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=
"glPatchParameter">
9 <holder>Khronos Group.
</holder>
12 <refentrytitle>glPatchParameter
</refentrytitle>
13 <manvolnum>3G
</manvolnum>
16 <refname>glPatchParameter
</refname>
17 <refpurpose>specifies the parameters for patch primitives
</refpurpose>
19 <refsynopsisdiv><title>C Specification
</title>
22 <funcdef>void
<function>glPatchParameteri
</function></funcdef>
23 <paramdef>GLenum
<parameter>pname
</parameter></paramdef>
24 <paramdef>GLint
<parameter>value
</parameter></paramdef>
29 <funcdef>void
<function>glPatchParameterfv
</function></funcdef>
30 <paramdef>GLenum
<parameter>pname
</parameter></paramdef>
31 <paramdef>const GLfloat *
<parameter>values
</parameter></paramdef>
35 <!-- eqn: ignoring delim $$ -->
36 <refsect1 id=
"parameters"><title>Parameters
</title>
39 <term><parameter>pname
</parameter></term>
42 Specifies the name of the parameter to set. The symbolc constants
<constant>GL_PATCH_VERTICES
</constant>,
43 <constant>GL_PATCH_DEFAULT_OUTER_LEVEL
</constant>, and
<constant>GL_PATCH_DEFAULT_INNER_LEVEL
</constant> are accepted.
48 <term><parameter>value
</parameter></term>
51 Specifies the new value for the parameter given by
<parameter>pname
</parameter>.
56 <term><parameter>values
</parameter></term>
59 Specifies the address of an array containing the new values for the parameter given by
<parameter>pname
</parameter>.
65 <refsect1 id=
"description"><title>Description
</title>
67 <function>glPatchParameter
</function> specifies the parameters that will be used for patch primitives.
<parameter>pname
</parameter>
68 specifies the parameter to modify and must be either
<constant>GL_PATCH_VERTICES
</constant>,
<constant>GL_PATCH_DEFAULT_OUTER_LEVEL
</constant>
69 or
<constant>GL_PATCH_DEFAULT_INNER_LEVEL
</constant>. For
<function>glPatchParameteri
</function>,
<parameter>value
</parameter> specifies
70 the new value for the parameter specified by
<parameter>pname
</parameter>. For
<function>glPatchParameterfv
</function>,
<parameter>values
</parameter>
71 specifies the address of an array containing the new values for the parameter specified by
<parameter>pname
</parameter>.
74 When
<parameter>pname
</parameter> is
<constant>GL_PATCH_VERTICES
</constant>,
<parameter>value
</parameter> specifies the number
75 of vertices that will be used to make up a single patch primitive. Patch primitives are consumed by the tessellation control
76 shader (if present) and subsequently used for tessellation. When primitives are specified using
77 <citerefentry><refentrytitle>glDrawArrays
</refentrytitle></citerefentry> or a similar function, each patch will be made
78 from
<parameter>parameter
</parameter> control points, each represented by a vertex taken from the enabeld vertex arrays.
79 <parameter>parameter
</parameter> must be greater than zero, and less than or equal to the value of
<constant>GL_MAX_PATCH_VERTICES
</constant>.
82 When
<parameter>pname
</parameter> is
<constant>GL_PATCH_DEFAULT_OUTER_LEVEL
</constant> or
<constant>GL_PATCH_DEFAULT_INNER_LEVEL
</constant>,
83 <parameter>values
</parameter> contains the address of an array contiaining the default outer or inner tessellation levels, respectively,
84 to be used when no tessellation control shader is present.
87 <refsect1 id=
"errors"><title>Errors
</title>
89 <constant>GL_INVALID_ENUM
</constant> is generated if
<parameter>pname
</parameter> is not an accepted value.
92 <constant>GL_INVALID_VALUE
</constant> is generated if
<parameter>pname
</parameter> is
<constant>GL_PATCH_VERTICES
</constant>
93 and
<parameter>value
</parameter> is less than or equal to zero, or greater than the value of
<constant>GL_MAX_PATCH_VERTICES
</constant>.
96 <refsect1 id=
"seealso"><title>See Also
</title>
98 <citerefentry><refentrytitle>glDrawArrays
</refentrytitle></citerefentry>,
99 <citerefentry><refentrytitle>glDrawArraysInstanced
</refentrytitle></citerefentry>,
100 <citerefentry><refentrytitle>glDrawElements
</refentrytitle></citerefentry>,
101 <citerefentry><refentrytitle>glDrawRangeElements
</refentrytitle></citerefentry>,
104 <refsect1 id=
"Copyright"><title>Copyright
</title>
106 Copyright
<trademark class=
"copyright"></trademark> 2010 Khronos Group.
107 This material may be distributed subject to the terms and conditions set forth in
108 the Open Publication License, v
1.0,
8 June
1999.
109 <ulink url=
"http://opencontent.org/openpub/">http://opencontent.org/openpub/
</ulink>.