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1 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> |
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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>glMaterial</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glMaterial"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glMaterial — specify material parameters for the lighting model</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">glMaterialf</b>(</code></td><td>GLenum </td><td><var class="pdparam">face</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>GLfloat </td><td><var class="pdparam">param</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">glMateriali</b>(</code></td><td>GLenum </td><td><var class="pdparam">face</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>GLint </td><td><var class="pdparam">param</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>face</code></em></span></dt><dd><p> | |
4 | Specifies which face or faces are being updated. | |
5 | Must be one of | |
6 | <code class="constant">GL_FRONT</code>, | |
7 | <code class="constant">GL_BACK</code>, or | |
8 | <code class="constant">GL_FRONT_AND_BACK</code>. | |
9 | </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p> | |
10 | Specifies the single-valued material parameter of the face or faces | |
11 | that is being updated. | |
12 | Must be <code class="constant">GL_SHININESS</code>. | |
13 | </p></dd><dt><span class="term"><em class="parameter"><code>param</code></em></span></dt><dd><p> | |
14 | Specifies the value that parameter <code class="constant">GL_SHININESS</code> will be set to. | |
15 | </p></dd></dl></div></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">glMaterialfv</b>(</code></td><td>GLenum </td><td><var class="pdparam">face</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>const GLfloat * </td><td><var class="pdparam">params</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">glMaterialiv</b>(</code></td><td>GLenum </td><td><var class="pdparam">face</var>, </td></tr><tr><td> </td><td>GLenum </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>const GLint * </td><td><var class="pdparam">params</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters2"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>face</code></em></span></dt><dd><p> | |
16 | Specifies which face or faces are being updated. | |
17 | Must be one of | |
18 | <code class="constant">GL_FRONT</code>, | |
19 | <code class="constant">GL_BACK</code>, or | |
20 | <code class="constant">GL_FRONT_AND_BACK</code>. | |
21 | </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p> | |
22 | Specifies the material parameter of the face or faces that is being updated. | |
23 | Must be one of | |
24 | <code class="constant">GL_AMBIENT</code>, | |
25 | <code class="constant">GL_DIFFUSE</code>, | |
26 | <code class="constant">GL_SPECULAR</code>, | |
27 | <code class="constant">GL_EMISSION</code>, | |
28 | <code class="constant">GL_SHININESS</code>, | |
29 | <code class="constant">GL_AMBIENT_AND_DIFFUSE</code>, or | |
30 | <code class="constant">GL_COLOR_INDEXES</code>. | |
31 | </p></dd><dt><span class="term"><em class="parameter"><code>params</code></em></span></dt><dd><p> | |
32 | Specifies a pointer to the value or values that <em class="parameter"><code>pname</code></em> will be set to. | |
33 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> | |
34 | <code class="function">glMaterial</code> assigns values to material parameters. | |
35 | There are two matched sets of material parameters. | |
36 | One, | |
37 | the <span class="emphasis"><em>front-facing</em></span> set, | |
38 | is used to shade points, | |
39 | lines, | |
40 | bitmaps, | |
41 | and all polygons | |
42 | (when two-sided lighting is disabled), | |
43 | or just front-facing polygons | |
44 | (when two-sided lighting is enabled). | |
45 | The other set, | |
46 | <span class="emphasis"><em>back-facing</em></span>, | |
47 | is used to shade back-facing polygons only when two-sided lighting is enabled. | |
48 | Refer to the <a class="citerefentry" href="glLightModel.xml"><span class="citerefentry"><span class="refentrytitle">glLightModel</span></span></a> reference page for details concerning one- and | |
49 | two-sided lighting calculations. | |
50 | </p><p> | |
51 | <code class="function">glMaterial</code> takes three arguments. | |
52 | The first, | |
53 | <em class="parameter"><code>face</code></em>, | |
54 | specifies whether the | |
55 | <code class="constant">GL_FRONT</code> materials, the | |
56 | <code class="constant">GL_BACK</code> materials, or both | |
57 | <code class="constant">GL_FRONT_AND_BACK</code> materials will be modified. | |
58 | The second, | |
59 | <em class="parameter"><code>pname</code></em>, | |
60 | specifies which of several parameters in one or both sets will be modified. | |
61 | The third, | |
62 | <em class="parameter"><code>params</code></em>, | |
63 | specifies what value or values will be assigned to the specified parameter. | |
64 | </p><p> | |
65 | Material parameters are used in the lighting equation that is optionally | |
66 | applied to each vertex. | |
67 | The equation is discussed in the <a class="citerefentry" href="glLightModel.xml"><span class="citerefentry"><span class="refentrytitle">glLightModel</span></span></a> reference page. | |
68 | The parameters that can be specified using <code class="function">glMaterial</code>, | |
69 | and their interpretations by the lighting equation, are as follows: | |
70 | </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_AMBIENT</code></span></dt><dd><p> | |
71 | <em class="parameter"><code>params</code></em> contains four integer or floating-point values that specify | |
72 | the ambient RGBA reflectance of the material. | |
73 | Integer values are mapped linearly such that the most positive representable | |
74 | value maps to 1.0, | |
75 | and the most negative representable value maps to | |
76 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
77 | ||
78 | <mml:mn>-1.0</mml:mn> | |
79 | </mml:math>. | |
80 | Floating-point values are mapped directly. | |
81 | Neither integer nor floating-point values are clamped. | |
82 | The initial ambient reflectance for both front- and back-facing materials | |
83 | is (0.2, 0.2, 0.2, 1.0). | |
84 | </p></dd><dt><span class="term"><code class="constant">GL_DIFFUSE</code></span></dt><dd><p> | |
85 | <em class="parameter"><code>params</code></em> contains four integer or floating-point values that specify | |
86 | the diffuse RGBA reflectance of the material. | |
87 | Integer values are mapped linearly such that the most positive representable | |
88 | value maps to 1.0, | |
89 | and the most negative representable value maps to | |
90 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
91 | ||
92 | <mml:mn>-1.0</mml:mn> | |
93 | </mml:math>. | |
94 | Floating-point values are mapped directly. | |
95 | Neither integer nor floating-point values are clamped. | |
96 | The initial diffuse reflectance for both front- and back-facing materials | |
97 | is (0.8, 0.8, 0.8, 1.0). | |
98 | </p></dd><dt><span class="term"><code class="constant">GL_SPECULAR</code></span></dt><dd><p> | |
99 | <em class="parameter"><code>params</code></em> contains four integer or floating-point values that specify | |
100 | the specular RGBA reflectance of the material. | |
101 | Integer values are mapped linearly such that the most positive representable | |
102 | value maps to 1.0, | |
103 | and the most negative representable value maps to | |
104 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
105 | ||
106 | <mml:mn>-1.0</mml:mn> | |
107 | </mml:math>. | |
108 | Floating-point values are mapped directly. | |
109 | Neither integer nor floating-point values are clamped. | |
110 | The initial specular reflectance for both front- and back-facing materials | |
111 | is (0, 0, 0, 1). | |
112 | </p></dd><dt><span class="term"><code class="constant">GL_EMISSION</code></span></dt><dd><p> | |
113 | <em class="parameter"><code>params</code></em> contains four integer or floating-point values that specify | |
114 | the RGBA emitted light intensity of the material. | |
115 | Integer values are mapped linearly such that the most positive representable | |
116 | value maps to 1.0, | |
117 | and the most negative representable value maps to | |
118 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
119 | ||
120 | <mml:mn>-1.0</mml:mn> | |
121 | </mml:math>. | |
122 | Floating-point values are mapped directly. | |
123 | Neither integer nor floating-point values are clamped. | |
124 | The initial emission intensity for both front- and back-facing materials | |
125 | is (0, 0, 0, 1). | |
126 | </p></dd><dt><span class="term"><code class="constant">GL_SHININESS</code></span></dt><dd><p> | |
127 | <em class="parameter"><code>params</code></em> is a single integer or floating-point value that specifies | |
128 | the RGBA specular exponent of the material. | |
129 | Integer and floating-point values are mapped directly. | |
130 | Only values in the range | |
131 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
132 | ||
133 | <mml:mfenced open="[" close="]"> | |
134 | <mml:mn>0</mml:mn> | |
135 | <mml:mn>128</mml:mn> | |
136 | </mml:mfenced> | |
137 | </mml:math> | |
138 | are accepted. | |
139 | The initial specular exponent for both front- and back-facing materials | |
140 | is 0. | |
141 | </p></dd><dt><span class="term"><code class="constant">GL_AMBIENT_AND_DIFFUSE</code></span></dt><dd><p> | |
142 | Equivalent to calling <code class="function">glMaterial</code> twice with the same parameter values, | |
143 | once with <code class="constant">GL_AMBIENT</code> and once with <code class="constant">GL_DIFFUSE</code>. | |
144 | </p></dd><dt><span class="term"><code class="constant">GL_COLOR_INDEXES</code></span></dt><dd><p> | |
145 | <em class="parameter"><code>params</code></em> contains three integer or floating-point values specifying | |
146 | the color indices for ambient, | |
147 | diffuse, | |
148 | and specular lighting. | |
149 | These three values, | |
150 | and <code class="constant">GL_SHININESS</code>, | |
151 | are the only material values used by the color index mode lighting equation. | |
152 | Refer to the <a class="citerefentry" href="glLightModel.xml"><span class="citerefentry"><span class="refentrytitle">glLightModel</span></span></a> reference page for a discussion | |
153 | of color index lighting. | |
154 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p> | |
155 | The material parameters can be updated at any time. | |
156 | In particular, | |
157 | <code class="function">glMaterial</code> can be called between a call to <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the corresponding | |
158 | call to <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>. | |
159 | If only a single material parameter is to be changed per vertex, | |
160 | however, | |
161 | <a class="citerefentry" href="glColorMaterial.xml"><span class="citerefentry"><span class="refentrytitle">glColorMaterial</span></span></a> is preferred over <code class="function">glMaterial</code> | |
162 | (see <a class="citerefentry" href="glColorMaterial.xml"><span class="citerefentry"><span class="refentrytitle">glColorMaterial</span></span></a>). | |
163 | </p><p> | |
164 | While the ambient, diffuse, specular and emission material parameters | |
165 | all have alpha components, only the diffuse alpha component is used in | |
166 | the lighting computation. | |
167 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> | |
168 | <code class="constant">GL_INVALID_ENUM</code> is generated if either <em class="parameter"><code>face</code></em> or <em class="parameter"><code>pname</code></em> is not | |
169 | an accepted value. | |
170 | </p><p> | |
171 | <code class="constant">GL_INVALID_VALUE</code> is generated if a specular exponent outside the range | |
172 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
173 | ||
174 | <mml:mfenced open="[" close="]"> | |
175 | <mml:mn>0</mml:mn> | |
176 | <mml:mn>128</mml:mn> | |
177 | </mml:mfenced> | |
178 | </mml:math> | |
179 | is specified. | |
180 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p> | |
181 | <a class="citerefentry" href="glGetMaterial.xml"><span class="citerefentry"><span class="refentrytitle">glGetMaterial</span></span></a> | |
182 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> | |
183 | <a class="citerefentry" href="glColorMaterial.xml"><span class="citerefentry"><span class="refentrytitle">glColorMaterial</span></span></a>, | |
184 | <a class="citerefentry" href="glLight.xml"><span class="citerefentry"><span class="refentrytitle">glLight</span></span></a>, | |
185 | <a class="citerefentry" href="glLightModel.xml"><span class="citerefentry"><span class="refentrytitle">glLightModel</span></span></a> | |
186 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
187 | Copyright <span class="trademark"></span>© 1991-2006 | |
188 | Silicon Graphics, Inc. This document is licensed under the SGI | |
189 | Free Software B License. For details, see | |
190 | <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>. | |
191 | </p></div></div></body></html> |