upstream-man-pages/man3/xhtml/glTexParameter.xml

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