Commit | Line | Data |
---|---|---|
7faf1d71 AW |
1 | <?xml version="1.0" encoding="UTF-8"?>\r |
2 | <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"\r | |
3 | "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">\r | |
4 | <refentry id="glSamplerParameter">\r | |
5 | <refmeta>\r | |
6 | <refmetainfo>\r | |
7 | <copyright>\r | |
8 | <year>2010</year>\r | |
9 | <holder>KhronosGroup</holder>\r | |
10 | </copyright>\r | |
11 | </refmetainfo>\r | |
12 | <refentrytitle>glSamplerParameter</refentrytitle>\r | |
13 | <manvolnum>3G</manvolnum>\r | |
14 | </refmeta>\r | |
15 | <refnamediv>\r | |
16 | <refname>glSamplerParameter</refname>\r | |
17 | <refpurpose>set sampler parameters</refpurpose>\r | |
18 | </refnamediv>\r | |
19 | <refsynopsisdiv><title>C Specification</title>\r | |
20 | <funcsynopsis>\r | |
21 | <funcprototype>\r | |
22 | <funcdef>void <function>glSamplerParameterf</function></funcdef>\r | |
23 | <paramdef>GLuint <parameter>sampler</parameter></paramdef>\r | |
24 | <paramdef>GLenum <parameter>pname</parameter></paramdef>\r | |
25 | <paramdef>GLfloat <parameter>param</parameter></paramdef>\r | |
26 | </funcprototype>\r | |
27 | </funcsynopsis>\r | |
28 | <funcsynopsis>\r | |
29 | <funcprototype>\r | |
30 | <funcdef>void <function>glSamplerParameteri</function></funcdef>\r | |
31 | <paramdef>GLuint <parameter>sampler</parameter></paramdef>\r | |
32 | <paramdef>GLenum <parameter>pname</parameter></paramdef>\r | |
33 | <paramdef>GLint <parameter>param</parameter></paramdef>\r | |
34 | </funcprototype>\r | |
35 | </funcsynopsis>\r | |
36 | </refsynopsisdiv>\r | |
37 | <!-- eqn: ignoring delim $$ -->\r | |
38 | <refsect1 id="parameters"><title>Parameters</title>\r | |
39 | <variablelist>\r | |
40 | <varlistentry>\r | |
41 | <term><parameter>sampler</parameter></term>\r | |
42 | <listitem>\r | |
43 | <para>\r | |
44 | Specifies the sampler object whose parameter to modify.\r | |
45 | </para>\r | |
46 | </listitem>\r | |
47 | </varlistentry>\r | |
48 | <varlistentry>\r | |
49 | <term><parameter>pname</parameter></term>\r | |
50 | <listitem>\r | |
51 | <para>\r | |
52 | Specifies the symbolic name of a single-valued sampler parameter.\r | |
53 | <parameter>pname</parameter> can be one of the following:\r | |
54 | <constant>GL_TEXTURE_WRAP_S</constant>,\r | |
55 | <constant>GL_TEXTURE_WRAP_T</constant>,\r | |
56 | <constant>GL_TEXTURE_WRAP_R</constant>,\r | |
57 | <constant>GL_TEXTURE_MIN_FILTER</constant>,\r | |
58 | <constant>GL_TEXTURE_MAG_FILTER</constant>,\r | |
59 | <constant>GL_TEXTURE_MIN_LOD</constant>,\r | |
60 | <constant>GL_TEXTURE_MAX_LOD</constant>,\r | |
61 | <constant>GL_TEXTURE_LOD_BIAS</constant>\r | |
62 | <constant>GL_TEXTURE_COMPARE_MODE</constant>, or\r | |
63 | <constant>GL_TEXTURE_COMPARE_FUNC</constant>.\r | |
64 | </para>\r | |
65 | </listitem>\r | |
66 | </varlistentry>\r | |
67 | <varlistentry>\r | |
68 | <term><parameter>param</parameter></term>\r | |
69 | <listitem>\r | |
70 | <para>\r | |
71 | Specifies the value of <parameter>pname</parameter>.\r | |
72 | </para>\r | |
73 | </listitem>\r | |
74 | </varlistentry>\r | |
75 | </variablelist>\r | |
76 | </refsect1>\r | |
77 | <refsynopsisdiv><title>C Specification</title>\r | |
78 | <funcsynopsis>\r | |
79 | <funcprototype>\r | |
80 | <funcdef>void <function>glSamplerParameterfv</function></funcdef>\r | |
81 | <paramdef>GLuint <parameter>sampler</parameter></paramdef>\r | |
82 | <paramdef>GLenum <parameter>pname</parameter></paramdef>\r | |
83 | <paramdef>const GLfloat * <parameter>params</parameter></paramdef>\r | |
84 | </funcprototype>\r | |
85 | </funcsynopsis>\r | |
86 | <funcsynopsis>\r | |
87 | <funcprototype>\r | |
88 | <funcdef>void <function>glSamplerParameteriv</function></funcdef>\r | |
89 | <paramdef>GLuint <parameter>sampler</parameter></paramdef>\r | |
90 | <paramdef>GLenum <parameter>pname</parameter></paramdef>\r | |
91 | <paramdef>const GLint * <parameter>params</parameter></paramdef>\r | |
92 | </funcprototype>\r | |
93 | </funcsynopsis>\r | |
94 | <funcsynopsis>\r | |
95 | <funcprototype>\r | |
96 | <funcdef>void <function>glSamplerParameterIiv</function></funcdef>\r | |
97 | <paramdef>GLuint <parameter>sampler</parameter></paramdef>\r | |
98 | <paramdef>GLenum <parameter>pname</parameter></paramdef>\r | |
99 | <paramdef>const GLint * <parameter>params</parameter></paramdef>\r | |
100 | </funcprototype>\r | |
101 | </funcsynopsis>\r | |
102 | <funcsynopsis>\r | |
103 | <funcprototype>\r | |
104 | <funcdef>void <function>glSamplerParameterIuiv</function></funcdef>\r | |
105 | <paramdef>GLuint <parameter>sampler</parameter></paramdef>\r | |
106 | <paramdef>GLenum <parameter>pname</parameter></paramdef>\r | |
107 | <paramdef>const GLuint * <parameter>params</parameter></paramdef>\r | |
108 | </funcprototype>\r | |
109 | </funcsynopsis>\r | |
110 | </refsynopsisdiv>\r | |
111 | <refsect1 id="parameters2"><title>Parameters</title>\r | |
112 | <variablelist>\r | |
113 | <varlistentry>\r | |
114 | <term><parameter>sampler</parameter></term>\r | |
115 | <listitem>\r | |
116 | <para>\r | |
117 | Specifies the sampler object whose parameter to modify.\r | |
118 | </para>\r | |
119 | </listitem>\r | |
120 | </varlistentry>\r | |
121 | <varlistentry>\r | |
122 | <term><parameter>pname</parameter></term>\r | |
123 | <listitem>\r | |
124 | <para>\r | |
125 | Specifies the symbolic name of a sampler parameter.\r | |
126 | <parameter>pname</parameter> can be one of the following:\r | |
127 | <constant>GL_TEXTURE_WRAP_S</constant>,\r | |
128 | <constant>GL_TEXTURE_WRAP_T</constant>,\r | |
129 | <constant>GL_TEXTURE_WRAP_R</constant>,\r | |
130 | <constant>GL_TEXTURE_MIN_FILTER</constant>,\r | |
131 | <constant>GL_TEXTURE_MAG_FILTER</constant>,\r | |
132 | <constant>GL_TEXTURE_BORDER_COLOR</constant>,\r | |
133 | <constant>GL_TEXTURE_MIN_LOD</constant>,\r | |
134 | <constant>GL_TEXTURE_MAX_LOD</constant>,\r | |
135 | <constant>GL_TEXTURE_LOD_BIAS</constant>\r | |
136 | <constant>GL_TEXTURE_COMPARE_MODE</constant>, or\r | |
137 | <constant>GL_TEXTURE_COMPARE_FUNC</constant>.\r | |
138 | </para>\r | |
139 | </listitem>\r | |
140 | </varlistentry>\r | |
141 | <varlistentry>\r | |
142 | <term><parameter>params</parameter></term>\r | |
143 | <listitem>\r | |
144 | <para>\r | |
145 | Specifies a pointer to an array where the value or values of <parameter>pname</parameter>\r | |
146 | are stored.\r | |
147 | </para>\r | |
148 | </listitem>\r | |
149 | </varlistentry>\r | |
150 | </variablelist>\r | |
151 | </refsect1>\r | |
152 | <refsect1 id="description"><title>Description</title>\r | |
153 | <para>\r | |
154 | <function>glSamplerParameter</function> assigns the value or values in <parameter>params</parameter> to the sampler parameter\r | |
155 | specified as <parameter>pname</parameter>.\r | |
156 | <parameter>sampler</parameter> specifies the sampler object to be modified, and must be the name of a sampler object previously\r | |
157 | returned from a call to <citerefentry><refentrytitle>glGenSamplers</refentrytitle></citerefentry>.\r | |
158 | The following symbols are accepted in <parameter>pname</parameter>:\r | |
159 | </para>\r | |
160 | <variablelist>\r | |
161 | <varlistentry>\r | |
162 | <term><constant>GL_TEXTURE_MIN_FILTER</constant></term>\r | |
163 | <listitem>\r | |
164 | <para>\r | |
165 | The texture minifying function is used whenever the pixel being textured\r | |
166 | maps to an area greater than one texture element.\r | |
167 | There are six defined minifying functions.\r | |
168 | Two of them use the nearest one or nearest four texture elements\r | |
169 | to compute the texture value.\r | |
170 | The other four use mipmaps.\r | |
171 | </para>\r | |
172 | <para>\r | |
173 | A mipmap is an ordered set of arrays representing the same image\r | |
174 | at progressively lower resolutions.\r | |
175 | If the texture has dimensions \r | |
176 | <inlineequation><mml:math>\r | |
177 | <!-- eqn: 2 sup n times 2 sup m: -->\r | |
178 | <mml:mrow>\r | |
179 | <mml:msup><mml:mn>2</mml:mn>\r | |
180 | <mml:mi mathvariant="italic">n</mml:mi>\r | |
181 | </mml:msup>\r | |
182 | <mml:mo>×</mml:mo>\r | |
183 | <mml:msup><mml:mn>2</mml:mn>\r | |
184 | <mml:mi mathvariant="italic">m</mml:mi>\r | |
185 | </mml:msup>\r | |
186 | </mml:mrow>\r | |
187 | </mml:math></inlineequation>,\r | |
188 | there are\r | |
189 | <inlineequation><mml:math>\r | |
190 | <!-- eqn: max ( n, m ) + 1: -->\r | |
191 | <mml:mrow>\r | |
192 | <mml:mrow>\r | |
193 | <mml:mi mathvariant="italic">max</mml:mi>\r | |
194 | <mml:mo>⁡</mml:mo>\r | |
195 | <mml:mfenced open="(" close=")">\r | |
196 | <mml:mi mathvariant="italic">n</mml:mi>\r | |
197 | <mml:mi mathvariant="italic">m</mml:mi>\r | |
198 | </mml:mfenced>\r | |
199 | </mml:mrow>\r | |
200 | <mml:mo>+</mml:mo>\r | |
201 | <mml:mn>1</mml:mn>\r | |
202 | </mml:mrow>\r | |
203 | </mml:math></inlineequation>\r | |
204 | mipmaps.\r | |
205 | The first mipmap is the original texture,\r | |
206 | with dimensions \r | |
207 | <inlineequation><mml:math>\r | |
208 | <!-- eqn: 2 sup n times 2 sup m: -->\r | |
209 | <mml:mrow>\r | |
210 | <mml:msup><mml:mn>2</mml:mn>\r | |
211 | <mml:mi mathvariant="italic">n</mml:mi>\r | |
212 | </mml:msup>\r | |
213 | <mml:mo>×</mml:mo>\r | |
214 | <mml:msup><mml:mn>2</mml:mn>\r | |
215 | <mml:mi mathvariant="italic">m</mml:mi>\r | |
216 | </mml:msup>\r | |
217 | </mml:mrow>\r | |
218 | </mml:math></inlineequation>.\r | |
219 | Each subsequent mipmap has dimensions \r | |
220 | <inlineequation><mml:math>\r | |
221 | <!-- eqn: 2 sup { k - 1 } times 2 sup { l - 1 }: -->\r | |
222 | <mml:mrow>\r | |
223 | <mml:msup><mml:mn>2</mml:mn>\r | |
224 | <mml:mfenced open="" close="">\r | |
225 | <mml:mrow>\r | |
226 | <mml:mi mathvariant="italic">k</mml:mi>\r | |
227 | <mml:mo>-</mml:mo>\r | |
228 | <mml:mn>1</mml:mn>\r | |
229 | </mml:mrow>\r | |
230 | </mml:mfenced>\r | |
231 | </mml:msup>\r | |
232 | <mml:mo>×</mml:mo>\r | |
233 | <mml:msup><mml:mn>2</mml:mn>\r | |
234 | <mml:mfenced open="" close="">\r | |
235 | <mml:mrow>\r | |
236 | <mml:mi mathvariant="italic">l</mml:mi>\r | |
237 | <mml:mo>-</mml:mo>\r | |
238 | <mml:mn>1</mml:mn>\r | |
239 | </mml:mrow>\r | |
240 | </mml:mfenced>\r | |
241 | </mml:msup>\r | |
242 | </mml:mrow>\r | |
243 | </mml:math></inlineequation>,\r | |
244 | where \r | |
245 | <inlineequation><mml:math>\r | |
246 | <!-- eqn: 2 sup k times 2 sup l: -->\r | |
247 | <mml:mrow>\r | |
248 | <mml:msup><mml:mn>2</mml:mn>\r | |
249 | <mml:mi mathvariant="italic">k</mml:mi>\r | |
250 | </mml:msup>\r | |
251 | <mml:mo>×</mml:mo>\r | |
252 | <mml:msup><mml:mn>2</mml:mn>\r | |
253 | <mml:mi mathvariant="italic">l</mml:mi>\r | |
254 | </mml:msup>\r | |
255 | </mml:mrow>\r | |
256 | </mml:math></inlineequation>\r | |
257 | are the dimensions of the previous mipmap,\r | |
258 | until either \r | |
259 | <inlineequation><mml:math>\r | |
260 | <!-- eqn: k = 0: -->\r | |
261 | <mml:mrow>\r | |
262 | <mml:mi mathvariant="italic">k</mml:mi>\r | |
263 | <mml:mo>=</mml:mo>\r | |
264 | <mml:mn>0</mml:mn>\r | |
265 | </mml:mrow>\r | |
266 | </mml:math></inlineequation>\r | |
267 | or \r | |
268 | <inlineequation><mml:math>\r | |
269 | <!-- eqn: l = 0: -->\r | |
270 | <mml:mrow>\r | |
271 | <mml:mi mathvariant="italic">l</mml:mi>\r | |
272 | <mml:mo>=</mml:mo>\r | |
273 | <mml:mn>0</mml:mn>\r | |
274 | </mml:mrow>\r | |
275 | </mml:math></inlineequation>.\r | |
276 | At that point,\r | |
277 | subsequent mipmaps have dimension \r | |
278 | <inlineequation><mml:math>\r | |
279 | <!-- eqn: 1 times 2 sup { l - 1 }: -->\r | |
280 | <mml:mrow>\r | |
281 | <mml:mn>1</mml:mn>\r | |
282 | <mml:mo>×</mml:mo>\r | |
283 | <mml:msup><mml:mn>2</mml:mn>\r | |
284 | <mml:mfenced open="" close="">\r | |
285 | <mml:mrow>\r | |
286 | <mml:mi mathvariant="italic">l</mml:mi>\r | |
287 | <mml:mo>-</mml:mo>\r | |
288 | <mml:mn>1</mml:mn>\r | |
289 | </mml:mrow>\r | |
290 | </mml:mfenced>\r | |
291 | </mml:msup>\r | |
292 | </mml:mrow>\r | |
293 | </mml:math></inlineequation>\r | |
294 | or \r | |
295 | <inlineequation><mml:math>\r | |
296 | <!-- eqn: 2 sup { k - 1} times 1: -->\r | |
297 | <mml:mrow>\r | |
298 | <mml:msup><mml:mn>2</mml:mn>\r | |
299 | <mml:mfenced open="" close="">\r | |
300 | <mml:mrow>\r | |
301 | <mml:mi mathvariant="italic">k</mml:mi>\r | |
302 | <mml:mo>-</mml:mo>\r | |
303 | <mml:mn>1</mml:mn>\r | |
304 | </mml:mrow>\r | |
305 | </mml:mfenced>\r | |
306 | </mml:msup>\r | |
307 | <mml:mo>×</mml:mo>\r | |
308 | <mml:mn>1</mml:mn>\r | |
309 | </mml:mrow>\r | |
310 | </mml:math></inlineequation>\r | |
311 | until the final mipmap,\r | |
312 | which has dimension \r | |
313 | <inlineequation><mml:math>\r | |
314 | <!-- eqn: 1 times 1: -->\r | |
315 | <mml:mrow>\r | |
316 | <mml:mn>1</mml:mn>\r | |
317 | <mml:mo>×</mml:mo>\r | |
318 | <mml:mn>1</mml:mn>\r | |
319 | </mml:mrow>\r | |
320 | </mml:math></inlineequation>.\r | |
321 | To define the mipmaps, call <citerefentry><refentrytitle>glTexImage1D</refentrytitle></citerefentry>, <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>,\r | |
322 | <citerefentry><refentrytitle>glTexImage3D</refentrytitle></citerefentry>,\r | |
323 | <citerefentry><refentrytitle>glCopyTexImage1D</refentrytitle></citerefentry>, or <citerefentry><refentrytitle>glCopyTexImage2D</refentrytitle></citerefentry>\r | |
324 | with the <emphasis>level</emphasis> argument indicating the order of the mipmaps.\r | |
325 | Level 0 is the original texture;\r | |
326 | level \r | |
327 | <inlineequation><mml:math>\r | |
328 | <!-- eqn: max ( n, m ): -->\r | |
329 | <mml:mrow>\r | |
330 | <mml:mi mathvariant="italic">max</mml:mi>\r | |
331 | <mml:mo>⁡</mml:mo>\r | |
332 | <mml:mfenced open="(" close=")">\r | |
333 | <mml:mi mathvariant="italic">n</mml:mi>\r | |
334 | <mml:mi mathvariant="italic">m</mml:mi>\r | |
335 | </mml:mfenced>\r | |
336 | </mml:mrow>\r | |
337 | </mml:math></inlineequation>\r | |
338 | is the final \r | |
339 | <inlineequation><mml:math>\r | |
340 | <!-- eqn: 1 times 1: -->\r | |
341 | <mml:mrow>\r | |
342 | <mml:mn>1</mml:mn>\r | |
343 | <mml:mo>×</mml:mo>\r | |
344 | <mml:mn>1</mml:mn>\r | |
345 | </mml:mrow>\r | |
346 | </mml:math></inlineequation>\r | |
347 | mipmap.\r | |
348 | </para>\r | |
349 | <para>\r | |
350 | <parameter>params</parameter> supplies a function for minifying the texture as one of the\r | |
351 | following:\r | |
352 | <variablelist>\r | |
353 | <varlistentry>\r | |
354 | <term><constant>GL_NEAREST</constant></term>\r | |
355 | <listitem>\r | |
356 | <para>\r | |
357 | Returns the value of the texture element that is nearest\r | |
358 | (in Manhattan distance)\r | |
359 | to the center of the pixel being textured.\r | |
360 | </para>\r | |
361 | </listitem>\r | |
362 | </varlistentry>\r | |
363 | <varlistentry>\r | |
364 | <term><constant>GL_LINEAR</constant></term>\r | |
365 | <listitem>\r | |
366 | <para>\r | |
367 | Returns the weighted average of the four texture elements\r | |
368 | that are closest to the center of the pixel being textured.\r | |
369 | These can include border texture elements,\r | |
370 | depending on the values of <constant>GL_TEXTURE_WRAP_S</constant> and <constant>GL_TEXTURE_WRAP_T</constant>,\r | |
371 | and on the exact mapping.\r | |
372 | </para>\r | |
373 | </listitem>\r | |
374 | </varlistentry>\r | |
375 | <varlistentry>\r | |
376 | <term><constant>GL_NEAREST_MIPMAP_NEAREST</constant></term>\r | |
377 | <listitem>\r | |
378 | <para>\r | |
379 | Chooses the mipmap that most closely matches the size of the pixel\r | |
380 | being textured and uses the <constant>GL_NEAREST</constant> criterion\r | |
381 | (the texture element nearest to the center of the pixel)\r | |
382 | to produce a texture value.\r | |
383 | </para>\r | |
384 | </listitem>\r | |
385 | </varlistentry>\r | |
386 | <varlistentry>\r | |
387 | <term><constant>GL_LINEAR_MIPMAP_NEAREST</constant></term>\r | |
388 | <listitem>\r | |
389 | <para>\r | |
390 | Chooses the mipmap that most closely matches the size of the pixel\r | |
391 | being textured and uses the <constant>GL_LINEAR</constant> criterion\r | |
392 | (a weighted average of the four texture elements that are closest\r | |
393 | to the center of the pixel)\r | |
394 | to produce a texture value.\r | |
395 | </para>\r | |
396 | </listitem>\r | |
397 | </varlistentry>\r | |
398 | <varlistentry>\r | |
399 | <term><constant>GL_NEAREST_MIPMAP_LINEAR</constant></term>\r | |
400 | <listitem>\r | |
401 | <para>\r | |
402 | Chooses the two mipmaps that most closely match the size of the pixel\r | |
403 | being textured and uses the <constant>GL_NEAREST</constant> criterion\r | |
404 | (the texture element nearest to the center of the pixel)\r | |
405 | to produce a texture value from each mipmap.\r | |
406 | The final texture value is a weighted average of those two values.\r | |
407 | </para>\r | |
408 | </listitem>\r | |
409 | </varlistentry>\r | |
410 | <varlistentry>\r | |
411 | <term><constant>GL_LINEAR_MIPMAP_LINEAR</constant></term>\r | |
412 | <listitem>\r | |
413 | <para>\r | |
414 | Chooses the two mipmaps that most closely match the size of the pixel\r | |
415 | being textured and uses the <constant>GL_LINEAR</constant> criterion\r | |
416 | (a weighted average of the four texture elements that are closest\r | |
417 | to the center of the pixel)\r | |
418 | to produce a texture value from each mipmap.\r | |
419 | The final texture value is a weighted average of those two values.\r | |
420 | </para>\r | |
421 | </listitem>\r | |
422 | </varlistentry>\r | |
423 | </variablelist>\r | |
424 | </para>\r | |
425 | <para>\r | |
426 | As more texture elements are sampled in the minification process,\r | |
427 | fewer aliasing artifacts will be apparent.\r | |
428 | While the <constant>GL_NEAREST</constant> and <constant>GL_LINEAR</constant> minification functions can be\r | |
429 | faster than the other four,\r | |
430 | they sample only one or four texture elements to determine the texture value\r | |
431 | of the pixel being rendered and can produce moire patterns\r | |
432 | or ragged transitions.\r | |
433 | The initial value of <constant>GL_TEXTURE_MIN_FILTER</constant> is\r | |
434 | <constant>GL_NEAREST_MIPMAP_LINEAR</constant>.\r | |
435 | </para>\r | |
436 | </listitem>\r | |
437 | </varlistentry>\r | |
438 | <varlistentry>\r | |
439 | <term><constant>GL_TEXTURE_MAG_FILTER</constant></term>\r | |
440 | <listitem>\r | |
441 | <para>\r | |
442 | The texture magnification function is used when the pixel being textured\r | |
443 | maps to an area less than or equal to one texture element.\r | |
444 | It sets the texture magnification function to either <constant>GL_NEAREST</constant>\r | |
445 | or <constant>GL_LINEAR</constant> (see below). <constant>GL_NEAREST</constant> is generally faster\r | |
446 | than <constant>GL_LINEAR</constant>,\r | |
447 | but it can produce textured images with sharper edges\r | |
448 | because the transition between texture elements is not as smooth.\r | |
449 | The initial value of <constant>GL_TEXTURE_MAG_FILTER</constant> is <constant>GL_LINEAR</constant>.\r | |
450 | <variablelist>\r | |
451 | <varlistentry>\r | |
452 | <term><constant>GL_NEAREST</constant></term>\r | |
453 | <listitem>\r | |
454 | <para>\r | |
455 | Returns the value of the texture element that is nearest\r | |
456 | (in Manhattan distance)\r | |
457 | to the center of the pixel being textured.\r | |
458 | </para>\r | |
459 | </listitem>\r | |
460 | </varlistentry>\r | |
461 | <varlistentry>\r | |
462 | <term><constant>GL_LINEAR</constant></term>\r | |
463 | <listitem>\r | |
464 | <para>\r | |
465 | Returns the weighted average of the four texture elements\r | |
466 | that are closest to the center of the pixel being textured.\r | |
467 | These can include border texture elements,\r | |
468 | depending on the values of <constant>GL_TEXTURE_WRAP_S</constant> and <constant>GL_TEXTURE_WRAP_T</constant>,\r | |
469 | and on the exact mapping.\r | |
470 | </para>\r | |
471 | </listitem>\r | |
472 | </varlistentry>\r | |
473 | </variablelist>\r | |
474 | <para>\r | |
475 | </para>\r | |
476 | </para>\r | |
477 | </listitem>\r | |
478 | </varlistentry>\r | |
479 | </variablelist>\r | |
480 | <para>\r | |
481 | </para>\r | |
482 | <variablelist>\r | |
483 | <varlistentry>\r | |
484 | <term><constant>GL_TEXTURE_MIN_LOD</constant></term>\r | |
485 | <listitem>\r | |
486 | <para>\r | |
487 | Sets the minimum level-of-detail parameter. This floating-point value\r | |
488 | limits the selection of highest resolution mipmap (lowest mipmap\r | |
489 | level). The initial value is -1000.\r | |
490 | </para>\r | |
491 | </listitem>\r | |
492 | </varlistentry>\r | |
493 | </variablelist>\r | |
494 | <para>\r | |
495 | </para>\r | |
496 | <variablelist>\r | |
497 | <varlistentry>\r | |
498 | <term><constant>GL_TEXTURE_MAX_LOD</constant></term>\r | |
499 | <listitem>\r | |
500 | <para>\r | |
501 | Sets the maximum level-of-detail parameter. This floating-point value\r | |
502 | limits the selection of the lowest resolution mipmap (highest mipmap\r | |
503 | level). The initial value is 1000.\r | |
504 | </para>\r | |
505 | </listitem>\r | |
506 | </varlistentry>\r | |
507 | </variablelist>\r | |
508 | <para>\r | |
509 | </para>\r | |
510 | <variablelist>\r | |
511 | <varlistentry>\r | |
512 | <term><constant>GL_TEXTURE_WRAP_S</constant></term>\r | |
513 | <listitem>\r | |
514 | <para>\r | |
515 | Sets the wrap parameter for texture coordinate \r | |
516 | <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>\r | |
517 | to either <constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_MIRRORED_REPEAT</constant>, or\r | |
518 | <constant>GL_REPEAT</constant>. <constant>GL_CLAMP_TO_BORDER</constant> causes the \r | |
519 | <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>\r | |
520 | coordinate to be clamped to the range\r | |
521 | <inlineequation><mml:math>\r | |
522 | <!-- eqn: left [ {-1 over 2N}, 1 + {1 over 2N} right ]: -->\r | |
523 | <mml:mfenced open="[" close="]">\r | |
524 | <mml:mfenced open="" close="">\r | |
525 | <mml:mrow>\r | |
526 | <mml:mfrac>\r | |
527 | <mml:mn>-1</mml:mn>\r | |
528 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>\r | |
529 | </mml:mfrac>\r | |
530 | </mml:mrow>\r | |
531 | </mml:mfenced>\r | |
532 | <mml:mrow>\r | |
533 | <mml:mn>1</mml:mn>\r | |
534 | <mml:mo>+</mml:mo>\r | |
535 | <mml:mfenced open="" close="">\r | |
536 | <mml:mrow>\r | |
537 | <mml:mfrac>\r | |
538 | <mml:mn>1</mml:mn>\r | |
539 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>\r | |
540 | </mml:mfrac>\r | |
541 | </mml:mrow>\r | |
542 | </mml:mfenced>\r | |
543 | </mml:mrow>\r | |
544 | </mml:mfenced>\r | |
545 | </mml:math></inlineequation>,\r | |
546 | where \r | |
547 | <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>\r | |
548 | is the size of the texture in the direction of\r | |
549 | clamping.<constant>GL_CLAMP_TO_EDGE</constant> causes \r | |
550 | <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>\r | |
551 | coordinates to be clamped to the\r | |
552 | range \r | |
553 | <inlineequation><mml:math>\r | |
554 | <!-- eqn: left [ {1 over 2N}, 1 - {1 over 2N} right ]: -->\r | |
555 | <mml:mfenced open="[" close="]">\r | |
556 | <mml:mfenced open="" close="">\r | |
557 | <mml:mrow>\r | |
558 | <mml:mfrac>\r | |
559 | <mml:mn>1</mml:mn>\r | |
560 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>\r | |
561 | </mml:mfrac>\r | |
562 | </mml:mrow>\r | |
563 | </mml:mfenced>\r | |
564 | <mml:mrow>\r | |
565 | <mml:mn>1</mml:mn>\r | |
566 | <mml:mo>-</mml:mo>\r | |
567 | <mml:mfenced open="" close="">\r | |
568 | <mml:mrow>\r | |
569 | <mml:mfrac>\r | |
570 | <mml:mn>1</mml:mn>\r | |
571 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>\r | |
572 | </mml:mfrac>\r | |
573 | </mml:mrow>\r | |
574 | </mml:mfenced>\r | |
575 | </mml:mrow>\r | |
576 | </mml:mfenced>\r | |
577 | </mml:math></inlineequation>,\r | |
578 | where \r | |
579 | <inlineequation><mml:math><mml:mi mathvariant="italic">N</mml:mi></mml:math></inlineequation>\r | |
580 | is the size\r | |
581 | of the texture in the direction of clamping. <constant>GL_REPEAT</constant> causes the\r | |
582 | integer part of the \r | |
583 | <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>\r | |
584 | coordinate to be ignored; the GL uses only the\r | |
585 | fractional part, thereby creating a repeating pattern.\r | |
586 | <constant>GL_MIRRORED_REPEAT</constant> causes the \r | |
587 | <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>\r | |
588 | coordinate to be set to the\r | |
589 | fractional part of the texture coordinate if the integer part of \r | |
590 | <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>\r | |
591 | is\r | |
592 | even; if the integer part of \r | |
593 | <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>\r | |
594 | is odd, then the \r | |
595 | <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>\r | |
596 | texture coordinate is\r | |
597 | set to \r | |
598 | <inlineequation><mml:math>\r | |
599 | <!-- eqn: 1 - frac(s): -->\r | |
600 | <mml:mrow>\r | |
601 | <mml:mn>1</mml:mn>\r | |
602 | <mml:mo>-</mml:mo>\r | |
603 | <mml:mrow>\r | |
604 | <mml:mi mathvariant="italic">frac</mml:mi>\r | |
605 | <mml:mo>⁡</mml:mo>\r | |
606 | <mml:mfenced open="(" close=")">\r | |
607 | <mml:mi mathvariant="italic">s</mml:mi>\r | |
608 | </mml:mfenced>\r | |
609 | </mml:mrow>\r | |
610 | </mml:mrow>\r | |
611 | </mml:math></inlineequation>,\r | |
612 | where \r | |
613 | <inlineequation><mml:math>\r | |
614 | <!-- eqn: frac(s): -->\r | |
615 | <mml:mrow>\r | |
616 | <mml:mi mathvariant="italic">frac</mml:mi>\r | |
617 | <mml:mo>⁡</mml:mo>\r | |
618 | <mml:mfenced open="(" close=")">\r | |
619 | <mml:mi mathvariant="italic">s</mml:mi>\r | |
620 | </mml:mfenced>\r | |
621 | </mml:mrow>\r | |
622 | </mml:math></inlineequation>\r | |
623 | represents the fractional part of\r | |
624 | <inlineequation><mml:math><mml:mi mathvariant="italic">s</mml:mi></mml:math></inlineequation>.\r | |
625 | Initially, <constant>GL_TEXTURE_WRAP_S</constant> is set to <constant>GL_REPEAT</constant>.\r | |
626 | </para>\r | |
627 | </listitem>\r | |
628 | </varlistentry>\r | |
629 | </variablelist>\r | |
630 | <para>\r | |
631 | </para>\r | |
632 | <variablelist>\r | |
633 | <varlistentry>\r | |
634 | <term><constant>GL_TEXTURE_WRAP_T</constant></term>\r | |
635 | <listitem>\r | |
636 | <para>\r | |
637 | Sets the wrap parameter for texture coordinate \r | |
638 | <inlineequation><mml:math><mml:mi mathvariant="italic">t</mml:mi></mml:math></inlineequation>\r | |
639 | to either <constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_MIRRORED_REPEAT</constant>, or\r | |
640 | <constant>GL_REPEAT</constant>. See the discussion under <constant>GL_TEXTURE_WRAP_S</constant>.\r | |
641 | Initially, <constant>GL_TEXTURE_WRAP_T</constant> is set to <constant>GL_REPEAT</constant>.\r | |
642 | </para>\r | |
643 | </listitem>\r | |
644 | </varlistentry>\r | |
645 | <varlistentry>\r | |
646 | <term><constant>GL_TEXTURE_WRAP_R</constant></term>\r | |
647 | <listitem>\r | |
648 | <para>\r | |
649 | Sets the wrap parameter for texture coordinate \r | |
650 | <inlineequation><mml:math><mml:mi mathvariant="italic">r</mml:mi></mml:math></inlineequation>\r | |
651 | to either <constant>GL_CLAMP_TO_EDGE</constant>, <constant>GL_MIRRORED_REPEAT</constant>, or\r | |
652 | <constant>GL_REPEAT</constant>. See the discussion under <constant>GL_TEXTURE_WRAP_S</constant>.\r | |
653 | Initially, <constant>GL_TEXTURE_WRAP_R</constant> is set to <constant>GL_REPEAT</constant>.\r | |
654 | </para>\r | |
655 | </listitem>\r | |
656 | </varlistentry>\r | |
657 | <varlistentry>\r | |
658 | <term><constant>GL_TEXTURE_BORDER_COLOR</constant></term>\r | |
659 | <listitem>\r | |
660 | <para>\r | |
661 | The data in <parameter>params</parameter> specifies four values that define the border values that\r | |
662 | should be used for border texels. If a texel is sampled from the border of the texture, the\r | |
663 | values of <constant>GL_TEXTURE_BORDER_COLOR</constant> are interpreted as an RGBA color to match the\r | |
664 | texture's internal format and substituted for the non-existent texel data. If the texture contains depth\r | |
665 | components, the first component of <constant>GL_TEXTURE_BORDER_COLOR</constant> is interpreted as a depth value.\r | |
666 | The initial value is\r | |
667 | <inlineequation><mml:math>\r | |
668 | <mml:mrow>\r | |
669 | <mml:mfenced open="(" close=")">\r | |
670 | <mml:mrow>\r | |
671 | <mml:mn>0.0</mml:mn>, <mml:mn>0.0</mml:mn>, <mml:mn>0.0</mml:mn>, <mml:mn>0.0</mml:mn>\r | |
672 | </mml:mrow>\r | |
673 | </mml:mfenced>\r | |
674 | </mml:mrow>\r | |
675 | </mml:math></inlineequation>.\r | |
676 | </para>\r | |
677 | </listitem>\r | |
678 | </varlistentry>\r | |
679 | <varlistentry>\r | |
680 | <term><constant>GL_TEXTURE_COMPARE_MODE</constant></term>\r | |
681 | <listitem>\r | |
682 | <para>\r | |
683 | Specifies the texture comparison mode for currently bound textures.\r | |
684 | That is, a texture whose internal format is <constant>GL_DEPTH_COMPONENT_*</constant>; see\r | |
685 | <citerefentry><refentrytitle>glTexImage2D</refentrytitle></citerefentry>)\r | |
686 | Permissible values are:\r | |
687 | <variablelist>\r | |
688 | <varlistentry>\r | |
689 | <term><constant>GL_COMPARE_REF_TO_TEXTURE</constant></term>\r | |
690 | <listitem>\r | |
691 | <para>\r | |
692 | Specifies that the interpolated and clamped \r | |
693 | <inlineequation><mml:math><mml:mi mathvariant="italic">r</mml:mi></mml:math></inlineequation>\r | |
694 | texture coordinate should\r | |
695 | be compared to the value in the currently bound texture. See the\r | |
696 | discussion of <constant>GL_TEXTURE_COMPARE_FUNC</constant> for details of how the comparison\r | |
697 | is evaluated. The result of the comparison is assigned to the red channel.\r | |
698 | </para>\r | |
699 | </listitem>\r | |
700 | </varlistentry>\r | |
701 | <varlistentry>\r | |
702 | <term><constant>GL_NONE</constant></term>\r | |
703 | <listitem>\r | |
704 | <para>\r | |
705 | Specifies that the red channel should be assigned the\r | |
706 | appropriate value from the currently bound texture.\r | |
707 | </para>\r | |
708 | </listitem>\r | |
709 | </varlistentry>\r | |
710 | </variablelist>\r | |
711 | </para>\r | |
712 | </listitem>\r | |
713 | </varlistentry>\r | |
714 | <varlistentry>\r | |
715 | <term><constant>GL_TEXTURE_COMPARE_FUNC</constant></term>\r | |
716 | <listitem>\r | |
717 | <para>\r | |
718 | Specifies the comparison operator used when <constant>GL_TEXTURE_COMPARE_MODE</constant> is\r | |
719 | set to <constant>GL_COMPARE_REF_TO_TEXTURE</constant>. Permissible values are:\r | |
720 | <informaltable frame="topbot">\r | |
721 | <tgroup cols="2" align="left">\r | |
722 | <colspec/>\r | |
723 | <colspec/>\r | |
724 | <thead>\r | |
725 | <row>\r | |
726 | <entry rowsep="1" align="left"><emphasis role="bold">\r | |
727 | Texture Comparison Function\r | |
728 | </emphasis></entry>\r | |
729 | <entry rowsep="1" align="left"><emphasis role="bold">\r | |
730 | Computed result \r | |
731 | </emphasis></entry>\r | |
732 | </row>\r | |
733 | </thead>\r | |
734 | <tbody>\r | |
735 | <row>\r | |
736 | <entry align="left">\r | |
737 | <constant>GL_LEQUAL</constant>\r | |
738 | </entry>\r | |
739 | <entry align="left">\r | |
740 | <informalequation><mml:math>\r | |
741 | <!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}: -->\r | |
742 | <mml:mrow>\r | |
743 | <mml:mi mathvariant="italic">result</mml:mi>\r | |
744 | <mml:mo>=</mml:mo>\r | |
745 | <mml:mfenced open="{" close="">\r | |
746 | <mml:mrow>\r | |
747 | <mml:mtable>\r | |
748 | <mml:mtr><mml:mtd>\r | |
749 | <mml:mn>1.0</mml:mn>\r | |
750 | </mml:mtd></mml:mtr>\r | |
751 | <mml:mtr><mml:mtd>\r | |
752 | <mml:mn>0.0</mml:mn>\r | |
753 | </mml:mtd></mml:mtr>\r | |
754 | </mml:mtable>\r | |
755 | <mml:mo>⁢ </mml:mo>\r | |
756 | <mml:mtable>\r | |
757 | <mml:mtr><mml:mtd>\r | |
758 | <mml:mrow>\r | |
759 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
760 | <mml:mo><=</mml:mo>\r | |
761 | <mml:mfenced open="" close="">\r | |
762 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
763 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
764 | </mml:msub>\r | |
765 | </mml:mfenced>\r | |
766 | </mml:mrow>\r | |
767 | </mml:mtd></mml:mtr>\r | |
768 | <mml:mtr><mml:mtd>\r | |
769 | <mml:mrow>\r | |
770 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
771 | <mml:mo>></mml:mo>\r | |
772 | <mml:mfenced open="" close="">\r | |
773 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
774 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
775 | </mml:msub>\r | |
776 | </mml:mfenced>\r | |
777 | </mml:mrow>\r | |
778 | </mml:mtd></mml:mtr>\r | |
779 | </mml:mtable>\r | |
780 | </mml:mrow>\r | |
781 | </mml:mfenced>\r | |
782 | </mml:mrow>\r | |
783 | </mml:math></informalequation>\r | |
784 | </entry>\r | |
785 | </row>\r | |
786 | <row>\r | |
787 | <entry align="left">\r | |
788 | <constant>GL_GEQUAL</constant>\r | |
789 | </entry>\r | |
790 | <entry align="left">\r | |
791 | <informalequation><mml:math>\r | |
792 | <!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}: -->\r | |
793 | <mml:mrow>\r | |
794 | <mml:mi mathvariant="italic">result</mml:mi>\r | |
795 | <mml:mo>=</mml:mo>\r | |
796 | <mml:mfenced open="{" close="">\r | |
797 | <mml:mrow>\r | |
798 | <mml:mtable>\r | |
799 | <mml:mtr><mml:mtd>\r | |
800 | <mml:mn>1.0</mml:mn>\r | |
801 | </mml:mtd></mml:mtr>\r | |
802 | <mml:mtr><mml:mtd>\r | |
803 | <mml:mn>0.0</mml:mn>\r | |
804 | </mml:mtd></mml:mtr>\r | |
805 | </mml:mtable>\r | |
806 | <mml:mo>⁢ </mml:mo>\r | |
807 | <mml:mtable>\r | |
808 | <mml:mtr><mml:mtd>\r | |
809 | <mml:mrow>\r | |
810 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
811 | <mml:mo>>=</mml:mo>\r | |
812 | <mml:mfenced open="" close="">\r | |
813 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
814 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
815 | </mml:msub>\r | |
816 | </mml:mfenced>\r | |
817 | </mml:mrow>\r | |
818 | </mml:mtd></mml:mtr>\r | |
819 | <mml:mtr><mml:mtd>\r | |
820 | <mml:mrow>\r | |
821 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
822 | <mml:mo><</mml:mo>\r | |
823 | <mml:mfenced open="" close="">\r | |
824 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
825 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
826 | </mml:msub>\r | |
827 | </mml:mfenced>\r | |
828 | </mml:mrow>\r | |
829 | </mml:mtd></mml:mtr>\r | |
830 | </mml:mtable>\r | |
831 | </mml:mrow>\r | |
832 | </mml:mfenced>\r | |
833 | </mml:mrow>\r | |
834 | </mml:math></informalequation>\r | |
835 | </entry>\r | |
836 | </row>\r | |
837 | <row>\r | |
838 | <entry align="left">\r | |
839 | <constant>GL_LESS</constant>\r | |
840 | </entry>\r | |
841 | <entry align="left">\r | |
842 | <informalequation><mml:math>\r | |
843 | <!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}: -->\r | |
844 | <mml:mrow>\r | |
845 | <mml:mi mathvariant="italic">result</mml:mi>\r | |
846 | <mml:mo>=</mml:mo>\r | |
847 | <mml:mfenced open="{" close="">\r | |
848 | <mml:mrow>\r | |
849 | <mml:mtable>\r | |
850 | <mml:mtr><mml:mtd>\r | |
851 | <mml:mn>1.0</mml:mn>\r | |
852 | </mml:mtd></mml:mtr>\r | |
853 | <mml:mtr><mml:mtd>\r | |
854 | <mml:mn>0.0</mml:mn>\r | |
855 | </mml:mtd></mml:mtr>\r | |
856 | </mml:mtable>\r | |
857 | <mml:mo>⁢ </mml:mo>\r | |
858 | <mml:mtable>\r | |
859 | <mml:mtr><mml:mtd>\r | |
860 | <mml:mrow>\r | |
861 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
862 | <mml:mo><</mml:mo>\r | |
863 | <mml:mfenced open="" close="">\r | |
864 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
865 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
866 | </mml:msub>\r | |
867 | </mml:mfenced>\r | |
868 | </mml:mrow>\r | |
869 | </mml:mtd></mml:mtr>\r | |
870 | <mml:mtr><mml:mtd>\r | |
871 | <mml:mrow>\r | |
872 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
873 | <mml:mo>>=</mml:mo>\r | |
874 | <mml:mfenced open="" close="">\r | |
875 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
876 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
877 | </mml:msub>\r | |
878 | </mml:mfenced>\r | |
879 | </mml:mrow>\r | |
880 | </mml:mtd></mml:mtr>\r | |
881 | </mml:mtable>\r | |
882 | </mml:mrow>\r | |
883 | </mml:mfenced>\r | |
884 | </mml:mrow>\r | |
885 | </mml:math></informalequation>\r | |
886 | </entry>\r | |
887 | </row>\r | |
888 | <row>\r | |
889 | <entry align="left">\r | |
890 | <constant>GL_GREATER</constant>\r | |
891 | </entry>\r | |
892 | <entry align="left">\r | |
893 | <informalequation><mml:math>\r | |
894 | <!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}: -->\r | |
895 | <mml:mrow>\r | |
896 | <mml:mi mathvariant="italic">result</mml:mi>\r | |
897 | <mml:mo>=</mml:mo>\r | |
898 | <mml:mfenced open="{" close="">\r | |
899 | <mml:mrow>\r | |
900 | <mml:mtable>\r | |
901 | <mml:mtr><mml:mtd>\r | |
902 | <mml:mn>1.0</mml:mn>\r | |
903 | </mml:mtd></mml:mtr>\r | |
904 | <mml:mtr><mml:mtd>\r | |
905 | <mml:mn>0.0</mml:mn>\r | |
906 | </mml:mtd></mml:mtr>\r | |
907 | </mml:mtable>\r | |
908 | <mml:mo>⁢ </mml:mo>\r | |
909 | <mml:mtable>\r | |
910 | <mml:mtr><mml:mtd>\r | |
911 | <mml:mrow>\r | |
912 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
913 | <mml:mo>></mml:mo>\r | |
914 | <mml:mfenced open="" close="">\r | |
915 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
916 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
917 | </mml:msub>\r | |
918 | </mml:mfenced>\r | |
919 | </mml:mrow>\r | |
920 | </mml:mtd></mml:mtr>\r | |
921 | <mml:mtr><mml:mtd>\r | |
922 | <mml:mrow>\r | |
923 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
924 | <mml:mo><=</mml:mo>\r | |
925 | <mml:mfenced open="" close="">\r | |
926 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
927 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
928 | </mml:msub>\r | |
929 | </mml:mfenced>\r | |
930 | </mml:mrow>\r | |
931 | </mml:mtd></mml:mtr>\r | |
932 | </mml:mtable>\r | |
933 | </mml:mrow>\r | |
934 | </mml:mfenced>\r | |
935 | </mml:mrow>\r | |
936 | </mml:math></informalequation>\r | |
937 | </entry>\r | |
938 | </row>\r | |
939 | <row>\r | |
940 | <entry align="left">\r | |
941 | <constant>GL_EQUAL</constant>\r | |
942 | </entry>\r | |
943 | <entry align="left">\r | |
944 | <informalequation><mml:math>\r | |
945 | <!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}: -->\r | |
946 | <mml:mrow>\r | |
947 | <mml:mi mathvariant="italic">result</mml:mi>\r | |
948 | <mml:mo>=</mml:mo>\r | |
949 | <mml:mfenced open="{" close="">\r | |
950 | <mml:mrow>\r | |
951 | <mml:mtable>\r | |
952 | <mml:mtr><mml:mtd>\r | |
953 | <mml:mn>1.0</mml:mn>\r | |
954 | </mml:mtd></mml:mtr>\r | |
955 | <mml:mtr><mml:mtd>\r | |
956 | <mml:mn>0.0</mml:mn>\r | |
957 | </mml:mtd></mml:mtr>\r | |
958 | </mml:mtable>\r | |
959 | <mml:mo>⁢ </mml:mo>\r | |
960 | <mml:mtable>\r | |
961 | <mml:mtr><mml:mtd>\r | |
962 | <mml:mrow>\r | |
963 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
964 | <mml:mo>=</mml:mo>\r | |
965 | <mml:mfenced open="" close="">\r | |
966 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
967 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
968 | </mml:msub>\r | |
969 | </mml:mfenced>\r | |
970 | </mml:mrow>\r | |
971 | </mml:mtd></mml:mtr>\r | |
972 | <mml:mtr><mml:mtd>\r | |
973 | <mml:mrow>\r | |
974 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
975 | <mml:mo>≠</mml:mo>\r | |
976 | <mml:mfenced open="" close="">\r | |
977 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
978 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
979 | </mml:msub>\r | |
980 | </mml:mfenced>\r | |
981 | </mml:mrow>\r | |
982 | </mml:mtd></mml:mtr>\r | |
983 | </mml:mtable>\r | |
984 | </mml:mrow>\r | |
985 | </mml:mfenced>\r | |
986 | </mml:mrow>\r | |
987 | </mml:math></informalequation>\r | |
988 | </entry>\r | |
989 | </row>\r | |
990 | <row>\r | |
991 | <entry align="left">\r | |
992 | <constant>GL_NOTEQUAL</constant>\r | |
993 | </entry>\r | |
994 | <entry align="left">\r | |
995 | <informalequation><mml:math>\r | |
996 | <!-- eqn: result = left { cpile {1.0 above 0.0} lpile {r <= {D sub t} above r > {D sub t}}: -->\r | |
997 | <mml:mrow>\r | |
998 | <mml:mi mathvariant="italic">result</mml:mi>\r | |
999 | <mml:mo>=</mml:mo>\r | |
1000 | <mml:mfenced open="{" close="">\r | |
1001 | <mml:mrow>\r | |
1002 | <mml:mtable>\r | |
1003 | <mml:mtr><mml:mtd>\r | |
1004 | <mml:mn>1.0</mml:mn>\r | |
1005 | </mml:mtd></mml:mtr>\r | |
1006 | <mml:mtr><mml:mtd>\r | |
1007 | <mml:mn>0.0</mml:mn>\r | |
1008 | </mml:mtd></mml:mtr>\r | |
1009 | </mml:mtable>\r | |
1010 | <mml:mo>⁢ </mml:mo>\r | |
1011 | <mml:mtable>\r | |
1012 | <mml:mtr><mml:mtd>\r | |
1013 | <mml:mrow>\r | |
1014 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
1015 | <mml:mo>≠</mml:mo>\r | |
1016 | <mml:mfenced open="" close="">\r | |
1017 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
1018 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
1019 | </mml:msub>\r | |
1020 | </mml:mfenced>\r | |
1021 | </mml:mrow>\r | |
1022 | </mml:mtd></mml:mtr>\r | |
1023 | <mml:mtr><mml:mtd>\r | |
1024 | <mml:mrow>\r | |
1025 | <mml:mi mathvariant="italic">r</mml:mi>\r | |
1026 | <mml:mo>=</mml:mo>\r | |
1027 | <mml:mfenced open="" close="">\r | |
1028 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
1029 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
1030 | </mml:msub>\r | |
1031 | </mml:mfenced>\r | |
1032 | </mml:mrow>\r | |
1033 | </mml:mtd></mml:mtr>\r | |
1034 | </mml:mtable>\r | |
1035 | </mml:mrow>\r | |
1036 | </mml:mfenced>\r | |
1037 | </mml:mrow>\r | |
1038 | </mml:math></informalequation>\r | |
1039 | </entry>\r | |
1040 | </row>\r | |
1041 | <row>\r | |
1042 | <entry align="left">\r | |
1043 | <constant>GL_ALWAYS</constant>\r | |
1044 | </entry>\r | |
1045 | <entry align="left">\r | |
1046 | <informalequation>\r | |
1047 | <mml:math>\r | |
1048 | <mml:mrow>\r | |
1049 | <mml:mi mathvariant="italic">result</mml:mi>\r | |
1050 | <mml:mo>=</mml:mo>\r | |
1051 | <mml:mi>1.0</mml:mi>\r | |
1052 | </mml:mrow>\r | |
1053 | </mml:math>\r | |
1054 | </informalequation>\r | |
1055 | </entry>\r | |
1056 | </row>\r | |
1057 | <row>\r | |
1058 | <entry align="left">\r | |
1059 | <constant>GL_NEVER</constant>\r | |
1060 | </entry>\r | |
1061 | <entry align="left">\r | |
1062 | <informalequation>\r | |
1063 | <mml:math>\r | |
1064 | <mml:mrow>\r | |
1065 | <mml:mi mathvariant="italic">result</mml:mi>\r | |
1066 | <mml:mo>=</mml:mo>\r | |
1067 | <mml:mi>0.0</mml:mi>\r | |
1068 | </mml:mrow>\r | |
1069 | </mml:math>\r | |
1070 | </informalequation>\r | |
1071 | </entry>\r | |
1072 | </row>\r | |
1073 | </tbody>\r | |
1074 | </tgroup>\r | |
1075 | </informaltable>\r | |
1076 | where <inlineequation><mml:math><mml:mi mathvariant="italic">r</mml:mi></mml:math></inlineequation>\r | |
1077 | is the current interpolated texture coordinate, and \r | |
1078 | <inlineequation><mml:math>\r | |
1079 | <!-- eqn: D sub t: -->\r | |
1080 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi>\r | |
1081 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
1082 | </mml:msub>\r | |
1083 | </mml:math></inlineequation>\r | |
1084 | is the texture value sampled from the currently bound texture.\r | |
1085 | <inlineequation><mml:math><mml:mi mathvariant="italic">result</mml:mi></mml:math></inlineequation>\r | |
1086 | is assigned to\r | |
1087 | <inlineequation><mml:math>\r | |
1088 | <!-- eqn: R sub t: -->\r | |
1089 | <mml:msub><mml:mi mathvariant="italic">R</mml:mi>\r | |
1090 | <mml:mi mathvariant="italic">t</mml:mi>\r | |
1091 | </mml:msub>\r | |
1092 | </mml:math></inlineequation>.\r | |
1093 | </para>\r | |
1094 | </listitem>\r | |
1095 | </varlistentry>\r | |
1096 | </variablelist>\r | |
1097 | </refsect1>\r | |
1098 | <refsect1 id="notes"><title>Notes</title>\r | |
1099 | <para>\r | |
1100 | <function>glSamplerParameter</function> is available only if the GL version is 3.3 or higher.\r | |
1101 | </para>\r | |
1102 | <para>\r | |
1103 | If a sampler object is bound to a texture unit and that unit is used to sample from a texture, the parameters in the sampler\r | |
1104 | are used to sample from the texture, rather than the equivalent parameters in the texture object bound to that unit. This\r | |
1105 | introduces the possibility of sampling from the same texture object with different sets of sampler state, which may lead to\r | |
1106 | a condition where a texture is <emphasis>incomplete</emphasis> with respect to one sampler object and not with respect to\r | |
1107 | another. Thus, completeness can be considered a function of a sampler object and a texture object bound to a single\r | |
1108 | texture unit, rather than a property of the texture object itself.\r | |
1109 | </para>\r | |
1110 | </refsect1>\r | |
1111 | <refsect1 id="errors"><title>Errors</title>\r | |
1112 | <para>\r | |
1113 | <constant>GL_INVALID_VALUE</constant> is generated if <parameter>sampler</parameter> is not the name of a sampler object previously\r | |
1114 | returned from a call to <citerefentry><refentrytitle>glGenSamplers</refentrytitle></citerefentry>.\r | |
1115 | </para>\r | |
1116 | <para>\r | |
1117 | <constant>GL_INVALID_ENUM</constant> is generated if <parameter>params</parameter> should have a defined\r | |
1118 | constant value (based on the value of <parameter>pname</parameter>) and does not.\r | |
1119 | </para>\r | |
1120 | </refsect1>\r | |
1121 | <refsect1 id="associatedgets"><title>Associated Gets</title>\r | |
1122 | <para>\r | |
1123 | <citerefentry><refentrytitle>glGetSamplerParameter</refentrytitle></citerefentry>\r | |
1124 | </para>\r | |
1125 | </refsect1>\r | |
1126 | <refsect1 id="seealso"><title>See Also</title>\r | |
1127 | <para>\r | |
1128 | <citerefentry><refentrytitle>glGenSamplers</refentrytitle></citerefentry>,\r | |
1129 | <citerefentry><refentrytitle>glBindSampler</refentrytitle></citerefentry>,\r | |
1130 | <citerefentry><refentrytitle>glDeleteSamplers</refentrytitle></citerefentry>,\r | |
1131 | <citerefentry><refentrytitle>glIsSampler</refentrytitle></citerefentry>,\r | |
1132 | <citerefentry><refentrytitle>glBindTexture</refentrytitle></citerefentry>,\r | |
1133 | <citerefentry><refentrytitle>glTexParameter</refentrytitle></citerefentry>\r | |
1134 | </para>\r | |
1135 | </refsect1>\r | |
1136 | <refsect1 id="Copyright"><title>Copyright</title>\r | |
1137 | <para>\r | |
1138 | Copyright <trademark class="copyright"></trademark> 2010 Khronos Group. \r | |
1139 | This material may be distributed subject to the terms and conditions set forth in \r | |
1140 | the Open Publication License, v 1.0, 8 June 1999.\r | |
1141 | <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.\r | |
1142 | </para>\r | |
1143 | </refsect1>\r | |
1144 | </refentry>\r |