ></HTML | |
| 222 > |