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<?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>glGetMaterial</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glGetMaterial"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetMaterial — return material 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">glGetMaterialfv</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">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">glGetMaterialiv</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">params</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>
                    Specifies which of the two materials is being queried.
                    <code class="constant">GL_FRONT</code> or <code class="constant">GL_BACK</code> are accepted,
                    representing the front and back materials,
                    respectively.
                </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p>
                    Specifies the material parameter to return.
                    <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>, and
                    <code class="constant">GL_COLOR_INDEXES</code>
                    are accepted.
                </p></dd><dt><span class="term"><em class="parameter"><code>params</code></em></span></dt><dd><p>
                    Returns the requested data.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">glGetMaterial</code> returns in <em class="parameter"><code>params</code></em> the value or values of parameter <em class="parameter"><code>pname</code></em>
            of material <em class="parameter"><code>face</code></em>. Six parameters are defined:
        </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> returns four integer or floating-point values representing the
                        ambient reflectance of the material.
                        Integer values,
                        when requested,
                        are linearly mapped from the internal floating-point representation
                        such that 1.0 maps to the most positive representable integer value,
                        and 
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                            <mml:mn>-1.0</mml:mn>
                        </mml:math>
                        maps to the most negative representable integer value.
                        If the internal value is outside the range 
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                            <mml:mfenced open="[" close="]">
                                <mml:mn>-1</mml:mn>
                                <mml:mn>1</mml:mn>
                            </mml:mfenced>
                        </mml:math>,
                        the corresponding integer return value is undefined. The initial value 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> returns four integer or floating-point values representing the
                        diffuse reflectance of the material.
                        Integer values,
                        when requested,
                        are linearly mapped from the internal floating-point representation
                        such that 1.0 maps to the most positive representable integer value,
                        and 
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                            <mml:mn>-1.0</mml:mn>
                        </mml:math>
                        maps to the most negative representable integer value.
                        If the internal value is outside the range 
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                            <mml:mfenced open="[" close="]">
                                <mml:mn>-1</mml:mn>
                                <mml:mn>1</mml:mn>
                            </mml:mfenced>
                        </mml:math>,
                        the corresponding integer return value is undefined. The initial value 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> returns four integer or floating-point values representing the
                        specular reflectance of the material.
                        Integer values,
                        when requested,
                        are linearly mapped from the internal floating-point representation
                        such that 1.0 maps to the most positive representable integer value,
                        and 
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                            <mml:mn>-1.0</mml:mn>
                        </mml:math>
                        maps to the most negative representable integer value.
                        If the internal value is outside the range 
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                            <mml:mfenced open="[" close="]">
                                <mml:mn>-1</mml:mn>
                                <mml:mn>1</mml:mn>
                            </mml:mfenced>
                        </mml:math>,
                        the corresponding integer return value is undefined. The initial value 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> returns four integer or floating-point values representing the
                        emitted light intensity of the material.
                        Integer values,
                        when requested,
                        are linearly mapped from the internal floating-point representation
                        such that 1.0 maps to the most positive representable integer value,
                        and 
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                            <mml:mn>-1.0</mml:mn>
                        </mml:math>
                        maps to the most negative representable integer value.
                        If the internal value is outside the range 
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                            <mml:mfenced open="[" close="]">
                                <mml:mn>-1</mml:mn>
                                <mml:mn>1</mml:mn>
                            </mml:mfenced>
                        </mml:math>,
                        the corresponding integer return value is undefined. The initial value 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> returns one integer or floating-point value representing the
                        specular exponent of the material.
                        Integer values,
                        when requested,
                        are computed by rounding the internal floating-point value to the
                        nearest integer value. The initial value is 0.
                    </p></dd><dt><span class="term"><code class="constant">GL_COLOR_INDEXES</code></span></dt><dd><p>
                        <em class="parameter"><code>params</code></em> returns three integer or floating-point values representing the
                        ambient, diffuse, and specular indices of the material.
                        These indices are used only for color index lighting.
                        (All the other parameters are used only for RGBA lighting.)
                        Integer values,
                        when requested,
                        are computed by rounding the internal floating-point values to the
                        nearest integer values.
                    </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
            If an error is generated,
            no change is made to the contents of <em class="parameter"><code>params</code></em>.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GL_INVALID_ENUM</code> is generated if <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_OPERATION</code> is generated if <code class="function">glGetMaterial</code>
            is executed between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a>
            and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="glMaterial.xml"><span class="citerefentry"><span class="refentrytitle">glMaterial</span></span></a>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 1991-2006
            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></body></html>
