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1 | <?xml version="1.0" encoding="UTF-8"?> |
2 | <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN" | |
3 | "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd"> | |
4 | <refentry id="glColorTable"> | |
5 | <refmeta> | |
6 | <refmetainfo> | |
7 | <copyright> | |
8 | <year>1991-2006</year> | |
9 | <holder>Silicon Graphics, Inc.</holder> | |
10 | </copyright> | |
11 | </refmetainfo> | |
12 | <refentrytitle>glColorTable</refentrytitle> | |
13 | <manvolnum>3G</manvolnum> | |
14 | </refmeta> | |
15 | <refnamediv> | |
16 | <refname>glColorTable</refname> | |
17 | <refpurpose>define a color lookup table</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
22 | <funcdef>void <function>glColorTable</function></funcdef> | |
23 | <paramdef>GLenum <parameter>target</parameter></paramdef> | |
24 | <paramdef>GLenum <parameter>internalformat</parameter></paramdef> | |
25 | <paramdef>GLsizei <parameter>width</parameter></paramdef> | |
26 | <paramdef>GLenum <parameter>format</parameter></paramdef> | |
27 | <paramdef>GLenum <parameter>type</parameter></paramdef> | |
28 | <paramdef>const GLvoid * <parameter>data</parameter></paramdef> | |
29 | </funcprototype> | |
30 | </funcsynopsis> | |
31 | </refsynopsisdiv> | |
32 | <refsect1 id="parameters"><title>Parameters</title> | |
33 | <variablelist> | |
34 | <varlistentry> | |
35 | <term><parameter>target</parameter></term> | |
36 | <listitem> | |
37 | <para> | |
38 | Must be one of | |
39 | <constant>GL_COLOR_TABLE</constant>, | |
40 | <constant>GL_POST_CONVOLUTION_COLOR_TABLE</constant>, | |
41 | <constant>GL_POST_COLOR_MATRIX_COLOR_TABLE</constant>, | |
42 | <constant>GL_PROXY_COLOR_TABLE</constant>, | |
43 | <constant>GL_PROXY_POST_CONVOLUTION_COLOR_TABLE</constant>, | |
44 | or | |
45 | <constant>GL_PROXY_POST_COLOR_MATRIX_COLOR_TABLE</constant>. | |
46 | </para> | |
47 | </listitem> | |
48 | </varlistentry> | |
49 | <varlistentry> | |
50 | <term><parameter>internalformat</parameter></term> | |
51 | <listitem> | |
52 | <para> | |
53 | The internal format of the color table. | |
54 | The allowable values are | |
55 | <constant>GL_ALPHA</constant>, | |
56 | <constant>GL_ALPHA4</constant>, | |
57 | <constant>GL_ALPHA8</constant>, | |
58 | <constant>GL_ALPHA12</constant>, | |
59 | <constant>GL_ALPHA16</constant>, | |
60 | <constant>GL_LUMINANCE</constant>, | |
61 | <constant>GL_LUMINANCE4</constant>, | |
62 | <constant>GL_LUMINANCE8</constant>, | |
63 | <constant>GL_LUMINANCE12</constant>, | |
64 | <constant>GL_LUMINANCE16</constant>, | |
65 | <constant>GL_LUMINANCE_ALPHA</constant>, | |
66 | <constant>GL_LUMINANCE4_ALPHA4</constant>, | |
67 | <constant>GL_LUMINANCE6_ALPHA2</constant>, | |
68 | <constant>GL_LUMINANCE8_ALPHA8</constant>, | |
69 | <constant>GL_LUMINANCE12_ALPHA4</constant>, | |
70 | <constant>GL_LUMINANCE12_ALPHA12</constant>, | |
71 | <constant>GL_LUMINANCE16_ALPHA16</constant>, | |
72 | <constant>GL_INTENSITY</constant>, | |
73 | <constant>GL_INTENSITY4</constant>, | |
74 | <constant>GL_INTENSITY8</constant>, | |
75 | <constant>GL_INTENSITY12</constant>, | |
76 | <constant>GL_INTENSITY16</constant>, | |
77 | <constant>GL_R3_G3_B2</constant>, | |
78 | <constant>GL_RGB</constant>, | |
79 | <constant>GL_RGB4</constant>, | |
80 | <constant>GL_RGB5</constant>, | |
81 | <constant>GL_RGB8</constant>, | |
82 | <constant>GL_RGB10</constant>, | |
83 | <constant>GL_RGB12</constant>, | |
84 | <constant>GL_RGB16</constant>, | |
85 | <constant>GL_RGBA</constant>, | |
86 | <constant>GL_RGBA2</constant>, | |
87 | <constant>GL_RGBA4</constant>, | |
88 | <constant>GL_RGB5_A1</constant>, | |
89 | <constant>GL_RGBA8</constant>, | |
90 | <constant>GL_RGB10_A2</constant>, | |
91 | <constant>GL_RGBA12</constant>, and | |
92 | <constant>GL_RGBA16</constant>. | |
93 | </para> | |
94 | </listitem> | |
95 | </varlistentry> | |
96 | <varlistentry> | |
97 | <term><parameter>width</parameter></term> | |
98 | <listitem> | |
99 | <para> | |
100 | The number of entries in the color lookup table specified by <parameter>data</parameter>. | |
101 | </para> | |
102 | </listitem> | |
103 | </varlistentry> | |
104 | <varlistentry> | |
105 | <term><parameter>format</parameter></term> | |
106 | <listitem> | |
107 | <para> | |
108 | The format of the pixel data in <parameter>data</parameter>. | |
109 | The allowable values are | |
110 | <constant>GL_RED</constant>, | |
111 | <constant>GL_GREEN</constant>, | |
112 | <constant>GL_BLUE</constant>, | |
113 | <constant>GL_ALPHA</constant>, | |
114 | <constant>GL_LUMINANCE</constant>, | |
115 | <constant>GL_LUMINANCE_ALPHA</constant>, | |
116 | <constant>GL_RGB</constant>, | |
117 | <constant>GL_BGR</constant>, | |
118 | <constant>GL_RGBA</constant>, and | |
119 | <constant>GL_BGRA</constant>. | |
120 | </para> | |
121 | </listitem> | |
122 | </varlistentry> | |
123 | <varlistentry> | |
124 | <term><parameter>type</parameter></term> | |
125 | <listitem> | |
126 | <para> | |
127 | The type of the pixel data in <parameter>data</parameter>. | |
128 | The allowable values are | |
129 | <constant>GL_UNSIGNED_BYTE</constant>, | |
130 | <constant>GL_BYTE</constant>, | |
131 | <constant>GL_UNSIGNED_SHORT</constant>, | |
132 | <constant>GL_SHORT</constant>, | |
133 | <constant>GL_UNSIGNED_INT</constant>, | |
134 | <constant>GL_INT</constant>, | |
135 | <constant>GL_FLOAT</constant>, | |
136 | <constant>GL_UNSIGNED_BYTE_3_3_2</constant>, | |
137 | <constant>GL_UNSIGNED_BYTE_2_3_3_REV</constant>, | |
138 | <constant>GL_UNSIGNED_SHORT_5_6_5</constant>, | |
139 | <constant>GL_UNSIGNED_SHORT_5_6_5_REV</constant>, | |
140 | <constant>GL_UNSIGNED_SHORT_4_4_4_4</constant>, | |
141 | <constant>GL_UNSIGNED_SHORT_4_4_4_4_REV</constant>, | |
142 | <constant>GL_UNSIGNED_SHORT_5_5_5_1</constant>, | |
143 | <constant>GL_UNSIGNED_SHORT_1_5_5_5_REV</constant>, | |
144 | <constant>GL_UNSIGNED_INT_8_8_8_8</constant>, | |
145 | <constant>GL_UNSIGNED_INT_8_8_8_8_REV</constant>, | |
146 | <constant>GL_UNSIGNED_INT_10_10_10_2</constant>, and | |
147 | <constant>GL_UNSIGNED_INT_2_10_10_10_REV</constant>. | |
148 | </para> | |
149 | </listitem> | |
150 | </varlistentry> | |
151 | <varlistentry> | |
152 | <term><parameter>data</parameter></term> | |
153 | <listitem> | |
154 | <para> | |
155 | Pointer to a one-dimensional array of pixel data that is processed to | |
156 | build the color table. | |
157 | </para> | |
158 | </listitem> | |
159 | </varlistentry> | |
160 | </variablelist> | |
161 | </refsect1> | |
162 | <refsect1 id="description"><title>Description</title> | |
163 | <para> | |
164 | <function>glColorTable</function> may be used in two ways: | |
165 | to test the actual size and color resolution of a lookup table | |
166 | given a particular set of parameters, | |
167 | or to load the contents of a color lookup | |
168 | table. | |
169 | Use the targets <constant>GL_PROXY_*</constant> for the first case | |
170 | and the other targets for the second case. | |
171 | </para> | |
172 | <para> | |
173 | If a non-zero named buffer object is bound to the <constant>GL_PIXEL_UNPACK_BUFFER</constant> target | |
174 | (see <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>) while a color table is | |
175 | specified, <parameter>data</parameter> is treated as a byte offset into the buffer object's data store. | |
176 | </para> | |
177 | <para> | |
178 | If <parameter>target</parameter> is <constant>GL_COLOR_TABLE</constant>, | |
179 | <constant>GL_POST_CONVOLUTION_COLOR_TABLE</constant>, | |
180 | or | |
181 | <constant>GL_POST_COLOR_MATRIX_COLOR_TABLE</constant>, | |
182 | <function>glColorTable</function> builds a color lookup table from an array of pixels. | |
183 | The pixel array specified by <parameter>width</parameter>, <parameter>format</parameter>, <parameter>type</parameter>, and <parameter>data</parameter> | |
184 | is extracted from memory and | |
185 | processed just as if <citerefentry><refentrytitle>glDrawPixels</refentrytitle></citerefentry> were called, but processing | |
186 | stops after the final expansion to RGBA is completed. | |
187 | </para> | |
188 | <para> | |
189 | The four scale parameters and the four bias parameters that are defined | |
190 | for the table are then used to scale and bias the R, G, B, and A components | |
191 | of each pixel. | |
192 | (Use <function>glColorTableParameter</function> to set these scale and bias | |
193 | parameters.) | |
194 | </para> | |
195 | <para> | |
196 | Next, the R, G, B, and A values are clamped to the range | |
197 | <inlineequation><mml:math> | |
198 | <!-- eqn: [0,1]:--> | |
199 | <mml:mfenced open="[" close="]"> | |
200 | <mml:mn>0</mml:mn> | |
201 | <mml:mn>1</mml:mn> | |
202 | </mml:mfenced> | |
203 | </mml:math></inlineequation>. | |
204 | Each pixel is then converted to the internal format specified by | |
205 | <parameter>internalformat</parameter>. | |
206 | This conversion simply maps the component values of the pixel (R, G, B, | |
207 | and A) to the values included in the internal format (red, green, blue, | |
208 | alpha, luminance, and intensity). The mapping is as follows: | |
209 | </para> | |
210 | <para> | |
211 | </para> | |
212 | <informaltable frame="topbot"> | |
213 | <tgroup cols="7" align="left"> | |
214 | <colspec colwidth="3*" /> | |
215 | <colspec colwidth="1*" align="center"/> | |
216 | <colspec colwidth="1*" align="center"/> | |
217 | <colspec colwidth="1*" align="center"/> | |
218 | <colspec colwidth="1*" align="center"/> | |
219 | <colspec colwidth="1.5*" align="center"/> | |
220 | <colspec colwidth="1.5*" align="center"/> | |
221 | <thead> | |
222 | <row> | |
223 | <entry rowsep="1" align="left"><emphasis role="bold"> | |
224 | Internal Format | |
225 | </emphasis></entry> | |
226 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
227 | Red | |
228 | </emphasis></entry> | |
229 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
230 | Green | |
231 | </emphasis></entry> | |
232 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
233 | Blue | |
234 | </emphasis></entry> | |
235 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
236 | Alpha | |
237 | </emphasis></entry> | |
238 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
239 | Luminance | |
240 | </emphasis></entry> | |
241 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
242 | Intensity | |
243 | </emphasis></entry> | |
244 | </row> | |
245 | </thead> | |
246 | <tbody> | |
247 | <row> | |
248 | <entry align="left"> | |
249 | <constant>GL_ALPHA</constant> | |
250 | </entry> | |
251 | <entry align="center"> | |
252 | </entry> | |
253 | <entry align="center"> | |
254 | </entry> | |
255 | <entry align="center"> | |
256 | </entry> | |
257 | <entry align="center"> | |
258 | A | |
259 | </entry> | |
260 | <entry align="center"> | |
261 | </entry> | |
262 | <entry align="center"> | |
263 | ||
264 | </entry> | |
265 | </row> | |
266 | <row> | |
267 | <entry align="left"> | |
268 | <constant>GL_LUMINANCE</constant> | |
269 | </entry> | |
270 | <entry align="center"> | |
271 | </entry> | |
272 | <entry align="center"> | |
273 | </entry> | |
274 | <entry align="center"> | |
275 | </entry> | |
276 | <entry align="center"> | |
277 | </entry> | |
278 | <entry align="center"> | |
279 | R | |
280 | </entry> | |
281 | <entry align="center"> | |
282 | ||
283 | </entry> | |
284 | </row> | |
285 | <row> | |
286 | <entry align="left"> | |
287 | <constant>GL_LUMINANCE_ALPHA</constant> | |
288 | </entry> | |
289 | <entry align="center"> | |
290 | </entry> | |
291 | <entry align="center"> | |
292 | </entry> | |
293 | <entry align="center"> | |
294 | </entry> | |
295 | <entry align="center"> | |
296 | A | |
297 | </entry> | |
298 | <entry align="center"> | |
299 | R | |
300 | </entry> | |
301 | <entry align="center"> | |
302 | ||
303 | </entry> | |
304 | </row> | |
305 | <row> | |
306 | <entry align="left"> | |
307 | <constant>GL_INTENSITY</constant> | |
308 | </entry> | |
309 | <entry align="center"> | |
310 | </entry> | |
311 | <entry align="center"> | |
312 | </entry> | |
313 | <entry align="center"> | |
314 | </entry> | |
315 | <entry align="center"> | |
316 | </entry> | |
317 | <entry align="center"> | |
318 | </entry> | |
319 | <entry align="center"> | |
320 | R | |
321 | </entry> | |
322 | </row> | |
323 | <row> | |
324 | <entry align="left"> | |
325 | <constant>GL_RGB</constant> | |
326 | </entry> | |
327 | <entry align="center"> | |
328 | R | |
329 | </entry> | |
330 | <entry align="center"> | |
331 | G | |
332 | </entry> | |
333 | <entry align="center"> | |
334 | B | |
335 | </entry> | |
336 | <entry align="center"> | |
337 | </entry> | |
338 | <entry align="center"> | |
339 | </entry> | |
340 | <entry align="center"> | |
341 | ||
342 | </entry> | |
343 | </row> | |
344 | <row> | |
345 | <entry align="left"> | |
346 | <constant>GL_RGBA</constant> | |
347 | </entry> | |
348 | <entry align="center"> | |
349 | R | |
350 | </entry> | |
351 | <entry align="center"> | |
352 | G | |
353 | </entry> | |
354 | <entry align="center"> | |
355 | B | |
356 | </entry> | |
357 | <entry align="center"> | |
358 | A | |
359 | </entry> | |
360 | <entry align="center"> | |
361 | </entry> | |
362 | <entry align="center"> | |
363 | ||
364 | </entry> | |
365 | </row> | |
366 | </tbody> | |
367 | </tgroup> | |
368 | </informaltable> | |
369 | <para> | |
370 | Finally, the red, green, blue, alpha, luminance, and/or intensity components of | |
371 | the resulting pixels are stored in the color table. | |
372 | They form a one-dimensional table with indices in the range | |
373 | <inlineequation><mml:math> | |
374 | <!-- eqn: [0, width-1]:--> | |
375 | <mml:mfenced open="[" close="]"> | |
376 | <mml:mn>0</mml:mn> | |
377 | <mml:mrow> | |
378 | <mml:mi mathvariant="italic">width</mml:mi> | |
379 | <mml:mo>-</mml:mo> | |
380 | <mml:mn>1</mml:mn> | |
381 | </mml:mrow> | |
382 | </mml:mfenced> | |
383 | </mml:math></inlineequation>. | |
384 | </para> | |
385 | <para> | |
386 | If <parameter>target</parameter> is <constant>GL_PROXY_*</constant>, | |
387 | <function>glColorTable</function> recomputes and stores the values of the proxy color table's state | |
388 | variables | |
389 | <constant>GL_COLOR_TABLE_FORMAT</constant>, | |
390 | <constant>GL_COLOR_TABLE_WIDTH</constant>, | |
391 | <constant>GL_COLOR_TABLE_RED_SIZE</constant>, | |
392 | <constant>GL_COLOR_TABLE_GREEN_SIZE</constant>, | |
393 | <constant>GL_COLOR_TABLE_BLUE_SIZE</constant>, | |
394 | <constant>GL_COLOR_TABLE_ALPHA_SIZE</constant>, | |
395 | <constant>GL_COLOR_TABLE_LUMINANCE_SIZE</constant>, and | |
396 | <constant>GL_COLOR_TABLE_INTENSITY_SIZE</constant>. | |
397 | There is no effect on the image or state of any actual color table. | |
398 | If the specified color table is too large to be supported, then all the | |
399 | proxy state variables listed above are set to zero. | |
400 | Otherwise, the color table could be supported by <function>glColorTable</function> | |
401 | using the corresponding non-proxy target, | |
402 | and the proxy state variables are set as if that target were being defined. | |
403 | </para> | |
404 | <para> | |
405 | The proxy state variables can be retrieved by calling | |
406 | <citerefentry><refentrytitle>glGetColorTableParameter</refentrytitle></citerefentry> with a target of | |
407 | <constant>GL_PROXY_*</constant>. | |
408 | This allows the application to decide if a particular <function>glColorTable</function> | |
409 | command would succeed, and to determine what the resulting color table | |
410 | attributes would be. | |
411 | </para> | |
412 | <para> | |
413 | If a color table is enabled, and its width is non-zero, then its | |
414 | contents are used to replace a subset of the components of each RGBA | |
415 | pixel group, based on the internal format of the table. | |
416 | </para> | |
417 | <para> | |
418 | Each pixel group has color components (R, G, B, A) | |
419 | that are in the range | |
420 | <inlineequation><mml:math> | |
421 | <!-- eqn: [0.0, 1.0]:--> | |
422 | <mml:mfenced open="[" close="]"> | |
423 | <mml:mn>0.0</mml:mn> | |
424 | <mml:mn>1.0</mml:mn> | |
425 | </mml:mfenced> | |
426 | </mml:math></inlineequation>. | |
427 | The color components are rescaled to | |
428 | the size of the color lookup table to form an index. | |
429 | Then a subset of the components based on the internal format of the table are | |
430 | replaced by the table entry selected by that index. | |
431 | If the color components and contents of the table are represented as follows: | |
432 | </para> | |
433 | <para> | |
434 | </para> | |
435 | <informaltable frame="topbot"> | |
436 | <tgroup cols="2" align="left"> | |
437 | <colspec align="center"/> | |
438 | <colspec align="center"/> | |
439 | <thead> | |
440 | <row> | |
441 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
442 | Representation | |
443 | </emphasis></entry> | |
444 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
445 | Meaning | |
446 | </emphasis></entry> | |
447 | </row> | |
448 | </thead> | |
449 | <tbody> | |
450 | <row> | |
451 | <entry align="center"> | |
452 | <code>r</code> | |
453 | </entry> | |
454 | <entry align="left"> | |
455 | Table index computed from <code>R</code> | |
456 | </entry> | |
457 | </row> | |
458 | <row> | |
459 | <entry align="center"> | |
460 | <code>g</code> | |
461 | </entry> | |
462 | <entry align="left"> | |
463 | Table index computed from <code>G</code> | |
464 | </entry> | |
465 | </row> | |
466 | <row> | |
467 | <entry align="center"> | |
468 | <code>b</code> | |
469 | </entry> | |
470 | <entry align="left"> | |
471 | Table index computed from <code>B</code> | |
472 | </entry> | |
473 | </row> | |
474 | <row> | |
475 | <entry align="center"> | |
476 | <code>a</code> | |
477 | </entry> | |
478 | <entry align="left"> | |
479 | Table index computed from <code>A</code> | |
480 | </entry> | |
481 | </row> | |
482 | <row> | |
483 | <entry align="center"> | |
484 | <code>L[i]</code> | |
485 | </entry> | |
486 | <entry align="left"> | |
487 | Luminance value at table index <code>i</code> | |
488 | </entry> | |
489 | </row> | |
490 | <row> | |
491 | <entry align="center"> | |
492 | <code>I[i]</code> | |
493 | </entry> | |
494 | <entry align="left"> | |
495 | Intensity value at table index <code>i</code> | |
496 | </entry> | |
497 | </row> | |
498 | <row> | |
499 | <entry align="center"> | |
500 | <code>R[i]</code> | |
501 | </entry> | |
502 | <entry align="left"> | |
503 | Red value at table index <code>i</code> | |
504 | </entry> | |
505 | </row> | |
506 | <row> | |
507 | <entry align="center"> | |
508 | <code>G[i]</code> | |
509 | </entry> | |
510 | <entry align="left"> | |
511 | Green value at table index <code>i</code> | |
512 | </entry> | |
513 | </row> | |
514 | <row> | |
515 | <entry align="center"> | |
516 | <code>B[i]</code> | |
517 | </entry> | |
518 | <entry align="left"> | |
519 | Blue value at table index <code>i</code> | |
520 | </entry> | |
521 | </row> | |
522 | <row> | |
523 | <entry align="center"> | |
524 | <code>A[i]</code> | |
525 | </entry> | |
526 | <entry align="left"> | |
527 | Alpha value at table index <code>i</code> | |
528 | </entry> | |
529 | </row> | |
530 | </tbody> | |
531 | </tgroup> | |
532 | </informaltable> | |
533 | <para> | |
534 | then the result of color table lookup is as follows: | |
535 | </para> | |
536 | <para> | |
537 | </para> | |
538 | <informaltable frame="topbot"> | |
539 | <tgroup cols="5" align="left"> | |
540 | <colspec colwidth="2*" /> | |
541 | <colspec colwidth="1*" colname="r"/> | |
542 | <colspec colwidth="1*" colname="g"/> | |
543 | <colspec colwidth="1*" colname="b"/> | |
544 | <colspec colwidth="1*" colname="a"/> | |
545 | <thead> | |
546 | <row> | |
547 | <entry align="left"><emphasis role="bold"> | |
548 | </emphasis></entry> | |
549 | <entry namest="r" nameend="a" align="center"><emphasis role="bold"> | |
550 | Resulting Texture Components | |
551 | </emphasis></entry> | |
552 | </row> | |
553 | <row> | |
554 | <entry rowsep="1" align="left"><emphasis role="bold"> | |
555 | Table Internal Format | |
556 | </emphasis></entry> | |
557 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
558 | R | |
559 | </emphasis></entry> | |
560 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
561 | G | |
562 | </emphasis></entry> | |
563 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
564 | B | |
565 | </emphasis></entry> | |
566 | <entry rowsep="1" align="center"><emphasis role="bold"> | |
567 | A | |
568 | </emphasis></entry> | |
569 | </row> | |
570 | </thead> | |
571 | <tbody> | |
572 | <row> | |
573 | <entry align="left"> | |
574 | <constant>GL_ALPHA</constant> | |
575 | </entry> | |
576 | <entry align="center"> | |
577 | <code>R</code> | |
578 | </entry> | |
579 | <entry align="center"> | |
580 | <code>G</code> | |
581 | </entry> | |
582 | <entry align="center"> | |
583 | <code>B</code> | |
584 | </entry> | |
585 | <entry align="center"> | |
586 | <code>A[a]</code> | |
587 | </entry> | |
588 | </row> | |
589 | <row> | |
590 | <entry align="left"> | |
591 | <constant>GL_LUMINANCE</constant> | |
592 | </entry> | |
593 | <entry align="center"> | |
594 | <code>L[r]</code> | |
595 | </entry> | |
596 | <entry align="center"> | |
597 | <code>L[g]</code> | |
598 | </entry> | |
599 | <entry align="center"> | |
600 | <code>L[b]</code> | |
601 | </entry> | |
602 | <entry align="center"> | |
603 | <code>At</code> | |
604 | </entry> | |
605 | </row> | |
606 | <row> | |
607 | <entry align="left"> | |
608 | <constant>GL_LUMINANCE_ALPHA</constant> | |
609 | </entry> | |
610 | <entry align="center"> | |
611 | <code>L[r]</code> | |
612 | </entry> | |
613 | <entry align="center"> | |
614 | <code>L[g]</code> | |
615 | </entry> | |
616 | <entry align="center"> | |
617 | <code>L[b]</code> | |
618 | </entry> | |
619 | <entry align="center"> | |
620 | <code>A[a]</code> | |
621 | </entry> | |
622 | </row> | |
623 | <row> | |
624 | <entry align="left"> | |
625 | <constant>GL_INTENSITY</constant> | |
626 | </entry> | |
627 | <entry align="center"> | |
628 | <code>I[r]</code> | |
629 | </entry> | |
630 | <entry align="center"> | |
631 | <code>I[g]</code> | |
632 | </entry> | |
633 | <entry align="center"> | |
634 | <code>I[b]</code> | |
635 | </entry> | |
636 | <entry align="center"> | |
637 | <code>I[a]</code> | |
638 | </entry> | |
639 | </row> | |
640 | <row> | |
641 | <entry align="left"> | |
642 | <constant>GL_RGB</constant> | |
643 | </entry> | |
644 | <entry align="center"> | |
645 | <code>R[r]</code> | |
646 | </entry> | |
647 | <entry align="center"> | |
648 | <code>G[g]</code> | |
649 | </entry> | |
650 | <entry align="center"> | |
651 | <code>B[b]</code> | |
652 | </entry> | |
653 | <entry align="center"> | |
654 | <code>A</code> | |
655 | </entry> | |
656 | </row> | |
657 | <row> | |
658 | <entry align="left"> | |
659 | <constant>GL_RGBA</constant> | |
660 | </entry> | |
661 | <entry align="center"> | |
662 | <code>R[r]</code> | |
663 | </entry> | |
664 | <entry align="center"> | |
665 | <code>G[g]</code> | |
666 | </entry> | |
667 | <entry align="center"> | |
668 | <code>B[b]</code> | |
669 | </entry> | |
670 | <entry align="center"> | |
671 | <code>A[a]</code> | |
672 | </entry> | |
673 | </row> | |
674 | </tbody> | |
675 | </tgroup> | |
676 | </informaltable> | |
677 | <para> | |
678 | When <constant>GL_COLOR_TABLE</constant> is enabled, the colors resulting from | |
679 | the pixel map operation (if it is enabled) are mapped | |
680 | by the color lookup table before being passed to the convolution | |
681 | operation. The colors resulting from the convolution operation | |
682 | are modified by the post convolution color lookup table when | |
683 | <constant>GL_POST_CONVOLUTION_COLOR_TABLE</constant> | |
684 | is enabled. These modified colors are then sent to the color matrix operation. | |
685 | Finally, if <constant>GL_POST_COLOR_MATRIX_COLOR_TABLE</constant> | |
686 | is enabled, the colors resulting from the color matrix operation | |
687 | are mapped by the post color matrix color lookup table before being | |
688 | used by the histogram operation. | |
689 | </para> | |
690 | <para> | |
691 | </para> | |
692 | </refsect1> | |
693 | <refsect1 id="notes"><title>Notes</title> | |
694 | <para> | |
695 | <function>glColorTable</function> is present only if <code>ARB_imaging</code> is returned when <citerefentry><refentrytitle>glGetString</refentrytitle></citerefentry> | |
696 | is called with an argument of <constant>GL_EXTENSIONS</constant>. | |
697 | </para> | |
698 | <para> | |
699 | If <parameter>target</parameter> is set to <constant>GL_COLOR_TABLE</constant>, | |
700 | <constant>GL_POST_CONVOLUTION_COLOR_TABLE</constant>, | |
701 | or <constant>GL_POST_COLOR_MATRIX_COLOR_TABLE</constant>, | |
702 | then <parameter>width</parameter> must be a power of two or a <constant>GL_INVALID_VALUE</constant> | |
703 | error is generated. | |
704 | </para> | |
705 | <para> | |
706 | </para> | |
707 | </refsect1> | |
708 | <refsect1 id="errors"><title>Errors</title> | |
709 | <para> | |
710 | <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not one of the allowable | |
711 | values. | |
712 | </para> | |
713 | <para> | |
714 | <constant>GL_INVALID_ENUM</constant> is generated if <parameter>internalformat</parameter> is not one of the | |
715 | allowable values. | |
716 | </para> | |
717 | <para> | |
718 | <constant>GL_INVALID_ENUM</constant> is generated if <parameter>format</parameter> is not one of the allowable | |
719 | values. | |
720 | </para> | |
721 | <para> | |
722 | <constant>GL_INVALID_ENUM</constant> is generated if <parameter>type</parameter> is not one of the allowable | |
723 | values. | |
724 | </para> | |
725 | <para> | |
726 | <constant>GL_INVALID_VALUE</constant> is generated if <parameter>width</parameter> is less than zero. | |
727 | </para> | |
728 | <para> | |
729 | <constant>GL_TABLE_TOO_LARGE</constant> is generated if the requested color table | |
730 | is too large to be supported by the implementation, and <parameter>target</parameter> is | |
731 | not a <constant>GL_PROXY_*</constant> target. | |
732 | </para> | |
733 | <para> | |
734 | <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the | |
735 | <constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the buffer object's data store is currently mapped. | |
736 | </para> | |
737 | <para> | |
738 | <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the | |
739 | <constant>GL_PIXEL_UNPACK_BUFFER</constant> target and the data would be unpacked from the buffer | |
740 | object such that the memory reads required would exceed the data store size. | |
741 | </para> | |
742 | <para> | |
743 | <constant>GL_INVALID_OPERATION</constant> is generated if a non-zero buffer object name is bound to the | |
744 | <constant>GL_PIXEL_UNPACK_BUFFER</constant> target and <parameter>data</parameter> is not evenly divisible | |
745 | into the number of bytes needed to store in memory a datum indicated by <parameter>type</parameter>. | |
746 | </para> | |
747 | <para> | |
748 | <constant>GL_INVALID_OPERATION</constant> is generated if <function>glColorTable</function> is executed | |
749 | between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the corresponding | |
750 | execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>. | |
751 | </para> | |
752 | </refsect1> | |
753 | <refsect1 id="associatedgets"><title>Associated Gets</title> | |
754 | <para> | |
755 | <citerefentry><refentrytitle>glGetColorTableParameter</refentrytitle></citerefentry> | |
756 | </para> | |
757 | <para> | |
758 | <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_PIXEL_UNPACK_BUFFER_BINDING</constant> | |
759 | </para> | |
760 | </refsect1> | |
761 | <refsect1 id="seealso"><title>See Also</title> | |
762 | <para> | |
763 | <citerefentry><refentrytitle>glColorSubTable</refentrytitle></citerefentry>, | |
764 | <function>glColorTableParameter</function>, | |
765 | <citerefentry><refentrytitle>glCopyColorTable</refentrytitle></citerefentry>, | |
766 | <citerefentry><refentrytitle>glCopyColorSubTable</refentrytitle></citerefentry>, | |
767 | <citerefentry><refentrytitle>glGetColorTable</refentrytitle></citerefentry> | |
768 | </para> | |
769 | </refsect1> | |
770 | <refsect1 id="Copyright"><title>Copyright</title> | |
771 | <para> | |
772 | Copyright <trademark class="copyright"></trademark> 1991-2006 | |
773 | Silicon Graphics, Inc. This document is licensed under the SGI | |
774 | Free Software B License. For details, see | |
775 | <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. | |
776 | </para> | |
777 | </refsect1> | |
778 | </refentry> |