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Added new docs for SDL 1.2.1
author Sam Lantinga <slouken@lokigames.com>
date Sun, 10 Jun 2001 19:31:57 +0000
parents 74212992fb08
children e5bc29de3f0a
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54:028447a8a758 55:55f1f1b3e27d
2 ><HEAD 2 ><HEAD
3 ><TITLE 3 ><TITLE
4 >SDL_PixelFormat</TITLE 4 >SDL_PixelFormat</TITLE
5 ><META 5 ><META
6 NAME="GENERATOR" 6 NAME="GENERATOR"
7 CONTENT="Modular DocBook HTML Stylesheet Version 1.61 7 CONTENT="Modular DocBook HTML Stylesheet Version 1.64
8 "><LINK 8 "><LINK
9 REL="HOME" 9 REL="HOME"
10 TITLE="SDL Library Documentation" 10 TITLE="SDL Library Documentation"
11 HREF="index.html"><LINK 11 HREF="index.html"><LINK
12 REL="UP" 12 REL="UP"
71 >SDL_PixelFormat</A 71 >SDL_PixelFormat</A
72 ></H1 72 ></H1
73 ><DIV 73 ><DIV
74 CLASS="REFNAMEDIV" 74 CLASS="REFNAMEDIV"
75 ><A 75 ><A
76 NAME="AEN2677" 76 NAME="AEN2756"
77 ></A 77 ></A
78 ><H2 78 ><H2
79 >Name</H2 79 >Name</H2
80 >SDL_PixelFormat&nbsp;--&nbsp;Stores surface format information</DIV 80 >SDL_PixelFormat&nbsp;--&nbsp;Stores surface format information</DIV
81 ><DIV 81 ><DIV
82 CLASS="REFSECT1" 82 CLASS="REFSECT1"
83 ><A 83 ><A
84 NAME="AEN2680" 84 NAME="AEN2759"
85 ></A 85 ></A
86 ><H2 86 ><H2
87 >Structure Definition</H2 87 >Structure Definition</H2
88 ><PRE 88 ><PRE
89 CLASS="PROGRAMLISTING" 89 CLASS="PROGRAMLISTING"
99 } SDL_PixelFormat;</PRE 99 } SDL_PixelFormat;</PRE
100 ></DIV 100 ></DIV
101 ><DIV 101 ><DIV
102 CLASS="REFSECT1" 102 CLASS="REFSECT1"
103 ><A 103 ><A
104 NAME="AEN2683" 104 NAME="AEN2762"
105 ></A 105 ></A
106 ><H2 106 ><H2
107 >Structure Data</H2 107 >Structure Data</H2
108 ><DIV 108 ><DIV
109 CLASS="INFORMALTABLE" 109 CLASS="INFORMALTABLE"
110 ><A 110 ><A
111 NAME="AEN2685" 111 NAME="AEN2764"
112 ></A 112 ></A
113 ><P 113 ><P
114 ></P 114 ></P
115 ><TABLE 115 ><TABLE
116 BORDER="0" 116 BORDER="0"
256 ></DIV 256 ></DIV
257 ></DIV 257 ></DIV
258 ><DIV 258 ><DIV
259 CLASS="REFSECT1" 259 CLASS="REFSECT1"
260 ><A 260 ><A
261 NAME="AEN2724" 261 NAME="AEN2803"
262 ></A 262 ></A
263 ><H2 263 ><H2
264 >Description</H2 264 >Description</H2
265 ><P 265 ><P
266 >A <SPAN 266 >A <SPAN
381 color-&#62;r, color-&#62;g, color-&#62;b, index); 381 color-&#62;r, color-&#62;g, color-&#62;b, index);
382 . 382 .
383 .</PRE 383 .</PRE
384 ></P 384 ></P
385 ><P 385 ><P
386 >Pixel formats above 8-bit are an entirely different experience. They are considered to be "TrueColor" formats and the color information is stored in the pixels themselves, not in a palette (packed-pixel). The mask, shift and loss fields tell us how the color information is encoded. The mask fields allow us to isolate each color component, the shift fields tell us how far left we have to shift the masked value and the loss fields tell us for far right we have to shift the final value to convert it to a full 8-bit color component. 386 >Pixel formats above 8-bit are an entirely different experience. They are
387 considered to be "TrueColor" formats and the color information is stored in the
388 pixels themselves, not in a palette. The mask, shift and loss fields tell us
389 how the color information is encoded. The mask fields allow us to isolate each
390 color component, the shift fields tell us the number of bits to the right of
391 each component in the pixel value and the loss fields tell us the number of
392 bits lost from each component when packing 8-bit color component in a pixel.
387 <PRE 393 <PRE
388 CLASS="PROGRAMLISTING" 394 CLASS="PROGRAMLISTING"
389 >/* Extracting color components from a 32-bit color value */ 395 >/* Extracting color components from a 32-bit color value */
390 SDL_PixelFormat *fmt; 396 SDL_PixelFormat *fmt;
391 SDL_Surface *surface; 397 SDL_Surface *surface;
394 . 400 .
395 . 401 .
396 . 402 .
397 fmt=surface-&#62;format; 403 fmt=surface-&#62;format;
398 SDL_LockSurface(surface); 404 SDL_LockSurface(surface);
399 pixel=(Uint32*)surface-&#62;pixels; 405 pixel=*((Uint32*)surface-&#62;pixels);
400 SDL_UnlockSurface(surface); 406 SDL_UnlockSurface(surface);
401 407
402 /* Get Red component */ 408 /* Get Red component */
403 temp=pixel&#38;fmt-&#62;Rmask; /* Isolate red component */ 409 temp=pixel&#38;fmt-&#62;Rmask; /* Isolate red component */
404 temp=temp&#62;&#62;fmt-&#62;Rshift;/* Shift it down to 8-bit */ 410 temp=temp&#62;&#62;fmt-&#62;Rshift;/* Shift it down to 8-bit */
430 ></P 436 ></P
431 ></DIV 437 ></DIV
432 ><DIV 438 ><DIV
433 CLASS="REFSECT1" 439 CLASS="REFSECT1"
434 ><A 440 ><A
435 NAME="AEN2751" 441 NAME="AEN2830"
436 ></A 442 ></A
437 ><H2 443 ><H2
438 >See Also</H2 444 >See Also</H2
439 ><P 445 ><P
440 ><A 446 ><A