--- /dev/null
+<?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="glBeginQuery">
+ <refmeta>
+ <refmetainfo>
+ <copyright>
+ <year>2005</year>
+ <holder>Sams Publishing</holder>
+ </copyright>
+ </refmetainfo>
+ <refentrytitle>glBeginQuery</refentrytitle>
+ <manvolnum>3G</manvolnum>
+ </refmeta>
+ <refnamediv>
+ <refname>glBeginQuery</refname>
+ <refpurpose>delimit the boundaries of a query object</refpurpose>
+ </refnamediv>
+ <refsynopsisdiv><title>C Specification</title>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>void <function>glBeginQuery</function></funcdef>
+ <paramdef>GLenum <parameter>target</parameter></paramdef>
+ <paramdef>GLuint <parameter>id</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+ <!-- eqn: ignoring delim $$ -->
+ <refsect1 id="parameters"><title>Parameters</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>target</parameter></term>
+ <listitem>
+ <para>
+ Specifies the target type of query object established between
+ <function>glBeginQuery</function> and the subsequent <citerefentry><refentrytitle>glEndQuery</refentrytitle></citerefentry>.
+ The symbolic constant must be one of <constant>GL_SAMPLES_PASSED</constant>, <constant>GL_ANY_SAMPLES_PASSED</constant>,
+ <constant>GL_ANY_SAMPLES_PASSED_CONSERVATIVE</constant>,
+ <constant>GL_PRIMITIVES_GENERATED</constant>, <constant>GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN</constant>, or
+ <constant>GL_TIME_ELAPSED</constant>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>id</parameter></term>
+ <listitem>
+ <para>
+ Specifies the name of a query object.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsynopsisdiv><title>C Specification</title>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>void <function>glEndQuery</function></funcdef>
+ <paramdef>GLenum <parameter>target</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+ <!-- eqn: ignoring delim $$ -->
+ <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_ANY_SAMPLES_PASSED_CONSERVATIVE</constant>,
+ <constant>GL_PRIMITIVES_GENERATED</constant>, <constant>GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN</constant>, or
+ <constant>GL_TIME_ELAPSED</constant>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1 id="description"><title>Description</title>
+ <para>
+ <function>glBeginQuery</function> and <citerefentry><refentrytitle>glEndQuery</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>
+ If <parameter>target</parameter> is <constant>GL_SAMPLES_PASSED</constant>, <parameter>id</parameter> must be an unused name,
+ or the name of an existing occlusion query object.
+ When <function>glBeginQuery</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>glEndQuery</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>.
+ </para>
+ <para>
+ If <parameter>target</parameter> is <constant>GL_ANY_SAMPLES_PASSED</constant> or <constant>GL_ANY_SAMPLES_PASSED_CONSERVATIVE</constant>,
+ <parameter>id</parameter> must be an unused name, or the name of an existing boolean occlusion query object.
+ When <function>glBeginQuery</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 in the case of <constant>GL_ANY_SAMPLES_PASSED</constant>,
+ or if the implementation determines that any sample might pass the depth test in the case of <constant>GL_ANY_SAMPLES_PASSED_CONSERVATIVE</constant>.
+ The implementation may be able to provide a more efficient test in the case of <constant>GL_ANY_SAMPLES_PASSED_CONSERVATIVE</constant>
+ if some false positives are acceptable to the application. When
+ <function>glEndQuery</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>.
+ </para>
+ <para>
+ If <parameter>target</parameter> is <constant>GL_PRIMITIVES_GENERATED</constant>, <parameter>id</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>glBeginQuery</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, or from the vertex shader if
+ no geometry shader is present. When <function>glEndQuery</function> is executed, the primitives-generated 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>.
+ </para>
+ <para>
+ If <parameter>target</parameter> is <constant>GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN</constant>, <parameter>id</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>glBeginQuery</function> is executed, the query object's primitives-written counter is reset to 0. Subsequent
+ rendering will increment the counter once for every vertex that is written into the bound transform feedback buffer(s). If transform feedback
+ mode is not activated between the call to <function>glBeginQuery</function> and <function>glEndQuery</function>, the counter will not be
+ incremented. When <function>glEndQuery</function> is executed, the primitives-written 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>.
+ </para>
+ <para>
+ If <parameter>target</parameter> is <constant>GL_TIME_ELAPSED</constant>, <parameter>id</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>glBeginQuery</function> is executed, the query object's time counter is reset to 0. When <function>glEndQuery</function>
+ is executed, the elapsed server time that has passed since the call to <function>glBeginQuery</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>.
+ </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>
+ The query targets <constant>GL_ANY_SAMPLES_PASSED</constant>, and <constant>GL_TIME_ELAPSED</constant> are availale only if
+ the GL version is 3.3 or higher.
+ </para>
+ <para>
+ The query target <constant>GL_ANY_SAMPLES_PASSED_CONSERVATIVE</constant> is available only of the GL version is 4.3 or higher.
+ </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_OPERATION</constant> is generated if <function>glBeginQuery</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>glEndQuery</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>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> 2005 Addison-Wesley.
+ Copyright <trademark class="copyright"></trademark> 2010-2012 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>
HCoop / clinton / guile-figl.git / blobdiff