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3 | <?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>glGetMap</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glGetMap"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetMap — return evaluator parameters</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glGetMapdv</b>(</code></td><td>GLenum </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">query</var>, </td></tr><tr><td> </td><td>GLdouble * </td><td><var class="pdparam">v</var><code>)</code>;</td></tr></table></div><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glGetMapfv</b>(</code></td><td>GLenum </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">query</var>, </td></tr><tr><td> </td><td>GLfloat * </td><td><var class="pdparam">v</var><code>)</code>;</td></tr></table></div><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glGetMapiv</b>(</code></td><td>GLenum </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">query</var>, </td></tr><tr><td> </td><td>GLint * </td><td><var class="pdparam">v</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>target</code></em></span></dt><dd><p> | |
4 | Specifies the symbolic name of a map. | |
5 | Accepted values are | |
6 | <code class="constant">GL_MAP1_COLOR_4</code>, | |
7 | <code class="constant">GL_MAP1_INDEX</code>, | |
8 | <code class="constant">GL_MAP1_NORMAL</code>, | |
9 | <code class="constant">GL_MAP1_TEXTURE_COORD_1</code>, | |
10 | <code class="constant">GL_MAP1_TEXTURE_COORD_2</code>, | |
11 | <code class="constant">GL_MAP1_TEXTURE_COORD_3</code>, | |
12 | <code class="constant">GL_MAP1_TEXTURE_COORD_4</code>, | |
13 | <code class="constant">GL_MAP1_VERTEX_3</code>, | |
14 | <code class="constant">GL_MAP1_VERTEX_4</code>, | |
15 | <code class="constant">GL_MAP2_COLOR_4</code>, | |
16 | <code class="constant">GL_MAP2_INDEX</code>, | |
17 | <code class="constant">GL_MAP2_NORMAL</code>, | |
18 | <code class="constant">GL_MAP2_TEXTURE_COORD_1</code>, | |
19 | <code class="constant">GL_MAP2_TEXTURE_COORD_2</code>, | |
20 | <code class="constant">GL_MAP2_TEXTURE_COORD_3</code>, | |
21 | <code class="constant">GL_MAP2_TEXTURE_COORD_4</code>, | |
22 | <code class="constant">GL_MAP2_VERTEX_3</code>, and | |
23 | <code class="constant">GL_MAP2_VERTEX_4</code>. | |
24 | </p></dd><dt><span class="term"><em class="parameter"><code>query</code></em></span></dt><dd><p> | |
25 | Specifies which parameter to return. | |
26 | Symbolic names | |
27 | <code class="constant">GL_COEFF</code>, | |
28 | <code class="constant">GL_ORDER</code>, and | |
29 | <code class="constant">GL_DOMAIN</code> are accepted. | |
30 | </p></dd><dt><span class="term"><em class="parameter"><code>v</code></em></span></dt><dd><p> | |
31 | Returns the requested data. | |
32 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> | |
33 | <a class="citerefentry" href="glMap1.xml"><span class="citerefentry"><span class="refentrytitle">glMap1</span></span></a> and <a class="citerefentry" href="glMap2.xml"><span class="citerefentry"><span class="refentrytitle">glMap2</span></span></a> define evaluators. | |
34 | <code class="function">glGetMap</code> returns evaluator parameters. | |
35 | <em class="parameter"><code>target</code></em> chooses a map, | |
36 | <em class="parameter"><code>query</code></em> selects a specific parameter, | |
37 | and <em class="parameter"><code>v</code></em> points to storage where the values will be returned. | |
38 | </p><p> | |
39 | The acceptable values for the <em class="parameter"><code>target</code></em> parameter are described | |
40 | in the <a class="citerefentry" href="glMap1.xml"><span class="citerefentry"><span class="refentrytitle">glMap1</span></span></a> and <a class="citerefentry" href="glMap2.xml"><span class="citerefentry"><span class="refentrytitle">glMap2</span></span></a> reference pages. | |
41 | </p><p> | |
42 | <em class="parameter"><code>query</code></em> can assume the following values: | |
43 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_COEFF</code></span></dt><dd><p> | |
44 | <em class="parameter"><code>v</code></em> returns the control points for the evaluator function. | |
45 | One-dimensional evaluators return | |
46 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">order</mml:mi></mml:math> | |
47 | control points, | |
48 | and two-dimensional evaluators return | |
49 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
50 | ||
51 | <mml:mrow> | |
52 | <mml:mi mathvariant="italic">uorder</mml:mi> | |
53 | <mml:mo>×</mml:mo> | |
54 | <mml:mi mathvariant="italic">vorder</mml:mi> | |
55 | </mml:mrow> | |
56 | </mml:math> | |
57 | control points. | |
58 | Each control point consists of one, two, three, or four integer, | |
59 | single-precision floating-point, | |
60 | or double-precision floating-point values, | |
61 | depending on the type of the evaluator. | |
62 | The GL returns two-dimensional control points in row-major order, | |
63 | incrementing the | |
64 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">uorder</mml:mi></mml:math> | |
65 | index quickly | |
66 | and the | |
67 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">vorder</mml:mi></mml:math> | |
68 | index after each row. | |
69 | Integer values, | |
70 | when requested, | |
71 | are computed by rounding the internal floating-point values to the | |
72 | nearest integer values. | |
73 | </p></dd><dt><span class="term"><code class="constant">GL_ORDER</code></span></dt><dd><p> | |
74 | <em class="parameter"><code>v</code></em> returns the order of the evaluator function. | |
75 | One-dimensional evaluators return a single value, | |
76 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">order</mml:mi></mml:math>. | |
77 | The initial value is 1. | |
78 | Two-dimensional evaluators return two values, | |
79 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">uorder</mml:mi></mml:math> | |
80 | and | |
81 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">vorder</mml:mi></mml:math>. | |
82 | The initial value is 1,1. | |
83 | </p></dd><dt><span class="term"><code class="constant">GL_DOMAIN</code></span></dt><dd><p> | |
84 | <em class="parameter"><code>v</code></em> returns the linear | |
85 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">u</mml:mi></mml:math> | |
86 | and | |
87 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">v</mml:mi></mml:math> | |
88 | mapping parameters. | |
89 | One-dimensional evaluators return two values, | |
90 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">u1</mml:mi></mml:math> | |
91 | and | |
92 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">u2</mml:mi></mml:math>, | |
93 | as specified by <a class="citerefentry" href="glMap1.xml"><span class="citerefentry"><span class="refentrytitle">glMap1</span></span></a>. | |
94 | Two-dimensional evaluators return four values | |
95 | (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">u1</mml:mi></mml:math>, | |
96 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">u2</mml:mi></mml:math>, | |
97 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">v1</mml:mi></mml:math>, | |
98 | and | |
99 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">v2</mml:mi></mml:math>) | |
100 | as specified by <a class="citerefentry" href="glMap2.xml"><span class="citerefentry"><span class="refentrytitle">glMap2</span></span></a>. | |
101 | Integer values, | |
102 | when requested, | |
103 | are computed by rounding the internal floating-point values to the | |
104 | nearest integer values. | |
105 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p> | |
106 | If an error is generated, | |
107 | no change is made to the contents of <em class="parameter"><code>v</code></em>. | |
108 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> | |
109 | <code class="constant">GL_INVALID_ENUM</code> is generated if either <em class="parameter"><code>target</code></em> or <em class="parameter"><code>query</code></em> is not | |
110 | an accepted value. | |
111 | </p><p> | |
112 | <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glGetMap</code> | |
113 | is executed between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> | |
114 | and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>. | |
115 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> | |
116 | <a class="citerefentry" href="glEvalCoord.xml"><span class="citerefentry"><span class="refentrytitle">glEvalCoord</span></span></a>, | |
117 | <a class="citerefentry" href="glMap1.xml"><span class="citerefentry"><span class="refentrytitle">glMap1</span></span></a>, | |
118 | <a class="citerefentry" href="glMap2.xml"><span class="citerefentry"><span class="refentrytitle">glMap2</span></span></a> | |
119 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
120 | Copyright <span class="trademark"></span>© 1991-2006 | |
121 | Silicon Graphics, Inc. This document is licensed under the SGI | |
122 | Free Software B License. For details, see | |
123 | <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>. | |
124 | </p></div></div></body></html> |