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=
"glDrawTransformFeedback">
9 <holder>Khronos Group.
</holder>
12 <refentrytitle>glDrawTransformFeedback
</refentrytitle>
13 <manvolnum>3G
</manvolnum>
16 <refname>glDrawTransformFeedback
</refname>
17 <refpurpose>render primitives using a count derived from a transform feedback object
</refpurpose>
19 <refsynopsisdiv><title>C Specification
</title>
22 <funcdef>void
<function>glDrawTransformFeedback
</function></funcdef>
23 <paramdef>GLenum
<parameter>mode
</parameter></paramdef>
24 <paramdef>GLuint
<parameter>id
</parameter></paramdef>
28 <!-- eqn: ignoring delim $$ -->
29 <refsect1 id=
"parameters"><title>Parameters
</title>
32 <term><parameter>mode
</parameter></term>
35 Specifies what kind of primitives to render.
37 <constant>GL_POINTS
</constant>,
38 <constant>GL_LINE_STRIP
</constant>,
39 <constant>GL_LINE_LOOP
</constant>,
40 <constant>GL_LINES
</constant>,
41 <constant>GL_LINE_STRIP_ADJACENCY
</constant>,
42 <constant>GL_LINES_ADJACENCY
</constant>,
43 <constant>GL_TRIANGLE_STRIP
</constant>,
44 <constant>GL_TRIANGLE_FAN
</constant>,
45 <constant>GL_TRIANGLES
</constant>,
46 <constant>GL_TRIANGLE_STRIP_ADJACENCY
</constant>,
47 <constant>GL_TRIANGLES_ADJACENCY
</constant>, and
48 <constant>GL_PATCHES
</constant>
54 <term><parameter>id
</parameter></term>
57 Specifies the name of a transform feedback object from which to retrieve a primitive count.
63 <refsect1 id=
"description"><title>Description
</title>
65 <function>glDrawTransformFeedback
</function> draws primitives of a type specified by
<parameter>mode
</parameter> using
66 a count retrieved from the transform feedback specified by
<parameter>id
</parameter>. Calling
<function>glDrawTransformFeedback
</function>
67 is equivalent to calling
<citerefentry><refentrytitle>glDrawArrays
</refentrytitle></citerefentry> with
<parameter>mode
</parameter>
68 as specified,
<parameter>first
</parameter> set to zero, and
<parameter>count
</parameter> set to the number of vertices captured
69 on vertex stream zero the last time transform feedback was active on the transform feedback object named by
<parameter>id
</parameter>.
72 <refsect1 id=
"errors"><title>Errors
</title>
74 <constant>GL_INVALID_ENUM
</constant> is generated if
<parameter>mode
</parameter> is not an accepted value.
77 <constant>GL_INVALID_VALUE
</constant> is generated if
<parameter>id
</parameter> is not the name of a transform feedback
81 <constant>GL_INVALID_OPERATION
</constant> is generated if a non-zero buffer object name is bound to an
82 enabled array and the buffer object's data store is currently mapped.
85 <constant>GL_INVALID_OPERATION
</constant> is generated if a geometry shader is active and
<parameter>mode
</parameter>
86 is incompatible with the input primitive type of the geometry shader in the currently installed program object.
89 <constant>GL_INVALID_OPERATION
</constant> is generated if
<parameter>mode
</parameter> is
<constant>GL_PATCHES
</constant>
90 and no tessellation control shader is active.
93 <constant>GL_INVALID_OPERATION
</constant> is generated if
<citerefentry><refentrytitle>glEndTransformFeedback
</refentrytitle></citerefentry>
94 has never been called while the transform feedback object named by
<parameter>id
</parameter> was bound.
97 <refsect1 id=
"seealso"><title>See Also
</title>
99 <citerefentry><refentrytitle>glDrawArrays
</refentrytitle></citerefentry>,
100 <citerefentry><refentrytitle>glDrawArraysInstanced
</refentrytitle></citerefentry>,
101 <citerefentry><refentrytitle>glDrawElements
</refentrytitle></citerefentry>,
102 <citerefentry><refentrytitle>glDrawRangeElements
</refentrytitle></citerefentry>,
103 <citerefentry><refentrytitle>glDrawTransformFeedbackStream
</refentrytitle></citerefentry>
106 <refsect1 id=
"Copyright"><title>Copyright
</title>
108 Copyright
<trademark class=
"copyright"></trademark> 2010 Khronos Group.
109 This material may be distributed subject to the terms and conditions set forth in
110 the Open Publication License, v
1.0,
8 June
1999.
111 <ulink url=
"http://opencontent.org/openpub/">http://opencontent.org/openpub/
</ulink>.