upstream-doc/man4/glGetQueryObject.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="glGetQueryObject">
   5     <refmeta>
   6         <refmetainfo>
   7             <copyright>
   8                 <year>2005</year>
   9                 <holder>Sams Publishing</holder>
  10             </copyright>
  11         </refmetainfo>
  12         <refentrytitle>glGetQueryObject</refentrytitle>
  13         <manvolnum>3G</manvolnum>
  14     </refmeta>
  15     <refnamediv>
  16         <refname>glGetQueryObject</refname>
  17         <refpurpose>return parameters of a query object</refpurpose>
  18     </refnamediv>
  19     <refsynopsisdiv><title>C Specification</title>
  20         <funcsynopsis>
  21             <funcprototype>
  22                 <funcdef>void <function>glGetQueryObjectiv</function></funcdef>
  23                 <paramdef>GLuint <parameter>id</parameter></paramdef>
  24                 <paramdef>GLenum <parameter>pname</parameter></paramdef>
  25                 <paramdef>GLint * <parameter>params</parameter></paramdef>
  26             </funcprototype>
  27         </funcsynopsis>
  28         <funcsynopsis>
  29             <funcprototype>
  30                 <funcdef>void <function>glGetQueryObjectuiv</function></funcdef>
  31                 <paramdef>GLuint <parameter>id</parameter></paramdef>
  32                 <paramdef>GLenum <parameter>pname</parameter></paramdef>
  33                 <paramdef>GLuint * <parameter>params</parameter></paramdef>
  34             </funcprototype>
  35         </funcsynopsis>
  36         <funcsynopsis>
  37             <funcprototype>
  38                 <funcdef>void <function>glGetQueryObjecti64v</function></funcdef>
  39                 <paramdef>GLuint <parameter>id</parameter></paramdef>
  40                 <paramdef>GLenum <parameter>pname</parameter></paramdef>
  41                 <paramdef>GLint64 * <parameter>params</parameter></paramdef>
  42             </funcprototype>
  43         </funcsynopsis>
  44         <funcsynopsis>
  45             <funcprototype>
  46                 <funcdef>void <function>glGetQueryObjectui64v</function></funcdef>
  47                 <paramdef>GLuint <parameter>id</parameter></paramdef>
  48                 <paramdef>GLenum <parameter>pname</parameter></paramdef>
  49                 <paramdef>GLuint64 * <parameter>params</parameter></paramdef>
  50             </funcprototype>
  51         </funcsynopsis>
  52     </refsynopsisdiv>
  53     <refsect1 id="parameters"><title>Parameters</title>
  54         <variablelist>
  55         <varlistentry>
  56             <term><parameter>id</parameter></term>
  57             <listitem>
  58                 <para>
  59                     Specifies the name of a query object.
  60                 </para>
  61             </listitem>
  62         </varlistentry>
  63         <varlistentry>
  64             <term><parameter>pname</parameter></term>
  65             <listitem>
  66                 <para>
  67                     Specifies the symbolic name of a query object parameter.
  68                     Accepted values are <constant>GL_QUERY_RESULT</constant> or <constant>GL_QUERY_RESULT_AVAILABLE</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>glGetQueryObject</function> returns in <parameter>params</parameter> a selected parameter of the query object
  85             specified by <parameter>id</parameter>.
  86         </para>
  87         <para>
  88             <parameter>pname</parameter> names a specific query object parameter.  <parameter>pname</parameter> can be as follows:
  89         </para>
  90         <variablelist>
  91             <varlistentry>
  92                 <term><constant>GL_QUERY_RESULT</constant></term>
  93                 <listitem>
  94                     <para>
  95                         <parameter>params</parameter> returns the value of the query object's passed samples counter.
  96                         The initial value is 0.
  97                     </para>
  98                 </listitem>
  99             </varlistentry>
 100             <varlistentry>
 101                 <term><constant>GL_QUERY_RESULT_AVAILABLE</constant></term>
 102                 <listitem>
 103                     <para>
 104                         <parameter>params</parameter> returns whether the passed samples counter is immediately available.
 105                         If a delay would occur waiting for the query result, <constant>GL_FALSE</constant> is returned.
 106                         Otherwise, <constant>GL_TRUE</constant> is returned, which also indicates that the results of all
 107                         previous queries are available as well.
 108                     </para>
 109                 </listitem>
 110             </varlistentry>
 111         </variablelist>
 112     </refsect1>
 113     <refsect1 id="notes"><title>Notes</title>
 114         <para>
 115             If an error is generated,
 116             no change is made to the contents of <parameter>params</parameter>.
 117         </para>
 118         <para>
 119             <function>glGetQueryObject</function> implicitly flushes the GL pipeline so that any incomplete rendering
 120             delimited by the occlusion query completes in finite time.
 121         </para>
 122         <para>
 123             If multiple queries are issued using the same query object <parameter>id</parameter> before calling
 124             <function>glGetQueryObject</function>, the results of the most recent query will be returned.  In this case,
 125             when issuing a new query, the results of the previous query are discarded.
 126         </para>
 127         <para>
 128             <function>glGetQueryObjecti64v</function> and <function>glGetQueryObjectui64v</function> are available only
 129             if the GL version is 3.3 or greater.
 130         </para>
 131     </refsect1>
 132     <refsect1 id="errors"><title>Errors</title>
 133         <para>
 134             <constant>GL_INVALID_ENUM</constant> is generated if <parameter>pname</parameter> is not an accepted value.
 135         </para>
 136         <para>
 137             <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>id</parameter> is not the name of a query object.
 138         </para>
 139         <para>
 140             <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>id</parameter> is the name of a currently active
 141             query object.
 142         </para>
 143     </refsect1>
 144     <refsect1 id="seealso"><title>See Also</title>
 145         <para>
 146             <citerefentry><refentrytitle>glBeginQuery</refentrytitle></citerefentry>,
 147             <citerefentry><refentrytitle>glEndQuery</refentrytitle></citerefentry>,
 148             <citerefentry><refentrytitle>glGetQueryiv</refentrytitle></citerefentry>,
 149             <citerefentry><refentrytitle>glIsQuery</refentrytitle></citerefentry>,
 150             <citerefentry><refentrytitle>glQueryCounter</refentrytitle></citerefentry>
 151         </para>
 152     </refsect1>
 153     <refsect1 id="Copyright"><title>Copyright</title>
 154         <para>
 155             Copyright <trademark class="copyright"></trademark> 2005 Addison-Wesley.
 156             This material may be distributed subject to the terms and conditions set forth in
 157             the Open Publication License, v 1.0, 8 June 1999.
 158             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 159         </para>
 160     </refsect1>
 161 </refentry>