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[clinton/guile-figl.git] / upstream-man-pages / man4 / xhtml / glTexParameter.xml
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>glTexParameter - OpenGL 4 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="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>
5 Specifies the target texture,
6 which must be either <code class="constant">GL_TEXTURE_1D</code>, <code class="constant">GL_TEXTURE_2D</code>,
7 <code class="constant">GL_TEXTURE_3D</code>, <code class="constant">GL_TEXTURE_1D_ARRAY</code>,
8 <code class="constant">GL_TEXTURE_2D_ARRAY</code>, <code class="constant">GL_TEXTURE_RECTANGLE</code>,
9 or <code class="constant">GL_TEXTURE_CUBE_MAP</code>.
10 </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p>
11 Specifies the symbolic name of a single-valued texture parameter.
12 <em class="parameter"><code>pname</code></em> can be one of the following:
13 <code class="constant">GL_DEPTH_STENCIL_TEXTURE_MODE</code>,
14 <code class="constant">GL_TEXTURE_BASE_LEVEL</code>,
15 <code class="constant">GL_TEXTURE_COMPARE_FUNC</code>,
16 <code class="constant">GL_TEXTURE_COMPARE_MODE</code>,
17 <code class="constant">GL_TEXTURE_LOD_BIAS</code>,
18 <code class="constant">GL_TEXTURE_MIN_FILTER</code>,
19 <code class="constant">GL_TEXTURE_MAG_FILTER</code>,
20 <code class="constant">GL_TEXTURE_MIN_LOD</code>,
21 <code class="constant">GL_TEXTURE_MAX_LOD</code>,
22 <code class="constant">GL_TEXTURE_MAX_LEVEL</code>,
23 <code class="constant">GL_TEXTURE_SWIZZLE_R</code>,
24 <code class="constant">GL_TEXTURE_SWIZZLE_G</code>,
25 <code class="constant">GL_TEXTURE_SWIZZLE_B</code>,
26 <code class="constant">GL_TEXTURE_SWIZZLE_A</code>,
27 <code class="constant">GL_TEXTURE_WRAP_S</code>,
28 <code class="constant">GL_TEXTURE_WRAP_T</code>, or
29 <code class="constant">GL_TEXTURE_WRAP_R</code>.
30 </p></dd><dt><span class="term"><em class="parameter"><code>param</code></em></span></dt><dd><p>
31 Specifies the value of <em class="parameter"><code>pname</code></em>.
32 </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 class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glTexParameterIiv</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 class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glTexParameterIuiv</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 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>target</code></em></span></dt><dd><p>
33 Specifies the target texture,
34 which must be either <code class="constant">GL_TEXTURE_1D</code>, <code class="constant">GL_TEXTURE_2D</code>,
35 <code class="constant">GL_TEXTURE_3D</code>, <code class="constant">GL_TEXTURE_1D_ARRAY</code>,
36 <code class="constant">GL_TEXTURE_2D_ARRAY</code>, <code class="constant">GL_TEXTURE_RECTANGLE</code>,
37 or <code class="constant">GL_TEXTURE_CUBE_MAP</code>.
38 </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p>
39 Specifies the symbolic name of a texture parameter.
40 <em class="parameter"><code>pname</code></em> can be one of the following:
41 <code class="constant">GL_DEPTH_STENCIL_TEXTURE_MODE</code>,
42 <code class="constant">GL_TEXTURE_BASE_LEVEL</code>,
43 <code class="constant">GL_TEXTURE_BORDER_COLOR</code>,
44 <code class="constant">GL_TEXTURE_COMPARE_FUNC</code>,
45 <code class="constant">GL_TEXTURE_COMPARE_MODE</code>,
46 <code class="constant">GL_TEXTURE_LOD_BIAS</code>,
47 <code class="constant">GL_TEXTURE_MIN_FILTER</code>,
48 <code class="constant">GL_TEXTURE_MAG_FILTER</code>,
49 <code class="constant">GL_TEXTURE_MIN_LOD</code>,
50 <code class="constant">GL_TEXTURE_MAX_LOD</code>,
51 <code class="constant">GL_TEXTURE_MAX_LEVEL</code>,
52 <code class="constant">GL_TEXTURE_SWIZZLE_R</code>,
53 <code class="constant">GL_TEXTURE_SWIZZLE_G</code>,
54 <code class="constant">GL_TEXTURE_SWIZZLE_B</code>,
55 <code class="constant">GL_TEXTURE_SWIZZLE_A</code>,
56 <code class="constant">GL_TEXTURE_SWIZZLE_RGBA</code>,
57 <code class="constant">GL_TEXTURE_WRAP_S</code>,
58 <code class="constant">GL_TEXTURE_WRAP_T</code>, or
59 <code class="constant">GL_TEXTURE_WRAP_R</code>.
60 </p></dd><dt><span class="term"><em class="parameter"><code>params</code></em></span></dt><dd><p>
61 Specifies a pointer to an array where the value or values of <em class="parameter"><code>pname</code></em>
62 are stored.
63 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
64 <code class="function">glTexParameter</code> assigns the value or values in <em class="parameter"><code>params</code></em> to the texture parameter
65 specified as <em class="parameter"><code>pname</code></em>.
66 <em class="parameter"><code>target</code></em> defines the target texture,
67 either <code class="constant">GL_TEXTURE_1D</code>, <code class="constant">GL_TEXTURE_2D</code>, <code class="constant">GL_TEXTURE_1D_ARRAY</code>,
68 <code class="constant">GL_TEXTURE_2D_ARRAY</code>, <code class="constant">GL_TEXTURE_RECTANGLE</code>, or <code class="constant">GL_TEXTURE_3D</code>.
69 The following symbols are accepted in <em class="parameter"><code>pname</code></em>:
70 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_DEPTH_STENCIL_TEXTURE_MODE</code></span></dt><dd><p>
71 Specifies the mode used to read from depth-stencil format textures. <em class="parameter"><code>params</code></em>
72 must be one of <code class="constant">GL_DEPTH_COMPONENT</code> or <code class="constant">GL_STENCIL_COMPONENT</code>.
73 If the depth stencil mode is <code class="constant">GL_DEPTH_COMPONENT</code>, then reads from depth-stencil
74 format textures will return the depth component of the texel in
75 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:msub><mml:mi>R</mml:mi><mml:mi>t</mml:mi></mml:msub></mml:math> and the stencil component
76 will be discarded. If the depth stencil mode is <code class="constant">GL_STENCIL_COMPONENT</code> then
77 the stencil component is returned in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:msub><mml:mi>R</mml:mi><mml:mi>t</mml:mi></mml:msub></mml:math>
78 and the depth component is discarded. The initial value is <code class="constant">GL_DEPTH_COMPONENT</code>.
79 </p></dd></dl></div><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_BASE_LEVEL</code></span></dt><dd><p>
80 Specifies the index of the lowest defined mipmap level. This is an
81 integer value. The initial value is 0.
82 </p></dd></dl></div><p>
83 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_BORDER_COLOR</code></span></dt><dd><p>
84 The data in <em class="parameter"><code>params</code></em> specifies four values that define the border values that
85 should be used for border texels. If a texel is sampled from the border of the texture, the
86 values of <code class="constant">GL_TEXTURE_BORDER_COLOR</code> are interpreted as an RGBA color to match the
87 texture's internal format and substituted for the non-existent texel data. If the texture contains depth
88 components, the first component of <code class="constant">GL_TEXTURE_BORDER_COLOR</code> is interpreted as a depth value.
89 The initial value is
90 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
91 <mml:mrow>
92 <mml:mfenced open="(" close=")">
93 <mml:mrow>
94 0.0, 0.0, 0.0, 0.0
95 </mml:mrow>
96 </mml:mfenced>
97 </mml:mrow>
98 </mml:math>.
99 </p><p>
100 If the values for <code class="constant">GL_TEXTURE_BORDER_COLOR</code> are specified with <code class="function">glTexParameterIiv</code>
101 or <code class="function">glTexParameterIuiv</code>, the values are stored unmodified with an internal data type of
102 integer. If specified with <code class="function">glTexParameteriv</code>, they are converted to floating point with the following
103 equation:
104 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
105 <mml:mrow>
106 <mml:mi mathvariant="italic">f</mml:mi>
107 <mml:mo>=</mml:mo>
108 <mml:mfrac>
109 <mml:mrow>
110 <mml:msub><mml:mn>2</mml:mn>
111 <mml:mi mathvariant="italic">c</mml:mi>
112 </mml:msub>
113 <mml:mo>+</mml:mo>
114 <mml:mn>1</mml:mn>
115 </mml:mrow>
116 <mml:mrow>
117 <mml:msup><mml:mn>2</mml:mn>
118 <mml:mi mathvariant="italic">b</mml:mi>
119 </mml:msup>
120 <mml:mo>-</mml:mo>
121 <mml:mn>1</mml:mn>
122 </mml:mrow>
123 </mml:mfrac>
124 </mml:mrow>
125 </mml:math>.
126 If specified with <code class="function">glTexParameterfv</code>, they are stored unmodified as floating-point values.
127 </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_COMPARE_FUNC</code></span></dt><dd><p>
128 Specifies the comparison operator used when <code class="constant">GL_TEXTURE_COMPARE_MODE</code> is
129 set to <code class="constant">GL_COMPARE_REF_TO_TEXTURE</code>. Permissible values are:
130 </p><div class="informaltable"><table border="1"><colgroup><col align="left" /><col align="left" /></colgroup><thead><tr><th align="left"><span class="bold"><strong>
131 Texture Comparison Function
132 </strong></span></th><th align="left"><span class="bold"><strong>
133 Computed result
134 </strong></span></th></tr></thead><tbody><tr><td align="left">
135 <code class="constant">GL_LEQUAL</code>
136 </td><td align="left">
137 <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
138
139 <mml:mrow>
140 <mml:mi mathvariant="italic">result</mml:mi>
141 <mml:mo>=</mml:mo>
142 <mml:mfenced open="{" close="">
143 <mml:mrow>
144 <mml:mtable>
145 <mml:mtr><mml:mtd>
146 <mml:mn>1.0</mml:mn>
147 </mml:mtd></mml:mtr>
148 <mml:mtr><mml:mtd>
149 <mml:mn>0.0</mml:mn>
150 </mml:mtd></mml:mtr>
151 </mml:mtable>
152 <mml:mo>⁢  </mml:mo>
153 <mml:mtable>
154 <mml:mtr><mml:mtd>
155 <mml:mrow>
156 <mml:mi mathvariant="italic">r</mml:mi>
157 <mml:mo>&lt;=</mml:mo>
158 <mml:mfenced open="" close="">
159 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
160 <mml:mi mathvariant="italic">t</mml:mi>
161 </mml:msub>
162 </mml:mfenced>
163 </mml:mrow>
164 </mml:mtd></mml:mtr>
165 <mml:mtr><mml:mtd>
166 <mml:mrow>
167 <mml:mi mathvariant="italic">r</mml:mi>
168 <mml:mo>&gt;</mml:mo>
169 <mml:mfenced open="" close="">
170 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
171 <mml:mi mathvariant="italic">t</mml:mi>
172 </mml:msub>
173 </mml:mfenced>
174 </mml:mrow>
175 </mml:mtd></mml:mtr>
176 </mml:mtable>
177 </mml:mrow>
178 </mml:mfenced>
179 </mml:mrow>
180 </mml:math></div>
181 </td></tr><tr><td align="left">
182 <code class="constant">GL_GEQUAL</code>
183 </td><td align="left">
184 <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
185
186 <mml:mrow>
187 <mml:mi mathvariant="italic">result</mml:mi>
188 <mml:mo>=</mml:mo>
189 <mml:mfenced open="{" close="">
190 <mml:mrow>
191 <mml:mtable>
192 <mml:mtr><mml:mtd>
193 <mml:mn>1.0</mml:mn>
194 </mml:mtd></mml:mtr>
195 <mml:mtr><mml:mtd>
196 <mml:mn>0.0</mml:mn>
197 </mml:mtd></mml:mtr>
198 </mml:mtable>
199 <mml:mo>⁢  </mml:mo>
200 <mml:mtable>
201 <mml:mtr><mml:mtd>
202 <mml:mrow>
203 <mml:mi mathvariant="italic">r</mml:mi>
204 <mml:mo>&gt;=</mml:mo>
205 <mml:mfenced open="" close="">
206 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
207 <mml:mi mathvariant="italic">t</mml:mi>
208 </mml:msub>
209 </mml:mfenced>
210 </mml:mrow>
211 </mml:mtd></mml:mtr>
212 <mml:mtr><mml:mtd>
213 <mml:mrow>
214 <mml:mi mathvariant="italic">r</mml:mi>
215 <mml:mo>&lt;</mml:mo>
216 <mml:mfenced open="" close="">
217 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
218 <mml:mi mathvariant="italic">t</mml:mi>
219 </mml:msub>
220 </mml:mfenced>
221 </mml:mrow>
222 </mml:mtd></mml:mtr>
223 </mml:mtable>
224 </mml:mrow>
225 </mml:mfenced>
226 </mml:mrow>
227 </mml:math></div>
228 </td></tr><tr><td align="left">
229 <code class="constant">GL_LESS</code>
230 </td><td align="left">
231 <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
232
233 <mml:mrow>
234 <mml:mi mathvariant="italic">result</mml:mi>
235 <mml:mo>=</mml:mo>
236 <mml:mfenced open="{" close="">
237 <mml:mrow>
238 <mml:mtable>
239 <mml:mtr><mml:mtd>
240 <mml:mn>1.0</mml:mn>
241 </mml:mtd></mml:mtr>
242 <mml:mtr><mml:mtd>
243 <mml:mn>0.0</mml:mn>
244 </mml:mtd></mml:mtr>
245 </mml:mtable>
246 <mml:mo>⁢  </mml:mo>
247 <mml:mtable>
248 <mml:mtr><mml:mtd>
249 <mml:mrow>
250 <mml:mi mathvariant="italic">r</mml:mi>
251 <mml:mo>&lt;</mml:mo>
252 <mml:mfenced open="" close="">
253 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
254 <mml:mi mathvariant="italic">t</mml:mi>
255 </mml:msub>
256 </mml:mfenced>
257 </mml:mrow>
258 </mml:mtd></mml:mtr>
259 <mml:mtr><mml:mtd>
260 <mml:mrow>
261 <mml:mi mathvariant="italic">r</mml:mi>
262 <mml:mo>&gt;=</mml:mo>
263 <mml:mfenced open="" close="">
264 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
265 <mml:mi mathvariant="italic">t</mml:mi>
266 </mml:msub>
267 </mml:mfenced>
268 </mml:mrow>
269 </mml:mtd></mml:mtr>
270 </mml:mtable>
271 </mml:mrow>
272 </mml:mfenced>
273 </mml:mrow>
274 </mml:math></div>
275 </td></tr><tr><td align="left">
276 <code class="constant">GL_GREATER</code>
277 </td><td align="left">
278 <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
279
280 <mml:mrow>
281 <mml:mi mathvariant="italic">result</mml:mi>
282 <mml:mo>=</mml:mo>
283 <mml:mfenced open="{" close="">
284 <mml:mrow>
285 <mml:mtable>
286 <mml:mtr><mml:mtd>
287 <mml:mn>1.0</mml:mn>
288 </mml:mtd></mml:mtr>
289 <mml:mtr><mml:mtd>
290 <mml:mn>0.0</mml:mn>
291 </mml:mtd></mml:mtr>
292 </mml:mtable>
293 <mml:mo>⁢  </mml:mo>
294 <mml:mtable>
295 <mml:mtr><mml:mtd>
296 <mml:mrow>
297 <mml:mi mathvariant="italic">r</mml:mi>
298 <mml:mo>&gt;</mml:mo>
299 <mml:mfenced open="" close="">
300 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
301 <mml:mi mathvariant="italic">t</mml:mi>
302 </mml:msub>
303 </mml:mfenced>
304 </mml:mrow>
305 </mml:mtd></mml:mtr>
306 <mml:mtr><mml:mtd>
307 <mml:mrow>
308 <mml:mi mathvariant="italic">r</mml:mi>
309 <mml:mo>&lt;=</mml:mo>
310 <mml:mfenced open="" close="">
311 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
312 <mml:mi mathvariant="italic">t</mml:mi>
313 </mml:msub>
314 </mml:mfenced>
315 </mml:mrow>
316 </mml:mtd></mml:mtr>
317 </mml:mtable>
318 </mml:mrow>
319 </mml:mfenced>
320 </mml:mrow>
321 </mml:math></div>
322 </td></tr><tr><td align="left">
323 <code class="constant">GL_EQUAL</code>
324 </td><td align="left">
325 <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
326
327 <mml:mrow>
328 <mml:mi mathvariant="italic">result</mml:mi>
329 <mml:mo>=</mml:mo>
330 <mml:mfenced open="{" close="">
331 <mml:mrow>
332 <mml:mtable>
333 <mml:mtr><mml:mtd>
334 <mml:mn>1.0</mml:mn>
335 </mml:mtd></mml:mtr>
336 <mml:mtr><mml:mtd>
337 <mml:mn>0.0</mml:mn>
338 </mml:mtd></mml:mtr>
339 </mml:mtable>
340 <mml:mo>⁢  </mml:mo>
341 <mml:mtable>
342 <mml:mtr><mml:mtd>
343 <mml:mrow>
344 <mml:mi mathvariant="italic">r</mml:mi>
345 <mml:mo>=</mml:mo>
346 <mml:mfenced open="" close="">
347 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
348 <mml:mi mathvariant="italic">t</mml:mi>
349 </mml:msub>
350 </mml:mfenced>
351 </mml:mrow>
352 </mml:mtd></mml:mtr>
353 <mml:mtr><mml:mtd>
354 <mml:mrow>
355 <mml:mi mathvariant="italic">r</mml:mi>
356 <mml:mo>≠</mml:mo>
357 <mml:mfenced open="" close="">
358 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
359 <mml:mi mathvariant="italic">t</mml:mi>
360 </mml:msub>
361 </mml:mfenced>
362 </mml:mrow>
363 </mml:mtd></mml:mtr>
364 </mml:mtable>
365 </mml:mrow>
366 </mml:mfenced>
367 </mml:mrow>
368 </mml:math></div>
369 </td></tr><tr><td align="left">
370 <code class="constant">GL_NOTEQUAL</code>
371 </td><td align="left">
372 <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
373
374 <mml:mrow>
375 <mml:mi mathvariant="italic">result</mml:mi>
376 <mml:mo>=</mml:mo>
377 <mml:mfenced open="{" close="">
378 <mml:mrow>
379 <mml:mtable>
380 <mml:mtr><mml:mtd>
381 <mml:mn>1.0</mml:mn>
382 </mml:mtd></mml:mtr>
383 <mml:mtr><mml:mtd>
384 <mml:mn>0.0</mml:mn>
385 </mml:mtd></mml:mtr>
386 </mml:mtable>
387 <mml:mo>⁢  </mml:mo>
388 <mml:mtable>
389 <mml:mtr><mml:mtd>
390 <mml:mrow>
391 <mml:mi mathvariant="italic">r</mml:mi>
392 <mml:mo>≠</mml:mo>
393 <mml:mfenced open="" close="">
394 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
395 <mml:mi mathvariant="italic">t</mml:mi>
396 </mml:msub>
397 </mml:mfenced>
398 </mml:mrow>
399 </mml:mtd></mml:mtr>
400 <mml:mtr><mml:mtd>
401 <mml:mrow>
402 <mml:mi mathvariant="italic">r</mml:mi>
403 <mml:mo>=</mml:mo>
404 <mml:mfenced open="" close="">
405 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
406 <mml:mi mathvariant="italic">t</mml:mi>
407 </mml:msub>
408 </mml:mfenced>
409 </mml:mrow>
410 </mml:mtd></mml:mtr>
411 </mml:mtable>
412 </mml:mrow>
413 </mml:mfenced>
414 </mml:mrow>
415 </mml:math></div>
416 </td></tr><tr><td align="left">
417 <code class="constant">GL_ALWAYS</code>
418 </td><td align="left">
419 <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
420 <mml:mrow>
421 <mml:mi mathvariant="italic">result</mml:mi>
422 <mml:mo>=</mml:mo>
423 <mml:mi>1.0</mml:mi>
424 </mml:mrow>
425 </mml:math></div>
426 </td></tr><tr><td align="left">
427 <code class="constant">GL_NEVER</code>
428 </td><td align="left">
429 <div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
430 <mml:mrow>
431 <mml:mi mathvariant="italic">result</mml:mi>
432 <mml:mo>=</mml:mo>
433 <mml:mi>0.0</mml:mi>
434 </mml:mrow>
435 </mml:math></div>
436 </td></tr></tbody></table></div><p>
437 where <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math>
438 is the current interpolated texture coordinate, and
439 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
440
441 <mml:msub><mml:mi mathvariant="italic">D</mml:mi>
442 <mml:mi mathvariant="italic">t</mml:mi>
443 </mml:msub>
444 </mml:math>
445 is the depth texture value sampled from the currently bound depth texture.
446 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">result</mml:mi></mml:math>
447 is assigned to the the red channel.
448 </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_COMPARE_MODE</code></span></dt><dd><p>
449 Specifies the texture comparison mode for currently bound depth textures.
450 That is, a texture whose internal format is <code class="constant">GL_DEPTH_COMPONENT_*</code>; see
451 <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>)
452 Permissible values are:
453 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_COMPARE_REF_TO_TEXTURE</code></span></dt><dd><p>
454 Specifies that the interpolated and clamped
455 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math>
456 texture coordinate should
457 be compared to the value in the currently bound depth texture. See the
458 discussion of <code class="constant">GL_TEXTURE_COMPARE_FUNC</code> for details of how the comparison
459 is evaluated. The result of the comparison is assigned to the red channel.
460 </p></dd><dt><span class="term"><code class="constant">GL_NONE</code></span></dt><dd><p>
461 Specifies that the red channel should be assigned the
462 appropriate value from the currently bound depth texture.
463 </p></dd></dl></div><p>
464 </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_LOD_BIAS</code></span></dt><dd><p>
465 <em class="parameter"><code>params</code></em> specifies a fixed bias value that is to be added to the level-of-detail
466 parameter for the texture before texture sampling. The specified value is added to the shader-supplied
467 bias value (if any) and subsequently clamped into the implementation-defined range
468 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
469 <mml:mfenced open="[" close="]">
470 <mml:mfenced open="" close="">
471 <mml:mrow>
472 -
473 <mml:msub><mml:mi mathvariant="italic">bias</mml:mi>
474 <mml:mi mathvariant="italic">max</mml:mi>
475 </mml:msub>
476 </mml:mrow>
477 </mml:mfenced>
478 <mml:mrow>
479 <mml:mfenced open="" close="">
480 <mml:mrow>
481 <mml:msub><mml:mi mathvariant="italic">bias</mml:mi>
482 <mml:mi mathvariant="italic">max</mml:mi>
483 </mml:msub>
484 </mml:mrow>
485 </mml:mfenced>
486 </mml:mrow>
487 </mml:mfenced>
488 </mml:math>,
489 where
490 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
491 <mml:mrow>
492 <mml:msub><mml:mi mathvariant="italic">bias</mml:mi>
493 <mml:mi mathvariant="italic">max</mml:mi>
494 </mml:msub>
495 </mml:mrow>
496 </mml:math>
497 is the value of the implementation defined constant <code class="constant">GL_MAX_TEXTURE_LOD_BIAS</code>. The initial value is 0.0.
498 </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_MIN_FILTER</code></span></dt><dd><p>
499 The texture minifying function is used whenever the level-of-detail function
500 used when sampling from the texture determines that the texture should be minified.
501 There are six defined minifying functions.
502 Two of them use either the nearest texture elements or a weighted average of multiple texture elements
503 to compute the texture value.
504 The other four use mipmaps.
505 </p><p>
506 A mipmap is an ordered set of arrays representing the same image
507 at progressively lower resolutions.
508 If the texture has dimensions
509 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
510
511 <mml:mrow>
512 <mml:msup><mml:mn>2</mml:mn>
513 <mml:mi mathvariant="italic">n</mml:mi>
514 </mml:msup>
515 <mml:mo>×</mml:mo>
516 <mml:msup><mml:mn>2</mml:mn>
517 <mml:mi mathvariant="italic">m</mml:mi>
518 </mml:msup>
519 </mml:mrow>
520 </mml:math>,
521 there are
522 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
523
524 <mml:mrow>
525 <mml:mrow>
526 <mml:mi mathvariant="italic">max</mml:mi>
527 <mml:mo>⁡</mml:mo>
528 <mml:mfenced open="(" close=")">
529 <mml:mi mathvariant="italic">n</mml:mi>
530 <mml:mi mathvariant="italic">m</mml:mi>
531 </mml:mfenced>
532 </mml:mrow>
533 <mml:mo>+</mml:mo>
534 <mml:mn>1</mml:mn>
535 </mml:mrow>
536 </mml:math>
537 mipmaps.
538 The first mipmap is the original texture,
539 with dimensions
540 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
541
542 <mml:mrow>
543 <mml:msup><mml:mn>2</mml:mn>
544 <mml:mi mathvariant="italic">n</mml:mi>
545 </mml:msup>
546 <mml:mo>×</mml:mo>
547 <mml:msup><mml:mn>2</mml:mn>
548 <mml:mi mathvariant="italic">m</mml:mi>
549 </mml:msup>
550 </mml:mrow>
551 </mml:math>.
552 Each subsequent mipmap has dimensions
553 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
554
555 <mml:mrow>
556 <mml:msup><mml:mn>2</mml:mn>
557 <mml:mfenced open="" close="">
558 <mml:mrow>
559 <mml:mi mathvariant="italic">k</mml:mi>
560 <mml:mo>-</mml:mo>
561 <mml:mn>1</mml:mn>
562 </mml:mrow>
563 </mml:mfenced>
564 </mml:msup>
565 <mml:mo>×</mml:mo>
566 <mml:msup><mml:mn>2</mml:mn>
567 <mml:mfenced open="" close="">
568 <mml:mrow>
569 <mml:mi mathvariant="italic">l</mml:mi>
570 <mml:mo>-</mml:mo>
571 <mml:mn>1</mml:mn>
572 </mml:mrow>
573 </mml:mfenced>
574 </mml:msup>
575 </mml:mrow>
576 </mml:math>,
577 where
578 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
579
580 <mml:mrow>
581 <mml:msup><mml:mn>2</mml:mn>
582 <mml:mi mathvariant="italic">k</mml:mi>
583 </mml:msup>
584 <mml:mo>×</mml:mo>
585 <mml:msup><mml:mn>2</mml:mn>
586 <mml:mi mathvariant="italic">l</mml:mi>
587 </mml:msup>
588 </mml:mrow>
589 </mml:math>
590 are the dimensions of the previous mipmap,
591 until either
592 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
593
594 <mml:mrow>
595 <mml:mi mathvariant="italic">k</mml:mi>
596 <mml:mo>=</mml:mo>
597 <mml:mn>0</mml:mn>
598 </mml:mrow>
599 </mml:math>
600 or
601 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
602
603 <mml:mrow>
604 <mml:mi mathvariant="italic">l</mml:mi>
605 <mml:mo>=</mml:mo>
606 <mml:mn>0</mml:mn>
607 </mml:mrow>
608 </mml:math>.
609 At that point,
610 subsequent mipmaps have dimension
611 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
612
613 <mml:mrow>
614 <mml:mn>1</mml:mn>
615 <mml:mo>×</mml:mo>
616 <mml:msup><mml:mn>2</mml:mn>
617 <mml:mfenced open="" close="">
618 <mml:mrow>
619 <mml:mi mathvariant="italic">l</mml:mi>
620 <mml:mo>-</mml:mo>
621 <mml:mn>1</mml:mn>
622 </mml:mrow>
623 </mml:mfenced>
624 </mml:msup>
625 </mml:mrow>
626 </mml:math>
627 or
628 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
629
630 <mml:mrow>
631 <mml:msup><mml:mn>2</mml:mn>
632 <mml:mfenced open="" close="">
633 <mml:mrow>
634 <mml:mi mathvariant="italic">k</mml:mi>
635 <mml:mo>-</mml:mo>
636 <mml:mn>1</mml:mn>
637 </mml:mrow>
638 </mml:mfenced>
639 </mml:msup>
640 <mml:mo>×</mml:mo>
641 <mml:mn>1</mml:mn>
642 </mml:mrow>
643 </mml:math>
644 until the final mipmap,
645 which has dimension
646 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
647
648 <mml:mrow>
649 <mml:mn>1</mml:mn>
650 <mml:mo>×</mml:mo>
651 <mml:mn>1</mml:mn>
652 </mml:mrow>
653 </mml:math>.
654 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>,
655 <a href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>,
656 <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>
657 with the <span class="emphasis"><em>level</em></span> argument indicating the order of the mipmaps.
658 Level 0 is the original texture;
659 level
660 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
661
662 <mml:mrow>
663 <mml:mi mathvariant="italic">max</mml:mi>
664 <mml:mo>⁡</mml:mo>
665 <mml:mfenced open="(" close=")">
666 <mml:mi mathvariant="italic">n</mml:mi>
667 <mml:mi mathvariant="italic">m</mml:mi>
668 </mml:mfenced>
669 </mml:mrow>
670 </mml:math>
671 is the final
672 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
673
674 <mml:mrow>
675 <mml:mn>1</mml:mn>
676 <mml:mo>×</mml:mo>
677 <mml:mn>1</mml:mn>
678 </mml:mrow>
679 </mml:math>
680 mipmap.
681 </p><p>
682 <em class="parameter"><code>params</code></em> supplies a function for minifying the texture as one of the
683 following:
684 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_NEAREST</code></span></dt><dd><p>
685 Returns the value of the texture element that is nearest
686 (in Manhattan distance)
687 to the specified texture coordinates.
688 </p></dd><dt><span class="term"><code class="constant">GL_LINEAR</code></span></dt><dd><p>
689 Returns the weighted average of the four texture elements
690 that are closest to the specified texture coordinates.
691 These can include items wrapped or repeated from other parts of a texture,
692 depending on the values of <code class="constant">GL_TEXTURE_WRAP_S</code> and <code class="constant">GL_TEXTURE_WRAP_T</code>,
693 and on the exact mapping.
694 </p></dd><dt><span class="term"><code class="constant">GL_NEAREST_MIPMAP_NEAREST</code></span></dt><dd><p>
695 Chooses the mipmap that most closely matches the size of the pixel
696 being textured and uses the <code class="constant">GL_NEAREST</code> criterion
697 (the texture element closest to the specified texture coordinates)
698 to produce a texture value.
699 </p></dd><dt><span class="term"><code class="constant">GL_LINEAR_MIPMAP_NEAREST</code></span></dt><dd><p>
700 Chooses the mipmap that most closely matches the size of the pixel
701 being textured and uses the <code class="constant">GL_LINEAR</code> criterion
702 (a weighted average of the four texture elements that are closest to the specified texture coordinates)
703 to produce a texture value.
704 </p></dd><dt><span class="term"><code class="constant">GL_NEAREST_MIPMAP_LINEAR</code></span></dt><dd><p>
705 Chooses the two mipmaps that most closely match the size of the pixel
706 being textured and uses the <code class="constant">GL_NEAREST</code> criterion
707 (the texture element closest to the specified texture coordinates )
708 to produce a texture value from each mipmap.
709 The final texture value is a weighted average of those two values.
710 </p></dd><dt><span class="term"><code class="constant">GL_LINEAR_MIPMAP_LINEAR</code></span></dt><dd><p>
711 Chooses the two mipmaps that most closely match the size of the pixel
712 being textured and uses the <code class="constant">GL_LINEAR</code> criterion
713 (a weighted average of the texture elements that are closest to the specified texture coordinates)
714 to produce a texture value from each mipmap.
715 The final texture value is a weighted average of those two values.
716 </p></dd></dl></div><p>
717 </p><p>
718 As more texture elements are sampled in the minification process,
719 fewer aliasing artifacts will be apparent.
720 While the <code class="constant">GL_NEAREST</code> and <code class="constant">GL_LINEAR</code> minification functions can be
721 faster than the other four,
722 they sample only one or multiple texture elements to determine the texture value
723 of the pixel being rendered and can produce moire patterns
724 or ragged transitions.
725 The initial value of <code class="constant">GL_TEXTURE_MIN_FILTER</code> is
726 <code class="constant">GL_NEAREST_MIPMAP_LINEAR</code>.
727 </p></dd></dl></div><p>
728 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MAG_FILTER</code></span></dt><dd><p>
729 The texture magnification function is used whenever the level-of-detail function
730 used when sampling from the texture determines that the texture should be magified.
731 It sets the texture magnification function to either <code class="constant">GL_NEAREST</code>
732 or <code class="constant">GL_LINEAR</code> (see below). <code class="constant">GL_NEAREST</code> is generally faster
733 than <code class="constant">GL_LINEAR</code>,
734 but it can produce textured images with sharper edges
735 because the transition between texture elements is not as smooth.
736 The initial value of <code class="constant">GL_TEXTURE_MAG_FILTER</code> is <code class="constant">GL_LINEAR</code>.
737 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_NEAREST</code></span></dt><dd><p>
738 Returns the value of the texture element that is nearest
739 (in Manhattan distance)
740 to the specified texture coordinates.
741 </p></dd><dt><span class="term"><code class="constant">GL_LINEAR</code></span></dt><dd><p>
742 Returns the weighted average of the texture elements
743 that are closest to the specified texture coordinates.
744 These can include items wrapped or repeated from other parts of a texture,
745 depending on the values of <code class="constant">GL_TEXTURE_WRAP_S</code> and <code class="constant">GL_TEXTURE_WRAP_T</code>,
746 and on the exact mapping.
747 </p></dd></dl></div><p>
748 </p><p>
749 </p><p>
750 </p></dd></dl></div><p>
751 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MIN_LOD</code></span></dt><dd><p>
752 Sets the minimum level-of-detail parameter. This floating-point value
753 limits the selection of highest resolution mipmap (lowest mipmap
754 level). The initial value is -1000.
755 </p></dd></dl></div><p>
756 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MAX_LOD</code></span></dt><dd><p>
757 Sets the maximum level-of-detail parameter. This floating-point value
758 limits the selection of the lowest resolution mipmap (highest mipmap
759 level). The initial value is 1000.
760 </p></dd></dl></div><p>
761 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_MAX_LEVEL</code></span></dt><dd><p>
762 Sets the index of the highest defined mipmap level. This is an integer
763 value. The initial value is 1000.
764 </p></dd></dl></div><p>
765 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_SWIZZLE_R</code></span></dt><dd><p>
766 Sets the swizzle that will be applied to the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math>
767 component of a texel before it is returned to the shader. Valid values for <em class="parameter"><code>param</code></em> are <code class="constant">GL_RED</code>,
768 <code class="constant">GL_GREEN</code>, <code class="constant">GL_BLUE</code>, <code class="constant">GL_ALPHA</code>, <code class="constant">GL_ZERO</code> and
769 <code class="constant">GL_ONE</code>.
770 If <code class="constant">GL_TEXTURE_SWIZZLE_R</code> is <code class="constant">GL_RED</code>, the value for
771 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> will be taken from the first
772 channel of the fetched texel.
773 If <code class="constant">GL_TEXTURE_SWIZZLE_R</code> is <code class="constant">GL_GREEN</code>, the value for
774 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> will be taken from the second
775 channel of the fetched texel.
776 If <code class="constant">GL_TEXTURE_SWIZZLE_R</code> is <code class="constant">GL_BLUE</code>, the value for
777 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> will be taken from the third
778 channel of the fetched texel.
779 If <code class="constant">GL_TEXTURE_SWIZZLE_R</code> is <code class="constant">GL_ALPHA</code>, the value for
780 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> will be taken from the fourth
781 channel of the fetched texel.
782 If <code class="constant">GL_TEXTURE_SWIZZLE_R</code> is <code class="constant">GL_ZERO</code>, the value for
783 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> will be subtituted with
784 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mn>0.0</mml:mn></mml:math>.
785 If <code class="constant">GL_TEXTURE_SWIZZLE_R</code> is <code class="constant">GL_ONE</code>, the value for
786 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math> will be subtituted with
787 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mn>1.0</mml:mn></mml:math>.
788 The initial value is <code class="constant">GL_RED</code>.
789 </p></dd></dl></div><p>
790 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_SWIZZLE_G</code></span></dt><dd><p>
791 Sets the swizzle that will be applied to the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">g</mml:mi></mml:math>
792 component of a texel before it is returned to the shader. Valid values for <em class="parameter"><code>param</code></em> and their effects are similar to
793 those of <code class="constant">GL_TEXTURE_SWIZZLE_R</code>.
794 The initial value is <code class="constant">GL_GREEN</code>.
795 </p></dd></dl></div><p>
796 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_SWIZZLE_B</code></span></dt><dd><p>
797 Sets the swizzle that will be applied to the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">b</mml:mi></mml:math>
798 component of a texel before it is returned to the shader. Valid values for <em class="parameter"><code>param</code></em> and their effects are similar to
799 those of <code class="constant">GL_TEXTURE_SWIZZLE_R</code>.
800 The initial value is <code class="constant">GL_BLUE</code>.
801 </p></dd></dl></div><p>
802 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_SWIZZLE_A</code></span></dt><dd><p>
803 Sets the swizzle that will be applied to the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">a</mml:mi></mml:math>
804 component of a texel before it is returned to the shader. Valid values for <em class="parameter"><code>param</code></em> and their effects are similar to
805 those of <code class="constant">GL_TEXTURE_SWIZZLE_R</code>.
806 The initial value is <code class="constant">GL_ALPHA</code>.
807 </p></dd></dl></div><p>
808 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_SWIZZLE_RGBA</code></span></dt><dd><p>
809 Sets the swizzles that will be applied to the
810 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math>,
811 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">g</mml:mi></mml:math>,
812 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">b</mml:mi></mml:math>, and
813 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">a</mml:mi></mml:math>
814 components of a texel before they are returned to the shader. Valid values for <em class="parameter"><code>params</code></em> and their effects are similar to
815 those of <code class="constant">GL_TEXTURE_SWIZZLE_R</code>, except that all channels are specified simultaneously.
816 Setting the value of <code class="constant">GL_TEXTURE_SWIZZLE_RGBA</code> is equivalent (assuming no errors are generated) to
817 setting the parameters of each of <code class="constant">GL_TEXTURE_SWIZZLE_R</code>,
818 <code class="constant">GL_TEXTURE_SWIZZLE_G</code>,
819 <code class="constant">GL_TEXTURE_SWIZZLE_B</code>, and
820 <code class="constant">GL_TEXTURE_SWIZZLE_A</code> successively.
821 </p></dd></dl></div><p>
822 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_WRAP_S</code></span></dt><dd><p>
823 Sets the wrap parameter for texture coordinate
824 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>
825 to either <code class="constant">GL_CLAMP_TO_EDGE</code>, <code class="constant">GL_CLAMP_TO_BORDER</code>,
826 <code class="constant">GL_MIRRORED_REPEAT</code>, or
827 <code class="constant">GL_REPEAT</code>. <code class="constant">GL_CLAMP_TO_EDGE</code> causes
828 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>
829 coordinates to be clamped to the
830 range
831 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
832
833 <mml:mfenced open="[" close="]">
834 <mml:mfenced open="" close="">
835 <mml:mrow>
836 <mml:mfrac>
837 <mml:mn>1</mml:mn>
838 <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>
839 </mml:mfrac>
840 </mml:mrow>
841 </mml:mfenced>
842 <mml:mrow>
843 <mml:mn>1</mml:mn>
844 <mml:mo>-</mml:mo>
845 <mml:mfenced open="" close="">
846 <mml:mrow>
847 <mml:mfrac>
848 <mml:mn>1</mml:mn>
849 <mml:mn>2<mml:mi mathvariant="italic">N</mml:mi></mml:mn>
850 </mml:mfrac>
851 </mml:mrow>
852 </mml:mfenced>
853 </mml:mrow>
854 </mml:mfenced>
855 </mml:math>,
856 where
857 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">N</mml:mi></mml:math>
858 is the size
859 of the texture in the direction of clamping.
860 <code class="constant">GL_CLAMP_TO_BORDER</code> evaluates <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math> coordinates in a similar manner to <code class="constant">GL_CLAMP_TO_EDGE</code>.
861 However, in cases where clamping would have occurred in <code class="constant">GL_CLAMP_TO_EDGE</code> mode, the fetched texel data
862 is substituted with the values specified by <code class="constant">GL_TEXTURE_BORDER_COLOR</code>.
863 <code class="constant">GL_REPEAT</code> causes the
864 integer part of the
865 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>
866 coordinate to be ignored; the GL uses only the
867 fractional part, thereby creating a repeating pattern.
868 <code class="constant">GL_MIRRORED_REPEAT</code> causes the
869 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>
870 coordinate to be set to the
871 fractional part of the texture coordinate if the integer part of
872 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>
873 is
874 even; if the integer part of
875 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>
876 is odd, then the
877 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>
878 texture coordinate is
879 set to
880 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
881
882 <mml:mrow>
883 <mml:mn>1</mml:mn>
884 <mml:mo>-</mml:mo>
885 <mml:mrow>
886 <mml:mi mathvariant="italic">frac</mml:mi>
887 <mml:mo>⁡</mml:mo>
888 <mml:mfenced open="(" close=")">
889 <mml:mi mathvariant="italic">s</mml:mi>
890 </mml:mfenced>
891 </mml:mrow>
892 </mml:mrow>
893 </mml:math>,
894 where
895 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
896
897 <mml:mrow>
898 <mml:mi mathvariant="italic">frac</mml:mi>
899 <mml:mo>⁡</mml:mo>
900 <mml:mfenced open="(" close=")">
901 <mml:mi mathvariant="italic">s</mml:mi>
902 </mml:mfenced>
903 </mml:mrow>
904 </mml:math>
905 represents the fractional part of
906 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">s</mml:mi></mml:math>.
907 Initially, <code class="constant">GL_TEXTURE_WRAP_S</code> is set to <code class="constant">GL_REPEAT</code>.
908 </p></dd></dl></div><p>
909 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_WRAP_T</code></span></dt><dd><p>
910 Sets the wrap parameter for texture coordinate
911 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">t</mml:mi></mml:math>
912 to either <code class="constant">GL_CLAMP_TO_EDGE</code>, <code class="constant">GL_CLAMP_TO_BORDER</code>,
913 <code class="constant">GL_MIRRORED_REPEAT</code>, or
914 <code class="constant">GL_REPEAT</code>. See the discussion under <code class="constant">GL_TEXTURE_WRAP_S</code>.
915 Initially, <code class="constant">GL_TEXTURE_WRAP_T</code> is set to <code class="constant">GL_REPEAT</code>.
916 </p></dd></dl></div><p>
917 </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_TEXTURE_WRAP_R</code></span></dt><dd><p>
918 Sets the wrap parameter for texture coordinate
919 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">r</mml:mi></mml:math>
920 to either <code class="constant">GL_CLAMP_TO_EDGE</code>, <code class="constant">GL_CLAMP_TO_BORDER</code>,
921 <code class="constant">GL_MIRRORED_REPEAT</code>, or
922 <code class="constant">GL_REPEAT</code>. See the discussion under <code class="constant">GL_TEXTURE_WRAP_S</code>.
923 Initially, <code class="constant">GL_TEXTURE_WRAP_R</code> is set to <code class="constant">GL_REPEAT</code>.
924 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
925 Suppose that a program attempts to sample from a texture and
926 has set <code class="constant">GL_TEXTURE_MIN_FILTER</code> to one of the functions that requires a
927 mipmap. If either the dimensions of the texture images currently defined
928 (with previous calls to <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>,
929 <a href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>, <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>) do not
930 follow the proper sequence for mipmaps (described above), or there are
931 fewer texture images defined than are needed, or the set of texture images
932 have differing numbers of texture components, then the texture is considered <span class="emphasis"><em>incomplete</em></span>.
933 </p><p>
934 Linear filtering accesses the four nearest texture elements only in 2D
935 textures. In 1D textures, linear filtering accesses the two nearest
936 texture elements. In 3D textures, linear filtering accesses the eight nearest
937 texture elements.
938 </p><p>
939 <code class="function">glTexParameter</code> specifies the texture parameters for the active texture unit, specified
940 by calling <a href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>.
941 </p><p>
942 <code class="constant">GL_DEPTH_STENCIL_TEXTURE_MODE</code> is available only if the GL version is 4.3 or greater.
943 </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
944 <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
945 one of the accepted defined values.
946 </p><p>
947 <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>params</code></em> should have a defined
948 constant value (based on the value of <em class="parameter"><code>pname</code></em>) and does not.
949 </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
950 <a href="glGetTexParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexParameter</span></span></a>
951 </p><p>
952 <a href="glGetTexLevelParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a>
953 </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
954 <a href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,
955 <a href="glBindTexture.xml"><span class="citerefentry"><span class="refentrytitle">glBindTexture</span></span></a>,
956 <a href="glCopyTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage1D</span></span></a>,
957 <a href="glCopyTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexImage2D</span></span></a>,
958 <a href="glCopyTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage1D</span></span></a>,
959 <a href="glCopyTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage2D</span></span></a>,
960 <a href="glCopyTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glCopyTexSubImage3D</span></span></a>,
961 <a href="glPixelStore.xml"><span class="citerefentry"><span class="refentrytitle">glPixelStore</span></span></a>,
962 <a href="glSamplerParameter.xml"><span class="citerefentry"><span class="refentrytitle">glSamplerParameter</span></span></a>,
963 <a href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>,
964 <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>,
965 <a href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>,
966 <a href="glTexSubImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage1D</span></span></a>,
967 <a href="glTexSubImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage2D</span></span></a>,
968 <a href="glTexSubImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexSubImage3D</span></span></a>
969 </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
970 Copyright <span class="trademark"></span>© 1991-2006
971 Silicon Graphics, Inc. This document is licensed under the SGI
972 Free Software B License. For details, see
973 <a href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
974 </p></div></div></body></html>
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