<div class="refentry" title="glMaterial"><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" title="C Specification"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">glMaterialf</b>(</code></td><td>GLenum <var class="pdparam">face</var>, </td></tr><tr><td> </td><td>GLenum <var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>GLfloat <var class="pdparam">param</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">glMaterialx</b>(</code></td><td>GLenum <var class="pdparam">face</var>, </td></tr><tr><td> </td><td>GLenum <var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>GLfixed <var class="pdparam">param</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Parameters"><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>Specifies which face or faces are being updated. Must be

<code class="constant">GL_FRONT_AND_BACK</code>.</p></dd><dt><span class="term">

<em class="parameter"><code>pname</code></em>

</span></dt><dd><p>Specifies the single-valued material parameter of

the face or faces that is being updated. Must be

<code class="constant">GL_SHININESS</code>.</p></dd><dt><span class="term">

<em class="parameter"><code>param</code></em>

</span></dt><dd><p>Specifies the value that parameter

<code class="constant">GL_SHININESS</code> will be set to.</p></dd></dl></div></div><div class="refsynopsisdiv" title="C Specification"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">glMaterialfv</b>(</code></td><td>GLenum <var class="pdparam">face</var>, </td></tr><tr><td> </td><td>GLenum <var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>const GLfloat * <var class="pdparam">params</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">glMaterialxv</b>(</code></td><td>GLenum <var class="pdparam">face</var>, </td></tr><tr><td> </td><td>GLenum <var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>const GLfixed * <var class="pdparam">params</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Parameters"><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>Specifies which face or faces are being updated.

Must be <code class="constant">GL_FRONT_AND_BACK</code>.

</p></dd><dt><span class="term">

<em class="parameter"><code>pname</code></em>

</span></dt><dd><p>Specifies the material parameter of the face or

faces that is being updated. Must be one of

<code class="constant">GL_AMBIENT</code>,

<code class="constant">GL_DIFFUSE</code>,

<code class="constant">GL_SPECULAR</code>,

<code class="constant">GL_EMISSION</code>,

<code class="constant">GL_SHININESS</code>, or

<code class="constant">GL_AMBIENT_AND_DIFFUSE</code>.</p></dd><dt><span class="term">

<em class="parameter"><code>params</code></em>

</span></dt><dd><p>Specifies a pointer to the value or values that

<em class="parameter"><code>pname</code></em>

will be set to.</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="description"></a><h2>Description</h2><p>

<code class="function">glMaterial</code>

assigns values to material parameters. There are two matched

sets of material parameters. One, the <em class="parameter"><code>front-facing</code></em>

set, is used to shade points, lines, and all polygons (when

two-sided lighting is disabled), or just front-facing polygons

(when two-sided lighting is enabled). The other set,

<em class="parameter"><code>back-facing</code></em>,

is used to shade back-facing polygons only when two-sided

lighting is enabled. Refer to the

<a class="citerefentry" href="glLightModel"><span class="citerefentry"><span class="refentrytitle">glLightModel</span></span></a>

reference page for details concerning one- and two-sided

lighting calculations.

</p><p>

<code class="function">glMaterial</code>

takes three arguments. The first, <em class="parameter"><code>face</code></em>,

must be <code class="constant">GL_FRONT_AND_BACK</code> and specifies that both

front and back materials will be modified.

The second, <em class="parameter"><code>pname</code></em>,

specifies which of several parameters in one or both sets

will be modified. The third, <em class="parameter"><code>params</code></em>,

specifies what value or values will be assigned to the

specified parameter.

</p><p>

Material parameters are used in the lighting equation

that is optionally applied to each vertex. The equation is

discussed in the

<a class="citerefentry" href="glLightModel"><span class="citerefentry"><span class="refentrytitle">glLightModel</span></span></a>

reference page. The parameters that can be specified using

<code class="function">glMaterial</code>,

and their interpretations by the lighting equation, are as follows:

</p><div class="variablelist"><dl><dt><span class="term">

<code class="constant">GL_AMBIENT</code>

</span></dt><dd><p><em class="parameter"><code>params</code></em>

contains four fixed-point or floating-point values that

specify the ambient RGBA reflectance of the material.

The values are not clamped. The initial ambient

reflectance is

(0.2, 0.2, 0.2, 1.0).</p></dd><dt><span class="term">

<code class="constant">GL_DIFFUSE</code>

</span></dt><dd><p><em class="parameter"><code>params</code></em>

contains four fixed-point or floating-point values that

specify the diffuse RGBA reflectance of the material.

The values are not clamped. The initial diffuse

reflectance is

(0.8, 0.8, 0.8, 1.0).</p></dd><dt><span class="term">

<code class="constant">GL_SPECULAR</code>

</span></dt><dd><p><em class="parameter"><code>params</code></em>

contains four fixed-point or floating-point values that

specify the specular RGBA reflectance of the material.

The values are not clamped. The initial specular

reflectance is

(0, 0, 0, 1).</p></dd><dt><span class="term">

<code class="constant">GL_EMISSION</code>

</span></dt><dd><p><em class="parameter"><code>params</code></em>

contains four fixed-point or floating-point values that

specify the RGBA emitted light intensity of the material.

The values are not clamped. The initial emission

intensity is

(0, 0, 0, 1).</p></dd><dt><span class="term">

<code class="constant">GL_SHININESS</code>

</span></dt><dd><p><em class="parameter"><code>params</code></em>

is a single fixed-point or floating-point value that

specifies the RGBA specular exponent of the material.

Only values in the range [0, 128] are accepted. The

initial specular exponent is 0.</p></dd><dt><span class="term">

<code class="constant">GL_AMBIENT_AND_DIFFUSE</code>

</span></dt><dd><p>Equivalent to calling <code class="function">glMaterial</code>

twice with the same parameter values, once with

<code class="constant">GL_AMBIENT</code>

and once with <code class="constant">GL_DIFFUSE</code>.</p></dd></dl></div></div><div class="refsect1" title="Notes"><a id="notes"></a><h2>Notes</h2><p>To change the diffuse and ambient material per vertex,

color material can be used.

To enable and disable

<code class="constant">GL_COLOR_MATERIAL</code>, call

<a class="citerefentry" href="glEnable"><span class="citerefentry"><span class="refentrytitle">glEnable</span></span></a> and

<a class="citerefentry" href="glDisable"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a> with

argument <code class="constant">GL_COLOR_MATERIAL</code>.

Color material is initially disabled.

</p><p>While the ambient, diffuse, specular and emission

material parameters all have alpha components, only the diffuse

alpha component is used in the lighting computation.</p></div><div class="refsect1" title="Errors"><a id="errors"></a><h2>Errors</h2><p>

<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 an accepted value.

</p><p>

<code class="constant">GL_INVALID_VALUE</code>

is generated if a specular exponent outside the range [0, 128]

is specified.

</p></div><div class="refsect1" title="Associated Gets"><a id="associatedgets"></a><h2>Associated Gets</h2><p>

<a class="citerefentry" href="glGetMaterial"><span class="citerefentry"><span class="refentrytitle">glGetMaterial</span></span></a>

</p></div><div class="refsect1" title="See Also"><a id="seealso"></a><h2>See Also</h2><p>

<a class="citerefentry" href="glEnable"><span class="citerefentry"><span class="refentrytitle">glEnable</span></span></a>,

<a class="citerefentry" href="glLight"><span class="citerefentry"><span class="refentrytitle">glLight</span></span></a>,

<a class="citerefentry" href="glLightModel"><span class="citerefentry"><span class="refentrytitle">glLightModel</span></span></a>

</p></div><div class="refsect1" title="Copyright"><a id="copyright"></a><h2>Copyright</h2><p>

Copyright <span class="trademark"></span>© 2003-2004

Silicon Graphics, Inc. This document is licensed under the SGI

Free Software B License. For details, see

<a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.

</p></div></div>