upstream-doc/man2/xhtml/gluBuild1DMipmaps.xml

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   3 <?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>gluBuild1DMipmaps</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="gluBuild1DMipmaps"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>gluBuild1DMipmaps — builds a one-dimensional mipmap</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">GLint <b class="fsfunc">gluBuild1DMipmaps</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLint  </td><td><var class="pdparam">internalFormat</var>, </td></tr><tr><td> </td><td>GLsizei  </td><td><var class="pdparam">width</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">format</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">type</var>, </td></tr><tr><td> </td><td>const void *  </td><td><var class="pdparam">data</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>target</code></em></span></dt><dd><p>
   4                     Specifies the target texture.  Must be <code class="constant">GLU_TEXTURE_1D</code>.
   5                 </p></dd><dt><span class="term"><em class="parameter"><code>internalFormat</code></em></span></dt><dd><p>
   6                     Requests the internal storage format of the texture image.  The most
   7                     current version of the SGI implementation of GLU does not check this
   8                     value for validity before passing it on to the underlying OpenGL
   9                     implementation.  A value that is not accepted by the OpenGL
  10                     implementation will lead to an OpenGL error.  The benefit of not
  11                     checking this value at the GLU level is that OpenGL extensions can add
  12                     new internal texture formats without requiring a revision of the GLU
  13                     implementation.  Older implementations of GLU check this value and
  14                     raise a GLU error if it is not 1, 2, 3, or 4 or one of the following
  15                     symbolic constants:
  16                     <code class="constant">GLU_ALPHA</code>,
  17                     <code class="constant">GLU_ALPHA4</code>,
  18                     <code class="constant">GLU_ALPHA8</code>,
  19                     <code class="constant">GLU_ALPHA12</code>,
  20                     <code class="constant">GLU_ALPHA16</code>,
  21                     <code class="constant">GLU_LUMINANCE</code>,
  22                     <code class="constant">GLU_LUMINANCE4</code>,
  23                     <code class="constant">GLU_LUMINANCE8</code>,
  24                     <code class="constant">GLU_LUMINANCE12</code>,
  25                     <code class="constant">GLU_LUMINANCE16</code>,
  26                     <code class="constant">GLU_LUMINANCE_ALPHA</code>,
  27                     <code class="constant">GLU_LUMINANCE4_ALPHA4</code>,
  28                     <code class="constant">GLU_LUMINANCE6_ALPHA2</code>,
  29                     <code class="constant">GLU_LUMINANCE8_ALPHA8</code>,
  30                     <code class="constant">GLU_LUMINANCE12_ALPHA4</code>,
  31                     <code class="constant">GLU_LUMINANCE12_ALPHA12</code>,
  32                     <code class="constant">GLU_LUMINANCE16_ALPHA16</code>,
  33                     <code class="constant">GLU_INTENSITY</code>,
  34                     <code class="constant">GLU_INTENSITY4</code>,
  35                     <code class="constant">GLU_INTENSITY8</code>,
  36                     <code class="constant">GLU_INTENSITY12</code>,
  37                     <code class="constant">GLU_INTENSITY16</code>,
  38                     <code class="constant">GLU_RGB</code>,
  39                     <code class="constant">GLU_R3_G3_B2</code>,
  40                     <code class="constant">GLU_RGB4</code>,
  41                     <code class="constant">GLU_RGB5</code>,
  42                     <code class="constant">GLU_RGB8</code>,
  43                     <code class="constant">GLU_RGB10</code>,
  44                     <code class="constant">GLU_RGB12</code>,
  45                     <code class="constant">GLU_RGB16</code>,
  46                     <code class="constant">GLU_RGBA</code>,
  47                     <code class="constant">GLU_RGBA2</code>,
  48                     <code class="constant">GLU_RGBA4</code>,
  49                     <code class="constant">GLU_RGB5_A1</code>,
  50                     <code class="constant">GLU_RGBA8</code>,
  51                     <code class="constant">GLU_RGB10_A2</code>,
  52                     <code class="constant">GLU_RGBA12</code>, or
  53                     <code class="constant">GLU_RGBA16</code>.
  54                 </p></dd><dt><span class="term"><em class="parameter"><code>width</code></em></span></dt><dd><p>
  55                     Specifies the width, in pixels, of the texture image.
  56                 </p></dd><dt><span class="term"><em class="parameter"><code>format</code></em></span></dt><dd><p>
  57                     Specifies the format of the pixel data.
  58                     Must be one of
  59                     <code class="constant">GLU_COLOR_INDEX</code>,
  60                     <code class="constant">GLU_DEPTH_COMPONENT</code>,
  61                     <code class="constant">GLU_RED</code>,
  62                     <code class="constant">GLU_GREEN</code>,
  63                     <code class="constant">GLU_BLUE</code>,
  64                     <code class="constant">GLU_ALPHA</code>,
  65                     <code class="constant">GLU_RGB</code>,
  66                     <code class="constant">GLU_RGBA</code>,
  67                     <code class="constant">GLU_BGR</code>,
  68                     <code class="constant">GLU_BGRA</code>,
  69                     <code class="constant">GLU_LUMINANCE</code>, or
  70                     <code class="constant">GLU_LUMINANCE_ALPHA</code>.
  71                 </p></dd><dt><span class="term"><em class="parameter"><code>type</code></em></span></dt><dd><p>
  72                     Specifies the data type for <em class="parameter"><code>data</code></em>.
  73                     Must be one of
  74                     <code class="constant">GLU_UNSIGNED_BYTE</code>,
  75                     <code class="constant">GLU_BYTE</code>,
  76                     <code class="constant">GLU_BITMAP</code>,
  77                     <code class="constant">GLU_UNSIGNED_SHORT</code>,
  78                     <code class="constant">GLU_SHORT</code>,
  79                     <code class="constant">GLU_UNSIGNED_INT</code>,
  80                     <code class="constant">GLU_INT</code>,
  81                     <code class="constant">GLU_FLOAT</code>,
  82                     <code class="constant">GLU_UNSIGNED_BYTE_3_3_2</code>,
  83                     <code class="constant">GLU_UNSIGNED_BYTE_2_3_3_REV</code>,
  84                     <code class="constant">GLU_UNSIGNED_SHORT_5_6_5</code>,
  85                     <code class="constant">GLU_UNSIGNED_SHORT_5_6_5_REV</code>,
  86                     <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4</code>,
  87                     <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4_REV</code>,
  88                     <code class="constant">GLU_UNSIGNED_SHORT_5_5_5_1</code>,
  89                     <code class="constant">GLU_UNSIGNED_SHORT_1_5_5_5_REV</code>,
  90                     <code class="constant">GLU_UNSIGNED_INT_8_8_8_8</code>,
  91                     <code class="constant">GLU_UNSIGNED_INT_8_8_8_8_REV</code>,
  92                     <code class="constant">GLU_UNSIGNED_INT_10_10_10_2</code>, or
  93                     <code class="constant">GLU_UNSIGNED_INT_2_10_10_10_REV</code>.
  94                 </p></dd><dt><span class="term"><em class="parameter"><code>data</code></em></span></dt><dd><p>
  95                     Specifies a pointer to the image data in memory.
  96                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  97             <code class="function">gluBuild1DMipmaps</code> builds a series of prefiltered one-dimensional texture maps of decreasing
  98             resolutions called a mipmap. This is used for the antialiasing of
  99             texture mapped primitives.
 100         </p><p>
 101             A return value of zero indicates success, otherwise a GLU error code is
 102             returned (see <a class="citerefentry" href="gluErrorString.xml"><span class="citerefentry"><span class="refentrytitle">gluErrorString</span></span></a>).
 103         </p><p>
 104             Initially, the <em class="parameter"><code>width</code></em> of <em class="parameter"><code>data</code></em> is checked to see if it is
 105             a power of 2. If not, a copy of <em class="parameter"><code>data</code></em> is scaled up or down to the
 106             nearest power of 2. (If <em class="parameter"><code>width</code></em> is exactly between powers of 2, then
 107             the copy of <em class="parameter"><code>data</code></em> will scale upwards.)  This copy will be used for
 108             subsequent mipmapping operations described below.
 109             For example, if <em class="parameter"><code>width</code></em> is 57, then a copy of <em class="parameter"><code>data</code></em>
 110             will scale up to 64 before mipmapping
 111             takes place.
 112         </p><p>
 113             Then, proxy textures (see <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>) are used to determine if
 114             the implementation can fit the requested texture. If not, <em class="parameter"><code>width</code></em> is
 115             continually halved until it fits.
 116         </p><p>
 117             Next, a series of mipmap levels is built by decimating a copy of
 118             <em class="parameter"><code>data</code></em> in half
 119             until size
 120             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 121
 122                 <mml:mrow>
 123                     <mml:mn>1</mml:mn>
 124                     <mml:mo>×</mml:mo>
 125                     <mml:mn>1</mml:mn>
 126                 </mml:mrow>
 127             </mml:math>
 128             is reached. At each level, each texel in the
 129             halved mipmap level is an average of the corresponding two texels in the larger
 130             mipmap level.
 131         </p><p>
 132             <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a> is called to load each of these mipmap levels.
 133             Level 0 is a copy of <em class="parameter"><code>data</code></em>.
 134             The highest level is
 135             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 136
 137                 <mml:mrow>
 138                     <mml:mfenced open="" close="">
 139                         <mml:msub><mml:mi mathvariant="italic">log</mml:mi>
 140                         <mml:mn>2</mml:mn>
 141                         </mml:msub>
 142                     </mml:mfenced>
 143                     <mml:mo>⁡</mml:mo>
 144                     <mml:mfenced open="(" close=")">
 145                         <mml:mi mathvariant="italic">width</mml:mi>
 146                     </mml:mfenced>
 147                 </mml:mrow>
 148             </mml:math>.
 149             For example, if <em class="parameter"><code>width</code></em> is 64 and the implementation can store a texture of
 150             this size, the following mipmap levels are
 151             built:
 152             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 153
 154                 <mml:mrow>
 155                     <mml:mn>64</mml:mn>
 156                     <mml:mo>×</mml:mo>
 157                     <mml:mn>1</mml:mn>
 158                 </mml:mrow>
 159             </mml:math>,
 160             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 161
 162                 <mml:mrow>
 163                     <mml:mn>32</mml:mn>
 164                     <mml:mo>×</mml:mo>
 165                     <mml:mn>1</mml:mn>
 166                 </mml:mrow>
 167             </mml:math>,
 168             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 169
 170                 <mml:mrow>
 171                     <mml:mn>16</mml:mn>
 172                     <mml:mo>×</mml:mo>
 173                     <mml:mn>1</mml:mn>
 174                 </mml:mrow>
 175             </mml:math>,
 176             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 177
 178                 <mml:mrow>
 179                     <mml:mn>8</mml:mn>
 180                     <mml:mo>×</mml:mo>
 181                     <mml:mn>1</mml:mn>
 182                 </mml:mrow>
 183             </mml:math>,
 184             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 185
 186                 <mml:mrow>
 187                     <mml:mn>4</mml:mn>
 188                     <mml:mo>×</mml:mo>
 189                     <mml:mn>1</mml:mn>
 190                 </mml:mrow>
 191             </mml:math>,
 192             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 193
 194                 <mml:mrow>
 195                     <mml:mn>2</mml:mn>
 196                     <mml:mo>×</mml:mo>
 197                     <mml:mn>1</mml:mn>
 198                 </mml:mrow>
 199             </mml:math>,
 200             and
 201             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 202
 203                 <mml:mrow>
 204                     <mml:mn>1</mml:mn>
 205                     <mml:mo>×</mml:mo>
 206                     <mml:mn>1</mml:mn>
 207                 </mml:mrow>
 208             </mml:math>.
 209             These correspond to
 210             levels 0 through 6, respectively.
 211         </p><p>
 212             See the <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a> reference page for a description of the
 213             acceptable values for the <em class="parameter"><code>type</code></em> parameter. See the <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a>
 214             reference page for a description of the acceptable values
 215             for the <em class="parameter"><code>data</code></em> parameter.
 216         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 217             Note that there is no direct way of querying the maximum level. This can
 218             be derived indirectly via <a class="citerefentry" href="glGetTexLevelParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a>. First, query
 219             for the
 220             width actually used at level 0.
 221             (The width may not be equal to <em class="parameter"><code>width</code></em> since
 222             proxy textures might have scaled it to fit the implementation.)
 223             Then the maximum
 224             level can be derived from the formula
 225             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 226
 227                 <mml:mrow>
 228                     <mml:mfenced open="" close="">
 229                         <mml:msub><mml:mi mathvariant="italic">log</mml:mi>
 230                         <mml:mn>2</mml:mn>
 231                         </mml:msub>
 232                     </mml:mfenced>
 233                     <mml:mo>⁡</mml:mo>
 234                     <mml:mfenced open="(" close=")">
 235                         <mml:mi mathvariant="italic">width</mml:mi>
 236                     </mml:mfenced>
 237                 </mml:mrow>
 238             </mml:math>.
 239         </p><p>
 240             Formats <code class="constant">GLU_BGR</code>, and <code class="constant">GLU_BGRA</code>, and types
 241             <code class="constant">GLU_UNSIGNED_BYTE_3_3_2</code>,
 242             <code class="constant">GLU_UNSIGNED_BYTE_2_3_3_REV</code>,
 243             <code class="constant">GLU_UNSIGNED_SHORT_5_6_5</code>,
 244             <code class="constant">GLU_UNSIGNED_SHORT_5_6_5_REV</code>,
 245             <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4</code>,
 246             <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4_REV</code>,
 247             <code class="constant">GLU_UNSIGNED_SHORT_5_5_5_1</code>,
 248             <code class="constant">GLU_UNSIGNED_SHORT_1_5_5_5_REV</code>,
 249             <code class="constant">GLU_UNSIGNED_INT_8_8_8_8</code>,
 250             <code class="constant">GLU_UNSIGNED_INT_8_8_8_8_REV</code>,
 251             <code class="constant">GLU_UNSIGNED_INT_10_10_10_2</code>, and
 252             <code class="constant">GLU_UNSIGNED_INT_2_10_10_10_REV</code> are only available if the GL version
 253             is 1.2 or greater, and if the GLU version is 1.3 or greater.
 254         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 255             <code class="constant">GLU_INVALID_VALUE</code> is returned if <em class="parameter"><code>width</code></em> is &lt; 1.
 256         </p><p>
 257             <code class="constant">GLU_INVALID_ENUM</code> is returned if <em class="parameter"><code>format</code></em> or <em class="parameter"><code>type</code></em> are not legal.
 258         </p><p>
 259             <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_BYTE_3_3_2</code> or <code class="constant">GLU_UNSIGNED_BYTE_2_3_3_REV</code>
 260             and <em class="parameter"><code>format</code></em> is not <code class="constant">GLU_RGB</code>.
 261         </p><p>
 262             <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_SHORT_5_6_5</code> or <code class="constant">GLU_UNSIGNED_SHORT_5_6_5_REV</code>
 263             and <em class="parameter"><code>format</code></em> is not <code class="constant">GLU_RGB</code>.
 264         </p><p>
 265             <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4</code> or <code class="constant">GLU_UNSIGNED_SHORT_4_4_4_4_REV</code>
 266             and <em class="parameter"><code>format</code></em> is neither <code class="constant">GLU_RGBA</code> nor <code class="constant">GLU_BGRA</code>.
 267         </p><p>
 268             <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_SHORT_5_5_5_1</code> or <code class="constant">GLU_UNSIGNED_SHORT_1_5_5_5_REV</code>
 269             and <em class="parameter"><code>format</code></em> is neither <code class="constant">GLU_RGBA</code> nor <code class="constant">GLU_BGRA</code>.
 270         </p><p>
 271             <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_INT_8_8_8_8</code> or <code class="constant">GLU_UNSIGNED_INT_8_8_8_8_REV</code>
 272             and <em class="parameter"><code>format</code></em> is neither <code class="constant">GLU_RGBA</code> nor <code class="constant">GLU_BGRA</code>.
 273         </p><p>
 274             <code class="constant">GLU_INVALID_OPERATION</code> is returned if <em class="parameter"><code>type</code></em> is <code class="constant">GLU_UNSIGNED_INT_10_10_10_2</code> or <code class="constant">GLU_UNSIGNED_INT_2_10_10_10_REV</code>
 275             and <em class="parameter"><code>format</code></em> is neither <code class="constant">GLU_RGBA</code> nor <code class="constant">GLU_BGRA</code>.
 276         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 277             <a class="citerefentry" href="gluBuild1DMipmapLevels.xml"><span class="citerefentry"><span class="refentrytitle">gluBuild1DMipmapLevels</span></span></a>,
 278             <a class="citerefentry" href="gluBuild2DMipmapLevels.xml"><span class="citerefentry"><span class="refentrytitle">gluBuild2DMipmapLevels</span></span></a>,
 279             <a class="citerefentry" href="gluBuild2DMipmaps.xml"><span class="citerefentry"><span class="refentrytitle">gluBuild2DMipmaps</span></span></a>,
 280             <a class="citerefentry" href="gluBuild3DMipmapLevels.xml"><span class="citerefentry"><span class="refentrytitle">gluBuild3DMipmapLevels</span></span></a>,
 281             <a class="citerefentry" href="gluBuild3DMipmaps.xml"><span class="citerefentry"><span class="refentrytitle">gluBuild3DMipmaps</span></span></a>,
 282             <a class="citerefentry" href="gluErrorString.xml"><span class="citerefentry"><span class="refentrytitle">gluErrorString</span></span></a>,
 283             <a class="citerefentry" href="glDrawPixels.xml"><span class="citerefentry"><span class="refentrytitle">glDrawPixels</span></span></a>,
 284             <a class="citerefentry" href="glGetTexImage.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexImage</span></span></a>,
 285             <a class="citerefentry" href="glGetTexLevelParameter.xml"><span class="citerefentry"><span class="refentrytitle">glGetTexLevelParameter</span></span></a>,
 286             <a class="citerefentry" href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>,
 287             <a class="citerefentry" href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>,
 288             <a class="citerefentry" href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>
 289         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 290             Copyright <span class="trademark"></span>© 1991-2006
 291             Silicon Graphics, Inc. This document is licensed under the SGI
 292             Free Software B License. For details, see
 293             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 294         </p></div></div></body></html>