Blame |
Last modification |
View Log
| RSS feed
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
<refentry id="glGetQueryObject">
<refmeta>
<refmetainfo>
<copyright>
<year>2005</year>
<holder>Sams Publishing</holder>
</copyright>
</refmetainfo>
<refentrytitle>glGetQueryObject</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glGetQueryObject</refname>
<refpurpose>return parameters of a query object</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glGetQueryObjectiv</function></funcdef>
<paramdef>GLuint <parameter>id</parameter></paramdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>GLint * <parameter>params</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glGetQueryObjectuiv</function></funcdef>
<paramdef>GLuint <parameter>id</parameter></paramdef>
<paramdef>GLenum <parameter>pname</parameter></paramdef>
<paramdef>GLuint * <parameter>params</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>id</parameter></term>
<listitem>
<para>
Specifies the name of a query object.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>pname</parameter></term>
<listitem>
<para>
Specifies the symbolic name of a query object parameter.
Accepted values are <constant>GL_QUERY_RESULT</constant> or <constant>GL_QUERY_RESULT_AVAILABLE</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>params</parameter></term>
<listitem>
<para>
Returns the requested data.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="description"><title>Description</title>
<para>
<function>glGetQueryObject</function> returns in <parameter>params</parameter> a selected parameter of the query object
specified by <parameter>id</parameter>.
</para>
<para>
<parameter>pname</parameter> names a specific query object parameter. <parameter>pname</parameter> can be as follows:
</para>
<variablelist>
<varlistentry>
<term><constant>GL_QUERY_RESULT</constant></term>
<listitem>
<para>
<parameter>params</parameter> returns the value of the query object's passed samples counter.
The initial value is 0.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><constant>GL_QUERY_RESULT_AVAILABLE</constant></term>
<listitem>
<para>
<parameter>params</parameter> returns whether the passed samples counter is immediately available.
If a delay would occur waiting for the query result, <constant>GL_FALSE</constant> is returned.
Otherwise, <constant>GL_TRUE</constant> is returned, which also indicates that the results of all
previous queries are available as well.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="notes"><title>Notes</title>
<para>
If an error is generated,
no change is made to the contents of <parameter>params</parameter>.
</para>
<para>
<function>glGetQueryObject</function> implicitly flushes the GL pipeline so that any incomplete rendering
delimited by the occlusion query completes in finite time.
</para>
<para>
If multiple queries are issued using the same query object <parameter>id</parameter> before calling
<function>glGetQueryObject</function>, the results of the most recent query will be returned. In this case,
when issuing a new query, the results of the previous query are discarded.
</para>
<para>
<function>glGetQueryObject</function> is available only if the GL version is 1.5 or greater.
</para>
</refsect1>
<refsect1 id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>pname</parameter> is not an accepted value.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>id</parameter> is not the name of a query object.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>id</parameter> is the name of a currently active
query object.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glGetQueryObject</function>
is executed between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry>
and the corresponding execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
</para>
</refsect1>
<refsect1 id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glBeginQuery</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glEndQuery</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glGetQueryiv</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glIsQuery</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"></trademark> 2005 Addison-Wesley.
This material may be distributed subject to the terms and conditions set forth in
the Open Publication License, v 1.0, 8 June 1999.
<ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
</para>
</refsect1>
</refentry>