upstream-man-pages/man2/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     </refsynopsisdiv>
  37     <refsect1 id="parameters"><title>Parameters</title>
  38         <variablelist>
  39         <varlistentry>
  40             <term><parameter>id</parameter></term>
  41             <listitem>
  42                 <para>
  43                     Specifies the name of a query object.
  44                 </para>
  45             </listitem>
  46         </varlistentry>
  47         <varlistentry>
  48             <term><parameter>pname</parameter></term>
  49             <listitem>
  50                 <para>
  51                     Specifies the symbolic name of a query object parameter.
  52                     Accepted values are <constant>GL_QUERY_RESULT</constant> or <constant>GL_QUERY_RESULT_AVAILABLE</constant>.
  53                 </para>
  54             </listitem>
  55         </varlistentry>
  56         <varlistentry>
  57             <term><parameter>params</parameter></term>
  58             <listitem>
  59                 <para>
  60                     Returns the requested data.
  61                 </para>
  62             </listitem>
  63         </varlistentry>
  64         </variablelist>
  65     </refsect1>
  66     <refsect1 id="description"><title>Description</title>
  67         <para>
  68             <function>glGetQueryObject</function> returns in <parameter>params</parameter> a selected parameter of the query object
  69             specified by <parameter>id</parameter>.
  70         </para>
  71         <para>
  72             <parameter>pname</parameter> names a specific query object parameter.  <parameter>pname</parameter> can be as follows:
  73         </para>
  74         <variablelist>
  75             <varlistentry>
  76                 <term><constant>GL_QUERY_RESULT</constant></term>
  77                 <listitem>
  78                     <para>
  79                         <parameter>params</parameter> returns the value of the query object's passed samples counter.
  80                         The initial value is 0.
  81                     </para>
  82                 </listitem>
  83             </varlistentry>
  84             <varlistentry>
  85                 <term><constant>GL_QUERY_RESULT_AVAILABLE</constant></term>
  86                 <listitem>
  87                     <para>
  88                         <parameter>params</parameter> returns whether the passed samples counter is immediately available.
  89                         If a delay would occur waiting for the query result, <constant>GL_FALSE</constant> is returned.
  90                         Otherwise, <constant>GL_TRUE</constant> is returned, which also indicates that the results of all
  91                         previous queries are available as well.
  92                     </para>
  93                 </listitem>
  94             </varlistentry>
  95         </variablelist>
  96     </refsect1>
  97     <refsect1 id="notes"><title>Notes</title>
  98         <para>
  99             If an error is generated,
 100             no change is made to the contents of <parameter>params</parameter>.
 101         </para>
 102         <para>
 103             <function>glGetQueryObject</function> implicitly flushes the GL pipeline so that any incomplete rendering
 104             delimited by the occlusion query completes in finite time.
 105         </para>
 106         <para>
 107             If multiple queries are issued using the same query object <parameter>id</parameter> before calling
 108             <function>glGetQueryObject</function>, the results of the most recent query will be returned.  In this case,
 109             when issuing a new query, the results of the previous query are discarded.
 110         </para>
 111         <para>
 112             <function>glGetQueryObject</function> is available only if the GL version is 1.5 or greater.
 113         </para>
 114     </refsect1>
 115     <refsect1 id="errors"><title>Errors</title>
 116         <para>
 117             <constant>GL_INVALID_ENUM</constant> is generated if <parameter>pname</parameter> is not an accepted value.
 118         </para>
 119         <para>
 120             <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>id</parameter> is not the name of a query object.
 121         </para>
 122         <para>
 123             <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>id</parameter> is the name of a currently active
 124             query object.
 125         </para>
 126         <para>
 127             <constant>GL_INVALID_OPERATION</constant> is generated if <function>glGetQueryObject</function>
 128             is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
 129             and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
 130         </para>
 131     </refsect1>
 132     <refsect1 id="seealso"><title>See Also</title>
 133         <para>
 134             <citerefentry><refentrytitle>glBeginQuery</refentrytitle></citerefentry>,
 135             <citerefentry><refentrytitle>glEndQuery</refentrytitle></citerefentry>,
 136             <citerefentry><refentrytitle>glGetQueryiv</refentrytitle></citerefentry>,
 137             <citerefentry><refentrytitle>glIsQuery</refentrytitle></citerefentry>
 138         </para>
 139     </refsect1>
 140     <refsect1 id="Copyright"><title>Copyright</title>
 141         <para>
 142             Copyright <trademark class="copyright"></trademark> 2005 Addison-Wesley.
 143             This material may be distributed subject to the terms and conditions set forth in
 144             the Open Publication License, v 1.0, 8 June 1999.
 145             <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
 146         </para>
 147     </refsect1>
 148 </refentry>