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1 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd"> |
2 | <!-- saved from url=(0013)about:internet --> | |
3 | <?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>glClearIndex</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glClearIndex"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glClearIndex — specify the clear value for the color index buffers</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">glClearIndex</b>(</code></td><td>GLfloat </td><td><var class="pdparam">c</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>c</code></em></span></dt><dd><p> | |
4 | Specifies the index used when the color index buffers are cleared. | |
5 | The initial value is 0. | |
6 | </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p> | |
7 | <code class="function">glClearIndex</code> specifies the index used by <a class="citerefentry" href="glClear.xml"><span class="citerefentry"><span class="refentrytitle">glClear</span></span></a> | |
8 | to clear the color index buffers. | |
9 | <em class="parameter"><code>c</code></em> is not clamped. | |
10 | Rather, | |
11 | <em class="parameter"><code>c</code></em> is converted to a fixed-point value with unspecified precision | |
12 | to the right of the binary point. | |
13 | The integer part of this value is then masked with | |
14 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> | |
15 | ||
16 | <mml:mrow> | |
17 | <mml:msup><mml:mn>2</mml:mn> | |
18 | <mml:mi mathvariant="italic">m</mml:mi> | |
19 | </mml:msup> | |
20 | <mml:mo>-</mml:mo> | |
21 | <mml:mn>1</mml:mn> | |
22 | </mml:mrow> | |
23 | </mml:math>, | |
24 | where | |
25 | <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:mi mathvariant="italic">m</mml:mi></mml:math> | |
26 | is the number of bits in a color index stored in the frame buffer. | |
27 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p> | |
28 | <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glClearIndex</code> | |
29 | is executed between the execution of <a class="citerefentry" href="glBegin.xml"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> | |
30 | and the corresponding execution of <a class="citerefentry" href="glEnd.xml"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>. | |
31 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p> | |
32 | <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_INDEX_CLEAR_VALUE</code> | |
33 | </p><p> | |
34 | <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_INDEX_BITS</code> | |
35 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p> | |
36 | <a class="citerefentry" href="glClear.xml"><span class="citerefentry"><span class="refentrytitle">glClear</span></span></a> | |
37 | </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p> | |
38 | Copyright <span class="trademark"></span>© 1991-2006 | |
39 | Silicon Graphics, Inc. This document is licensed under the SGI | |
40 | Free Software B License. For details, see | |
41 | <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>. | |
42 | </p></div></div></body></html> |