upstream-doc/man2/glGetBufferParameteriv.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="glGetBufferParameteriv">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2005</year>
   9                 <holder>Sams Publishing</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glGetBufferParameteriv</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glGetBufferParameteriv</refname>
  17         <refpurpose>return parameters of a buffer object</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glGetBufferParameteriv</function></funcdef>
  23                 <paramdef>GLenum <parameter>target</parameter></paramdef>
  24                 <paramdef>GLenum <parameter>value</parameter></paramdef>
  25                 <paramdef>GLint * <parameter>data</parameter></paramdef>
  26             </funcprototype>
  27         </funcsynopsis>
  28     </refsynopsisdiv>
  29     <refsect1 id="parameters"><title>Parameters</title>
  30         <variablelist>
  31         <varlistentry>
  32             <term><parameter>target</parameter></term>
  33             <listitem>
  34                 <para>
  35                     Specifies the target buffer object.
  36                     The symbolic constant must be <constant>GL_ARRAY_BUFFER</constant>,
  37                     <constant>GL_ELEMENT_ARRAY_BUFFER</constant>,
  38                     <constant>GL_PIXEL_PACK_BUFFER</constant>, or
  39                     <constant>GL_PIXEL_UNPACK_BUFFER</constant>.
  40                 </para>
  41             </listitem>
  42         </varlistentry>
  43         <varlistentry>
  44             <term><parameter>value</parameter></term>
  45             <listitem>
  46                 <para>
  47                     Specifies the symbolic name of a buffer object parameter.
  48                     Accepted values are <constant>GL_BUFFER_ACCESS</constant>, <constant>GL_BUFFER_MAPPED</constant>,
  49                     <constant>GL_BUFFER_SIZE</constant>, or <constant>GL_BUFFER_USAGE</constant>.
  50                 </para>
  51             </listitem>
  52         </varlistentry>
  53         <varlistentry>
  54             <term><parameter>data</parameter></term>
  55             <listitem>
  56                 <para>
  57                     Returns the requested parameter.
  58                 </para>
  59             </listitem>
  60         </varlistentry>
  61         </variablelist>
  62     </refsect1>
  63     <refsect1 id="description"><title>Description</title>
  64         <para>
  65             <function>glGetBufferParameteriv</function> returns in <parameter>data</parameter> a selected parameter of the buffer object
  66             specified by <parameter>target</parameter>.
  67         </para>
  68         <para>
  69             <parameter>value</parameter> names a specific buffer object parameter, as follows:
  70         </para>
  71         <variablelist>
  72             <varlistentry>
  73                 <term><constant>GL_BUFFER_ACCESS</constant></term>
  74                 <listitem>
  75                     <para>
  76                         <parameter>params</parameter> returns the access policy set while mapping the buffer object.
  77                         The initial value is <constant>GL_READ_WRITE</constant>.
  78                     </para>
  79                 </listitem>
  80             </varlistentry>
  81             <varlistentry>
  82                 <term><constant>GL_BUFFER_MAPPED</constant></term>
  83                 <listitem>
  84                     <para>
  85                         <parameter>params</parameter> returns a flag indicating whether the buffer object is currently
  86                         mapped. The initial value is <constant>GL_FALSE</constant>.
  87                     </para>
  88                 </listitem>
  89             </varlistentry>
  90             <varlistentry>
  91                 <term><constant>GL_BUFFER_SIZE</constant></term>
  92                 <listitem>
  93                     <para>
  94                         <parameter>params</parameter> returns the size of the buffer object, measured in bytes.
  95                         The initial value is 0.
  96                     </para>
  97                 </listitem>
  98             </varlistentry>
  99             <varlistentry>
 100                 <term><constant>GL_BUFFER_USAGE</constant></term>
 101                 <listitem>
 102                     <para>
 103                         <parameter>params</parameter> returns the buffer object's usage pattern.  The initial value is
 104                         <constant>GL_STATIC_DRAW</constant>.
 105                     </para>
 106                 </listitem>
 107             </varlistentry>
 108         </variablelist>
 109     </refsect1>
 110     <refsect1 id="notes"><title>Notes</title>
 111         <para>
 112             If an error is generated,
 113             no change is made to the contents of <parameter>data</parameter>.
 114         </para>
 115         <para>
 116             <function>glGetBufferParameteriv</function> is available only if the GL version is 1.5 or greater.
 117         </para>
 118         <para>
 119             Targets <constant>GL_PIXEL_PACK_BUFFER</constant> and <constant>GL_PIXEL_UNPACK_BUFFER</constant> are available
 120             only if the GL version is 2.1 or greater.
 121         </para>
 122     </refsect1>
 123     <refsect1 id="errors"><title>Errors</title>
 124         <para>
 125             <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> or <parameter>value</parameter> is not an
 126             accepted value.
 127         </para>
 128         <para>
 129             <constant>GL_INVALID_OPERATION</constant> is generated if the reserved buffer object name 0 is bound to <parameter>target</parameter>.
 130         </para>
 131         <para>
 132             <constant>GL_INVALID_OPERATION</constant> is generated if <function>glGetBufferParameteriv</function>
 133             is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
 134             and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
 135         </para>
 136     </refsect1>
 137     <refsect1 id="seealso"><title>See Also</title>
 138         <para>
 139             <citerefentry><refentrytitle>glBindBuffer</refentrytitle></citerefentry>,
 140             <citerefentry><refentrytitle>glBufferData</refentrytitle></citerefentry>,
 141             <citerefentry><refentrytitle>glMapBuffer</refentrytitle></citerefentry>,
 142             <citerefentry><refentrytitle>glUnmapBuffer</refentrytitle></citerefentry>
 143         </para>
 144     </refsect1>
 145     <refsect1 id="Copyright"><title>Copyright</title>
 146         <para>
 147             Copyright <trademark class="copyright"></trademark> 2005 Addison-Wesley.
 148             This material may be distributed subject to the terms and conditions set forth in
 149             the Open Publication License, v 1.0, 8 June 1999.
 150             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 151         </para>
 152     </refsect1>
 153 </refentry>