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<refentry id="glBeginQueryIndexed">
<refmeta>
<refmetainfo>
<copyright>
<year>2010</year>
<holder>Khronos Group.</holder>
</copyright>
</refmetainfo>
<refentrytitle>glBeginQueryIndexed, glEndQueryIndexed</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glBeginQueryIndexed, glEndQueryIndexed</refname>
<refpurpose>delimit the boundaries of a query object on an indexed target</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glBeginQueryIndexed</function></funcdef>
<paramdef>GLenum <parameter>target</parameter></paramdef>
<paramdef>GLuint <parameter>index</parameter></paramdef>
<paramdef>GLuint <parameter>id</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<!-- eqn: ignoring delim $$ -->
<refsect1 id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>target</parameter></term>
<listitem>
<para>
Specifies the target type of query object established between
<function>glBeginQueryIndexed</function> and the subsequent <citerefentry><refentrytitle>glEndQueryIndexed</refentrytitle></citerefentry>.
The symbolic constant must be one of <constant>GL_SAMPLES_PASSED</constant>, <constant>GL_ANY_SAMPLES_PASSED</constant>,
<constant>GL_PRIMITIVES_GENERATED</constant>, <constant>GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN</constant>, or
<constant>GL_TIME_ELAPSED</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>index</parameter></term>
<listitem>
<para>
Specifies the index of the query target upon which to begin the query.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>id</parameter></term>
<listitem>
<para>
Specifies the name of a query object.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glEndQueryIndexed</function></funcdef>
<paramdef>GLenum <parameter>target</parameter></paramdef>
<paramdef>GLuint <parameter>index</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<!-- eqn: ignoring delim $$ -->
<refsect1 id="parameters2"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>target</parameter></term>
<listitem>
<para>
Specifies the target type of query object to be concluded.
The symbolic constant must be one of <constant>GL_SAMPLES_PASSED</constant>, <constant>GL_ANY_SAMPLES_PASSED</constant>,
<constant>GL_PRIMITIVES_GENERATED</constant>, <constant>GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN</constant>, or
<constant>GL_TIME_ELAPSED</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>index</parameter></term>
<listitem>
<para>
Specifies the index of the query target upon which to end the query.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="description"><title>Description</title>
<para>
<function>glBeginQueryIndexed</function> and <citerefentry><refentrytitle>glEndQueryIndexed</refentrytitle></citerefentry> delimit the
boundaries of a query object. <parameter>query</parameter> must be a name previously returned from a call to
<citerefentry><refentrytitle>glGenQueries</refentrytitle></citerefentry>. If a query object with name <parameter>id</parameter>
does not yet exist it is created with the type determined by <parameter>target</parameter>. <parameter>target</parameter> must
be one of <constant>GL_SAMPLES_PASSED</constant>, <constant>GL_ANY_SAMPLES_PASSED</constant>, <constant>GL_PRIMITIVES_GENERATED</constant>,
<constant>GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN</constant>, or <constant>GL_TIME_ELAPSED</constant>. The behavior of the query
object depends on its type and is as follows.
</para>
<para>
<parameter>index</parameter> specifies the index of the query target and must be between a <parameter>target</parameter>-specific
maximum.
</para>
<para>
If <parameter>target</parameter> is <constant>GL_SAMPLES_PASSED</constant>, <parameter>target</parameter> must be an unused name,
or the name of an existing occlusion query object.
When <function>glBeginQueryIndexed</function> is executed, the query object's samples-passed counter is reset to 0. Subsequent
rendering will increment the counter for every sample that passes the depth test. If the value of <constant>GL_SAMPLE_BUFFERS</constant>
is 0, then the samples-passed count is incremented by 1 for each fragment. If the value of <constant>GL_SAMPLE_BUFFERS</constant>
is 1, then the samples-passed count is incremented by the number of samples whose coverage bit is set. However, implementations, at their
discression may instead increase the samples-passed count by the value of <constant>GL_SAMPLES</constant> if any sample in the fragment
is covered. When <function>glEndQueryIndexed</function>
is executed, the samples-passed counter is assigned to the query object's result value. This value can be queried by
calling <citerefentry><refentrytitle>glGetQueryObject</refentrytitle></citerefentry> with <parameter>pname</parameter>
<constant>GL_QUERY_RESULT</constant>.
When <parameter>target</parameter> is <constant>GL_SAMPLES_PASSED</constant>, <parameter>index</parameter> must be zero.
</para>
<para>
If <parameter>target</parameter> is <constant>GL_ANY_SAMPLES_PASSED</constant>, <parameter>target</parameter> must be an unused name,
or the name of an existing boolean occlusion query object.
When <function>glBeginQueryIndexed</function> is executed, the query object's samples-passed flag is reset to <constant>GL_FALSE</constant>.
Subsequent rendering causes the flag to be set to <constant>GL_TRUE</constant> if any sample passes the depth test. When
<function>glEndQueryIndexed</function> is executed, the samples-passed flag is assigned to the query object's result value. This value can
be queried by calling <citerefentry><refentrytitle>glGetQueryObject</refentrytitle></citerefentry> with <parameter>pname</parameter>
<constant>GL_QUERY_RESULT</constant>.
When <parameter>target</parameter> is <constant>GL_ANY_SAMPLES_PASSED</constant>, <parameter>index</parameter> must be zero.
</para>
<para>
If <parameter>target</parameter> is <constant>GL_PRIMITIVES_GENERATED</constant>, <parameter>target</parameter> must be an unused
name, or the name of an existing primitive query object previously bound to the <constant>GL_PRIMITIVES_GENERATED</constant> query binding.
When <function>glBeginQueryIndexed</function> is executed, the query object's primitives-generated counter is reset to 0. Subsequent
rendering will increment the counter once for every vertex that is emitted from the geometry shader to the stream given by <parameter>index</parameter>,
or from the vertex shader if <parameter>index</parameter> is zero and no geometry shader is present.
When <function>glEndQueryIndexed</function> is executed, the primitives-generated counter for stream <parameter>index</parameter> is assigned to
the query object's result value. This value can be queried by calling <citerefentry><refentrytitle>glGetQueryObject</refentrytitle></citerefentry>
with <parameter>pname</parameter> <constant>GL_QUERY_RESULT</constant>.
When <parameter>target</parameter> is <constant>GL_PRIMITIVES_GENERATED</constant>, <parameter>index</parameter> must be
less than the value of <constant>GL_MAX_VERTEX_STREAMS</constant>.
</para>
<para>
If <parameter>target</parameter> is <constant>GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN</constant>, <parameter>target</parameter> must be
an unused name, or the name of an existing primitive query object previously bound to the <constant>GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN</constant>
query binding. When <function>glBeginQueryIndexed</function> is executed, the query object's primitives-written counter for the stream specified by
<parameter>index</parameter> is reset to 0. Subsequent rendering will increment the counter once for every vertex that is written into the bound
transform feedback buffer(s) for stream <parameter>index</parameter>. If transform feedback
mode is not activated between the call to <function>glBeginQueryIndexed</function> and <function>glEndQueryIndexed</function>, the counter will not be
incremented. When <function>glEndQueryIndexed</function> is executed, the primitives-written counter for stream <parameter>index</parameter> is assigned to
the query object's result value. This value can be queried by calling <citerefentry><refentrytitle>glGetQueryObject</refentrytitle></citerefentry> with <parameter>pname</parameter>
<constant>GL_QUERY_RESULT</constant>.
When <parameter>target</parameter> is <constant>GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN</constant>, <parameter>index</parameter> must be
less than the value of <constant>GL_MAX_VERTEX_STREAMS</constant>.
</para>
<para>
If <parameter>target</parameter> is <constant>GL_TIME_ELAPSED</constant>, <parameter>target</parameter> must be
an unused name, or the name of an existing timer query object previously bound to the <constant>GL_TIME_ELAPSED</constant>
query binding. When <function>glBeginQueryIndexed</function> is executed, the query object's time counter is reset to 0. When <function>glEndQueryIndexed</function>
is executed, the elapsed server time that has passed since the call to <function>glBeginQueryIndexed</function> is written into the query object's
time counter. This value can be queried by calling <citerefentry><refentrytitle>glGetQueryObject</refentrytitle></citerefentry> with <parameter>pname</parameter>
<constant>GL_QUERY_RESULT</constant>.
When <parameter>target</parameter> is <constant>GL_TIME_ELAPSED</constant>, <parameter>index</parameter> must be zero.
</para>
<para>
Querying the <constant>GL_QUERY_RESULT</constant> implicitly flushes the GL pipeline until the rendering delimited by the
query object has completed and the result is available. <constant>GL_QUERY_RESULT_AVAILABLE</constant> can be queried to
determine if the result is immediately available or if the rendering is not yet complete.
</para>
</refsect1>
<refsect1 id="notes"><title>Notes</title>
<para>
If the query target's count exceeds the maximum value representable in the number of available bits, as reported by
<citerefentry><refentrytitle>glGetQueryiv</refentrytitle></citerefentry> with <parameter>target</parameter> set to the
appropriate query target and <parameter>pname</parameter>
<constant>GL_QUERY_COUNTER_BITS</constant>, the count becomes undefined.
</para>
<para>
An implementation may support 0 bits in its counter, in which case query results are always undefined
and essentially useless.
</para>
<para>
When <constant>GL_SAMPLE_BUFFERS</constant> is 0, the samples-passed counter of an occlusion query will increment once for each
fragment that passes the depth test. When <constant>GL_SAMPLE_BUFFERS</constant> is 1, an implementation may either increment
the samples-passed counter individually for each sample of a fragment that passes the depth test, or it may choose to increment
the counter for all samples of a fragment if any one of them passes the depth test.
</para>
<para>
Calling <citerefentry><refentrytitle>glBeginQuery</refentrytitle></citerefentry> or
<citerefentry><refentrytitle>glEndQuery</refentrytitle></citerefentry> is equivalent to
calling <citerefentry><refentrytitle>glBeginQueryIndexed</refentrytitle></citerefentry> or
<citerefentry><refentrytitle>glEndQueryIndexed</refentrytitle></citerefentry> with
<parameter>index</parameter> set to zero, respectively.
</para>
</refsect1>
<refsect1 id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_ENUM</constant> is generated if <parameter>target</parameter> is not one of the accepted tokens.
</para>
<para>
<constant>GL_INVALID_VALUE</constant> is generated if <parameter>index</parameter> is greater than the
query target-specific maximum.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <function>glBeginQueryIndexed</function> is executed while
a query object of the same <parameter>target</parameter> is already active.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <citerefentry><refentrytitle>glEndQueryIndexed</refentrytitle></citerefentry>
is executed when a query object of the same <parameter>target</parameter> is not active.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>id</parameter> is 0.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>id</parameter> is the name of an already active query object.
</para>
<para>
<constant>GL_INVALID_OPERATION</constant> is generated if <parameter>id</parameter> refers to an existing query object whose type
does not does not match <parameter>target</parameter>.
</para>
</refsect1>
<refsect1 id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glDeleteQueries</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glBeginQuery</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glEndQuery</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glGenQueries</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glGetQueryiv</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glGetQueryObject</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glIsQuery</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 id="Copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"></trademark> 2010 Khronos Group.
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>