upstream-man-pages/man2/glGetQueryiv.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="glGetQueryiv">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2005</year>
   9                 <holder>Sams Publishing</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glGetQueryiv</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glGetQueryiv</refname>
  17         <refpurpose>return parameters of a query object target</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glGetQueryiv</function></funcdef>
  23                 <paramdef>GLenum <parameter>target</parameter></paramdef>
  24                 <paramdef>GLenum <parameter>pname</parameter></paramdef>
  25                 <paramdef>GLint * <parameter>params</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 a query object target.
  36                     Must be <constant>GL_SAMPLES_PASSED</constant>.
  37                 </para>
  38             </listitem>
  39         </varlistentry>
  40         <varlistentry>
  41             <term><parameter>pname</parameter></term>
  42             <listitem>
  43                 <para>
  44                     Specifies the symbolic name of a query object target parameter.
  45                     Accepted values are <constant>GL_CURRENT_QUERY</constant> or <constant>GL_QUERY_COUNTER_BITS</constant>.
  46                 </para>
  47             </listitem>
  48         </varlistentry>
  49         <varlistentry>
  50             <term><parameter>params</parameter></term>
  51             <listitem>
  52                 <para>
  53                     Returns the requested data.
  54                 </para>
  55             </listitem>
  56         </varlistentry>
  57         </variablelist>
  58     </refsect1>
  59     <refsect1 id="description"><title>Description</title>
  60         <para>
  61             <function>glGetQueryiv</function> returns in <parameter>params</parameter> a selected parameter of the query object target
  62             specified by <parameter>target</parameter>.
  63         </para>
  64         <para>
  65             <parameter>pname</parameter> names a specific query object target parameter.  When <parameter>target</parameter> is
  66             <constant>GL_SAMPLES_PASSED</constant>, <parameter>pname</parameter> can be as follows:
  67         </para>
  68         <variablelist>
  69             <varlistentry>
  70                 <term><constant>GL_CURRENT_QUERY</constant></term>
  71                 <listitem>
  72                     <para>
  73                         <parameter>params</parameter> returns the name of the currently active occlusion query object.
  74                         If no occlusion query is active, 0 is returned.  The initial value is 0.
  75                     </para>
  76                 </listitem>
  77             </varlistentry>
  78             <varlistentry>
  79                 <term><constant>GL_QUERY_COUNTER_BITS</constant></term>
  80                 <listitem>
  81                     <para>
  82                         <parameter>params</parameter> returns the number of bits in the query counter used to accumulate passing samples.
  83                         If the number of bits returned is 0, the implementation does not support a query counter, and the results
  84                         obtained from <citerefentry><refentrytitle>glGetQueryObject</refentrytitle></citerefentry> are useless.
  85                     </para>
  86                 </listitem>
  87             </varlistentry>
  88         </variablelist>
  89     </refsect1>
  90     <refsect1 id="notes"><title>Notes</title>
  91         <para>
  92             If an error is generated,
  93             no change is made to the contents of <parameter>params</parameter>.
  94         </para>
  95         <para>
  96             <function>glGetQueryiv</function> is available only if the GL version is 1.5 or greater.
  97         </para>
  98     </refsect1>
  99     <refsect1 id="errors"><title>Errors</title>
 100         <para>
 101             <constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> or <parameter>pname</parameter> is not an
 102             accepted value.
 103         </para>
 104         <para>
 105             <constant>GL_INVALID_OPERATION</constant> is generated if <function>glGetQueryiv</function>
 106             is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
 107             and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
 108         </para>
 109     </refsect1>
 110     <refsect1 id="seealso"><title>See Also</title>
 111         <para>
 112             <citerefentry><refentrytitle>glGetQueryObject</refentrytitle></citerefentry>,
 113             <citerefentry><refentrytitle>glIsQuery</refentrytitle></citerefentry>
 114         </para>
 115     </refsect1>
 116     <refsect1 id="Copyright"><title>Copyright</title>
 117         <para>
 118             Copyright <trademark class="copyright"></trademark> 2005 Addison-Wesley.
 119             This material may be distributed subject to the terms and conditions set forth in
 120             the Open Publication License, v 1.0, 8 June 1999.
 121             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 122         </para>
 123     </refsect1>
 124 </refentry>