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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>glBlendColor</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1" /></head><body><div class="refentry"><a id="glBlendColor"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glBlendColor — set the blend color</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">void <strong class="fsfunc">glBlendColor</strong>(</code></td><td>GLclampf <var class="pdparam">red</var>, </td></tr><tr><td> </td><td>GLclampf <var class="pdparam">green</var>, </td></tr><tr><td> </td><td>GLclampf <var class="pdparam">blue</var>, </td></tr><tr><td> </td><td>GLclampf <var class="pdparam">alpha</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>red</code></em>, </span><span class="term"><em class="parameter"><code>green</code></em>, </span><span class="term"><em class="parameter"><code>blue</code></em>, </span><span class="term"><em class="parameter"><code>alpha</code></em></span></dt><dd><p>
                    specify the components of <code class="constant">GL_BLEND_COLOR</code>
                </p></dd></dl></div></div><div class="refsect1"><a id="description"></a><h2>Description</h2><p>
            The <code class="constant">GL_BLEND_COLOR</code> may be used to calculate the source and destination
            blending factors. The color components are clamped to the range 
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            before being stored. See <a class="citerefentry" href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a> for a complete description of the
            blending operations.
            Initially the <code class="constant">GL_BLEND_COLOR</code> is set to (0, 0, 0, 0).
        </p></div><div class="refsect1"><a id="notes"></a><h2>Notes</h2><p>
            <code class="function">glBlendColor</code> is part of the <code class="code">ARB_imaging</code> subset. <code class="function">glBlendColor</code> is present only
            if <code class="code">ARB_imaging</code> is returned when <a class="citerefentry" href="glGetString.xml"><span class="citerefentry"><span class="refentrytitle">glGetString</span></span></a> is called with
            <code class="constant">GL_EXTENSIONS</code> as its argument.
        </p></div><div class="refsect1"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glBlendColor</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><p>
        </p></div><div class="refsect1"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
            <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with an argument of <code class="constant">GL_BLEND_COLOR</code>
        </p></div><div class="refsect1"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="glBlendEquation.xml"><span class="citerefentry"><span class="refentrytitle">glBlendEquation</span></span></a>,
            <a class="citerefentry" href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a>,
            <a class="citerefentry" href="glGetString.xml"><span class="citerefentry"><span class="refentrytitle">glGetString</span></span></a>
        </p></div><div class="refsect1"><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>