upstream-man-pages/man2/xhtml/glGetMap.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>glGetMap</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glGetMap"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetMap — return evaluator 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">glGetMapdv</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">query</var>, </td></tr><tr><td> </td><td>GLdouble *  </td><td><var class="pdparam">v</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">glGetMapfv</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">query</var>, </td></tr><tr><td> </td><td>GLfloat *  </td><td><var class="pdparam">v</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">glGetMapiv</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">query</var>, </td></tr><tr><td> </td><td>GLint *  </td><td><var class="pdparam">v</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 symbolic name of a map.
   5                     Accepted values are
   6                     <code class="constant">GL_MAP1_COLOR_4</code>,
   7                     <code class="constant">GL_MAP1_INDEX</code>,
   8                     <code class="constant">GL_MAP1_NORMAL</code>,
   9                     <code class="constant">GL_MAP1_TEXTURE_COORD_1</code>,
  10                     <code class="constant">GL_MAP1_TEXTURE_COORD_2</code>,
  11                     <code class="constant">GL_MAP1_TEXTURE_COORD_3</code>,
  12                     <code class="constant">GL_MAP1_TEXTURE_COORD_4</code>,
  13                     <code class="constant">GL_MAP1_VERTEX_3</code>,
  14                     <code class="constant">GL_MAP1_VERTEX_4</code>,
  15                     <code class="constant">GL_MAP2_COLOR_4</code>,
  16                     <code class="constant">GL_MAP2_INDEX</code>,
  17                     <code class="constant">GL_MAP2_NORMAL</code>,
  18                     <code class="constant">GL_MAP2_TEXTURE_COORD_1</code>,
  19                     <code class="constant">GL_MAP2_TEXTURE_COORD_2</code>,
  20                     <code class="constant">GL_MAP2_TEXTURE_COORD_3</code>,
  21                     <code class="constant">GL_MAP2_TEXTURE_COORD_4</code>,
  22                     <code class="constant">GL_MAP2_VERTEX_3</code>, and
  23                     <code class="constant">GL_MAP2_VERTEX_4</code>.
  24                 </p></dd><dt><span class="term"><em class="parameter"><code>query</code></em></span></dt><dd><p>
  25                     Specifies which parameter to return.
  26                     Symbolic names
  27                     <code class="constant">GL_COEFF</code>,
  28                     <code class="constant">GL_ORDER</code>, and
  29                     <code class="constant">GL_DOMAIN</code> are accepted.
  30                 </p></dd><dt><span class="term"><em class="parameter"><code>v</code></em></span></dt><dd><p>
  31                     Returns the requested data.
  32                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  33             <a class="citerefentry" href="glMap1.xml"><span class="citerefentry"><span class="refentrytitle">glMap1</span></span></a> and <a class="citerefentry" href="glMap2.xml"><span class="citerefentry"><span class="refentrytitle">glMap2</span></span></a> define evaluators.
  34             <code class="function">glGetMap</code> returns evaluator parameters.
  35             <em class="parameter"><code>target</code></em> chooses a map,
  36             <em class="parameter"><code>query</code></em> selects a specific parameter,
  37             and <em class="parameter"><code>v</code></em> points to storage where the values will be returned.
  38         </p><p>
  39             The acceptable values for the <em class="parameter"><code>target</code></em> parameter are described
  40             in the <a class="citerefentry" href="glMap1.xml"><span class="citerefentry"><span class="refentrytitle">glMap1</span></span></a> and <a class="citerefentry" href="glMap2.xml"><span class="citerefentry"><span class="refentrytitle">glMap2</span></span></a> reference pages.
  41         </p><p>
  42             <em class="parameter"><code>query</code></em> can assume the following values:
  43         </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_COEFF</code></span></dt><dd><p>
  44                         <em class="parameter"><code>v</code></em> returns the control points for the evaluator function.
  45                         One-dimensional evaluators return
  46                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">order</mml:mi></mml:math>
  47                         control points,
  48                         and two-dimensional evaluators return
  49                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  50
  51                             <mml:mrow>
  52                                 <mml:mi mathvariant="italic">uorder</mml:mi>
  53                                 <mml:mo>×</mml:mo>
  54                                 <mml:mi mathvariant="italic">vorder</mml:mi>
  55                             </mml:mrow>
  56                         </mml:math>
  57                         control points.
  58                         Each control point consists of one, two, three, or four integer,
  59                         single-precision floating-point,
  60                         or double-precision floating-point values,
  61                         depending on the type of the evaluator.
  62                         The GL returns two-dimensional control points in row-major order,
  63                         incrementing the
  64                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">uorder</mml:mi></mml:math>
  65                         index quickly
  66                         and the
  67                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">vorder</mml:mi></mml:math>
  68                         index after each row.
  69                         Integer values,
  70                         when requested,
  71                         are computed by rounding the internal floating-point values to the
  72                         nearest integer values.
  73                     </p></dd><dt><span class="term"><code class="constant">GL_ORDER</code></span></dt><dd><p>
  74                         <em class="parameter"><code>v</code></em> returns the order of the evaluator function.
  75                         One-dimensional evaluators return a single value,
  76                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">order</mml:mi></mml:math>.
  77                         The initial value is 1.
  78                         Two-dimensional evaluators return two values,
  79                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">uorder</mml:mi></mml:math>
  80                         and
  81                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">vorder</mml:mi></mml:math>.
  82                         The initial value is 1,1.
  83                     </p></dd><dt><span class="term"><code class="constant">GL_DOMAIN</code></span></dt><dd><p>
  84                         <em class="parameter"><code>v</code></em> returns the linear
  85                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">u</mml:mi></mml:math>
  86                         and
  87                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">v</mml:mi></mml:math>
  88                         mapping parameters.
  89                         One-dimensional evaluators return two values,
  90                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">u1</mml:mi></mml:math>
  91                         and
  92                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">u2</mml:mi></mml:math>,
  93                         as specified by <a class="citerefentry" href="glMap1.xml"><span class="citerefentry"><span class="refentrytitle">glMap1</span></span></a>.
  94                         Two-dimensional evaluators return four values
  95                         (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">u1</mml:mi></mml:math>,
  96                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">u2</mml:mi></mml:math>,
  97                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">v1</mml:mi></mml:math>,
  98                         and
  99                         <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">v2</mml:mi></mml:math>)
 100                         as specified by <a class="citerefentry" href="glMap2.xml"><span class="citerefentry"><span class="refentrytitle">glMap2</span></span></a>.
 101                         Integer values,
 102                         when requested,
 103                         are computed by rounding the internal floating-point values to the
 104                         nearest integer values.
 105                     </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 106             If an error is generated,
 107             no change is made to the contents of <em class="parameter"><code>v</code></em>.
 108         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
 109             <code class="constant">GL_INVALID_ENUM</code> is generated if either <em class="parameter"><code>target</code></em> or <em class="parameter"><code>query</code></em> is not
 110             an accepted value.
 111         </p><p>
 112             <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glGetMap</code>
 113             is executed between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a>
 114             and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
 115         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 116             <a class="citerefentry" href="glEvalCoord.xml"><span class="citerefentry"><span class="refentrytitle">glEvalCoord</span></span></a>,
 117             <a class="citerefentry" href="glMap1.xml"><span class="citerefentry"><span class="refentrytitle">glMap1</span></span></a>,
 118             <a class="citerefentry" href="glMap2.xml"><span class="citerefentry"><span class="refentrytitle">glMap2</span></span></a>
 119         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 120             Copyright <span class="trademark"></span>© 1991-2006
 121             Silicon Graphics, Inc. This document is licensed under the SGI
 122             Free Software B License. For details, see
 123             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 124         </p></div></div></body></html>