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=
"glGetMap">
9 <holder>Silicon Graphics, Inc.
</holder>
12 <refentrytitle>glGetMap
</refentrytitle>
13 <manvolnum>3G
</manvolnum>
16 <refname>glGetMap
</refname>
17 <refpurpose>return evaluator parameters
</refpurpose>
19 <refsynopsisdiv><title>C Specification
</title>
22 <funcdef>void
<function>glGetMapdv
</function></funcdef>
23 <paramdef>GLenum
<parameter>target
</parameter></paramdef>
24 <paramdef>GLenum
<parameter>query
</parameter></paramdef>
25 <paramdef>GLdouble *
<parameter>v
</parameter></paramdef>
30 <funcdef>void
<function>glGetMapfv
</function></funcdef>
31 <paramdef>GLenum
<parameter>target
</parameter></paramdef>
32 <paramdef>GLenum
<parameter>query
</parameter></paramdef>
33 <paramdef>GLfloat *
<parameter>v
</parameter></paramdef>
38 <funcdef>void
<function>glGetMapiv
</function></funcdef>
39 <paramdef>GLenum
<parameter>target
</parameter></paramdef>
40 <paramdef>GLenum
<parameter>query
</parameter></paramdef>
41 <paramdef>GLint *
<parameter>v
</parameter></paramdef>
45 <!-- eqn: ignoring delim $$ -->
46 <refsect1 id=
"parameters"><title>Parameters
</title>
49 <term><parameter>target
</parameter></term>
52 Specifies the symbolic name of a map.
54 <constant>GL_MAP1_COLOR_4
</constant>,
55 <constant>GL_MAP1_INDEX
</constant>,
56 <constant>GL_MAP1_NORMAL
</constant>,
57 <constant>GL_MAP1_TEXTURE_COORD_1
</constant>,
58 <constant>GL_MAP1_TEXTURE_COORD_2
</constant>,
59 <constant>GL_MAP1_TEXTURE_COORD_3
</constant>,
60 <constant>GL_MAP1_TEXTURE_COORD_4
</constant>,
61 <constant>GL_MAP1_VERTEX_3
</constant>,
62 <constant>GL_MAP1_VERTEX_4
</constant>,
63 <constant>GL_MAP2_COLOR_4
</constant>,
64 <constant>GL_MAP2_INDEX
</constant>,
65 <constant>GL_MAP2_NORMAL
</constant>,
66 <constant>GL_MAP2_TEXTURE_COORD_1
</constant>,
67 <constant>GL_MAP2_TEXTURE_COORD_2
</constant>,
68 <constant>GL_MAP2_TEXTURE_COORD_3
</constant>,
69 <constant>GL_MAP2_TEXTURE_COORD_4
</constant>,
70 <constant>GL_MAP2_VERTEX_3
</constant>, and
71 <constant>GL_MAP2_VERTEX_4
</constant>.
76 <term><parameter>query
</parameter></term>
79 Specifies which parameter to return.
81 <constant>GL_COEFF
</constant>,
82 <constant>GL_ORDER
</constant>, and
83 <constant>GL_DOMAIN
</constant> are accepted.
88 <term><parameter>v
</parameter></term>
91 Returns the requested data.
97 <refsect1 id=
"description"><title>Description
</title>
99 <citerefentry><refentrytitle>glMap1
</refentrytitle></citerefentry> and
<citerefentry><refentrytitle>glMap2
</refentrytitle></citerefentry> define evaluators.
100 <function>glGetMap
</function> returns evaluator parameters.
101 <parameter>target
</parameter> chooses a map,
102 <parameter>query
</parameter> selects a specific parameter,
103 and
<parameter>v
</parameter> points to storage where the values will be returned.
106 The acceptable values for the
<parameter>target
</parameter> parameter are described
107 in the
<citerefentry><refentrytitle>glMap1
</refentrytitle></citerefentry> and
<citerefentry><refentrytitle>glMap2
</refentrytitle></citerefentry> reference pages.
110 <parameter>query
</parameter> can assume the following values:
114 <term><constant>GL_COEFF
</constant></term>
117 <parameter>v
</parameter> returns the control points for the evaluator function.
118 One-dimensional evaluators return
119 <inlineequation><mml:math><mml:mi mathvariant=
"italic">order
</mml:mi></mml:math></inlineequation>
121 and two-dimensional evaluators return
122 <inlineequation><mml:math>
123 <!-- eqn: uorder times vorder:-->
125 <mml:mi mathvariant=
"italic">uorder
</mml:mi>
126 <mml:mo>×</mml:mo>
127 <mml:mi mathvariant=
"italic">vorder
</mml:mi>
129 </mml:math></inlineequation>
131 Each control point consists of one, two, three, or four integer,
132 single-precision floating-point,
133 or double-precision floating-point values,
134 depending on the type of the evaluator.
135 The GL returns two-dimensional control points in row-major order,
137 <inlineequation><mml:math><mml:mi mathvariant=
"italic">uorder
</mml:mi></mml:math></inlineequation>
140 <inlineequation><mml:math><mml:mi mathvariant=
"italic">vorder
</mml:mi></mml:math></inlineequation>
141 index after each row.
144 are computed by rounding the internal floating-point values to the
145 nearest integer values.
150 <term><constant>GL_ORDER
</constant></term>
153 <parameter>v
</parameter> returns the order of the evaluator function.
154 One-dimensional evaluators return a single value,
155 <inlineequation><mml:math><mml:mi mathvariant=
"italic">order
</mml:mi></mml:math></inlineequation>.
156 The initial value is
1.
157 Two-dimensional evaluators return two values,
158 <inlineequation><mml:math><mml:mi mathvariant=
"italic">uorder
</mml:mi></mml:math></inlineequation>
160 <inlineequation><mml:math><mml:mi mathvariant=
"italic">vorder
</mml:mi></mml:math></inlineequation>.
161 The initial value is
1,
1.
166 <term><constant>GL_DOMAIN
</constant></term>
169 <parameter>v
</parameter> returns the linear
170 <inlineequation><mml:math><mml:mi mathvariant=
"italic">u
</mml:mi></mml:math></inlineequation>
172 <inlineequation><mml:math><mml:mi mathvariant=
"italic">v
</mml:mi></mml:math></inlineequation>
174 One-dimensional evaluators return two values,
175 <inlineequation><mml:math><mml:mi mathvariant=
"italic">u1
</mml:mi></mml:math></inlineequation>
177 <inlineequation><mml:math><mml:mi mathvariant=
"italic">u2
</mml:mi></mml:math></inlineequation>,
178 as specified by
<citerefentry><refentrytitle>glMap1
</refentrytitle></citerefentry>.
179 Two-dimensional evaluators return four values
180 (
<inlineequation><mml:math><mml:mi mathvariant=
"italic">u1
</mml:mi></mml:math></inlineequation>,
181 <inlineequation><mml:math><mml:mi mathvariant=
"italic">u2
</mml:mi></mml:math></inlineequation>,
182 <inlineequation><mml:math><mml:mi mathvariant=
"italic">v1
</mml:mi></mml:math></inlineequation>,
184 <inlineequation><mml:math><mml:mi mathvariant=
"italic">v2
</mml:mi></mml:math></inlineequation>)
185 as specified by
<citerefentry><refentrytitle>glMap2
</refentrytitle></citerefentry>.
188 are computed by rounding the internal floating-point values to the
189 nearest integer values.
195 <refsect1 id=
"notes"><title>Notes
</title>
197 If an error is generated,
198 no change is made to the contents of
<parameter>v
</parameter>.
201 <refsect1 id=
"errors"><title>Errors
</title>
203 <constant>GL_INVALID_ENUM
</constant> is generated if either
<parameter>target
</parameter> or
<parameter>query
</parameter> is not
207 <constant>GL_INVALID_OPERATION
</constant> is generated if
<function>glGetMap
</function>
208 is executed between the execution of
<citerefentry><refentrytitle>glBegin
</refentrytitle></citerefentry>
209 and the corresponding execution of
<citerefentry><refentrytitle>glEnd
</refentrytitle></citerefentry>.
212 <refsect1 id=
"seealso"><title>See Also
</title>
214 <citerefentry><refentrytitle>glEvalCoord
</refentrytitle></citerefentry>,
215 <citerefentry><refentrytitle>glMap1
</refentrytitle></citerefentry>,
216 <citerefentry><refentrytitle>glMap2
</refentrytitle></citerefentry>
219 <refsect1 id=
"Copyright"><title>Copyright
</title>
221 Copyright
<trademark class=
"copyright"></trademark> 1991-
2006
222 Silicon Graphics, Inc. This document is licensed under the SGI
223 Free Software B License. For details, see
224 <ulink url=
"http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/
</ulink>.