<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 class="funcprototype-table" 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 class="funcprototype-table" 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"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a> enable and disable various capabilities.

Use <a class="citerefentry" href="glIsEnabled"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a> or <a class="citerefentry" href="glGet"><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"><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"><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"><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"><span class="citerefentry"><span class="refentrytitle">glDepthFunc</span></span></a> and

<a class="citerefentry" href="glDepthRangef"><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"><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"><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"><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"><span class="citerefentry"><span class="refentrytitle">glStencilFunc</span></span></a> and <a class="citerefentry" href="glStencilOp"><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"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a>

</p><p>

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

</p></div>

{$pipelinestall}{$examples}

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

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

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

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

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

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

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

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

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

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

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

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

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

<a class="citerefentry" href="glTexImage2D"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>

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

Copyright © 1991-2006

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

Free Software B License. For details, see

<a class="ulink" href="https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/" target="_top">https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/</a>.

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