upstream-doc/man2/xhtml/gluProject.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>gluProject</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="gluProject"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>gluProject — map object coordinates to window coordinates</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">gluProject</b>(</code></td><td>GLdouble  </td><td><var class="pdparam">objX</var>, </td></tr><tr><td> </td><td>GLdouble  </td><td><var class="pdparam">objY</var>, </td></tr><tr><td> </td><td>GLdouble  </td><td><var class="pdparam">objZ</var>, </td></tr><tr><td> </td><td>const GLdouble *  </td><td><var class="pdparam">model</var>, </td></tr><tr><td> </td><td>const GLdouble *  </td><td><var class="pdparam">proj</var>, </td></tr><tr><td> </td><td>const GLint *  </td><td><var class="pdparam">view</var>, </td></tr><tr><td> </td><td>GLdouble*  </td><td><var class="pdparam">winX</var>, </td></tr><tr><td> </td><td>GLdouble*  </td><td><var class="pdparam">winY</var>, </td></tr><tr><td> </td><td>GLdouble*  </td><td><var class="pdparam">winZ</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>objX</code></em>, </span><span class="term"><em class="parameter"><code>objY</code></em>, </span><span class="term"><em class="parameter"><code>objZ</code></em></span></dt><dd><p>
   4                     Specify the object coordinates.
   5                 </p></dd><dt><span class="term"><em class="parameter"><code>model</code></em></span></dt><dd><p>
   6                     Specifies the current modelview matrix (as from a <a class="citerefentry" href="glGetDoublev.xml"><span class="citerefentry"><span class="refentrytitle">glGetDoublev</span></span></a> call).
   7                 </p></dd><dt><span class="term"><em class="parameter"><code>proj</code></em></span></dt><dd><p>
   8                     Specifies the current projection matrix (as from a <a class="citerefentry" href="glGetDoublev.xml"><span class="citerefentry"><span class="refentrytitle">glGetDoublev</span></span></a> call).
   9                 </p></dd><dt><span class="term"><em class="parameter"><code>view</code></em></span></dt><dd><p>
  10                     Specifies the current viewport (as from a <a class="citerefentry" href="glGetIntegerv.xml"><span class="citerefentry"><span class="refentrytitle">glGetIntegerv</span></span></a> call).
  11                 </p></dd><dt><span class="term"><em class="parameter"><code>winX</code></em>, </span><span class="term"><em class="parameter"><code>winY</code></em>, </span><span class="term"><em class="parameter"><code>winZ</code></em></span></dt><dd><p>
  12                     Return the computed window coordinates.
  13                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  14             <code class="function">gluProject</code> transforms the specified object coordinates into window coordinates
  15             using <em class="parameter"><code>model</code></em>, <em class="parameter"><code>proj</code></em>, and <em class="parameter"><code>view</code></em>. The result is stored
  16             in <em class="parameter"><code>winX</code></em>, <em class="parameter"><code>winY</code></em>, and <em class="parameter"><code>winZ</code></em>. A return value of
  17             <code class="constant">GLU_TRUE</code> indicates success, a return value of <code class="constant">GLU_FALSE</code>
  18             indicates failure.
  19         </p><p>
  20             To compute the coordinates,
  21             let
  22             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  23
  24                 <mml:mrow>
  25                     <mml:mi mathvariant="italic">v</mml:mi>
  26                     <mml:mo>=</mml:mo>
  27                     <mml:mfenced open="(" close=")">
  28                         <mml:mi mathvariant="italic">objX</mml:mi>
  29                         <mml:mi mathvariant="italic">objY</mml:mi>
  30                         <mml:mi mathvariant="italic">objZ</mml:mi>
  31                         <mml:mn>1.0</mml:mn>
  32                     </mml:mfenced>
  33                 </mml:mrow>
  34             </mml:math>
  35             represented as a matrix with 4 rows and 1 column.
  36             Then <code class="function">gluProject</code> computes
  37             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  38
  39                 <mml:msup><mml:mi mathvariant="italic">v</mml:mi>
  40                 <mml:mo>″</mml:mo>
  41                 </mml:msup>
  42             </mml:math>
  43             as follows:
  44         </p><p>
  45             </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  46
  47                 <mml:mrow>
  48                     <mml:msup><mml:mi mathvariant="italic">v</mml:mi>
  49                     <mml:mo>″</mml:mo>
  50                     </mml:msup>
  51                     <mml:mo>=</mml:mo>
  52                     <mml:mrow>
  53                         <mml:mi mathvariant="italic">P</mml:mi>
  54                         <mml:mo>×</mml:mo>
  55                         <mml:mi mathvariant="italic">M</mml:mi>
  56                         <mml:mo>×</mml:mo>
  57                         <mml:mi mathvariant="italic">v</mml:mi>
  58                     </mml:mrow>
  59                 </mml:mrow>
  60             </mml:math></div><p>
  61         </p><p>
  62             where
  63             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">P</mml:mi></mml:math>
  64             is the current projection matrix <em class="parameter"><code>proj</code></em> and
  65             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">M</mml:mi></mml:math>
  66             is the current
  67             modelview matrix <em class="parameter"><code>model</code></em> (both represented as
  68             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  69
  70                 <mml:mrow>
  71                     <mml:mn>4</mml:mn>
  72                     <mml:mo>×</mml:mo>
  73                     <mml:mn>4</mml:mn>
  74                 </mml:mrow>
  75             </mml:math>
  76             matrices in column-major order).
  77         </p><p>
  78             The window coordinates are then computed as follows:
  79         </p><p>
  80             </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  81
  82                 <mml:mrow>
  83                     <mml:mi mathvariant="italic">winX</mml:mi>
  84                     <mml:mo>=</mml:mo>
  85                     <mml:mrow>
  86                         <mml:mrow>
  87                             <mml:mi mathvariant="italic">view</mml:mi>
  88                             <mml:mo>⁡</mml:mo>
  89                             <mml:mfenced open="(" close=")">
  90                                 <mml:mn>0</mml:mn>
  91                             </mml:mfenced>
  92                         </mml:mrow>
  93                         <mml:mo>+</mml:mo>
  94                         <mml:mfrac>
  95                             <mml:mrow>
  96                                 <mml:mrow>
  97                                     <mml:mi mathvariant="italic">view</mml:mi>
  98                                     <mml:mo>⁡</mml:mo>
  99                                     <mml:mfenced open="(" close=")">
 100                                         <mml:mn>2</mml:mn>
 101                                     </mml:mfenced>
 102                                 </mml:mrow>
 103                                 <mml:mo>×</mml:mo>
 104                                 <mml:mfenced open="(" close=")">
 105                                     <mml:mrow>
 106                                         <mml:mrow>
 107                                             <mml:msup><mml:mi mathvariant="italic">v</mml:mi>
 108                                             <mml:mo>″</mml:mo>
 109                                             </mml:msup>
 110                                             <mml:mo>⁡</mml:mo>
 111                                             <mml:mfenced open="(" close=")">
 112                                                 <mml:mn>0</mml:mn>
 113                                             </mml:mfenced>
 114                                         </mml:mrow>
 115                                         <mml:mo>+</mml:mo>
 116                                         <mml:mn>1</mml:mn>
 117                                     </mml:mrow>
 118                                 </mml:mfenced>
 119                             </mml:mrow>
 120                             <mml:mn>2</mml:mn>
 121                         </mml:mfrac>
 122                     </mml:mrow>
 123                 </mml:mrow>
 124             </mml:math></div><p>
 125             </p><p>
 126                 </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
 127
 128                     <mml:mrow>
 129                         <mml:mi mathvariant="italic">winY</mml:mi>
 130                         <mml:mo>=</mml:mo>
 131                         <mml:mrow>
 132                             <mml:mrow>
 133                                 <mml:mi mathvariant="italic">view</mml:mi>
 134                                 <mml:mo>⁡</mml:mo>
 135                                 <mml:mfenced open="(" close=")">
 136                                     <mml:mn>1</mml:mn>
 137                                 </mml:mfenced>
 138                             </mml:mrow>
 139                             <mml:mo>+</mml:mo>
 140                             <mml:mfrac>
 141                                 <mml:mrow>
 142                                     <mml:mrow>
 143                                         <mml:mi mathvariant="italic">view</mml:mi>
 144                                         <mml:mo>⁡</mml:mo>
 145                                         <mml:mfenced open="(" close=")">
 146                                             <mml:mn>3</mml:mn>
 147                                         </mml:mfenced>
 148                                     </mml:mrow>
 149                                     <mml:mo>×</mml:mo>
 150                                     <mml:mfenced open="(" close=")">
 151                                         <mml:mrow>
 152                                             <mml:mrow>
 153                                                 <mml:msup><mml:mi mathvariant="italic">v</mml:mi>
 154                                                 <mml:mo>″</mml:mo>
 155                                                 </mml:msup>
 156                                                 <mml:mo>⁡</mml:mo>
 157                                                 <mml:mfenced open="(" close=")">
 158                                                     <mml:mn>1</mml:mn>
 159                                                 </mml:mfenced>
 160                                             </mml:mrow>
 161                                             <mml:mo>+</mml:mo>
 162                                             <mml:mn>1</mml:mn>
 163                                         </mml:mrow>
 164                                     </mml:mfenced>
 165                                 </mml:mrow>
 166                                 <mml:mn>2</mml:mn>
 167                             </mml:mfrac>
 168                         </mml:mrow>
 169                     </mml:mrow>
 170                 </mml:math></div><p>
 171             </p><p>
 172             </p><p>
 173                 </p><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">winZ</mml:mi>
 177                         <mml:mo>=</mml:mo>
 178                         <mml:mfrac>
 179                             <mml:mfenced open="(" close=")">
 180                                 <mml:mrow>
 181                                     <mml:mrow>
 182                                         <mml:msup><mml:mi mathvariant="italic">v</mml:mi>
 183                                         <mml:mo>″</mml:mo>
 184                                         </mml:msup>
 185                                         <mml:mo>⁡</mml:mo>
 186                                         <mml:mfenced open="(" close=")">
 187                                             <mml:mn>2</mml:mn>
 188                                         </mml:mfenced>
 189                                     </mml:mrow>
 190                                     <mml:mo>+</mml:mo>
 191                                     <mml:mn>1</mml:mn>
 192                                 </mml:mrow>
 193                             </mml:mfenced>
 194                             <mml:mn>2</mml:mn>
 195                         </mml:mfrac>
 196                     </mml:mrow>
 197                 </mml:math></div><p>
 198             </p><p>
 199         </p><p>
 200         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 201             <a class="citerefentry" href="gluUnProject.xml"><span class="citerefentry"><span class="refentrytitle">gluUnProject</span></span></a>,
 202             <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
 203         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 204             Copyright <span class="trademark"></span>© 1991-2006
 205             Silicon Graphics, Inc. This document is licensed under the SGI
 206             Free Software B License. For details, see
 207             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 208         </p></div></div></body></html>