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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> |