<div class="refentry"><a id="glSampleCoverage"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glSampleCoverage — specify multisample coverage parameters</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">glSampleCoverage</strong>(</code></td><td>GLclampf <var class="pdparam">value</var>, </td></tr><tr><td> </td><td>GLboolean <var class="pdparam">invert</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>value</code></em></span></dt><dd><p>

Specify a single floating-point sample coverage value. The value is

clamped to the range

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<mn>0</mn>

<mn>1</mn>

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</math>.

The initial value is 1.0.

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

Specify a single boolean value representing if the coverage masks should be

inverted. <code class="constant">GL_TRUE</code> and <code class="constant">GL_FALSE</code> are accepted. The initial value

is <code class="constant">GL_FALSE</code>.

</p></dd></dl></div></div><div class="refsect1"><a id="description"></a><h2>Description</h2><p>

Multisampling samples a pixel multiple times at various

implementation-dependent subpixel locations to generate antialiasing

effects. Multisampling transparently antialiases points, lines, and polygons

if it is enabled.

</p><p>

<em class="parameter"><code>value</code></em> is used in constructing a temporary mask used in determining which

samples will be used in resolving the final fragment color. This mask is

bitwise-anded with the coverage mask generated from the multisampling

computation. If the <em class="parameter"><code>invert</code></em> flag is set, the temporary mask is inverted

(all bits flipped) and then the bitwise-and is computed.

</p><p>

If an implementation does not have any multisample buffers available, or

multisampling is disabled, rasterization occurs with only a single sample

computing a pixel's final RGB color.

</p><p>

Provided an implementation supports multisample buffers, and multisampling

is enabled, then a pixel's final color is generated by combining several

samples per pixel. Each sample contains color, depth, and stencil

information, allowing those operations to be performed on each sample.

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

<a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_SAMPLE_COVERAGE_VALUE</code>

</p><p>

<a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_SAMPLE_COVERAGE_INVERT</code>

</p><p>

<a class="citerefentry" href="glIsEnabled"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a> with argument <code class="constant">GL_SAMPLE_ALPHA_TO_COVERAGE</code>

</p><p>

<a class="citerefentry" href="glIsEnabled"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a> with argument <code class="constant">GL_SAMPLE_COVERAGE</code>

</p></div>

{$pipelinestall}{$examples}

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

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