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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="glMaterial"> | |
5 | <refmeta> | |
6 | <refmetainfo> | |
7 | <copyright> | |
8 | <year>1991-2006</year> | |
9 | <holder>Silicon Graphics, Inc.</holder> | |
10 | </copyright> | |
11 | </refmetainfo> | |
12 | <refentrytitle>glMaterial</refentrytitle> | |
13 | <manvolnum>3G</manvolnum> | |
14 | </refmeta> | |
15 | <refnamediv> | |
16 | <refname>glMaterial</refname> | |
17 | <refpurpose>specify material parameters for the lighting model</refpurpose> | |
18 | </refnamediv> | |
19 | <refsynopsisdiv><title>C Specification</title> | |
20 | <funcsynopsis> | |
21 | <funcprototype> | |
22 | <funcdef>void <function>glMaterialf</function></funcdef> | |
23 | <paramdef>GLenum <parameter>face</parameter></paramdef> | |
24 | <paramdef>GLenum <parameter>pname</parameter></paramdef> | |
25 | <paramdef>GLfloat <parameter>param</parameter></paramdef> | |
26 | </funcprototype> | |
27 | </funcsynopsis> | |
28 | <funcsynopsis> | |
29 | <funcprototype> | |
30 | <funcdef>void <function>glMateriali</function></funcdef> | |
31 | <paramdef>GLenum <parameter>face</parameter></paramdef> | |
32 | <paramdef>GLenum <parameter>pname</parameter></paramdef> | |
33 | <paramdef>GLint <parameter>param</parameter></paramdef> | |
34 | </funcprototype> | |
35 | </funcsynopsis> | |
36 | </refsynopsisdiv> | |
37 | <refsect1 id="parameters"><title>Parameters</title> | |
38 | <variablelist> | |
39 | <varlistentry> | |
40 | <term><parameter>face</parameter></term> | |
41 | <listitem> | |
42 | <para> | |
43 | Specifies which face or faces are being updated. | |
44 | Must be one of | |
45 | <constant>GL_FRONT</constant>, | |
46 | <constant>GL_BACK</constant>, or | |
47 | <constant>GL_FRONT_AND_BACK</constant>. | |
48 | </para> | |
49 | </listitem> | |
50 | </varlistentry> | |
51 | <varlistentry> | |
52 | <term><parameter>pname</parameter></term> | |
53 | <listitem> | |
54 | <para> | |
55 | Specifies the single-valued material parameter of the face or faces | |
56 | that is being updated. | |
57 | Must be <constant>GL_SHININESS</constant>. | |
58 | </para> | |
59 | </listitem> | |
60 | </varlistentry> | |
61 | <varlistentry> | |
62 | <term><parameter>param</parameter></term> | |
63 | <listitem> | |
64 | <para> | |
65 | Specifies the value that parameter <constant>GL_SHININESS</constant> will be set to. | |
66 | </para> | |
67 | </listitem> | |
68 | </varlistentry> | |
69 | </variablelist> | |
70 | </refsect1> | |
71 | <refsynopsisdiv><title>C Specification</title> | |
72 | <funcsynopsis> | |
73 | <funcprototype> | |
74 | <funcdef>void <function>glMaterialfv</function></funcdef> | |
75 | <paramdef>GLenum <parameter>face</parameter></paramdef> | |
76 | <paramdef>GLenum <parameter>pname</parameter></paramdef> | |
77 | <paramdef>const GLfloat * <parameter>params</parameter></paramdef> | |
78 | </funcprototype> | |
79 | </funcsynopsis> | |
80 | <funcsynopsis> | |
81 | <funcprototype> | |
82 | <funcdef>void <function>glMaterialiv</function></funcdef> | |
83 | <paramdef>GLenum <parameter>face</parameter></paramdef> | |
84 | <paramdef>GLenum <parameter>pname</parameter></paramdef> | |
85 | <paramdef>const GLint * <parameter>params</parameter></paramdef> | |
86 | </funcprototype> | |
87 | </funcsynopsis> | |
88 | </refsynopsisdiv> | |
89 | <refsect1 id="parameters2"><title>Parameters</title> | |
90 | <variablelist> | |
91 | <varlistentry> | |
92 | <term><parameter>face</parameter></term> | |
93 | <listitem> | |
94 | <para> | |
95 | Specifies which face or faces are being updated. | |
96 | Must be one of | |
97 | <constant>GL_FRONT</constant>, | |
98 | <constant>GL_BACK</constant>, or | |
99 | <constant>GL_FRONT_AND_BACK</constant>. | |
100 | </para> | |
101 | </listitem> | |
102 | </varlistentry> | |
103 | <varlistentry> | |
104 | <term><parameter>pname</parameter></term> | |
105 | <listitem> | |
106 | <para> | |
107 | Specifies the material parameter of the face or faces that is being updated. | |
108 | Must be one of | |
109 | <constant>GL_AMBIENT</constant>, | |
110 | <constant>GL_DIFFUSE</constant>, | |
111 | <constant>GL_SPECULAR</constant>, | |
112 | <constant>GL_EMISSION</constant>, | |
113 | <constant>GL_SHININESS</constant>, | |
114 | <constant>GL_AMBIENT_AND_DIFFUSE</constant>, or | |
115 | <constant>GL_COLOR_INDEXES</constant>. | |
116 | </para> | |
117 | </listitem> | |
118 | </varlistentry> | |
119 | <varlistentry> | |
120 | <term><parameter>params</parameter></term> | |
121 | <listitem> | |
122 | <para> | |
123 | Specifies a pointer to the value or values that <parameter>pname</parameter> will be set to. | |
124 | </para> | |
125 | </listitem> | |
126 | </varlistentry> | |
127 | </variablelist> | |
128 | </refsect1> | |
129 | <refsect1 id="description"><title>Description</title> | |
130 | <para> | |
131 | <function>glMaterial</function> assigns values to material parameters. | |
132 | There are two matched sets of material parameters. | |
133 | One, | |
134 | the <emphasis>front-facing</emphasis> set, | |
135 | is used to shade points, | |
136 | lines, | |
137 | bitmaps, | |
138 | and all polygons | |
139 | (when two-sided lighting is disabled), | |
140 | or just front-facing polygons | |
141 | (when two-sided lighting is enabled). | |
142 | The other set, | |
143 | <emphasis>back-facing</emphasis>, | |
144 | is used to shade back-facing polygons only when two-sided lighting is enabled. | |
145 | Refer to the <citerefentry><refentrytitle>glLightModel</refentrytitle></citerefentry> reference page for details concerning one- and | |
146 | two-sided lighting calculations. | |
147 | </para> | |
148 | <para> | |
149 | <function>glMaterial</function> takes three arguments. | |
150 | The first, | |
151 | <parameter>face</parameter>, | |
152 | specifies whether the | |
153 | <constant>GL_FRONT</constant> materials, the | |
154 | <constant>GL_BACK</constant> materials, or both | |
155 | <constant>GL_FRONT_AND_BACK</constant> materials will be modified. | |
156 | The second, | |
157 | <parameter>pname</parameter>, | |
158 | specifies which of several parameters in one or both sets will be modified. | |
159 | The third, | |
160 | <parameter>params</parameter>, | |
161 | specifies what value or values will be assigned to the specified parameter. | |
162 | </para> | |
163 | <para> | |
164 | Material parameters are used in the lighting equation that is optionally | |
165 | applied to each vertex. | |
166 | The equation is discussed in the <citerefentry><refentrytitle>glLightModel</refentrytitle></citerefentry> reference page. | |
167 | The parameters that can be specified using <function>glMaterial</function>, | |
168 | and their interpretations by the lighting equation, are as follows: | |
169 | </para> | |
170 | <variablelist> | |
171 | <varlistentry> | |
172 | <term><constant>GL_AMBIENT</constant></term> | |
173 | <listitem> | |
174 | <para> | |
175 | <parameter>params</parameter> contains four integer or floating-point values that specify | |
176 | the ambient RGBA reflectance of the material. | |
177 | Integer values are mapped linearly such that the most positive representable | |
178 | value maps to 1.0, | |
179 | and the most negative representable value maps to | |
180 | <inlineequation><mml:math> | |
181 | <!-- eqn: -1.0:--> | |
182 | <mml:mn>-1.0</mml:mn> | |
183 | </mml:math></inlineequation>. | |
184 | Floating-point values are mapped directly. | |
185 | Neither integer nor floating-point values are clamped. | |
186 | The initial ambient reflectance for both front- and back-facing materials | |
187 | is (0.2, 0.2, 0.2, 1.0). | |
188 | </para> | |
189 | </listitem> | |
190 | </varlistentry> | |
191 | <varlistentry> | |
192 | <term><constant>GL_DIFFUSE</constant></term> | |
193 | <listitem> | |
194 | <para> | |
195 | <parameter>params</parameter> contains four integer or floating-point values that specify | |
196 | the diffuse RGBA reflectance of the material. | |
197 | Integer values are mapped linearly such that the most positive representable | |
198 | value maps to 1.0, | |
199 | and the most negative representable value maps to | |
200 | <inlineequation><mml:math> | |
201 | <!-- eqn: -1.0:--> | |
202 | <mml:mn>-1.0</mml:mn> | |
203 | </mml:math></inlineequation>. | |
204 | Floating-point values are mapped directly. | |
205 | Neither integer nor floating-point values are clamped. | |
206 | The initial diffuse reflectance for both front- and back-facing materials | |
207 | is (0.8, 0.8, 0.8, 1.0). | |
208 | </para> | |
209 | </listitem> | |
210 | </varlistentry> | |
211 | <varlistentry> | |
212 | <term><constant>GL_SPECULAR</constant></term> | |
213 | <listitem> | |
214 | <para> | |
215 | <parameter>params</parameter> contains four integer or floating-point values that specify | |
216 | the specular RGBA reflectance of the material. | |
217 | Integer values are mapped linearly such that the most positive representable | |
218 | value maps to 1.0, | |
219 | and the most negative representable value maps to | |
220 | <inlineequation><mml:math> | |
221 | <!-- eqn: -1.0:--> | |
222 | <mml:mn>-1.0</mml:mn> | |
223 | </mml:math></inlineequation>. | |
224 | Floating-point values are mapped directly. | |
225 | Neither integer nor floating-point values are clamped. | |
226 | The initial specular reflectance for both front- and back-facing materials | |
227 | is (0, 0, 0, 1). | |
228 | </para> | |
229 | </listitem> | |
230 | </varlistentry> | |
231 | <varlistentry> | |
232 | <term><constant>GL_EMISSION</constant></term> | |
233 | <listitem> | |
234 | <para> | |
235 | <parameter>params</parameter> contains four integer or floating-point values that specify | |
236 | the RGBA emitted light intensity of the material. | |
237 | Integer values are mapped linearly such that the most positive representable | |
238 | value maps to 1.0, | |
239 | and the most negative representable value maps to | |
240 | <inlineequation><mml:math> | |
241 | <!-- eqn: -1.0:--> | |
242 | <mml:mn>-1.0</mml:mn> | |
243 | </mml:math></inlineequation>. | |
244 | Floating-point values are mapped directly. | |
245 | Neither integer nor floating-point values are clamped. | |
246 | The initial emission intensity for both front- and back-facing materials | |
247 | is (0, 0, 0, 1). | |
248 | </para> | |
249 | </listitem> | |
250 | </varlistentry> | |
251 | <varlistentry> | |
252 | <term><constant>GL_SHININESS</constant></term> | |
253 | <listitem> | |
254 | <para> | |
255 | <parameter>params</parameter> is a single integer or floating-point value that specifies | |
256 | the RGBA specular exponent of the material. | |
257 | Integer and floating-point values are mapped directly. | |
258 | Only values in the range | |
259 | <inlineequation><mml:math> | |
260 | <!-- eqn: [0,128]:--> | |
261 | <mml:mfenced open="[" close="]"> | |
262 | <mml:mn>0</mml:mn> | |
263 | <mml:mn>128</mml:mn> | |
264 | </mml:mfenced> | |
265 | </mml:math></inlineequation> | |
266 | are accepted. | |
267 | The initial specular exponent for both front- and back-facing materials | |
268 | is 0. | |
269 | </para> | |
270 | </listitem> | |
271 | </varlistentry> | |
272 | <varlistentry> | |
273 | <term><constant>GL_AMBIENT_AND_DIFFUSE</constant></term> | |
274 | <listitem> | |
275 | <para> | |
276 | Equivalent to calling <function>glMaterial</function> twice with the same parameter values, | |
277 | once with <constant>GL_AMBIENT</constant> and once with <constant>GL_DIFFUSE</constant>. | |
278 | </para> | |
279 | </listitem> | |
280 | </varlistentry> | |
281 | <varlistentry> | |
282 | <term><constant>GL_COLOR_INDEXES</constant></term> | |
283 | <listitem> | |
284 | <para> | |
285 | <parameter>params</parameter> contains three integer or floating-point values specifying | |
286 | the color indices for ambient, | |
287 | diffuse, | |
288 | and specular lighting. | |
289 | These three values, | |
290 | and <constant>GL_SHININESS</constant>, | |
291 | are the only material values used by the color index mode lighting equation. | |
292 | Refer to the <citerefentry><refentrytitle>glLightModel</refentrytitle></citerefentry> reference page for a discussion | |
293 | of color index lighting. | |
294 | </para> | |
295 | </listitem> | |
296 | </varlistentry> | |
297 | </variablelist> | |
298 | </refsect1> | |
299 | <refsect1 id="notes"><title>Notes</title> | |
300 | <para> | |
301 | The material parameters can be updated at any time. | |
302 | In particular, | |
303 | <function>glMaterial</function> can be called between a call to <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the corresponding | |
304 | call to <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>. | |
305 | If only a single material parameter is to be changed per vertex, | |
306 | however, | |
307 | <citerefentry><refentrytitle>glColorMaterial</refentrytitle></citerefentry> is preferred over <function>glMaterial</function> | |
308 | (see <citerefentry><refentrytitle>glColorMaterial</refentrytitle></citerefentry>). | |
309 | </para> | |
310 | <para> | |
311 | While the ambient, diffuse, specular and emission material parameters | |
312 | all have alpha components, only the diffuse alpha component is used in | |
313 | the lighting computation. | |
314 | </para> | |
315 | </refsect1> | |
316 | <refsect1 id="errors"><title>Errors</title> | |
317 | <para> | |
318 | <constant>GL_INVALID_ENUM</constant> is generated if either <parameter>face</parameter> or <parameter>pname</parameter> is not | |
319 | an accepted value. | |
320 | </para> | |
321 | <para> | |
322 | <constant>GL_INVALID_VALUE</constant> is generated if a specular exponent outside the range | |
323 | <inlineequation><mml:math> | |
324 | <!-- eqn: [0,128]:--> | |
325 | <mml:mfenced open="[" close="]"> | |
326 | <mml:mn>0</mml:mn> | |
327 | <mml:mn>128</mml:mn> | |
328 | </mml:mfenced> | |
329 | </mml:math></inlineequation> | |
330 | is specified. | |
331 | </para> | |
332 | </refsect1> | |
333 | <refsect1 id="associatedgets"><title>Associated Gets</title> | |
334 | <para> | |
335 | <citerefentry><refentrytitle>glGetMaterial</refentrytitle></citerefentry> | |
336 | </para> | |
337 | </refsect1> | |
338 | <refsect1 id="seealso"><title>See Also</title> | |
339 | <para> | |
340 | <citerefentry><refentrytitle>glColorMaterial</refentrytitle></citerefentry>, | |
341 | <citerefentry><refentrytitle>glLight</refentrytitle></citerefentry>, | |
342 | <citerefentry><refentrytitle>glLightModel</refentrytitle></citerefentry> | |
343 | </para> | |
344 | </refsect1> | |
345 | <refsect1 id="Copyright"><title>Copyright</title> | |
346 | <para> | |
347 | Copyright <trademark class="copyright"></trademark> 1991-2006 | |
348 | Silicon Graphics, Inc. This document is licensed under the SGI | |
349 | Free Software B License. For details, see | |
350 | <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>. | |
351 | </para> | |
352 | </refsect1> | |
353 | </refentry> |