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</title><meta name=
"generator" content=
"DocBook XSL Stylesheets V1.69.1" /></head><body><div class=
"refentry" lang=
"en" xml:
lang=
"en"><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 border=
"0" summary=
"Function synopsis" cellspacing=
"0" cellpadding=
"0"><tr><td><code class=
"funcdef">void
<b class=
"fsfunc">glSampleCoverage
</b>(
</code></td><td>GLclampf
</td><td><var class=
"pdparam">value
</var>,
</td></tr><tr><td> </td><td>GLboolean
</td><td><var class=
"pdparam">invert
</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>value
</code></em></span></dt><dd><p>
5 Specify a single floating-point sample coverage value. The value is
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mml=
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"scroll">
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"[" close=
"]">
14 The initial value is
1.0.
15 </p></dd><dt><span class=
"term"><em class=
"parameter"><code>invert
</code></em></span></dt><dd><p>
16 Specify a single boolean value representing if the coverage masks should be
17 inverted.
<code class=
"constant">GL_TRUE
</code> and
<code class=
"constant">GL_FALSE
</code> are accepted. The initial value
18 is
<code class=
"constant">GL_FALSE
</code>.
19 </p></dd></dl></div></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"description"></a><h2>Description
</h2><p>
20 Multisampling samples a pixel multiple times at various
21 implementation-dependent subpixel locations to generate antialiasing
22 effects. Multisampling transparently antialiases points, lines, polygons,
23 and images if it is enabled.
25 <em class=
"parameter"><code>value
</code></em> is used in constructing a temporary mask used in determining which
26 samples will be used in resolving the final fragment color. This mask is
27 bitwise-anded with the coverage mask generated from the multisampling
28 computation. If the
<em class=
"parameter"><code>invert
</code></em> flag is set, the temporary mask is inverted
29 (all bits flipped) and then the bitwise-and is computed.
31 If an implementation does not have any multisample buffers available, or
32 multisampling is disabled, rasterization occurs with only a single sample
33 computing a pixel's final RGB color.
35 Provided an implementation supports multisample buffers, and multisampling
36 is enabled, then a pixel's final color is generated by combining several
37 samples per pixel. Each sample contains color, depth, and stencil
38 information, allowing those operations to be performed on each sample.
39 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"associatedgets"></a><h2>Associated Gets
</h2><p>
40 <a href=
"glGet.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGet
</span></span></a> with argument
<code class=
"constant">GL_SAMPLE_COVERAGE_VALUE
</code>
42 <a href=
"glGet.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glGet
</span></span></a> with argument
<code class=
"constant">GL_SAMPLE_COVERAGE_INVERT
</code>
44 <a href=
"glIsEnabled.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glIsEnabled
</span></span></a> with argument
<code class=
"constant">GL_MULTISAMPLE
</code>
46 <a href=
"glIsEnabled.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glIsEnabled
</span></span></a> with argument
<code class=
"constant">GL_SAMPLE_ALPHA_TO_COVERAGE
</code>
48 <a href=
"glIsEnabled.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glIsEnabled
</span></span></a> with argument
<code class=
"constant">GL_SAMPLE_ALPHA_TO_ONE
</code>
50 <a href=
"glIsEnabled.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glIsEnabled
</span></span></a> with argument
<code class=
"constant">GL_SAMPLE_COVERAGE
</code>
51 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"seealso"></a><h2>See Also
</h2><p>
52 <a href=
"glEnable.xml"><span class=
"citerefentry"><span class=
"refentrytitle">glEnable
</span></span></a>
53 </p></div><div class=
"refsect1" lang=
"en" xml:
lang=
"en"><a id=
"Copyright"></a><h2>Copyright
</h2><p>
54 Copyright
<span class=
"trademark"></span>©
1991-
2006
55 Silicon Graphics, Inc. This document is licensed under the SGI
56 Free Software B License. For details, see
57 <a href=
"http://oss.sgi.com/projects/FreeB/" target=
"_top">http://oss.sgi.com/projects/FreeB/
</a>.
58 </p></div></div></body></html>