upstream-man-pages/man2/xhtml/glGetMaterial.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>glGetMaterial</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glGetMaterial"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetMaterial — return material 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">glGetMaterialfv</b>(</code></td><td>GLenum  </td><td><var class="pdparam">face</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">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">glGetMaterialiv</b>(</code></td><td>GLenum  </td><td><var class="pdparam">face</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">params</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>face</code></em></span></dt><dd><p>
   4                     Specifies which of the two materials is being queried.
   5                     <code class="constant">GL_FRONT</code> or <code class="constant">GL_BACK</code> are accepted,
   6                     representing the front and back materials,
   7                     respectively.
   8                 </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p>
   9                     Specifies the material parameter to return.
  10                     <code class="constant">GL_AMBIENT</code>,
  11                     <code class="constant">GL_DIFFUSE</code>,
  12                     <code class="constant">GL_SPECULAR</code>,
  13                     <code class="constant">GL_EMISSION</code>,
  14                     <code class="constant">GL_SHININESS</code>, and
  15                     <code class="constant">GL_COLOR_INDEXES</code>
  16                     are accepted.
  17                 </p></dd><dt><span class="term"><em class="parameter"><code>params</code></em></span></dt><dd><p>
  18                     Returns the requested data.
  19                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  20             <code class="function">glGetMaterial</code> returns in <em class="parameter"><code>params</code></em> the value or values of parameter <em class="parameter"><code>pname</code></em>
  21             of material <em class="parameter"><code>face</code></em>. Six parameters are defined:
  22         </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_AMBIENT</code></span></dt><dd><p>
  23                         <em class="parameter"><code>params</code></em> returns four integer or floating-point values representing the
  24                         ambient reflectance of the material.
  25                         Integer values,
  26                         when requested,
  27                         are linearly mapped from the internal floating-point representation
  28                         such that 1.0 maps to the most positive representable integer value,
  29                         and
  30                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  31
  32                             <mml:mn>-1.0</mml:mn>
  33                         </mml:math>
  34                         maps to the most negative representable integer value.
  35                         If the internal value is outside the range
  36                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  37
  38                             <mml:mfenced open="[" close="]">
  39                                 <mml:mn>-1</mml:mn>
  40                                 <mml:mn>1</mml:mn>
  41                             </mml:mfenced>
  42                         </mml:math>,
  43                         the corresponding integer return value is undefined. The initial value is
  44                         (0.2, 0.2, 0.2, 1.0)
  45                     </p></dd><dt><span class="term"><code class="constant">GL_DIFFUSE</code></span></dt><dd><p>
  46                         <em class="parameter"><code>params</code></em> returns four integer or floating-point values representing the
  47                         diffuse reflectance of the material.
  48                         Integer values,
  49                         when requested,
  50                         are linearly mapped from the internal floating-point representation
  51                         such that 1.0 maps to the most positive representable integer value,
  52                         and
  53                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  54
  55                             <mml:mn>-1.0</mml:mn>
  56                         </mml:math>
  57                         maps to the most negative representable integer value.
  58                         If the internal value is outside the range
  59                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  60
  61                             <mml:mfenced open="[" close="]">
  62                                 <mml:mn>-1</mml:mn>
  63                                 <mml:mn>1</mml:mn>
  64                             </mml:mfenced>
  65                         </mml:math>,
  66                         the corresponding integer return value is undefined. The initial value is
  67                         (0.8, 0.8, 0.8, 1.0).
  68                     </p></dd><dt><span class="term"><code class="constant">GL_SPECULAR</code></span></dt><dd><p>
  69                         <em class="parameter"><code>params</code></em> returns four integer or floating-point values representing the
  70                         specular reflectance of the material.
  71                         Integer values,
  72                         when requested,
  73                         are linearly mapped from the internal floating-point representation
  74                         such that 1.0 maps to the most positive representable integer value,
  75                         and
  76                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  77
  78                             <mml:mn>-1.0</mml:mn>
  79                         </mml:math>
  80                         maps to the most negative representable integer value.
  81                         If the internal value is outside the range
  82                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  83
  84                             <mml:mfenced open="[" close="]">
  85                                 <mml:mn>-1</mml:mn>
  86                                 <mml:mn>1</mml:mn>
  87                             </mml:mfenced>
  88                         </mml:math>,
  89                         the corresponding integer return value is undefined. The initial value is
  90                         (0, 0, 0, 1).
  91                     </p></dd><dt><span class="term"><code class="constant">GL_EMISSION</code></span></dt><dd><p>
  92                         <em class="parameter"><code>params</code></em> returns four integer or floating-point values representing the
  93                         emitted light intensity of the material.
  94                         Integer values,
  95                         when requested,
  96                         are linearly mapped from the internal floating-point representation
  97                         such that 1.0 maps to the most positive representable integer value,
  98                         and
  99                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 100
 101                             <mml:mn>-1.0</mml:mn>
 102                         </mml:math>
 103                         maps to the most negative representable integer value.
 104                         If the internal value is outside the range
 105                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 106
 107                             <mml:mfenced open="[" close="]">
 108                                 <mml:mn>-1</mml:mn>
 109                                 <mml:mn>1</mml:mn>
 110                             </mml:mfenced>
 111                         </mml:math>,
 112                         the corresponding integer return value is undefined. The initial value is
 113                         (0, 0, 0, 1).
 114                     </p></dd><dt><span class="term"><code class="constant">GL_SHININESS</code></span></dt><dd><p>
 115                         <em class="parameter"><code>params</code></em> returns one integer or floating-point value representing the
 116                         specular exponent of the material.
 117                         Integer values,
 118                         when requested,
 119                         are computed by rounding the internal floating-point value to the
 120                         nearest integer value. The initial value is 0.
 121                     </p></dd><dt><span class="term"><code class="constant">GL_COLOR_INDEXES</code></span></dt><dd><p>
 122                         <em class="parameter"><code>params</code></em> returns three integer or floating-point values representing the
 123                         ambient, diffuse, and specular indices of the material.
 124                         These indices are used only for color index lighting.
 125                         (All the other parameters are used only for RGBA lighting.)
 126                         Integer values,
 127                         when requested,
 128                         are computed by rounding the internal floating-point values to the
 129                         nearest integer values.
 130                     </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 131             If an error is generated,
 132             no change is made to the contents of <em class="parameter"><code>params</code></em>.
 133         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 134             <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>face</code></em> or <em class="parameter"><code>pname</code></em> is not an
 135             accepted value.
 136         </p><p>
 137             <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glGetMaterial</code>
 138             is executed between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a>
 139             and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
 140         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 141             <a class="citerefentry" href="glMaterial.xml"><span class="citerefentry"><span class="refentrytitle">glMaterial</span></span></a>
 142         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 143             Copyright <span class="trademark"></span>© 1991-2006
 144             Silicon Graphics, Inc. This document is licensed under the SGI
 145             Free Software B License. For details, see
 146             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 147         </p></div></div></body></html>