upstream-man-pages/man2/glGetTexGen.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
   3               "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
   4 <refentry id="glGetTexGen">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>1991-2006</year>
   9                 <holder>Silicon Graphics, Inc.</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glGetTexGen</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glGetTexGen</refname>
  17         <refpurpose>return texture coordinate generation parameters</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glGetTexGendv</function></funcdef>
  23                 <paramdef>GLenum <parameter>coord</parameter></paramdef>
  24                 <paramdef>GLenum <parameter>pname</parameter></paramdef>
  25                 <paramdef>GLdouble * <parameter>params</parameter></paramdef>
  26             </funcprototype>
  27         </funcsynopsis>
  28         <funcsynopsis>
  29             <funcprototype>
  30                 <funcdef>void <function>glGetTexGenfv</function></funcdef>
  31                 <paramdef>GLenum <parameter>coord</parameter></paramdef>
  32                 <paramdef>GLenum <parameter>pname</parameter></paramdef>
  33                 <paramdef>GLfloat * <parameter>params</parameter></paramdef>
  34             </funcprototype>
  35         </funcsynopsis>
  36         <funcsynopsis>
  37             <funcprototype>
  38                 <funcdef>void <function>glGetTexGeniv</function></funcdef>
  39                 <paramdef>GLenum <parameter>coord</parameter></paramdef>
  40                 <paramdef>GLenum <parameter>pname</parameter></paramdef>
  41                 <paramdef>GLint * <parameter>params</parameter></paramdef>
  42             </funcprototype>
  43         </funcsynopsis>
  44     </refsynopsisdiv>
  45     <!-- eqn: ignoring delim $$ -->
  46     <refsect1 id="parameters"><title>Parameters</title>
  47         <variablelist>
  48         <varlistentry>
  49             <term><parameter>coord</parameter></term>
  50             <listitem>
  51                 <para>
  52                     Specifies a texture coordinate.
  53                     Must be
  54                     <constant>GL_S</constant>,
  55                     <constant>GL_T</constant>,
  56                     <constant>GL_R</constant>, or
  57                     <constant>GL_Q</constant>.
  58                 </para>
  59             </listitem>
  60         </varlistentry>
  61         <varlistentry>
  62             <term><parameter>pname</parameter></term>
  63             <listitem>
  64                 <para>
  65                     Specifies the symbolic name of the value(s) to be returned.
  66                     Must be either <constant>GL_TEXTURE_GEN_MODE</constant>
  67                     or the name of one of the texture generation plane equations:
  68                     <constant>GL_OBJECT_PLANE</constant> or <constant>GL_EYE_PLANE</constant>.
  69                 </para>
  70             </listitem>
  71         </varlistentry>
  72         <varlistentry>
  73             <term><parameter>params</parameter></term>
  74             <listitem>
  75                 <para>
  76                     Returns the requested data.
  77                 </para>
  78             </listitem>
  79         </varlistentry>
  80         </variablelist>
  81     </refsect1>
  82     <refsect1 id="description"><title>Description</title>
  83         <para>
  84             <function>glGetTexGen</function> returns in <parameter>params</parameter> selected parameters of a texture coordinate
  85             generation function that was specified using <citerefentry><refentrytitle>glTexGen</refentrytitle></citerefentry>.
  86             <parameter>coord</parameter> names one of the (<emphasis>s</emphasis>, <emphasis>t</emphasis>, <emphasis>r</emphasis>, <emphasis>q</emphasis>)
  87             texture coordinates,
  88             using the symbolic constant
  89             <constant>GL_S</constant>,
  90             <constant>GL_T</constant>,
  91             <constant>GL_R</constant>, or
  92             <constant>GL_Q</constant>.
  93         </para>
  94         <para>
  95             <parameter>pname</parameter> specifies one of three symbolic names:
  96         </para>
  97         <variablelist>
  98             <varlistentry>
  99                 <term><constant>GL_TEXTURE_GEN_MODE</constant></term>
 100                 <listitem>
 101                     <para>
 102                         <parameter>params</parameter> returns the single-valued texture generation function,
 103                         a symbolic constant. The initial value is <constant>GL_EYE_LINEAR</constant>.
 104                     </para>
 105                 </listitem>
 106             </varlistentry>
 107             <varlistentry>
 108                 <term><constant>GL_OBJECT_PLANE</constant></term>
 109                 <listitem>
 110                     <para>
 111                         <parameter>params</parameter> returns the four plane equation coefficients that specify
 112                         object linear-coordinate generation.
 113                         Integer values, when requested,
 114                         are mapped directly from the internal floating-point representation.
 115                     </para>
 116                 </listitem>
 117             </varlistentry>
 118             <varlistentry>
 119                 <term><constant>GL_EYE_PLANE</constant></term>
 120                 <listitem>
 121                     <para>
 122                         <parameter>params</parameter> returns the four plane equation coefficients that specify
 123                         eye linear-coordinate generation.
 124                         Integer values,
 125                         when requested,
 126                         are mapped directly from the internal floating-point representation.
 127                         The returned values are those maintained in eye coordinates.
 128                         They are not equal to the values specified using <citerefentry><refentrytitle>glTexGen</refentrytitle></citerefentry>,
 129                         unless the modelview matrix was identity when <citerefentry><refentrytitle>glTexGen</refentrytitle></citerefentry> was called.
 130                     </para>
 131                 </listitem>
 132             </varlistentry>
 133         </variablelist>
 134     </refsect1>
 135     <refsect1 id="notes"><title>Notes</title>
 136         <para>
 137             If an error is generated,
 138             no change is made to the contents of <parameter>params</parameter>.
 139         </para>
 140         <para>
 141             For OpenGL versions 1.3 and greater, or when the <code>ARB_multitexture</code> extension is supported, <function>glGetTexGen</function> returns
 142             the texture coordinate generation parameters for the active texture unit.
 143         </para>
 144     </refsect1>
 145     <refsect1 id="errors"><title>Errors</title>
 146         <para>
 147             <constant>GL_INVALID_ENUM</constant> is generated if <parameter>coord</parameter> or <parameter>pname</parameter> is not an
 148             accepted value.
 149         </para>
 150         <para>
 151             <constant>GL_INVALID_OPERATION</constant> is generated if <function>glGetTexGen</function>
 152             is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
 153             and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
 154         </para>
 155     </refsect1>
 156     <refsect1 id="seealso"><title>See Also</title>
 157         <para>
 158             <citerefentry><refentrytitle>glActiveTexture</refentrytitle></citerefentry>,
 159             <citerefentry><refentrytitle>glTexGen</refentrytitle></citerefentry>
 160         </para>
 161     </refsect1>
 162     <refsect1 id="Copyright"><title>Copyright</title>
 163         <para>
 164             Copyright <trademark class="copyright"></trademark> 1991-2006
 165             Silicon Graphics, Inc. This document is licensed under the SGI
 166             Free Software B License. For details, see
 167             <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
 168         </para>
 169     </refsect1>
 170 </refentry>