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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="glGetMap"> | |
5 | <refmeta> | |
6 | <refmetainfo> | |
7 | <copyright> | |
8 | <year>1991-2006</year> | |
9 | <holder>Silicon Graphics, Inc.</holder> | |
10 | </copyright> | |
11 | </refmetainfo> | |
12 | <refentrytitle>glGetMap</refentrytitle> | |
13 | <manvolnum>3G</manvolnum> | |
14 | </refmeta> | |
15 | <refnamediv> | |
16 | <refname>glGetMap</refname> | |
17 | <refpurpose>return evaluator parameters</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
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> | |
26 | </funcprototype> | |
27 | </funcsynopsis> | |
28 | <funcsynopsis> | |
29 | <funcprototype> | |
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> | |
34 | </funcprototype> | |
35 | </funcsynopsis> | |
36 | <funcsynopsis> | |
37 | <funcprototype> | |
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> | |
42 | </funcprototype> | |
43 | </funcsynopsis> | |
44 | </refsynopsisdiv> | |
45 | <!-- eqn: ignoring delim $$ --> | |
46 | <refsect1 id="parameters"><title>Parameters</title> | |
47 | <variablelist> | |
48 | <varlistentry> | |
49 | <term><parameter>target</parameter></term> | |
50 | <listitem> | |
51 | <para> | |
52 | Specifies the symbolic name of a map. | |
53 | Accepted values are | |
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>. | |
72 | </para> | |
73 | </listitem> | |
74 | </varlistentry> | |
75 | <varlistentry> | |
76 | <term><parameter>query</parameter></term> | |
77 | <listitem> | |
78 | <para> | |
79 | Specifies which parameter to return. | |
80 | Symbolic names | |
81 | <constant>GL_COEFF</constant>, | |
82 | <constant>GL_ORDER</constant>, and | |
83 | <constant>GL_DOMAIN</constant> are accepted. | |
84 | </para> | |
85 | </listitem> | |
86 | </varlistentry> | |
87 | <varlistentry> | |
88 | <term><parameter>v</parameter></term> | |
89 | <listitem> | |
90 | <para> | |
91 | Returns the requested data. | |
92 | </para> | |
93 | </listitem> | |
94 | </varlistentry> | |
95 | </variablelist> | |
96 | </refsect1> | |
97 | <refsect1 id="description"><title>Description</title> | |
98 | <para> | |
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. | |
104 | </para> | |
105 | <para> | |
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. | |
108 | </para> | |
109 | <para> | |
110 | <parameter>query</parameter> can assume the following values: | |
111 | </para> | |
112 | <variablelist> | |
113 | <varlistentry> | |
114 | <term><constant>GL_COEFF</constant></term> | |
115 | <listitem> | |
116 | <para> | |
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> | |
120 | control points, | |
121 | and two-dimensional evaluators return | |
122 | <inlineequation><mml:math> | |
123 | <!-- eqn: uorder times vorder:--> | |
124 | <mml:mrow> | |
125 | <mml:mi mathvariant="italic">uorder</mml:mi> | |
126 | <mml:mo>×</mml:mo> | |
127 | <mml:mi mathvariant="italic">vorder</mml:mi> | |
128 | </mml:mrow> | |
129 | </mml:math></inlineequation> | |
130 | control points. | |
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, | |
136 | incrementing the | |
137 | <inlineequation><mml:math><mml:mi mathvariant="italic">uorder</mml:mi></mml:math></inlineequation> | |
138 | index quickly | |
139 | and the | |
140 | <inlineequation><mml:math><mml:mi mathvariant="italic">vorder</mml:mi></mml:math></inlineequation> | |
141 | index after each row. | |
142 | Integer values, | |
143 | when requested, | |
144 | are computed by rounding the internal floating-point values to the | |
145 | nearest integer values. | |
146 | </para> | |
147 | </listitem> | |
148 | </varlistentry> | |
149 | <varlistentry> | |
150 | <term><constant>GL_ORDER</constant></term> | |
151 | <listitem> | |
152 | <para> | |
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> | |
159 | and | |
160 | <inlineequation><mml:math><mml:mi mathvariant="italic">vorder</mml:mi></mml:math></inlineequation>. | |
161 | The initial value is 1,1. | |
162 | </para> | |
163 | </listitem> | |
164 | </varlistentry> | |
165 | <varlistentry> | |
166 | <term><constant>GL_DOMAIN</constant></term> | |
167 | <listitem> | |
168 | <para> | |
169 | <parameter>v</parameter> returns the linear | |
170 | <inlineequation><mml:math><mml:mi mathvariant="italic">u</mml:mi></mml:math></inlineequation> | |
171 | and | |
172 | <inlineequation><mml:math><mml:mi mathvariant="italic">v</mml:mi></mml:math></inlineequation> | |
173 | mapping parameters. | |
174 | One-dimensional evaluators return two values, | |
175 | <inlineequation><mml:math><mml:mi mathvariant="italic">u1</mml:mi></mml:math></inlineequation> | |
176 | and | |
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>, | |
183 | and | |
184 | <inlineequation><mml:math><mml:mi mathvariant="italic">v2</mml:mi></mml:math></inlineequation>) | |
185 | as specified by <citerefentry><refentrytitle>glMap2</refentrytitle></citerefentry>. | |
186 | Integer values, | |
187 | when requested, | |
188 | are computed by rounding the internal floating-point values to the | |
189 | nearest integer values. | |
190 | </para> | |
191 | </listitem> | |
192 | </varlistentry> | |
193 | </variablelist> | |
194 | </refsect1> | |
195 | <refsect1 id="notes"><title>Notes</title> | |
196 | <para> | |
197 | If an error is generated, | |
198 | no change is made to the contents of <parameter>v</parameter>. | |
199 | </para> | |
200 | </refsect1> | |
201 | <refsect1 id="errors"><title>Errors</title> | |
202 | <para> | |
203 | <constant>GL_INVALID_ENUM</constant> is generated if either <parameter>target</parameter> or <parameter>query</parameter> is not | |
204 | an accepted value. | |
205 | </para> | |
206 | <para> | |
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>. | |
210 | </para> | |
211 | </refsect1> | |
212 | <refsect1 id="seealso"><title>See Also</title> | |
213 | <para> | |
214 | <citerefentry><refentrytitle>glEvalCoord</refentrytitle></citerefentry>, | |
215 | <citerefentry><refentrytitle>glMap1</refentrytitle></citerefentry>, | |
216 | <citerefentry><refentrytitle>glMap2</refentrytitle></citerefentry> | |
217 | </para> | |
218 | </refsect1> | |
219 | <refsect1 id="Copyright"><title>Copyright</title> | |
220 | <para> | |
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>. | |
225 | </para> | |
226 | </refsect1> | |
227 | </refentry> |