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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>glEnable</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1" /></head><body><div class="refentry"><a id="glEnable"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glEnable — enable or disable server-side GL capabilities</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">glEnable</strong>(</code></td><td>GLenum <var class="pdparam">cap</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>cap</code></em></span></dt><dd><p>
                    Specifies a symbolic constant indicating a GL capability.
                </p></dd></dl></div></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">glDisable</strong>(</code></td><td>GLenum <var class="pdparam">cap</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="parameters2"></a><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>cap</code></em></span></dt><dd><p>
                    Specifies a symbolic constant indicating a GL capability.
                </p></dd></dl></div></div><div class="refsect1"><a id="description"></a><h2>Description</h2><p>
            <code class="function">glEnable</code> and <a class="citerefentry" href="glDisable.xml"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a> enable and disable various capabilities.
            Use <a class="citerefentry" href="glIsEnabled.xml"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a> or <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> to determine the current setting
            of any capability. The initial value for each capability with the
            exception of <code class="constant">GL_DITHER</code> is <code class="constant">GL_FALSE</code>. The initial value for
            <code class="constant">GL_DITHER</code> is <code class="constant">GL_TRUE</code>.
        </p><p>
            Both <code class="function">glEnable</code> and <a class="citerefentry" href="glDisable.xml"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a> take a single argument, <em class="parameter"><code>cap</code></em>,
            which can assume one of the following values:
        </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="constant">GL_BLEND</code></span></dt><dd><p>
                        If enabled,
                        blend the computed fragment color values with the values in the color
                        buffers. See <a class="citerefentry" href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a>.
                    </p></dd><dt><span class="term"><code class="constant">GL_CULL_FACE</code></span></dt><dd><p>
                        If enabled,
                        cull polygons based on their winding in window coordinates.
                        See <a class="citerefentry" href="glCullFace.xml"><span class="citerefentry"><span class="refentrytitle">glCullFace</span></span></a>.
                    </p></dd><dt><span class="term"><code class="constant">GL_DEPTH_TEST</code></span></dt><dd><p>
                        If enabled,
                        do depth comparisons and update the depth buffer. Note that even if
                        the depth buffer exists and the depth mask is non-zero, the
                        depth buffer is not updated if the depth test is disabled. See
                        <a class="citerefentry" href="glDepthFunc.xml"><span class="citerefentry"><span class="refentrytitle">glDepthFunc</span></span></a> and
                        <a class="citerefentry" href="glDepthRangef.xml"><span class="citerefentry"><span class="refentrytitle">glDepthRangef</span></span></a>.
                    </p></dd><dt><span class="term"><code class="constant">GL_DITHER</code>	</span></dt><dd><p>
                        If enabled,
                        dither color components or indices before they are written to the
                        color buffer.
                    </p></dd><dt><span class="term"><code class="constant">GL_POLYGON_OFFSET_FILL</code></span></dt><dd><p>
                        If enabled, an offset is added to depth values of a polygon's
                        fragments produced by rasterization.
                        See <a class="citerefentry" href="glPolygonOffset.xml"><span class="citerefentry"><span class="refentrytitle">glPolygonOffset</span></span></a>.
                    </p></dd><dt><span class="term"><code class="constant">GL_SAMPLE_ALPHA_TO_COVERAGE</code></span></dt><dd><p>
                        If enabled,
                        compute a temporary coverage value where each bit is determined by the
                        alpha value at the corresponding sample location.  The temporary coverage
                        value is then ANDed with the fragment coverage value.
                    </p></dd><dt><span class="term"><code class="constant">GL_SAMPLE_COVERAGE</code></span></dt><dd><p>
                        If enabled,
                        the fragment's coverage is ANDed with the temporary coverage value.  If
                        <code class="constant">GL_SAMPLE_COVERAGE_INVERT</code> is set to <code class="constant">GL_TRUE</code>, invert the coverage
                        value.
                        See <a class="citerefentry" href="glSampleCoverage.xml"><span class="citerefentry"><span class="refentrytitle">glSampleCoverage</span></span></a>.
                    </p></dd><dt><span class="term"><code class="constant">GL_SCISSOR_TEST</code></span></dt><dd><p>
                        If enabled,
                        discard fragments that are outside the scissor rectangle.
                        See <a class="citerefentry" href="glScissor.xml"><span class="citerefentry"><span class="refentrytitle">glScissor</span></span></a>.
                    </p></dd><dt><span class="term"><code class="constant">GL_STENCIL_TEST</code></span></dt><dd><p>
                        If enabled,
                        do stencil testing and update the stencil buffer.
                        See <a class="citerefentry" href="glStencilFunc.xml"><span class="citerefentry"><span class="refentrytitle">glStencilFunc</span></span></a> and <a class="citerefentry" href="glStencilOp.xml"><span class="citerefentry"><span class="refentrytitle">glStencilOp</span></span></a>.
                    </p></dd></dl></div></div><div class="refsect1"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>cap</code></em> is not one of the values
            listed previously.
        </p></div><div class="refsect1"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
            <a class="citerefentry" href="glIsEnabled.xml"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a>
        </p><p>
            <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
        </p></div><div class="refsect1"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,
            <a class="citerefentry" href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a>,
            <a class="citerefentry" href="glCullFace.xml"><span class="citerefentry"><span class="refentrytitle">glCullFace</span></span></a>,
            <a class="citerefentry" href="glDepthFunc.xml"><span class="citerefentry"><span class="refentrytitle">glDepthFunc</span></span></a>,
            <a class="citerefentry" href="glDepthRangef.xml"><span class="citerefentry"><span class="refentrytitle">glDepthRangef</span></span></a>,
            <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>,
            <a class="citerefentry" href="glIsEnabled.xml"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a>,
            <a class="citerefentry" href="glLineWidth.xml"><span class="citerefentry"><span class="refentrytitle">glLineWidth</span></span></a>,
            <a class="citerefentry" href="glPolygonOffset.xml"><span class="citerefentry"><span class="refentrytitle">glPolygonOffset</span></span></a>,
            <a class="citerefentry" href="glScissor.xml"><span class="citerefentry"><span class="refentrytitle">glScissor</span></span></a>,
            <a class="citerefentry" href="glStencilFunc.xml"><span class="citerefentry"><span class="refentrytitle">glStencilFunc</span></span></a>,
            <a class="citerefentry" href="glStencilOp.xml"><span class="citerefentry"><span class="refentrytitle">glStencilOp</span></span></a>,
            <a class="citerefentry" href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</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>