upstream-doc/man2/xhtml/gluUnProject4.xml

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
   2 <!-- saved from url=(0013)about:internet -->
   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>gluUnProject4</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="gluUnProject4"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>gluUnProject4 — map window and clip coordinates to object 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">gluUnProject4</b>(</code></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>, </td></tr><tr><td> </td><td>GLdouble  </td><td><var class="pdparam">clipW</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">nearVal</var>, </td></tr><tr><td> </td><td>GLdouble  </td><td><var class="pdparam">farVal</var>, </td></tr><tr><td> </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>GLdouble*  </td><td><var class="pdparam">objW</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>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>
   4                     Specify the window coordinates to be mapped.
   5                 </p></dd><dt><span class="term"><em class="parameter"><code>clipW</code></em></span></dt><dd><p>
   6                     Specify the clip w coordinate to be mapped.
   7                 </p></dd><dt><span class="term"><em class="parameter"><code>model</code></em></span></dt><dd><p>
   8                     Specifies the modelview 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>proj</code></em></span></dt><dd><p>
  10                     Specifies the projection matrix (as from a <a class="citerefentry" href="glGetDoublev.xml"><span class="citerefentry"><span class="refentrytitle">glGetDoublev</span></span></a> call).
  11                 </p></dd><dt><span class="term"><em class="parameter"><code>view</code></em></span></dt><dd><p>
  12                     Specifies the viewport (as from a <a class="citerefentry" href="glGetIntegerv.xml"><span class="citerefentry"><span class="refentrytitle">glGetIntegerv</span></span></a> call).
  13                 </p></dd><dt><span class="term"><em class="parameter"><code>nearVal</code></em>, </span><span class="term"><em class="parameter"><code>farVal</code></em></span></dt><dd><p>
  14                     Specifies the near and far planes (as from a <a class="citerefentry" href="glGetDoublev.xml"><span class="citerefentry"><span class="refentrytitle">glGetDoublev</span></span></a> call).
  15                 </p></dd><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><span class="term"><em class="parameter"><code>objW</code></em></span></dt><dd><p>
  16                     Returns the computed object coordinates.
  17                 </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
  18             <code class="function">gluUnProject4</code> maps the specified window coordinatesi: <em class="parameter"><code>winX</code></em>, <em class="parameter"><code>winY</code></em>, and <em class="parameter"><code>winZ</code></em>
  19             and its clip w coordinate <em class="parameter"><code>clipW</code></em>
  20             into object
  21             coordinates
  22             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  23
  24                 <mml:mfenced open="(" close=")">
  25                     <mml:mi mathvariant="italic">objX</mml:mi>
  26                     <mml:mi mathvariant="italic">objY</mml:mi>
  27                     <mml:mi mathvariant="italic">objZ</mml:mi>
  28                     <mml:mi mathvariant="italic">objW</mml:mi>
  29                 </mml:mfenced>
  30             </mml:math>
  31             using <em class="parameter"><code>model</code></em>, <em class="parameter"><code>proj</code></em>, and <em class="parameter"><code>view</code></em>. <em class="parameter"><code>clipW</code></em> can be other than
  32             1 as for vertices in <a class="citerefentry" href="glFeedbackBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glFeedbackBuffer</span></span></a> when data type
  33             <code class="constant">GLU_4D_COLOR_TEXTURE</code> is returned.
  34             This also handles the case
  35             where the <em class="parameter"><code>nearVal</code></em> and <em class="parameter"><code>farVal</code></em> planes are different from the default,
  36             0 and 1, respectively.
  37             A return
  38             value of <code class="constant">GLU_TRUE</code> indicates success; a return value of <code class="constant">GLU_FALSE</code>
  39             indicates failure.
  40         </p><p>
  41             To compute the coordinates
  42             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  43
  44                 <mml:mfenced open="(" close=")">
  45                     <mml:mi mathvariant="italic">objX</mml:mi>
  46                     <mml:mi mathvariant="italic">objY</mml:mi>
  47                     <mml:mi mathvariant="italic">objZ</mml:mi>
  48                     <mml:mi mathvariant="italic">objW</mml:mi>
  49                 </mml:mfenced>
  50             </mml:math>,
  51             <code class="function">gluUnProject4</code> multiplies the normalized device coordinates by the inverse of
  52             <em class="parameter"><code>model</code></em> * <em class="parameter"><code>proj</code></em> as follows:
  53         </p><p>
  54             </p><div class="informalequation"><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
  55
  56                 <mml:mrow>
  57                     <mml:mfenced open="(" close=")">
  58                         <mml:mtable>
  59                             <mml:mtr><mml:mtd>
  60                                 <mml:mi mathvariant="italic">objX</mml:mi>
  61                             </mml:mtd></mml:mtr>
  62                             <mml:mtr><mml:mtd>
  63                                 <mml:mi mathvariant="italic">objY</mml:mi>
  64                             </mml:mtd></mml:mtr>
  65                             <mml:mtr><mml:mtd>
  66                                 <mml:mi mathvariant="italic">objZ</mml:mi>
  67                             </mml:mtd></mml:mtr>
  68                             <mml:mtr><mml:mtd>
  69                                 <mml:mi mathvariant="italic">objW</mml:mi>
  70                             </mml:mtd></mml:mtr>
  71                         </mml:mtable>
  72                     </mml:mfenced>
  73                     <mml:mo>=</mml:mo>
  74                     <mml:mrow>
  75                         <mml:mrow>
  76                             <mml:mi mathvariant="italic">INV</mml:mi>
  77                             <mml:mo>⁡</mml:mo>
  78                             <mml:mfenced open="(" close=")">
  79                                 <mml:mrow>
  80                                     <mml:mi mathvariant="italic">P</mml:mi>
  81                                     <mml:mo>⁢</mml:mo>
  82                                     <mml:mi mathvariant="italic">M</mml:mi>
  83                                 </mml:mrow>
  84                             </mml:mfenced>
  85                         </mml:mrow>
  86                         <mml:mo>⁢</mml:mo>
  87                         <mml:mfenced open="(" close=")">
  88                             <mml:mtable>
  89                                 <mml:mtr><mml:mtd>
  90                                     <mml:mrow>
  91                                         <mml:mfrac>
  92                                             <mml:mfenced open="" close="">
  93                                                 <mml:mrow>
  94                                                     <mml:mn>2</mml:mn>
  95                                                     <mml:mo>⁡</mml:mo>
  96                                                     <mml:mfenced open="(" close=")">
  97                                                         <mml:mrow>
  98                                                             <mml:mi mathvariant="italic">winX</mml:mi>
  99                                                             <mml:mo>-</mml:mo>
 100                                                             <mml:mrow>
 101                                                                 <mml:mi mathvariant="italic">view</mml:mi>
 102                                                                 <mml:mo>⁡</mml:mo>
 103                                                                 <mml:mfenced open="[" close="]">
 104                                                                     <mml:mn>0</mml:mn>
 105                                                                 </mml:mfenced>
 106                                                             </mml:mrow>
 107                                                         </mml:mrow>
 108                                                     </mml:mfenced>
 109                                                 </mml:mrow>
 110                                             </mml:mfenced>
 111                                             <mml:mfenced open="" close="">
 112                                                 <mml:mrow>
 113                                                     <mml:mi mathvariant="italic">view</mml:mi>
 114                                                     <mml:mo>⁡</mml:mo>
 115                                                     <mml:mfenced open="[" close="]">
 116                                                         <mml:mn>2</mml:mn>
 117                                                     </mml:mfenced>
 118                                                 </mml:mrow>
 119                                             </mml:mfenced>
 120                                         </mml:mfrac>
 121                                         <mml:mo>-</mml:mo>
 122                                         <mml:mn>1</mml:mn>
 123                                     </mml:mrow>
 124                                 </mml:mtd></mml:mtr>
 125                                 <mml:mtr><mml:mtd>
 126                                     <mml:mrow>
 127                                         <mml:mfrac>
 128                                             <mml:mfenced open="" close="">
 129                                                 <mml:mrow>
 130                                                     <mml:mn>2</mml:mn>
 131                                                     <mml:mo>⁡</mml:mo>
 132                                                     <mml:mfenced open="(" close=")">
 133                                                         <mml:mrow>
 134                                                             <mml:mi mathvariant="italic">winY</mml:mi>
 135                                                             <mml:mo>-</mml:mo>
 136                                                             <mml:mrow>
 137                                                                 <mml:mi mathvariant="italic">view</mml:mi>
 138                                                                 <mml:mo>⁡</mml:mo>
 139                                                                 <mml:mfenced open="[" close="]">
 140                                                                     <mml:mn>1</mml:mn>
 141                                                                 </mml:mfenced>
 142                                                             </mml:mrow>
 143                                                         </mml:mrow>
 144                                                     </mml:mfenced>
 145                                                 </mml:mrow>
 146                                             </mml:mfenced>
 147                                             <mml:mfenced open="" close="">
 148                                                 <mml:mrow>
 149                                                     <mml:mi mathvariant="italic">view</mml:mi>
 150                                                     <mml:mo>⁡</mml:mo>
 151                                                     <mml:mfenced open="[" close="]">
 152                                                         <mml:mn>3</mml:mn>
 153                                                     </mml:mfenced>
 154                                                 </mml:mrow>
 155                                             </mml:mfenced>
 156                                         </mml:mfrac>
 157                                         <mml:mo>-</mml:mo>
 158                                         <mml:mn>1</mml:mn>
 159                                     </mml:mrow>
 160                                 </mml:mtd></mml:mtr>
 161                                 <mml:mtr><mml:mtd>
 162                                     <mml:mrow>
 163                                         <mml:mfrac>
 164                                             <mml:mfenced open="" close="">
 165                                                 <mml:mrow>
 166                                                     <mml:mn>2</mml:mn>
 167                                                     <mml:mo>⁡</mml:mo>
 168                                                     <mml:mfenced open="(" close=")">
 169                                                         <mml:mrow>
 170                                                             <mml:mi mathvariant="italic">winZ</mml:mi>
 171                                                             <mml:mo>-</mml:mo>
 172                                                             <mml:mi mathvariant="italic">nearVal</mml:mi>
 173                                                         </mml:mrow>
 174                                                     </mml:mfenced>
 175                                                 </mml:mrow>
 176                                             </mml:mfenced>
 177                                             <mml:mfenced open="" close="">
 178                                                 <mml:mfenced open="(" close=")">
 179                                                     <mml:mrow>
 180                                                         <mml:mi mathvariant="italic">farVal</mml:mi>
 181                                                         <mml:mo>-</mml:mo>
 182                                                         <mml:mi mathvariant="italic">nearVal</mml:mi>
 183                                                     </mml:mrow>
 184                                                 </mml:mfenced>
 185                                             </mml:mfenced>
 186                                         </mml:mfrac>
 187                                         <mml:mo>-</mml:mo>
 188                                         <mml:mn>1</mml:mn>
 189                                     </mml:mrow>
 190                                 </mml:mtd></mml:mtr>
 191                                 <mml:mtr><mml:mtd>
 192                                     <mml:mi mathvariant="italic">clipW</mml:mi>
 193                                 </mml:mtd></mml:mtr>
 194                             </mml:mtable>
 195                         </mml:mfenced>
 196                     </mml:mrow>
 197                 </mml:mrow>
 198             </mml:math></div><p>
 199         </p><p>
 200             <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">INV</mml:mi></mml:math>
 201             denotes matrix inversion.
 202         </p><p>
 203             <code class="function">gluUnProject4</code> is equivalent to <a class="citerefentry" href="gluUnProject.xml"><span class="citerefentry"><span class="refentrytitle">gluUnProject</span></span></a> when <em class="parameter"><code>clipW</code></em> is 1, <em class="parameter"><code>nearVal</code></em> is 0, and
 204             <em class="parameter"><code>farVal</code></em> is 1.
 205         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
 206             <code class="function">gluUnProject4</code> is available only if the GLU version is 1.3 or greater.
 207         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
 208             <a class="citerefentry" href="gluProject.xml"><span class="citerefentry"><span class="refentrytitle">gluProject</span></span></a>,
 209             <a class="citerefentry" href="gluUnProject.xml"><span class="citerefentry"><span class="refentrytitle">gluUnProject</span></span></a>,
 210             <a class="citerefentry" href="glFeedbackBuffer.xml"><span class="citerefentry"><span class="refentrytitle">glFeedbackBuffer</span></span></a>,
 211             <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
 212         </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
 213             Copyright <span class="trademark"></span>© 1991-2006
 214             Silicon Graphics, Inc. This document is licensed under the SGI
 215             Free Software B License. For details, see
 216             <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
 217         </p></div></div></body></html>