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1 | <?xml version="1.0" encoding="UTF-8"?> |
2 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> | |
3 | <!-- saved from url=(0013)about:internet --> | |
4 | <?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>glSamplerParameter - OpenGL 3.3 Reference Pages</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glSamplerParameter"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glSamplerParameter — set sampler parameters</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glSamplerParameterf</b>(</code></td><td>GLuint </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>GLfloat </td><td><var class="pdparam">param</var><code>)</code>;</td></tr></table></div><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glSamplerParameteri</b>(</code></td><td>GLuint </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>GLint </td><td><var class="pdparam">param</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>sampler</code></em></span></dt><dd><p> | |
5 | Specifies the sampler object whose parameter to modify. | |
6 | </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p> | |
7 | Specifies the symbolic name of a single-valued sampler parameter. | |
8 | <em class="parameter"><code>pname</code></em> can be one of the following: | |
9 | <code class="constant">GL_TEXTURE_WRAP_S</code>, | |
10 | <code class="constant">GL_TEXTURE_WRAP_T</code>, | |
11 | <code class="constant">GL_TEXTURE_WRAP_R</code>, | |
12 | <code class="constant">GL_TEXTURE_MIN_FILTER</code>, | |
13 | <code class="constant">GL_TEXTURE_MAG_FILTER</code>, | |
14 | <code class="constant">GL_TEXTURE_MIN_LOD</code>, | |
15 | <code class="constant">GL_TEXTURE_MAX_LOD</code>, | |
16 | <code class="constant">GL_TEXTURE_LOD_BIAS</code> | |
17 | <code class="constant">GL_TEXTURE_COMPARE_MODE</code>, or | |
18 | <code class="constant">GL_TEXTURE_COMPARE_FUNC</code>. | |
19 | </p></dd><dt><span class="term"><em class="parameter"><code>param</code></em></span></dt><dd><p> | |
20 | Specifies the value of <em class="parameter"><code>pname</code></em>. | |
21 | </p></dd></dl></div></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glSamplerParameterfv</b>(</code></td><td>GLuint </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>const GLfloat * </td><td><var class="pdparam">params</var><code>)</code>;</td></tr></table></div><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glSamplerParameteriv</b>(</code></td><td>GLuint </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>const GLint * </td><td><var class="pdparam">params</var><code>)</code>;</td></tr></table></div><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glSamplerParameterIiv</b>(</code></td><td>GLuint </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>const GLint * </td><td><var class="pdparam">params</var><code>)</code>;</td></tr></table></div><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glSamplerParameterIuiv</b>(</code></td><td>GLuint </td><td><var class="pdparam">sampler</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>const GLuint * </td><td><var class="pdparam">params</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters2"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>sampler</code></em></span></dt><dd><p> | |
22 | Specifies the sampler object whose parameter to modify. | |
23 | </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p> | |
24 | Specifies the symbolic name of a sampler parameter. | |
25 | <em class="parameter"><code>pname</code></em> can be one of the following: | |
26 | <code class="constant">GL_TEXTURE_WRAP_S</code>, | |
27 | <code class="constant">GL_TEXTURE_WRAP_T</code>, | |
28 | <code class="constant">GL_TEXTURE_WRAP_R</code>, | |
29 | <code class="constant">GL_TEXTURE_MIN_FILTER</code>, | |
30 | <code class="constant">GL_TEXTURE_MAG_FILTER</code>, | |
31 | <code class="constant">GL_TEXTURE_BORDER_COLOR</code>, | |
32 | <code class="constant">GL_TEXTURE_MIN_LOD</code>, | |
33 | <code class="constant">GL_TEXTURE_MAX_LOD</code>, | |
34 | <code class="constant">GL_TEXTURE_LOD_BIAS</code> | |
35 | <code class="constant">GL_TEXTURE_COMPARE_MODE</code>, or | |
36 | <code class="constant">GL_TEXTURE_COMPARE_FUNC</code>. | |
37 | </p></dd><dt><span class="term"><em class="parameter"><code>params</code></em></span></dt><dd><p> | |
38 | Specifies a pointer to an array where the value or values of <em class="parameter"><code>pname</code></em> | |
39 | are stored. | |
40 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> | |
41 | <code class="function">glSamplerParameter</code> assigns the value or values in <em class="parameter"><code>params</code></em> to the sampler parameter | |
42 | specified as <em class="parameter"><code>pname</code></em>. | |
43 | <em class="parameter"><code>sampler</code></em> specifies the sampler object to be modified, and must be the name of a sampler object previously | |
44 | returned from a call to <a href="glGenSamplers.xml"><span class="citerefentry"><span class="refentrytitle">glGenSamplers</span></span></a>. | |
45 | The following symbols are accepted in <em class="parameter"><code>pname</code></em>: | |
46 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MIN_FILTER</code></span></dt><dd><p> | |
47 | The texture minifying function is used whenever the pixel being textured | |
48 | maps to an area greater than one texture element. | |
49 | There are six defined minifying functions. | |
50 | Two of them use the nearest one or nearest four texture elements | |
51 | to compute the texture value. | |
52 | The other four use mipmaps. | |
53 | </p><p> | |
54 | A mipmap is an ordered set of arrays representing the same image | |
55 | at progressively lower resolutions. | |
56 | If the texture has dimensions | |
57 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
58 | ||
59 | <mml:mrow> | |
60 | <mml:msup><mml:mn>2</mml:mn> | |
61 | <mml:mi mathvariant="italic">n</mml:mi> | |
62 | </mml:msup> | |
63 | <mml:mo>×</mml:mo> | |
64 | <mml:msup><mml:mn>2</mml:mn> | |
65 | <mml:mi mathvariant="italic">m</mml:mi> | |
66 | </mml:msup> | |
67 | </mml:mrow> | |
68 | </mml:math>, | |
69 | there are | |
70 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
71 | ||
72 | <mml:mrow> | |
73 | <mml:mrow> | |
74 | <mml:mi mathvariant="italic">max</mml:mi> | |
75 | <mml:mo></mml:mo> | |
76 | <mml:mfenced open="(" close=")"> | |
77 | <mml:mi mathvariant="italic">n</mml:mi> | |
78 | <mml:mi mathvariant="italic">m</mml:mi> | |
79 | </mml:mfenced> | |
80 | </mml:mrow> | |
81 | <mml:mo>+</mml:mo> | |
82 | <mml:mn>1</mml:mn> | |
83 | </mml:mrow> | |
84 | </mml:math> | |
85 | mipmaps. | |
86 | The first mipmap is the original texture, | |
87 | with dimensions | |
88 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
89 | ||
90 | <mml:mrow> | |
91 | <mml:msup><mml:mn>2</mml:mn> | |
92 | <mml:mi mathvariant="italic">n</mml:mi> | |
93 | </mml:msup> | |
94 | <mml:mo>×</mml:mo> | |
95 | <mml:msup><mml:mn>2</mml:mn> | |
96 | <mml:mi mathvariant="italic">m</mml:mi> | |
97 | </mml:msup> | |
98 | </mml:mrow> | |
99 | </mml:math>. | |
100 | Each subsequent mipmap has dimensions | |
101 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
102 | ||
103 | <mml:mrow> | |
104 | <mml:msup><mml:mn>2</mml:mn> | |
105 | <mml:mfenced open="" close=""> | |
106 | <mml:mrow> | |
107 | <mml:mi mathvariant="italic">k</mml:mi> | |
108 | <mml:mo>-</mml:mo> | |
109 | <mml:mn>1</mml:mn> | |
110 | </mml:mrow> | |
111 | </mml:mfenced> | |
112 | </mml:msup> | |
113 | <mml:mo>×</mml:mo> | |
114 | <mml:msup><mml:mn>2</mml:mn> | |
115 | <mml:mfenced open="" close=""> | |
116 | <mml:mrow> | |
117 | <mml:mi mathvariant="italic">l</mml:mi> | |
118 | <mml:mo>-</mml:mo> | |
119 | <mml:mn>1</mml:mn> | |
120 | </mml:mrow> | |
121 | </mml:mfenced> | |
122 | </mml:msup> | |
123 | </mml:mrow> | |
124 | </mml:math>, | |
125 | where | |
126 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
127 | ||
128 | <mml:mrow> | |
129 | <mml:msup><mml:mn>2</mml:mn> | |
130 | <mml:mi mathvariant="italic">k</mml:mi> | |
131 | </mml:msup> | |
132 | <mml:mo>×</mml:mo> | |
133 | <mml:msup><mml:mn>2</mml:mn> | |
134 | <mml:mi mathvariant="italic">l</mml:mi> | |
135 | </mml:msup> | |
136 | </mml:mrow> | |
137 | </mml:math> | |
138 | are the dimensions of the previous mipmap, | |
139 | until either | |
140 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
141 | ||
142 | <mml:mrow> | |
143 | <mml:mi mathvariant="italic">k</mml:mi> | |
144 | <mml:mo>=</mml:mo> | |
145 | <mml:mn>0</mml:mn> | |
146 | </mml:mrow> | |
147 | </mml:math> | |
148 | or | |
149 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
150 | ||
151 | <mml:mrow> | |
152 | <mml:mi mathvariant="italic">l</mml:mi> | |
153 | <mml:mo>=</mml:mo> | |
154 | <mml:mn>0</mml:mn> | |
155 | </mml:mrow> | |
156 | </mml:math>. | |
157 | At that point, | |
158 | subsequent mipmaps have dimension | |
159 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
160 | ||
161 | <mml:mrow> | |
162 | <mml:mn>1</mml:mn> | |
163 | <mml:mo>×</mml:mo> | |
164 | <mml:msup><mml:mn>2</mml:mn> | |
165 | <mml:mfenced open="" close=""> | |
166 | <mml:mrow> | |
167 | <mml:mi mathvariant="italic">l</mml:mi> | |
168 | <mml:mo>-</mml:mo> | |
169 | <mml:mn>1</mml:mn> | |
170 | </mml:mrow> | |
171 | </mml:mfenced> | |
172 | </mml:msup> | |
173 | </mml:mrow> | |
174 | </mml:math> | |
175 | or | |
176 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
177 | ||
178 | <mml:mrow> | |
179 | <mml:msup><mml:mn>2</mml:mn> | |
180 | <mml:mfenced open="" close=""> | |
181 | <mml:mrow> | |
182 | <mml:mi mathvariant="italic">k</mml:mi> | |
183 | <mml:mo>-</mml:mo> | |
184 | <mml:mn>1</mml:mn> | |
185 | </mml:mrow> | |
186 | </mml:mfenced> | |
187 | </mml:msup> | |
188 | <mml:mo>×</mml:mo> | |
189 | <mml:mn>1</mml:mn> | |
190 | </mml:mrow> | |
191 | </mml:math> | |
192 | until the final mipmap, | |
193 | which has dimension | |
194 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
195 | ||
196 | <mml:mrow> | |
197 | <mml:mn>1</mml:mn> | |
198 | <mml:mo>×</mml:mo> | |
199 | <mml:mn>1</mml:mn> | |
200 | </mml:mrow> | |
201 | </mml:math>. | |
202 | To define the mipmaps, call <a href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>, <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>, | |
203 | <a href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>, | |
204 | <a href="glCopyTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>, or <a href="glCopyTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a> | |
205 | with the <span class="emphasis"><em>level</em></span> argument indicating the order of the mipmaps. | |
206 | Level 0 is the original texture; | |
207 | level | |
208 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
209 | ||
210 | <mml:mrow> | |
211 | <mml:mi mathvariant="italic">max</mml:mi> | |
212 | <mml:mo></mml:mo> | |
213 | <mml:mfenced open="(" close=")"> | |
214 | <mml:mi mathvariant="italic">n</mml:mi> | |
215 | <mml:mi mathvariant="italic">m</mml:mi> | |
216 | </mml:mfenced> | |
217 | </mml:mrow> | |
218 | </mml:math> | |
219 | is the final | |
220 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
221 | ||
222 | <mml:mrow> | |
223 | <mml:mn>1</mml:mn> | |
224 | <mml:mo>×</mml:mo> | |
225 | <mml:mn>1</mml:mn> | |
226 | </mml:mrow> | |
227 | </mml:math> | |
228 | mipmap. | |
229 | </p><p> | |
230 | <em class="parameter"><code>params</code></em> supplies a function for minifying the texture as one of the | |
231 | following: | |
232 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_NEAREST</code></span></dt><dd><p> | |
233 | Returns the value of the texture element that is nearest | |
234 | (in Manhattan distance) | |
235 | to the center of the pixel being textured. | |
236 | </p></dd><dt><span class="term"><code class="constant">GL_LINEAR</code></span></dt><dd><p> | |
237 | Returns the weighted average of the four texture elements | |
238 | that are closest to the center of the pixel being textured. | |
239 | These can include border texture elements, | |
240 | depending on the values of <code class="constant">GL_TEXTURE_WRAP_S</code> and <code class="constant">GL_TEXTURE_WRAP_T</code>, | |
241 | and on the exact mapping. | |
242 | </p></dd><dt><span class="term"><code class="constant">GL_NEAREST_MIPMAP_NEAREST</code></span></dt><dd><p> | |
243 | Chooses the mipmap that most closely matches the size of the pixel | |
244 | being textured and uses the <code class="constant">GL_NEAREST</code> criterion | |
245 | (the texture element nearest to the center of the pixel) | |
246 | to produce a texture value. | |
247 | </p></dd><dt><span class="term"><code class="constant">GL_LINEAR_MIPMAP_NEAREST</code></span></dt><dd><p> | |
248 | Chooses the mipmap that most closely matches the size of the pixel | |
249 | being textured and uses the <code class="constant">GL_LINEAR</code> criterion | |
250 | (a weighted average of the four texture elements that are closest | |
251 | to the center of the pixel) | |
252 | to produce a texture value. | |
253 | </p></dd><dt><span class="term"><code class="constant">GL_NEAREST_MIPMAP_LINEAR</code></span></dt><dd><p> | |
254 | Chooses the two mipmaps that most closely match the size of the pixel | |
255 | being textured and uses the <code class="constant">GL_NEAREST</code> criterion | |
256 | (the texture element nearest to the center of the pixel) | |
257 | to produce a texture value from each mipmap. | |
258 | The final texture value is a weighted average of those two values. | |
259 | </p></dd><dt><span class="term"><code class="constant">GL_LINEAR_MIPMAP_LINEAR</code></span></dt><dd><p> | |
260 | Chooses the two mipmaps that most closely match the size of the pixel | |
261 | being textured and uses the <code class="constant">GL_LINEAR</code> criterion | |
262 | (a weighted average of the four texture elements that are closest | |
263 | to the center of the pixel) | |
264 | to produce a texture value from each mipmap. | |
265 | The final texture value is a weighted average of those two values. | |
266 | </p></dd></dl></div><p> | |
267 | </p><p> | |
268 | As more texture elements are sampled in the minification process, | |
269 | fewer aliasing artifacts will be apparent. | |
270 | While the <code class="constant">GL_NEAREST</code> and <code class="constant">GL_LINEAR</code> minification functions can be | |
271 | faster than the other four, | |
272 | they sample only one or four texture elements to determine the texture value | |
273 | of the pixel being rendered and can produce moire patterns | |
274 | or ragged transitions. | |
275 | The initial value of <code class="constant">GL_TEXTURE_MIN_FILTER</code> is | |
276 | <code class="constant">GL_NEAREST_MIPMAP_LINEAR</code>. | |
277 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_MAG_FILTER</code></span></dt><dd><p> | |
278 | The texture magnification function is used when the pixel being textured | |
279 | maps to an area less than or equal to one texture element. | |
280 | It sets the texture magnification function to either <code class="constant">GL_NEAREST</code> | |
281 | or <code class="constant">GL_LINEAR</code> (see below). <code class="constant">GL_NEAREST</code> is generally faster | |
282 | than <code class="constant">GL_LINEAR</code>, | |
283 | but it can produce textured images with sharper edges | |
284 | because the transition between texture elements is not as smooth. | |
285 | The initial value of <code class="constant">GL_TEXTURE_MAG_FILTER</code> is <code class="constant">GL_LINEAR</code>. | |
286 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_NEAREST</code></span></dt><dd><p> | |
287 | Returns the value of the texture element that is nearest | |
288 | (in Manhattan distance) | |
289 | to the center of the pixel being textured. | |
290 | </p></dd><dt><span class="term"><code class="constant">GL_LINEAR</code></span></dt><dd><p> | |
291 | Returns the weighted average of the four texture elements | |
292 | that are closest to the center of the pixel being textured. | |
293 | These can include border texture elements, | |
294 | depending on the values of <code class="constant">GL_TEXTURE_WRAP_S</code> and <code class="constant">GL_TEXTURE_WRAP_T</code>, | |
295 | and on the exact mapping. | |
296 | </p></dd></dl></div><p> | |
297 | </p><p> | |
298 | </p><p> | |
299 | </p></dd></dl></div><p> | |
300 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MIN_LOD</code></span></dt><dd><p> | |
301 | Sets the minimum level-of-detail parameter. This floating-point value | |
302 | limits the selection of highest resolution mipmap (lowest mipmap | |
303 | level). The initial value is -1000. | |
304 | </p></dd></dl></div><p> | |
305 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MAX_LOD</code></span></dt><dd><p> | |
306 | Sets the maximum level-of-detail parameter. This floating-point value | |
307 | limits the selection of the lowest resolution mipmap (highest mipmap | |
308 | level). The initial value is 1000. | |
309 | </p></dd></dl></div><p> | |
310 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_WRAP_S</code></span></dt><dd><p> | |
311 | Sets the wrap parameter for texture coordinate | |
312 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
313 | to either <code class="constant">GL_CLAMP_TO_EDGE</code>, <code class="constant">GL_MIRRORED_REPEAT</code>, or | |
314 | <code class="constant">GL_REPEAT</code>. <code class="constant">GL_CLAMP_TO_BORDER</code> causes the | |
315 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
316 | coordinate to be clamped to the range | |
317 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
318 | ||
319 | <mml:mfenced open="[" close="]"> | |
320 | <mml:mfenced open="" close=""> | |
321 | <mml:mrow> | |
322 | <mml:mfrac> | |
323 | <mml:mn>-1</mml:mn> | |
324 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn> | |
325 | </mml:mfrac> | |
326 | </mml:mrow> | |
327 | </mml:mfenced> | |
328 | <mml:mrow> | |
329 | <mml:mn>1</mml:mn> | |
330 | <mml:mo>+</mml:mo> | |
331 | <mml:mfenced open="" close=""> | |
332 | <mml:mrow> | |
333 | <mml:mfrac> | |
334 | <mml:mn>1</mml:mn> | |
335 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn> | |
336 | </mml:mfrac> | |
337 | </mml:mrow> | |
338 | </mml:mfenced> | |
339 | </mml:mrow> | |
340 | </mml:mfenced> | |
341 | </mml:math>, | |
342 | where | |
343 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">N</mml:mi></mml:math> | |
344 | is the size of the texture in the direction of | |
345 | clamping.<code class="constant">GL_CLAMP_TO_EDGE</code> causes | |
346 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
347 | coordinates to be clamped to the | |
348 | range | |
349 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
350 | ||
351 | <mml:mfenced open="[" close="]"> | |
352 | <mml:mfenced open="" close=""> | |
353 | <mml:mrow> | |
354 | <mml:mfrac> | |
355 | <mml:mn>1</mml:mn> | |
356 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn> | |
357 | </mml:mfrac> | |
358 | </mml:mrow> | |
359 | </mml:mfenced> | |
360 | <mml:mrow> | |
361 | <mml:mn>1</mml:mn> | |
362 | <mml:mo>-</mml:mo> | |
363 | <mml:mfenced open="" close=""> | |
364 | <mml:mrow> | |
365 | <mml:mfrac> | |
366 | <mml:mn>1</mml:mn> | |
367 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn> | |
368 | </mml:mfrac> | |
369 | </mml:mrow> | |
370 | </mml:mfenced> | |
371 | </mml:mrow> | |
372 | </mml:mfenced> | |
373 | </mml:math>, | |
374 | where | |
375 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">N</mml:mi></mml:math> | |
376 | is the size | |
377 | of the texture in the direction of clamping. <code class="constant">GL_REPEAT</code> causes the | |
378 | integer part of the | |
379 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
380 | coordinate to be ignored; the GL uses only the | |
381 | fractional part, thereby creating a repeating pattern. | |
382 | <code class="constant">GL_MIRRORED_REPEAT</code> causes the | |
383 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
384 | coordinate to be set to the | |
385 | fractional part of the texture coordinate if the integer part of | |
386 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
387 | is | |
388 | even; if the integer part of | |
389 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
390 | is odd, then the | |
391 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
392 | texture coordinate is | |
393 | set to | |
394 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
395 | ||
396 | <mml:mrow> | |
397 | <mml:mn>1</mml:mn> | |
398 | <mml:mo>-</mml:mo> | |
399 | <mml:mrow> | |
400 | <mml:mi mathvariant="italic">frac</mml:mi> | |
401 | <mml:mo></mml:mo> | |
402 | <mml:mfenced open="(" close=")"> | |
403 | <mml:mi mathvariant="italic">s</mml:mi> | |
404 | </mml:mfenced> | |
405 | </mml:mrow> | |
406 | </mml:mrow> | |
407 | </mml:math>, | |
408 | where | |
409 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
410 | ||
411 | <mml:mrow> | |
412 | <mml:mi mathvariant="italic">frac</mml:mi> | |
413 | <mml:mo></mml:mo> | |
414 | <mml:mfenced open="(" close=")"> | |
415 | <mml:mi mathvariant="italic">s</mml:mi> | |
416 | </mml:mfenced> | |
417 | </mml:mrow> | |
418 | </mml:math> | |
419 | represents the fractional part of | |
420 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>. | |
421 | Initially, <code class="constant">GL_TEXTURE_WRAP_S</code> is set to <code class="constant">GL_REPEAT</code>. | |
422 | </p></dd></dl></div><p> | |
423 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_WRAP_T</code></span></dt><dd><p> | |
424 | Sets the wrap parameter for texture coordinate | |
425 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">t</mml:mi></mml:math> | |
426 | to either <code class="constant">GL_CLAMP_TO_EDGE</code>, <code class="constant">GL_MIRRORED_REPEAT</code>, or | |
427 | <code class="constant">GL_REPEAT</code>. See the discussion under <code class="constant">GL_TEXTURE_WRAP_S</code>. | |
428 | Initially, <code class="constant">GL_TEXTURE_WRAP_T</code> is set to <code class="constant">GL_REPEAT</code>. | |
429 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_WRAP_R</code></span></dt><dd><p> | |
430 | Sets the wrap parameter for texture coordinate | |
431 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> | |
432 | to either <code class="constant">GL_CLAMP_TO_EDGE</code>, <code class="constant">GL_MIRRORED_REPEAT</code>, or | |
433 | <code class="constant">GL_REPEAT</code>. See the discussion under <code class="constant">GL_TEXTURE_WRAP_S</code>. | |
434 | Initially, <code class="constant">GL_TEXTURE_WRAP_R</code> is set to <code class="constant">GL_REPEAT</code>. | |
435 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_BORDER_COLOR</code></span></dt><dd><p> | |
436 | The data in <em class="parameter"><code>params</code></em> specifies four values that define the border values that | |
437 | should be used for border texels. If a texel is sampled from the border of the texture, the | |
438 | values of <code class="constant">GL_TEXTURE_BORDER_COLOR</code> are interpreted as an RGBA color to match the | |
439 | texture's internal format and substituted for the non-existent texel data. If the texture contains depth | |
440 | components, the first component of <code class="constant">GL_TEXTURE_BORDER_COLOR</code> is interpreted as a depth value. | |
441 | The initial value is | |
442 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
443 | <mml:mrow> | |
444 | <mml:mfenced open="(" close=")"> | |
445 | <mml:mrow> | |
446 | <mml:mn>0.0</mml:mn>, <mml:mn>0.0</mml:mn>, <mml:mn>0.0</mml:mn>, <mml:mn>0.0</mml:mn> | |
447 | </mml:mrow> | |
448 | </mml:mfenced> | |
449 | </mml:mrow> | |
450 | </mml:math>. | |
451 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_COMPARE_MODE</code></span></dt><dd><p> | |
452 | Specifies the texture comparison mode for currently bound textures. | |
453 | That is, a texture whose internal format is <code class="constant">GL_DEPTH_COMPONENT_*</code>; see | |
454 | <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>) | |
455 | Permissible values are: | |
456 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_COMPARE_REF_TO_TEXTURE</code></span></dt><dd><p> | |
457 | Specifies that the interpolated and clamped | |
458 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> | |
459 | texture coordinate should | |
460 | be compared to the value in the currently bound texture. See the | |
461 | discussion of <code class="constant">GL_TEXTURE_COMPARE_FUNC</code> for details of how the comparison | |
462 | is evaluated. The result of the comparison is assigned to the red channel. | |
463 | </p></dd><dt><span class="term"><code class="constant">GL_NONE</code></span></dt><dd><p> | |
464 | Specifies that the red channel should be assigned the | |
465 | appropriate value from the currently bound texture. | |
466 | </p></dd></dl></div><p> | |
467 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_COMPARE_FUNC</code></span></dt><dd><p> | |
468 | Specifies the comparison operator used when <code class="constant">GL_TEXTURE_COMPARE_MODE</code> is | |
469 | set to <code class="constant">GL_COMPARE_REF_TO_TEXTURE</code>. Permissible values are: | |
470 | </p><div class="informaltable"><table border="1"><colgroup><col align="left" /><col align="left" /></colgroup><thead><tr><th align="left"><span class="bold"><strong> | |
471 | Texture Comparison Function | |
472 | </strong></span></th><th align="left"><span class="bold"><strong> | |
473 | Computed result | |
474 | </strong></span></th></tr></thead><tbody><tr><td align="left"> | |
475 | <code class="constant">GL_LEQUAL</code> | |
476 | </td><td align="left"> | |
477 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
478 | ||
479 | <mml:mrow> | |
480 | <mml:mi mathvariant="italic">result</mml:mi> | |
481 | <mml:mo>=</mml:mo> | |
482 | <mml:mfenced open="{" close=""> | |
483 | <mml:mrow> | |
484 | <mml:mtable> | |
485 | <mml:mtr><mml:mtd> | |
486 | <mml:mn>1.0</mml:mn> | |
487 | </mml:mtd></mml:mtr> | |
488 | <mml:mtr><mml:mtd> | |
489 | <mml:mn>0.0</mml:mn> | |
490 | </mml:mtd></mml:mtr> | |
491 | </mml:mtable> | |
492 | <mml:mo> </mml:mo> | |
493 | <mml:mtable> | |
494 | <mml:mtr><mml:mtd> | |
495 | <mml:mrow> | |
496 | <mml:mi mathvariant="italic">r</mml:mi> | |
497 | <mml:mo><=</mml:mo> | |
498 | <mml:mfenced open="" close=""> | |
499 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
500 | <mml:mi mathvariant="italic">t</mml:mi> | |
501 | </mml:msub> | |
502 | </mml:mfenced> | |
503 | </mml:mrow> | |
504 | </mml:mtd></mml:mtr> | |
505 | <mml:mtr><mml:mtd> | |
506 | <mml:mrow> | |
507 | <mml:mi mathvariant="italic">r</mml:mi> | |
508 | <mml:mo>></mml:mo> | |
509 | <mml:mfenced open="" close=""> | |
510 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
511 | <mml:mi mathvariant="italic">t</mml:mi> | |
512 | </mml:msub> | |
513 | </mml:mfenced> | |
514 | </mml:mrow> | |
515 | </mml:mtd></mml:mtr> | |
516 | </mml:mtable> | |
517 | </mml:mrow> | |
518 | </mml:mfenced> | |
519 | </mml:mrow> | |
520 | </mml:math></div> | |
521 | </td></tr><tr><td align="left"> | |
522 | <code class="constant">GL_GEQUAL</code> | |
523 | </td><td align="left"> | |
524 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
525 | ||
526 | <mml:mrow> | |
527 | <mml:mi mathvariant="italic">result</mml:mi> | |
528 | <mml:mo>=</mml:mo> | |
529 | <mml:mfenced open="{" close=""> | |
530 | <mml:mrow> | |
531 | <mml:mtable> | |
532 | <mml:mtr><mml:mtd> | |
533 | <mml:mn>1.0</mml:mn> | |
534 | </mml:mtd></mml:mtr> | |
535 | <mml:mtr><mml:mtd> | |
536 | <mml:mn>0.0</mml:mn> | |
537 | </mml:mtd></mml:mtr> | |
538 | </mml:mtable> | |
539 | <mml:mo> </mml:mo> | |
540 | <mml:mtable> | |
541 | <mml:mtr><mml:mtd> | |
542 | <mml:mrow> | |
543 | <mml:mi mathvariant="italic">r</mml:mi> | |
544 | <mml:mo>>=</mml:mo> | |
545 | <mml:mfenced open="" close=""> | |
546 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
547 | <mml:mi mathvariant="italic">t</mml:mi> | |
548 | </mml:msub> | |
549 | </mml:mfenced> | |
550 | </mml:mrow> | |
551 | </mml:mtd></mml:mtr> | |
552 | <mml:mtr><mml:mtd> | |
553 | <mml:mrow> | |
554 | <mml:mi mathvariant="italic">r</mml:mi> | |
555 | <mml:mo><</mml:mo> | |
556 | <mml:mfenced open="" close=""> | |
557 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
558 | <mml:mi mathvariant="italic">t</mml:mi> | |
559 | </mml:msub> | |
560 | </mml:mfenced> | |
561 | </mml:mrow> | |
562 | </mml:mtd></mml:mtr> | |
563 | </mml:mtable> | |
564 | </mml:mrow> | |
565 | </mml:mfenced> | |
566 | </mml:mrow> | |
567 | </mml:math></div> | |
568 | </td></tr><tr><td align="left"> | |
569 | <code class="constant">GL_LESS</code> | |
570 | </td><td align="left"> | |
571 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
572 | ||
573 | <mml:mrow> | |
574 | <mml:mi mathvariant="italic">result</mml:mi> | |
575 | <mml:mo>=</mml:mo> | |
576 | <mml:mfenced open="{" close=""> | |
577 | <mml:mrow> | |
578 | <mml:mtable> | |
579 | <mml:mtr><mml:mtd> | |
580 | <mml:mn>1.0</mml:mn> | |
581 | </mml:mtd></mml:mtr> | |
582 | <mml:mtr><mml:mtd> | |
583 | <mml:mn>0.0</mml:mn> | |
584 | </mml:mtd></mml:mtr> | |
585 | </mml:mtable> | |
586 | <mml:mo> </mml:mo> | |
587 | <mml:mtable> | |
588 | <mml:mtr><mml:mtd> | |
589 | <mml:mrow> | |
590 | <mml:mi mathvariant="italic">r</mml:mi> | |
591 | <mml:mo><</mml:mo> | |
592 | <mml:mfenced open="" close=""> | |
593 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
594 | <mml:mi mathvariant="italic">t</mml:mi> | |
595 | </mml:msub> | |
596 | </mml:mfenced> | |
597 | </mml:mrow> | |
598 | </mml:mtd></mml:mtr> | |
599 | <mml:mtr><mml:mtd> | |
600 | <mml:mrow> | |
601 | <mml:mi mathvariant="italic">r</mml:mi> | |
602 | <mml:mo>>=</mml:mo> | |
603 | <mml:mfenced open="" close=""> | |
604 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
605 | <mml:mi mathvariant="italic">t</mml:mi> | |
606 | </mml:msub> | |
607 | </mml:mfenced> | |
608 | </mml:mrow> | |
609 | </mml:mtd></mml:mtr> | |
610 | </mml:mtable> | |
611 | </mml:mrow> | |
612 | </mml:mfenced> | |
613 | </mml:mrow> | |
614 | </mml:math></div> | |
615 | </td></tr><tr><td align="left"> | |
616 | <code class="constant">GL_GREATER</code> | |
617 | </td><td align="left"> | |
618 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
619 | ||
620 | <mml:mrow> | |
621 | <mml:mi mathvariant="italic">result</mml:mi> | |
622 | <mml:mo>=</mml:mo> | |
623 | <mml:mfenced open="{" close=""> | |
624 | <mml:mrow> | |
625 | <mml:mtable> | |
626 | <mml:mtr><mml:mtd> | |
627 | <mml:mn>1.0</mml:mn> | |
628 | </mml:mtd></mml:mtr> | |
629 | <mml:mtr><mml:mtd> | |
630 | <mml:mn>0.0</mml:mn> | |
631 | </mml:mtd></mml:mtr> | |
632 | </mml:mtable> | |
633 | <mml:mo> </mml:mo> | |
634 | <mml:mtable> | |
635 | <mml:mtr><mml:mtd> | |
636 | <mml:mrow> | |
637 | <mml:mi mathvariant="italic">r</mml:mi> | |
638 | <mml:mo>></mml:mo> | |
639 | <mml:mfenced open="" close=""> | |
640 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
641 | <mml:mi mathvariant="italic">t</mml:mi> | |
642 | </mml:msub> | |
643 | </mml:mfenced> | |
644 | </mml:mrow> | |
645 | </mml:mtd></mml:mtr> | |
646 | <mml:mtr><mml:mtd> | |
647 | <mml:mrow> | |
648 | <mml:mi mathvariant="italic">r</mml:mi> | |
649 | <mml:mo><=</mml:mo> | |
650 | <mml:mfenced open="" close=""> | |
651 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
652 | <mml:mi mathvariant="italic">t</mml:mi> | |
653 | </mml:msub> | |
654 | </mml:mfenced> | |
655 | </mml:mrow> | |
656 | </mml:mtd></mml:mtr> | |
657 | </mml:mtable> | |
658 | </mml:mrow> | |
659 | </mml:mfenced> | |
660 | </mml:mrow> | |
661 | </mml:math></div> | |
662 | </td></tr><tr><td align="left"> | |
663 | <code class="constant">GL_EQUAL</code> | |
664 | </td><td align="left"> | |
665 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
666 | ||
667 | <mml:mrow> | |
668 | <mml:mi mathvariant="italic">result</mml:mi> | |
669 | <mml:mo>=</mml:mo> | |
670 | <mml:mfenced open="{" close=""> | |
671 | <mml:mrow> | |
672 | <mml:mtable> | |
673 | <mml:mtr><mml:mtd> | |
674 | <mml:mn>1.0</mml:mn> | |
675 | </mml:mtd></mml:mtr> | |
676 | <mml:mtr><mml:mtd> | |
677 | <mml:mn>0.0</mml:mn> | |
678 | </mml:mtd></mml:mtr> | |
679 | </mml:mtable> | |
680 | <mml:mo> </mml:mo> | |
681 | <mml:mtable> | |
682 | <mml:mtr><mml:mtd> | |
683 | <mml:mrow> | |
684 | <mml:mi mathvariant="italic">r</mml:mi> | |
685 | <mml:mo>=</mml:mo> | |
686 | <mml:mfenced open="" close=""> | |
687 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
688 | <mml:mi mathvariant="italic">t</mml:mi> | |
689 | </mml:msub> | |
690 | </mml:mfenced> | |
691 | </mml:mrow> | |
692 | </mml:mtd></mml:mtr> | |
693 | <mml:mtr><mml:mtd> | |
694 | <mml:mrow> | |
695 | <mml:mi mathvariant="italic">r</mml:mi> | |
696 | <mml:mo>≠</mml:mo> | |
697 | <mml:mfenced open="" close=""> | |
698 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
699 | <mml:mi mathvariant="italic">t</mml:mi> | |
700 | </mml:msub> | |
701 | </mml:mfenced> | |
702 | </mml:mrow> | |
703 | </mml:mtd></mml:mtr> | |
704 | </mml:mtable> | |
705 | </mml:mrow> | |
706 | </mml:mfenced> | |
707 | </mml:mrow> | |
708 | </mml:math></div> | |
709 | </td></tr><tr><td align="left"> | |
710 | <code class="constant">GL_NOTEQUAL</code> | |
711 | </td><td align="left"> | |
712 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
713 | ||
714 | <mml:mrow> | |
715 | <mml:mi mathvariant="italic">result</mml:mi> | |
716 | <mml:mo>=</mml:mo> | |
717 | <mml:mfenced open="{" close=""> | |
718 | <mml:mrow> | |
719 | <mml:mtable> | |
720 | <mml:mtr><mml:mtd> | |
721 | <mml:mn>1.0</mml:mn> | |
722 | </mml:mtd></mml:mtr> | |
723 | <mml:mtr><mml:mtd> | |
724 | <mml:mn>0.0</mml:mn> | |
725 | </mml:mtd></mml:mtr> | |
726 | </mml:mtable> | |
727 | <mml:mo> </mml:mo> | |
728 | <mml:mtable> | |
729 | <mml:mtr><mml:mtd> | |
730 | <mml:mrow> | |
731 | <mml:mi mathvariant="italic">r</mml:mi> | |
732 | <mml:mo>≠</mml:mo> | |
733 | <mml:mfenced open="" close=""> | |
734 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
735 | <mml:mi mathvariant="italic">t</mml:mi> | |
736 | </mml:msub> | |
737 | </mml:mfenced> | |
738 | </mml:mrow> | |
739 | </mml:mtd></mml:mtr> | |
740 | <mml:mtr><mml:mtd> | |
741 | <mml:mrow> | |
742 | <mml:mi mathvariant="italic">r</mml:mi> | |
743 | <mml:mo>=</mml:mo> | |
744 | <mml:mfenced open="" close=""> | |
745 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
746 | <mml:mi mathvariant="italic">t</mml:mi> | |
747 | </mml:msub> | |
748 | </mml:mfenced> | |
749 | </mml:mrow> | |
750 | </mml:mtd></mml:mtr> | |
751 | </mml:mtable> | |
752 | </mml:mrow> | |
753 | </mml:mfenced> | |
754 | </mml:mrow> | |
755 | </mml:math></div> | |
756 | </td></tr><tr><td align="left"> | |
757 | <code class="constant">GL_ALWAYS</code> | |
758 | </td><td align="left"> | |
759 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
760 | <mml:mrow> | |
761 | <mml:mi mathvariant="italic">result</mml:mi> | |
762 | <mml:mo>=</mml:mo> | |
763 | <mml:mi>1.0</mml:mi> | |
764 | </mml:mrow> | |
765 | </mml:math></div> | |
766 | </td></tr><tr><td align="left"> | |
767 | <code class="constant">GL_NEVER</code> | |
768 | </td><td align="left"> | |
769 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
770 | <mml:mrow> | |
771 | <mml:mi mathvariant="italic">result</mml:mi> | |
772 | <mml:mo>=</mml:mo> | |
773 | <mml:mi>0.0</mml:mi> | |
774 | </mml:mrow> | |
775 | </mml:math></div> | |
776 | </td></tr></tbody></table></div><p> | |
777 | where <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> | |
778 | is the current interpolated texture coordinate, and | |
779 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
780 | ||
781 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
782 | <mml:mi mathvariant="italic">t</mml:mi> | |
783 | </mml:msub> | |
784 | </mml:math> | |
785 | is the texture value sampled from the currently bound texture. | |
786 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">result</mml:mi></mml:math> | |
787 | is assigned to | |
788 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
789 | ||
790 | <mml:msub><mml:mi mathvariant="italic">R</mml:mi> | |
791 | <mml:mi mathvariant="italic">t</mml:mi> | |
792 | </mml:msub> | |
793 | </mml:math>. | |
794 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p> | |
795 | <code class="function">glSamplerParameter</code> is available only if the GL version is 3.3 or higher. | |
796 | </p><p> | |
797 | 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 | |
798 | are used to sample from the texture, rather than the equivalent parameters in the texture object bound to that unit. This | |
799 | introduces the possibility of sampling from the same texture object with different sets of sampler state, which may lead to | |
800 | a condition where a texture is <span class="emphasis"><em>incomplete</em></span> with respect to one sampler object and not with respect to | |
801 | another. Thus, completeness can be considered a function of a sampler object and a texture object bound to a single | |
802 | texture unit, rather than a property of the texture object itself. | |
803 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> | |
804 | <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>sampler</code></em> is not the name of a sampler object previously | |
805 | returned from a call to <a href="glGenSamplers.xml"><span class="citerefentry"><span class="refentrytitle">glGenSamplers</span></span></a>. | |
806 | </p><p> | |
807 | <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>params</code></em> should have a defined | |
808 | constant value (based on the value of <em class="parameter"><code>pname</code></em>) and does not. | |
809 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p> | |
810 | <a href="glGetSamplerParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetSamplerParameter</span></span></a> | |
811 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> | |
812 | <a href="glGenSamplers.xml"><span class="citerefentry"><span class="refentrytitle">glGenSamplers</span></span></a>, | |
813 | <a href="glBindSampler.xml"><span class="citerefentry"><span class="refentrytitle">glBindSampler</span></span></a>, | |
814 | <a href="glDeleteSamplers.xml"><span class="citerefentry"><span class="refentrytitle">glDeleteSamplers</span></span></a>, | |
815 | <a href="glIsSampler.xml"><span class="citerefentry"><span class="refentrytitle">glIsSampler</span></span></a>, | |
816 | <a href="glBindTexture.xml"><span class="citerefentry"><span class="refentrytitle">glBindTexture</span></span></a>, | |
817 | <a href="glTexParameter.xml"><span class="citerefentry"><span class="refentrytitle">glTexParameter</span></span></a> | |
818 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
819 | Copyright <span class="trademark"></span>© 2010 Khronos Group. | |
820 | This material may be distributed subject to the terms and conditions set forth in | |
821 | the Open Publication License, v 1.0, 8 June 1999. | |
822 | <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>. | |
823 | </p></div></div></body></html> |