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1 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> |
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3 | <?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" /><title>glTexParameter</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glTexParameter"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glTexParameter — set texture 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">glTexParameterf</b>(</code></td><td>GLenum </td><td><var class="pdparam">target</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">glTexParameteri</b>(</code></td><td>GLenum </td><td><var class="pdparam">target</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>target</code></em></span></dt><dd><p> | |
4 | Specifies the target texture, | |
5 | which must be either <code class="constant">GL_TEXTURE_1D</code>, <code class="constant">GL_TEXTURE_2D</code>, | |
6 | <code class="constant">GL_TEXTURE_3D</code>, or <code class="constant">GL_TEXTURE_CUBE_MAP</code>. | |
7 | </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p> | |
8 | Specifies the symbolic name of a single-valued texture parameter. | |
9 | <em class="parameter"><code>pname</code></em> can be one of the following: | |
10 | <code class="constant">GL_TEXTURE_MIN_FILTER</code>, | |
11 | <code class="constant">GL_TEXTURE_MAG_FILTER</code>, | |
12 | <code class="constant">GL_TEXTURE_MIN_LOD</code>, | |
13 | <code class="constant">GL_TEXTURE_MAX_LOD</code>, | |
14 | <code class="constant">GL_TEXTURE_BASE_LEVEL</code>, | |
15 | <code class="constant">GL_TEXTURE_MAX_LEVEL</code>, | |
16 | <code class="constant">GL_TEXTURE_WRAP_S</code>, | |
17 | <code class="constant">GL_TEXTURE_WRAP_T</code>, | |
18 | <code class="constant">GL_TEXTURE_WRAP_R</code>, | |
19 | <code class="constant">GL_TEXTURE_PRIORITY</code>, | |
20 | <code class="constant">GL_TEXTURE_COMPARE_MODE</code>, | |
21 | <code class="constant">GL_TEXTURE_COMPARE_FUNC</code>, | |
22 | <code class="constant">GL_DEPTH_TEXTURE_MODE</code>, or | |
23 | <code class="constant">GL_GENERATE_MIPMAP</code>. | |
24 | </p></dd><dt><span class="term"><em class="parameter"><code>param</code></em></span></dt><dd><p> | |
25 | Specifies the value of <em class="parameter"><code>pname</code></em>. | |
26 | </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">glTexParameterfv</b>(</code></td><td>GLenum </td><td><var class="pdparam">target</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">glTexParameteriv</b>(</code></td><td>GLenum </td><td><var class="pdparam">target</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><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>target</code></em></span></dt><dd><p> | |
27 | Specifies the target texture, | |
28 | which must be either <code class="constant">GL_TEXTURE_1D</code>, <code class="constant">GL_TEXTURE_2D</code> or | |
29 | <code class="constant">GL_TEXTURE_3D</code>. | |
30 | </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p> | |
31 | Specifies the symbolic name of a texture parameter. | |
32 | <em class="parameter"><code>pname</code></em> can be one of the following: | |
33 | <code class="constant">GL_TEXTURE_MIN_FILTER</code>, | |
34 | <code class="constant">GL_TEXTURE_MAG_FILTER</code>, | |
35 | <code class="constant">GL_TEXTURE_MIN_LOD</code>, | |
36 | <code class="constant">GL_TEXTURE_MAX_LOD</code>, | |
37 | <code class="constant">GL_TEXTURE_BASE_LEVEL</code>, | |
38 | <code class="constant">GL_TEXTURE_MAX_LEVEL</code>, | |
39 | <code class="constant">GL_TEXTURE_WRAP_S</code>, | |
40 | <code class="constant">GL_TEXTURE_WRAP_T</code>, | |
41 | <code class="constant">GL_TEXTURE_WRAP_R</code>, | |
42 | <code class="constant">GL_TEXTURE_BORDER_COLOR</code>, | |
43 | <code class="constant">GL_TEXTURE_PRIORITY</code>, | |
44 | <code class="constant">GL_TEXTURE_COMPARE_MODE</code>, | |
45 | <code class="constant">GL_TEXTURE_COMPARE_FUNC</code>, | |
46 | <code class="constant">GL_DEPTH_TEXTURE_MODE</code>, or | |
47 | <code class="constant">GL_GENERATE_MIPMAP</code>. | |
48 | </p></dd><dt><span class="term"><em class="parameter"><code>params</code></em></span></dt><dd><p> | |
49 | Specifies a pointer to an array where the value or values of <em class="parameter"><code>pname</code></em> | |
50 | are stored. | |
51 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> | |
52 | Texture mapping is a technique that applies an image onto an object's surface | |
53 | as if the image were a decal or cellophane shrink-wrap. | |
54 | The image is created in texture space, | |
55 | with an | |
56 | (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>, | |
57 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">t</mml:mi></mml:math>) | |
58 | coordinate system. | |
59 | A texture is a one- or two-dimensional image and a set of parameters | |
60 | that determine how samples are derived from the image. | |
61 | </p><p> | |
62 | <code class="function">glTexParameter</code> assigns the value or values in <em class="parameter"><code>params</code></em> to the texture parameter | |
63 | specified as <em class="parameter"><code>pname</code></em>. | |
64 | <em class="parameter"><code>target</code></em> defines the target texture, | |
65 | either <code class="constant">GL_TEXTURE_1D</code>, <code class="constant">GL_TEXTURE_2D</code>, or <code class="constant">GL_TEXTURE_3D</code>. | |
66 | The following symbols are accepted in <em class="parameter"><code>pname</code></em>: | |
67 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MIN_FILTER</code></span></dt><dd><p> | |
68 | The texture minifying function is used whenever the pixel being textured | |
69 | maps to an area greater than one texture element. | |
70 | There are six defined minifying functions. | |
71 | Two of them use the nearest one or nearest four texture elements | |
72 | to compute the texture value. | |
73 | The other four use mipmaps. | |
74 | </p><p> | |
75 | A mipmap is an ordered set of arrays representing the same image | |
76 | at progressively lower resolutions. | |
77 | If the texture has dimensions | |
78 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
79 | ||
80 | <mml:mrow> | |
81 | <mml:msup><mml:mn>2</mml:mn> | |
82 | <mml:mi mathvariant="italic">n</mml:mi> | |
83 | </mml:msup> | |
84 | <mml:mo>×</mml:mo> | |
85 | <mml:msup><mml:mn>2</mml:mn> | |
86 | <mml:mi mathvariant="italic">m</mml:mi> | |
87 | </mml:msup> | |
88 | </mml:mrow> | |
89 | </mml:math>, | |
90 | there are | |
91 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
92 | ||
93 | <mml:mrow> | |
94 | <mml:mrow> | |
95 | <mml:mi mathvariant="italic">max</mml:mi> | |
96 | <mml:mo></mml:mo> | |
97 | <mml:mfenced open="(" close=")"> | |
98 | <mml:mi mathvariant="italic">n</mml:mi> | |
99 | <mml:mi mathvariant="italic">m</mml:mi> | |
100 | </mml:mfenced> | |
101 | </mml:mrow> | |
102 | <mml:mo>+</mml:mo> | |
103 | <mml:mn>1</mml:mn> | |
104 | </mml:mrow> | |
105 | </mml:math> | |
106 | mipmaps. | |
107 | The first mipmap is the original texture, | |
108 | with dimensions | |
109 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
110 | ||
111 | <mml:mrow> | |
112 | <mml:msup><mml:mn>2</mml:mn> | |
113 | <mml:mi mathvariant="italic">n</mml:mi> | |
114 | </mml:msup> | |
115 | <mml:mo>×</mml:mo> | |
116 | <mml:msup><mml:mn>2</mml:mn> | |
117 | <mml:mi mathvariant="italic">m</mml:mi> | |
118 | </mml:msup> | |
119 | </mml:mrow> | |
120 | </mml:math>. | |
121 | Each subsequent mipmap has dimensions | |
122 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
123 | ||
124 | <mml:mrow> | |
125 | <mml:msup><mml:mn>2</mml:mn> | |
126 | <mml:mfenced open="" close=""> | |
127 | <mml:mrow> | |
128 | <mml:mi mathvariant="italic">k</mml:mi> | |
129 | <mml:mo>-</mml:mo> | |
130 | <mml:mn>1</mml:mn> | |
131 | </mml:mrow> | |
132 | </mml:mfenced> | |
133 | </mml:msup> | |
134 | <mml:mo>×</mml:mo> | |
135 | <mml:msup><mml:mn>2</mml:mn> | |
136 | <mml:mfenced open="" close=""> | |
137 | <mml:mrow> | |
138 | <mml:mi mathvariant="italic">l</mml:mi> | |
139 | <mml:mo>-</mml:mo> | |
140 | <mml:mn>1</mml:mn> | |
141 | </mml:mrow> | |
142 | </mml:mfenced> | |
143 | </mml:msup> | |
144 | </mml:mrow> | |
145 | </mml:math>, | |
146 | where | |
147 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
148 | ||
149 | <mml:mrow> | |
150 | <mml:msup><mml:mn>2</mml:mn> | |
151 | <mml:mi mathvariant="italic">k</mml:mi> | |
152 | </mml:msup> | |
153 | <mml:mo>×</mml:mo> | |
154 | <mml:msup><mml:mn>2</mml:mn> | |
155 | <mml:mi mathvariant="italic">l</mml:mi> | |
156 | </mml:msup> | |
157 | </mml:mrow> | |
158 | </mml:math> | |
159 | are the dimensions of the previous mipmap, | |
160 | until either | |
161 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
162 | ||
163 | <mml:mrow> | |
164 | <mml:mi mathvariant="italic">k</mml:mi> | |
165 | <mml:mo>=</mml:mo> | |
166 | <mml:mn>0</mml:mn> | |
167 | </mml:mrow> | |
168 | </mml:math> | |
169 | or | |
170 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
171 | ||
172 | <mml:mrow> | |
173 | <mml:mi mathvariant="italic">l</mml:mi> | |
174 | <mml:mo>=</mml:mo> | |
175 | <mml:mn>0</mml:mn> | |
176 | </mml:mrow> | |
177 | </mml:math>. | |
178 | At that point, | |
179 | subsequent mipmaps have dimension | |
180 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
181 | ||
182 | <mml:mrow> | |
183 | <mml:mn>1</mml:mn> | |
184 | <mml:mo>×</mml:mo> | |
185 | <mml:msup><mml:mn>2</mml:mn> | |
186 | <mml:mfenced open="" close=""> | |
187 | <mml:mrow> | |
188 | <mml:mi mathvariant="italic">l</mml:mi> | |
189 | <mml:mo>-</mml:mo> | |
190 | <mml:mn>1</mml:mn> | |
191 | </mml:mrow> | |
192 | </mml:mfenced> | |
193 | </mml:msup> | |
194 | </mml:mrow> | |
195 | </mml:math> | |
196 | or | |
197 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
198 | ||
199 | <mml:mrow> | |
200 | <mml:msup><mml:mn>2</mml:mn> | |
201 | <mml:mfenced open="" close=""> | |
202 | <mml:mrow> | |
203 | <mml:mi mathvariant="italic">k</mml:mi> | |
204 | <mml:mo>-</mml:mo> | |
205 | <mml:mn>1</mml:mn> | |
206 | </mml:mrow> | |
207 | </mml:mfenced> | |
208 | </mml:msup> | |
209 | <mml:mo>×</mml:mo> | |
210 | <mml:mn>1</mml:mn> | |
211 | </mml:mrow> | |
212 | </mml:math> | |
213 | until the final mipmap, | |
214 | which has dimension | |
215 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
216 | ||
217 | <mml:mrow> | |
218 | <mml:mn>1</mml:mn> | |
219 | <mml:mo>×</mml:mo> | |
220 | <mml:mn>1</mml:mn> | |
221 | </mml:mrow> | |
222 | </mml:math>. | |
223 | To define the mipmaps, call <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>, <a class="citerefentry" href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>, | |
224 | <a class="citerefentry" href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>, | |
225 | <a class="citerefentry" href="glCopyTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>, or <a class="citerefentry" href="glCopyTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a> | |
226 | with the <span class="emphasis"><em>level</em></span> argument indicating the order of the mipmaps. | |
227 | Level 0 is the original texture; | |
228 | level | |
229 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
230 | ||
231 | <mml:mrow> | |
232 | <mml:mi mathvariant="italic">max</mml:mi> | |
233 | <mml:mo></mml:mo> | |
234 | <mml:mfenced open="(" close=")"> | |
235 | <mml:mi mathvariant="italic">n</mml:mi> | |
236 | <mml:mi mathvariant="italic">m</mml:mi> | |
237 | </mml:mfenced> | |
238 | </mml:mrow> | |
239 | </mml:math> | |
240 | is the final | |
241 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
242 | ||
243 | <mml:mrow> | |
244 | <mml:mn>1</mml:mn> | |
245 | <mml:mo>×</mml:mo> | |
246 | <mml:mn>1</mml:mn> | |
247 | </mml:mrow> | |
248 | </mml:math> | |
249 | mipmap. | |
250 | </p><p> | |
251 | <em class="parameter"><code>params</code></em> supplies a function for minifying the texture as one of the | |
252 | following: | |
253 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_NEAREST</code></span></dt><dd><p> | |
254 | Returns the value of the texture element that is nearest | |
255 | (in Manhattan distance) | |
256 | to the center of the pixel being textured. | |
257 | </p></dd><dt><span class="term"><code class="constant">GL_LINEAR</code></span></dt><dd><p> | |
258 | Returns the weighted average of the four texture elements | |
259 | that are closest to the center of the pixel being textured. | |
260 | These can include border texture elements, | |
261 | depending on the values of <code class="constant">GL_TEXTURE_WRAP_S</code> and <code class="constant">GL_TEXTURE_WRAP_T</code>, | |
262 | and on the exact mapping. | |
263 | </p></dd><dt><span class="term"><code class="constant">GL_NEAREST_MIPMAP_NEAREST</code></span></dt><dd><p> | |
264 | Chooses the mipmap that most closely matches the size of the pixel | |
265 | being textured and uses the <code class="constant">GL_NEAREST</code> criterion | |
266 | (the texture element nearest to the center of the pixel) | |
267 | to produce a texture value. | |
268 | </p></dd><dt><span class="term"><code class="constant">GL_LINEAR_MIPMAP_NEAREST</code></span></dt><dd><p> | |
269 | Chooses the mipmap that most closely matches the size of the pixel | |
270 | being textured and uses the <code class="constant">GL_LINEAR</code> criterion | |
271 | (a weighted average of the four texture elements that are closest | |
272 | to the center of the pixel) | |
273 | to produce a texture value. | |
274 | </p></dd><dt><span class="term"><code class="constant">GL_NEAREST_MIPMAP_LINEAR</code></span></dt><dd><p> | |
275 | Chooses the two mipmaps that most closely match the size of the pixel | |
276 | being textured and uses the <code class="constant">GL_NEAREST</code> criterion | |
277 | (the texture element nearest to the center of the pixel) | |
278 | to produce a texture value from each mipmap. | |
279 | The final texture value is a weighted average of those two values. | |
280 | </p></dd><dt><span class="term"><code class="constant">GL_LINEAR_MIPMAP_LINEAR</code></span></dt><dd><p> | |
281 | Chooses the two mipmaps that most closely match the size of the pixel | |
282 | being textured and uses the <code class="constant">GL_LINEAR</code> criterion | |
283 | (a weighted average of the four texture elements that are closest | |
284 | to the center of the pixel) | |
285 | to produce a texture value from each mipmap. | |
286 | The final texture value is a weighted average of those two values. | |
287 | </p></dd></dl></div><p> | |
288 | </p><p> | |
289 | As more texture elements are sampled in the minification process, | |
290 | fewer aliasing artifacts will be apparent. | |
291 | While the <code class="constant">GL_NEAREST</code> and <code class="constant">GL_LINEAR</code> minification functions can be | |
292 | faster than the other four, | |
293 | they sample only one or four texture elements to determine the texture value | |
294 | of the pixel being rendered and can produce moire patterns | |
295 | or ragged transitions. | |
296 | The initial value of <code class="constant">GL_TEXTURE_MIN_FILTER</code> is | |
297 | <code class="constant">GL_NEAREST_MIPMAP_LINEAR</code>. | |
298 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_MAG_FILTER</code></span></dt><dd><p> | |
299 | The texture magnification function is used when the pixel being textured | |
300 | maps to an area less than or equal to one texture element. | |
301 | It sets the texture magnification function to either <code class="constant">GL_NEAREST</code> | |
302 | or <code class="constant">GL_LINEAR</code> (see below). <code class="constant">GL_NEAREST</code> is generally faster | |
303 | than <code class="constant">GL_LINEAR</code>, | |
304 | but it can produce textured images with sharper edges | |
305 | because the transition between texture elements is not as smooth. | |
306 | The initial value of <code class="constant">GL_TEXTURE_MAG_FILTER</code> is <code class="constant">GL_LINEAR</code>. | |
307 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_NEAREST</code></span></dt><dd><p> | |
308 | Returns the value of the texture element that is nearest | |
309 | (in Manhattan distance) | |
310 | to the center of the pixel being textured. | |
311 | </p></dd><dt><span class="term"><code class="constant">GL_LINEAR</code></span></dt><dd><p> | |
312 | Returns the weighted average of the four texture elements | |
313 | that are closest to the center of the pixel being textured. | |
314 | These can include border texture elements, | |
315 | depending on the values of <code class="constant">GL_TEXTURE_WRAP_S</code> and <code class="constant">GL_TEXTURE_WRAP_T</code>, | |
316 | and on the exact mapping. | |
317 | </p></dd></dl></div><p> | |
318 | </p><p> | |
319 | </p><p> | |
320 | </p></dd></dl></div><p> | |
321 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MIN_LOD</code></span></dt><dd><p> | |
322 | Sets the minimum level-of-detail parameter. This floating-point value | |
323 | limits the selection of highest resolution mipmap (lowest mipmap | |
324 | level). The initial value is -1000. | |
325 | </p></dd></dl></div><p> | |
326 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MAX_LOD</code></span></dt><dd><p> | |
327 | Sets the maximum level-of-detail parameter. This floating-point value | |
328 | limits the selection of the lowest resolution mipmap (highest mipmap | |
329 | level). The initial value is 1000. | |
330 | </p></dd></dl></div><p> | |
331 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_BASE_LEVEL</code></span></dt><dd><p> | |
332 | Specifies the index of the lowest defined mipmap level. This is an | |
333 | integer value. The initial value is 0. | |
334 | </p></dd></dl></div><p> | |
335 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MAX_LEVEL</code></span></dt><dd><p> | |
336 | Sets the index of the highest defined mipmap level. This is an integer | |
337 | value. The initial value is 1000. | |
338 | </p></dd></dl></div><p> | |
339 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_WRAP_S</code></span></dt><dd><p> | |
340 | Sets the wrap parameter for texture coordinate | |
341 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
342 | to either <code class="constant">GL_CLAMP</code>, | |
343 | <code class="constant">GL_CLAMP_TO_BORDER</code>, <code class="constant">GL_CLAMP_TO_EDGE</code>, <code class="constant">GL_MIRRORED_REPEAT</code>, or | |
344 | <code class="constant">GL_REPEAT</code>. <code class="constant">GL_CLAMP</code> causes | |
345 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
346 | coordinates to be clamped to the | |
347 | range [0,1] and is useful for preventing wrapping artifacts when mapping a | |
348 | single image onto an object. <code class="constant">GL_CLAMP_TO_BORDER</code> causes the | |
349 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
350 | coordinate to be clamped to the range | |
351 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
352 | ||
353 | <mml:mfenced open="[" close="]"> | |
354 | <mml:mfenced open="" close=""> | |
355 | <mml:mrow> | |
356 | <mml:mfrac> | |
357 | <mml:mn>-1</mml:mn> | |
358 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn> | |
359 | </mml:mfrac> | |
360 | </mml:mrow> | |
361 | </mml:mfenced> | |
362 | <mml:mrow> | |
363 | <mml:mn>1</mml:mn> | |
364 | <mml:mo>+</mml:mo> | |
365 | <mml:mfenced open="" close=""> | |
366 | <mml:mrow> | |
367 | <mml:mfrac> | |
368 | <mml:mn>1</mml:mn> | |
369 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn> | |
370 | </mml:mfrac> | |
371 | </mml:mrow> | |
372 | </mml:mfenced> | |
373 | </mml:mrow> | |
374 | </mml:mfenced> | |
375 | </mml:math>, | |
376 | where | |
377 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">N</mml:mi></mml:math> | |
378 | is the size of the texture in the direction of | |
379 | clamping.<code class="constant">GL_CLAMP_TO_EDGE</code> causes | |
380 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
381 | coordinates to be clamped to the | |
382 | range | |
383 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
384 | ||
385 | <mml:mfenced open="[" close="]"> | |
386 | <mml:mfenced open="" close=""> | |
387 | <mml:mrow> | |
388 | <mml:mfrac> | |
389 | <mml:mn>1</mml:mn> | |
390 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn> | |
391 | </mml:mfrac> | |
392 | </mml:mrow> | |
393 | </mml:mfenced> | |
394 | <mml:mrow> | |
395 | <mml:mn>1</mml:mn> | |
396 | <mml:mo>-</mml:mo> | |
397 | <mml:mfenced open="" close=""> | |
398 | <mml:mrow> | |
399 | <mml:mfrac> | |
400 | <mml:mn>1</mml:mn> | |
401 | <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn> | |
402 | </mml:mfrac> | |
403 | </mml:mrow> | |
404 | </mml:mfenced> | |
405 | </mml:mrow> | |
406 | </mml:mfenced> | |
407 | </mml:math>, | |
408 | where | |
409 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">N</mml:mi></mml:math> | |
410 | is the size | |
411 | of the texture in the direction of clamping. <code class="constant">GL_REPEAT</code> causes the | |
412 | integer part of the | |
413 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
414 | coordinate to be ignored; the GL uses only the | |
415 | fractional part, thereby creating a repeating pattern. | |
416 | <code class="constant">GL_MIRRORED_REPEAT</code> causes the | |
417 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
418 | coordinate to be set to the | |
419 | fractional part of the texture coordinate if the integer 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 | is | |
422 | even; if the integer part of | |
423 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
424 | is odd, then the | |
425 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> | |
426 | texture coordinate is | |
427 | set to | |
428 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
429 | ||
430 | <mml:mrow> | |
431 | <mml:mn>1</mml:mn> | |
432 | <mml:mo>-</mml:mo> | |
433 | <mml:mrow> | |
434 | <mml:mi mathvariant="italic">frac</mml:mi> | |
435 | <mml:mo></mml:mo> | |
436 | <mml:mfenced open="(" close=")"> | |
437 | <mml:mi mathvariant="italic">s</mml:mi> | |
438 | </mml:mfenced> | |
439 | </mml:mrow> | |
440 | </mml:mrow> | |
441 | </mml:math>, | |
442 | where | |
443 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
444 | ||
445 | <mml:mrow> | |
446 | <mml:mi mathvariant="italic">frac</mml:mi> | |
447 | <mml:mo></mml:mo> | |
448 | <mml:mfenced open="(" close=")"> | |
449 | <mml:mi mathvariant="italic">s</mml:mi> | |
450 | </mml:mfenced> | |
451 | </mml:mrow> | |
452 | </mml:math> | |
453 | represents the fractional part of | |
454 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>. | |
455 | Border texture | |
456 | elements are accessed only if wrapping is set to <code class="constant">GL_CLAMP</code> or <code class="constant">GL_CLAMP_TO_BORDER</code>. Initially, | |
457 | <code class="constant">GL_TEXTURE_WRAP_S</code> is set to <code class="constant">GL_REPEAT</code>. | |
458 | </p></dd></dl></div><p> | |
459 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_WRAP_T</code></span></dt><dd><p> | |
460 | Sets the wrap parameter for texture coordinate | |
461 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">t</mml:mi></mml:math> | |
462 | to either <code class="constant">GL_CLAMP</code>, | |
463 | <code class="constant">GL_CLAMP_TO_BORDER</code>, <code class="constant">GL_CLAMP_TO_EDGE</code>, <code class="constant">GL_MIRRORED_REPEAT</code>, or | |
464 | <code class="constant">GL_REPEAT</code>. See the discussion under <code class="constant">GL_TEXTURE_WRAP_S</code>. | |
465 | Initially, <code class="constant">GL_TEXTURE_WRAP_T</code> is set to <code class="constant">GL_REPEAT</code>. | |
466 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_WRAP_R</code></span></dt><dd><p> | |
467 | Sets the wrap parameter for texture coordinate | |
468 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> | |
469 | to either <code class="constant">GL_CLAMP</code>, | |
470 | <code class="constant">GL_CLAMP_TO_BORDER</code>, <code class="constant">GL_CLAMP_TO_EDGE</code>, <code class="constant">GL_MIRRORED_REPEAT</code>, or | |
471 | <code class="constant">GL_REPEAT</code>. See the discussion under <code class="constant">GL_TEXTURE_WRAP_S</code>. | |
472 | Initially, <code class="constant">GL_TEXTURE_WRAP_R</code> is set to <code class="constant">GL_REPEAT</code>. | |
473 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_BORDER_COLOR</code></span></dt><dd><p> | |
474 | Sets a border color. <em class="parameter"><code>params</code></em> contains four values that comprise the RGBA | |
475 | color of the texture border. Integer color components are interpreted | |
476 | linearly such that the most positive integer maps to 1.0, and the most | |
477 | negative integer maps to -1.0. The values are clamped to the range [0,1] | |
478 | when they are specified. Initially, the border color is (0, 0, 0, 0). | |
479 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_PRIORITY</code></span></dt><dd><p> | |
480 | Specifies the texture residence priority of the currently bound texture. | |
481 | Permissible values are in the range | |
482 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
483 | ||
484 | <mml:mfenced open="[" close="]"> | |
485 | <mml:mn>0</mml:mn> | |
486 | <mml:mn>1</mml:mn> | |
487 | </mml:mfenced> | |
488 | </mml:math>. | |
489 | See <a class="citerefentry" href="glPrioritizeTextures.xml"><span class="citerefentry"><span class="refentrytitle">glPrioritizeTextures</span></span></a> and <a class="citerefentry" href="glBindTexture.xml"><span class="citerefentry"><span class="refentrytitle">glBindTexture</span></span></a> for more information. | |
490 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_COMPARE_MODE</code></span></dt><dd><p> | |
491 | Specifies the texture comparison mode for currently bound depth textures. | |
492 | That is, a texture whose internal format is <code class="constant">GL_DEPTH_COMPONENT_*</code>; see | |
493 | <a class="citerefentry" href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>) | |
494 | Permissible values are: | |
495 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_COMPARE_R_TO_TEXTURE</code></span></dt><dd><p> | |
496 | Specifies that the interpolated and clamped | |
497 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> | |
498 | texture coordinate should | |
499 | be compared to the value in the currently bound depth texture. See the | |
500 | discussion of <code class="constant">GL_TEXTURE_COMPARE_FUNC</code> for details of how the comparison | |
501 | is evaluated. The result of the comparison is assigned to luminance, | |
502 | intensity, or alpha (as specified by <code class="constant">GL_DEPTH_TEXTURE_MODE</code>). | |
503 | </p></dd><dt><span class="term"><code class="constant">GL_NONE</code></span></dt><dd><p> | |
504 | Specifies that the luminance, intensity, or alpha (as specified by | |
505 | <code class="constant">GL_DEPTH_TEXTURE_MODE</code>) should be assigned the | |
506 | appropriate value from the currently bound depth texture. | |
507 | </p></dd></dl></div><p> | |
508 | </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_COMPARE_FUNC</code></span></dt><dd><p> | |
509 | Specifies the comparison operator used when <code class="constant">GL_TEXTURE_COMPARE_MODE</code> is | |
510 | set to <code class="constant">GL_COMPARE_R_TO_TEXTURE</code>. Permissible values are: | |
511 | </p><div class="informaltable"><table border="1"><colgroup><col align="left" /><col align="left" /></colgroup><thead><tr><th align="left"><span class="bold"><strong> | |
512 | Texture Comparison Function | |
513 | </strong></span></th><th align="left"><span class="bold"><strong> | |
514 | Computed result | |
515 | </strong></span></th></tr></thead><tbody><tr><td align="left"> | |
516 | <code class="constant">GL_LEQUAL</code> | |
517 | </td><td align="left"> | |
518 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
519 | ||
520 | <mml:mrow> | |
521 | <mml:mi mathvariant="italic">result</mml:mi> | |
522 | <mml:mo>=</mml:mo> | |
523 | <mml:mfenced open="{" close=""> | |
524 | <mml:mrow> | |
525 | <mml:mtable> | |
526 | <mml:mtr><mml:mtd> | |
527 | <mml:mn>1.0</mml:mn> | |
528 | </mml:mtd></mml:mtr> | |
529 | <mml:mtr><mml:mtd> | |
530 | <mml:mn>0.0</mml:mn> | |
531 | </mml:mtd></mml:mtr> | |
532 | </mml:mtable> | |
533 | <mml:mo> </mml:mo> | |
534 | <mml:mtable> | |
535 | <mml:mtr><mml:mtd> | |
536 | <mml:mrow> | |
537 | <mml:mi mathvariant="italic">r</mml:mi> | |
538 | <mml:mo><=</mml:mo> | |
539 | <mml:mfenced open="" close=""> | |
540 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
541 | <mml:mi mathvariant="italic">t</mml:mi> | |
542 | </mml:msub> | |
543 | </mml:mfenced> | |
544 | </mml:mrow> | |
545 | </mml:mtd></mml:mtr> | |
546 | <mml:mtr><mml:mtd> | |
547 | <mml:mrow> | |
548 | <mml:mi mathvariant="italic">r</mml:mi> | |
549 | <mml:mo>></mml:mo> | |
550 | <mml:mfenced open="" close=""> | |
551 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
552 | <mml:mi mathvariant="italic">t</mml:mi> | |
553 | </mml:msub> | |
554 | </mml:mfenced> | |
555 | </mml:mrow> | |
556 | </mml:mtd></mml:mtr> | |
557 | </mml:mtable> | |
558 | </mml:mrow> | |
559 | </mml:mfenced> | |
560 | </mml:mrow> | |
561 | </mml:math></div> | |
562 | </td></tr><tr><td align="left"> | |
563 | <code class="constant">GL_GEQUAL</code> | |
564 | </td><td align="left"> | |
565 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
566 | ||
567 | <mml:mrow> | |
568 | <mml:mi mathvariant="italic">result</mml:mi> | |
569 | <mml:mo>=</mml:mo> | |
570 | <mml:mfenced open="{" close=""> | |
571 | <mml:mrow> | |
572 | <mml:mtable> | |
573 | <mml:mtr><mml:mtd> | |
574 | <mml:mn>1.0</mml:mn> | |
575 | </mml:mtd></mml:mtr> | |
576 | <mml:mtr><mml:mtd> | |
577 | <mml:mn>0.0</mml:mn> | |
578 | </mml:mtd></mml:mtr> | |
579 | </mml:mtable> | |
580 | <mml:mo> </mml:mo> | |
581 | <mml:mtable> | |
582 | <mml:mtr><mml:mtd> | |
583 | <mml:mrow> | |
584 | <mml:mi mathvariant="italic">r</mml:mi> | |
585 | <mml:mo>>=</mml:mo> | |
586 | <mml:mfenced open="" close=""> | |
587 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
588 | <mml:mi mathvariant="italic">t</mml:mi> | |
589 | </mml:msub> | |
590 | </mml:mfenced> | |
591 | </mml:mrow> | |
592 | </mml:mtd></mml:mtr> | |
593 | <mml:mtr><mml:mtd> | |
594 | <mml:mrow> | |
595 | <mml:mi mathvariant="italic">r</mml:mi> | |
596 | <mml:mo><</mml:mo> | |
597 | <mml:mfenced open="" close=""> | |
598 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
599 | <mml:mi mathvariant="italic">t</mml:mi> | |
600 | </mml:msub> | |
601 | </mml:mfenced> | |
602 | </mml:mrow> | |
603 | </mml:mtd></mml:mtr> | |
604 | </mml:mtable> | |
605 | </mml:mrow> | |
606 | </mml:mfenced> | |
607 | </mml:mrow> | |
608 | </mml:math></div> | |
609 | </td></tr><tr><td align="left"> | |
610 | <code class="constant">GL_LESS</code> | |
611 | </td><td align="left"> | |
612 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
613 | ||
614 | <mml:mrow> | |
615 | <mml:mi mathvariant="italic">result</mml:mi> | |
616 | <mml:mo>=</mml:mo> | |
617 | <mml:mfenced open="{" close=""> | |
618 | <mml:mrow> | |
619 | <mml:mtable> | |
620 | <mml:mtr><mml:mtd> | |
621 | <mml:mn>1.0</mml:mn> | |
622 | </mml:mtd></mml:mtr> | |
623 | <mml:mtr><mml:mtd> | |
624 | <mml:mn>0.0</mml:mn> | |
625 | </mml:mtd></mml:mtr> | |
626 | </mml:mtable> | |
627 | <mml:mo> </mml:mo> | |
628 | <mml:mtable> | |
629 | <mml:mtr><mml:mtd> | |
630 | <mml:mrow> | |
631 | <mml:mi mathvariant="italic">r</mml:mi> | |
632 | <mml:mo><</mml:mo> | |
633 | <mml:mfenced open="" close=""> | |
634 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
635 | <mml:mi mathvariant="italic">t</mml:mi> | |
636 | </mml:msub> | |
637 | </mml:mfenced> | |
638 | </mml:mrow> | |
639 | </mml:mtd></mml:mtr> | |
640 | <mml:mtr><mml:mtd> | |
641 | <mml:mrow> | |
642 | <mml:mi mathvariant="italic">r</mml:mi> | |
643 | <mml:mo>>=</mml:mo> | |
644 | <mml:mfenced open="" close=""> | |
645 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
646 | <mml:mi mathvariant="italic">t</mml:mi> | |
647 | </mml:msub> | |
648 | </mml:mfenced> | |
649 | </mml:mrow> | |
650 | </mml:mtd></mml:mtr> | |
651 | </mml:mtable> | |
652 | </mml:mrow> | |
653 | </mml:mfenced> | |
654 | </mml:mrow> | |
655 | </mml:math></div> | |
656 | </td></tr><tr><td align="left"> | |
657 | <code class="constant">GL_GREATER</code> | |
658 | </td><td align="left"> | |
659 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
660 | ||
661 | <mml:mrow> | |
662 | <mml:mi mathvariant="italic">result</mml:mi> | |
663 | <mml:mo>=</mml:mo> | |
664 | <mml:mfenced open="{" close=""> | |
665 | <mml:mrow> | |
666 | <mml:mtable> | |
667 | <mml:mtr><mml:mtd> | |
668 | <mml:mn>1.0</mml:mn> | |
669 | </mml:mtd></mml:mtr> | |
670 | <mml:mtr><mml:mtd> | |
671 | <mml:mn>0.0</mml:mn> | |
672 | </mml:mtd></mml:mtr> | |
673 | </mml:mtable> | |
674 | <mml:mo> </mml:mo> | |
675 | <mml:mtable> | |
676 | <mml:mtr><mml:mtd> | |
677 | <mml:mrow> | |
678 | <mml:mi mathvariant="italic">r</mml:mi> | |
679 | <mml:mo>></mml:mo> | |
680 | <mml:mfenced open="" close=""> | |
681 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
682 | <mml:mi mathvariant="italic">t</mml:mi> | |
683 | </mml:msub> | |
684 | </mml:mfenced> | |
685 | </mml:mrow> | |
686 | </mml:mtd></mml:mtr> | |
687 | <mml:mtr><mml:mtd> | |
688 | <mml:mrow> | |
689 | <mml:mi mathvariant="italic">r</mml:mi> | |
690 | <mml:mo><=</mml:mo> | |
691 | <mml:mfenced open="" close=""> | |
692 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
693 | <mml:mi mathvariant="italic">t</mml:mi> | |
694 | </mml:msub> | |
695 | </mml:mfenced> | |
696 | </mml:mrow> | |
697 | </mml:mtd></mml:mtr> | |
698 | </mml:mtable> | |
699 | </mml:mrow> | |
700 | </mml:mfenced> | |
701 | </mml:mrow> | |
702 | </mml:math></div> | |
703 | </td></tr><tr><td align="left"> | |
704 | <code class="constant">GL_EQUAL</code> | |
705 | </td><td align="left"> | |
706 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
707 | ||
708 | <mml:mrow> | |
709 | <mml:mi mathvariant="italic">result</mml:mi> | |
710 | <mml:mo>=</mml:mo> | |
711 | <mml:mfenced open="{" close=""> | |
712 | <mml:mrow> | |
713 | <mml:mtable> | |
714 | <mml:mtr><mml:mtd> | |
715 | <mml:mn>1.0</mml:mn> | |
716 | </mml:mtd></mml:mtr> | |
717 | <mml:mtr><mml:mtd> | |
718 | <mml:mn>0.0</mml:mn> | |
719 | </mml:mtd></mml:mtr> | |
720 | </mml:mtable> | |
721 | <mml:mo> </mml:mo> | |
722 | <mml:mtable> | |
723 | <mml:mtr><mml:mtd> | |
724 | <mml:mrow> | |
725 | <mml:mi mathvariant="italic">r</mml:mi> | |
726 | <mml:mo>=</mml:mo> | |
727 | <mml:mfenced open="" close=""> | |
728 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
729 | <mml:mi mathvariant="italic">t</mml:mi> | |
730 | </mml:msub> | |
731 | </mml:mfenced> | |
732 | </mml:mrow> | |
733 | </mml:mtd></mml:mtr> | |
734 | <mml:mtr><mml:mtd> | |
735 | <mml:mrow> | |
736 | <mml:mi mathvariant="italic">r</mml:mi> | |
737 | <mml:mo>≠</mml:mo> | |
738 | <mml:mfenced open="" close=""> | |
739 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
740 | <mml:mi mathvariant="italic">t</mml:mi> | |
741 | </mml:msub> | |
742 | </mml:mfenced> | |
743 | </mml:mrow> | |
744 | </mml:mtd></mml:mtr> | |
745 | </mml:mtable> | |
746 | </mml:mrow> | |
747 | </mml:mfenced> | |
748 | </mml:mrow> | |
749 | </mml:math></div> | |
750 | </td></tr><tr><td align="left"> | |
751 | <code class="constant">GL_NOTEQUAL</code> | |
752 | </td><td align="left"> | |
753 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
754 | ||
755 | <mml:mrow> | |
756 | <mml:mi mathvariant="italic">result</mml:mi> | |
757 | <mml:mo>=</mml:mo> | |
758 | <mml:mfenced open="{" close=""> | |
759 | <mml:mrow> | |
760 | <mml:mtable> | |
761 | <mml:mtr><mml:mtd> | |
762 | <mml:mn>1.0</mml:mn> | |
763 | </mml:mtd></mml:mtr> | |
764 | <mml:mtr><mml:mtd> | |
765 | <mml:mn>0.0</mml:mn> | |
766 | </mml:mtd></mml:mtr> | |
767 | </mml:mtable> | |
768 | <mml:mo> </mml:mo> | |
769 | <mml:mtable> | |
770 | <mml:mtr><mml:mtd> | |
771 | <mml:mrow> | |
772 | <mml:mi mathvariant="italic">r</mml:mi> | |
773 | <mml:mo>≠</mml:mo> | |
774 | <mml:mfenced open="" close=""> | |
775 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
776 | <mml:mi mathvariant="italic">t</mml:mi> | |
777 | </mml:msub> | |
778 | </mml:mfenced> | |
779 | </mml:mrow> | |
780 | </mml:mtd></mml:mtr> | |
781 | <mml:mtr><mml:mtd> | |
782 | <mml:mrow> | |
783 | <mml:mi mathvariant="italic">r</mml:mi> | |
784 | <mml:mo>=</mml:mo> | |
785 | <mml:mfenced open="" close=""> | |
786 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
787 | <mml:mi mathvariant="italic">t</mml:mi> | |
788 | </mml:msub> | |
789 | </mml:mfenced> | |
790 | </mml:mrow> | |
791 | </mml:mtd></mml:mtr> | |
792 | </mml:mtable> | |
793 | </mml:mrow> | |
794 | </mml:mfenced> | |
795 | </mml:mrow> | |
796 | </mml:math></div> | |
797 | </td></tr><tr><td align="left"> | |
798 | <code class="constant">GL_ALWAYS</code> | |
799 | </td><td align="left"> | |
800 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
801 | <mml:mrow> | |
802 | <mml:mi mathvariant="italic">result</mml:mi> | |
803 | <mml:mo>=</mml:mo> | |
804 | <mml:mi>1.0</mml:mi> | |
805 | </mml:mrow> | |
806 | </mml:math></div> | |
807 | </td></tr><tr><td align="left"> | |
808 | <code class="constant">GL_NEVER</code> | |
809 | </td><td align="left"> | |
810 | <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
811 | <mml:mrow> | |
812 | <mml:mi mathvariant="italic">result</mml:mi> | |
813 | <mml:mo>=</mml:mo> | |
814 | <mml:mi>0.0</mml:mi> | |
815 | </mml:mrow> | |
816 | </mml:math></div> | |
817 | </td></tr></tbody></table></div><p> | |
818 | where <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> | |
819 | is the current interpolated texture coordinate, and | |
820 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
821 | ||
822 | <mml:msub><mml:mi mathvariant="italic">D</mml:mi> | |
823 | <mml:mi mathvariant="italic">t</mml:mi> | |
824 | </mml:msub> | |
825 | </mml:math> | |
826 | is the depth texture value sampled from the currently bound depth texture. | |
827 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">result</mml:mi></mml:math> | |
828 | is assigned to the either the luminance, intensity, or alpha (as | |
829 | specified by <code class="constant">GL_DEPTH_TEXTURE_MODE</code>.) | |
830 | </p></dd><dt><span class="term"><code class="constant">GL_DEPTH_TEXTURE_MODE</code></span></dt><dd><p> | |
831 | Specifies a single symbolic constant indicating how depth values should be | |
832 | treated during filtering and texture application. Accepted values are | |
833 | <code class="constant">GL_LUMINANCE</code>, <code class="constant">GL_INTENSITY</code>, and <code class="constant">GL_ALPHA</code>. The initial value | |
834 | is <code class="constant">GL_LUMINANCE</code>. | |
835 | </p></dd><dt><span class="term"><code class="constant">GL_GENERATE_MIPMAP</code></span></dt><dd><p> | |
836 | Specifies a boolean value that indicates if all levels of a mipmap array | |
837 | should be automatically updated when any modification to the base level | |
838 | mipmap is done. The initial value is <code class="constant">GL_FALSE</code>. | |
839 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p> | |
840 | <code class="constant">GL_TEXTURE_3D</code>, <code class="constant">GL_TEXTURE_MIN_LOD</code>, <code class="constant">GL_TEXTURE_MAX_LOD</code>, | |
841 | <code class="constant">GL_CLAMP_TO_EDGE</code>, <code class="constant">GL_TEXTURE_BASE_LEVEL</code>, and <code class="constant">GL_TEXTURE_MAX_LEVEL</code> are | |
842 | available only if the GL version is 1.2 or greater. | |
843 | </p><p> | |
844 | <code class="constant">GL_CLAMP_TO_BORDER</code> is available only if the GL version is 1.3 or greater. | |
845 | </p><p> | |
846 | <code class="constant">GL_MIRRORED_REPEAT</code>, <code class="constant">GL_TEXTURE_COMPARE_MODE</code>, | |
847 | <code class="constant">GL_TEXTURE_COMPARE_FUNC</code>, <code class="constant">GL_DEPTH_TEXTURE_MODE</code>, and | |
848 | <code class="constant">GL_GENERATE_MIPMAP</code> are available only if the GL version is 1.4 or | |
849 | greater. | |
850 | </p><p> | |
851 | <code class="constant">GL_TEXTURE_COMPARE_FUNC</code> allows the following additional comparison modes only | |
852 | if the GL version is 1.5 or greater: | |
853 | <code class="constant">GL_LESS</code>, <code class="constant">GL_GREATER</code>, | |
854 | <code class="constant">GL_EQUAL</code>, <code class="constant">GL_NOTEQUAL</code>, | |
855 | <code class="constant">GL_ALWAYS</code>, and <code class="constant">GL_NEVER</code>. | |
856 | </p><p> | |
857 | Suppose that a program has enabled texturing (by calling <a class="citerefentry" href="glEnable.xml"><span class="citerefentry"><span class="refentrytitle">glEnable</span></span></a> with | |
858 | argument <code class="constant">GL_TEXTURE_1D</code>, <code class="constant">GL_TEXTURE_2D</code>, or <code class="constant">GL_TEXTURE_3D</code>) and | |
859 | has set <code class="constant">GL_TEXTURE_MIN_FILTER</code> to one of the functions that requires a | |
860 | mipmap. If either the dimensions of the texture images currently defined | |
861 | (with previous calls to <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>, <a class="citerefentry" href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>, | |
862 | <a class="citerefentry" href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>, <a class="citerefentry" href="glCopyTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>, or <a class="citerefentry" href="glCopyTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a>) do not | |
863 | follow the proper sequence for mipmaps (described above), or there are | |
864 | fewer texture images defined than are needed, or the set of texture images | |
865 | have differing numbers of texture components, then it is as if texture | |
866 | mapping were disabled. | |
867 | </p><p> | |
868 | Linear filtering accesses the four nearest texture elements only in 2D | |
869 | textures. In 1D textures, linear filtering accesses the two nearest | |
870 | texture elements. | |
871 | </p><p> | |
872 | For OpenGL versions 1.3 and greater, or when the <code class="code">ARB_multitexture</code> extension is supported, <code class="function">glTexParameter</code> | |
873 | specifies the texture parameters for the active texture unit, specified | |
874 | by calling <a class="citerefentry" href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>. | |
875 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> | |
876 | <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>target</code></em> or <em class="parameter"><code>pname</code></em> is not | |
877 | one of the accepted defined values. | |
878 | </p><p> | |
879 | <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>params</code></em> should have a defined | |
880 | constant value (based on the value of <em class="parameter"><code>pname</code></em>) and does not. | |
881 | </p><p> | |
882 | <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glTexParameter</code> is executed between the | |
883 | execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>. | |
884 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p> | |
885 | <a class="citerefentry" href="glGetTexParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexParameter</span></span></a> | |
886 | </p><p> | |
887 | <a class="citerefentry" href="glGetTexLevelParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a> | |
888 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> | |
889 | <a class="citerefentry" href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>, | |
890 | <a class="citerefentry" href="glBindTexture.xml"><span class="citerefentry"><span class="refentrytitle">glBindTexture</span></span></a>, | |
891 | <a class="citerefentry" href="glCopyPixels.xml"><span class="citerefentry"><span class="refentrytitle">glCopyPixels</span></span></a>, | |
892 | <a class="citerefentry" href="glCopyTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>, | |
893 | <a class="citerefentry" href="glCopyTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a>, | |
894 | <a class="citerefentry" href="glCopyTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage1D</span></span></a>, | |
895 | <a class="citerefentry" href="glCopyTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>, | |
896 | <a class="citerefentry" href="glCopyTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage3D</span></span></a>, | |
897 | <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a>, | |
898 | <a class="citerefentry" href="glPixelStore.xml"><span class="citerefentry"><span class="refentrytitle">glPixelStore</span></span></a>, | |
899 | <a class="citerefentry" href="glPixelTransfer.xml"><span class="citerefentry"><span class="refentrytitle">glPixelTransfer</span></span></a>, | |
900 | <a class="citerefentry" href="glPrioritizeTextures.xml"><span class="citerefentry"><span class="refentrytitle">glPrioritizeTextures</span></span></a>, | |
901 | <a class="citerefentry" href="glTexEnv.xml"><span class="citerefentry"><span class="refentrytitle">glTexEnv</span></span></a>, | |
902 | <a class="citerefentry" href="glTexGen.xml"><span class="citerefentry"><span class="refentrytitle">glTexGen</span></span></a>, | |
903 | <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>, | |
904 | <a class="citerefentry" href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>, | |
905 | <a class="citerefentry" href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>, | |
906 | <a class="citerefentry" href="glTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage1D</span></span></a>, | |
907 | <a class="citerefentry" href="glTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage2D</span></span></a>, | |
908 | <a class="citerefentry" href="glTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage3D</span></span></a> | |
909 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
910 | Copyright <span class="trademark"></span>© 1991-2006 | |
911 | Silicon Graphics, Inc. This document is licensed under the SGI | |
912 | Free Software B License. For details, see | |
913 | <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>. | |
914 | </p></div></div></body></html> |