1 <?xml version=
"1.0" encoding=
"UTF-8"?>
2 <!DOCTYPE book PUBLIC
"-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
3 "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
4 <refentry id=
"glBlendColor">
9 <holder>Silicon Graphics, Inc.
</holder>
12 <refentrytitle>glBlendColor
</refentrytitle>
13 <manvolnum>3G
</manvolnum>
16 <refname>glBlendColor
</refname>
17 <refpurpose>set the blend color
</refpurpose>
19 <refsynopsisdiv><title>C Specification
</title>
22 <funcdef>void
<function>glBlendColor
</function></funcdef>
23 <paramdef>GLclampf
<parameter>red
</parameter></paramdef>
24 <paramdef>GLclampf
<parameter>green
</parameter></paramdef>
25 <paramdef>GLclampf
<parameter>blue
</parameter></paramdef>
26 <paramdef>GLclampf
<parameter>alpha
</parameter></paramdef>
30 <!-- eqn: ignoring delim $$ -->
31 <refsect1 id=
"parameters"><title>Parameters
</title>
34 <term><parameter>red
</parameter></term>
35 <term><parameter>green
</parameter></term>
36 <term><parameter>blue
</parameter></term>
37 <term><parameter>alpha
</parameter></term>
40 specify the components of
<constant>GL_BLEND_COLOR
</constant>
46 <refsect1 id=
"description"><title>Description
</title>
48 The
<constant>GL_BLEND_COLOR
</constant> may be used to calculate the source and destination
49 blending factors. The color components are clamped to the range
50 <inlineequation><mml:math>
52 <mml:mfenced open=
"[" close=
"]">
56 </mml:math></inlineequation>
57 before being stored. See
<citerefentry><refentrytitle>glBlendFunc
</refentrytitle></citerefentry> for a complete description of the
59 Initially the
<constant>GL_BLEND_COLOR
</constant> is set to (
0,
0,
0,
0).
62 <refsect1 id=
"notes"><title>Notes
</title>
64 <function>glBlendColor
</function> is part of the
<code>ARB_imaging
</code> subset.
<function>glBlendColor
</function> is present only
65 if
<code>ARB_imaging
</code> is returned when
<citerefentry><refentrytitle>glGetString
</refentrytitle></citerefentry> is called with
66 <constant>GL_EXTENSIONS
</constant> as its argument.
69 <refsect1 id=
"errors"><title>Errors
</title>
71 <constant>GL_INVALID_OPERATION
</constant> is generated if
<function>glBlendColor
</function> is executed
72 between the execution of
<citerefentry><refentrytitle>glBegin
</refentrytitle></citerefentry> and the corresponding
73 execution of
<citerefentry><refentrytitle>glEnd
</refentrytitle></citerefentry>.
78 <refsect1 id=
"associatedgets"><title>Associated Gets
</title>
80 <citerefentry><refentrytitle>glGet
</refentrytitle></citerefentry> with an argument of
<constant>GL_BLEND_COLOR
</constant>
83 <refsect1 id=
"seealso"><title>See Also
</title>
85 <citerefentry><refentrytitle>glBlendEquation
</refentrytitle></citerefentry>,
86 <citerefentry><refentrytitle>glBlendFunc
</refentrytitle></citerefentry>,
87 <citerefentry><refentrytitle>glGetString
</refentrytitle></citerefentry>
90 <refsect1 id=
"Copyright"><title>Copyright
</title>
92 Copyright
<trademark class=
"copyright"></trademark> 1991-
2006
93 Silicon Graphics, Inc. This document is licensed under the SGI
94 Free Software B License. For details, see
95 <ulink url=
"http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/
</ulink>.