<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
              "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
<refentry id="glBlendEquation">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>1991-2006</year>
                <holder>Silicon Graphics, Inc.</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glBlendEquation</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glBlendEquation</refname>
        <refpurpose>specify the equation used for both the RGB blend equation and the Alpha blend equation</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glBlendEquation</function></funcdef>
                <paramdef>GLenum <parameter>mode</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <!-- eqn: ignoring delim $$ -->
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>mode</parameter></term>
            <listitem>
                <para>
                    specifies how source and destination colors are combined.
                    It must be <constant>GL_FUNC_ADD</constant>, <constant>GL_FUNC_SUBTRACT</constant>,
                    <constant>GL_FUNC_REVERSE_SUBTRACT</constant>, <constant>GL_MIN</constant>, <constant>GL_MAX</constant>.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            The blend equations determine how a new pixel (the ''source'' color)
            is combined with a pixel already in the framebuffer (the ''destination''
            color).  This function sets both the RGB blend equation and the alpha 
            blend equation to a single equation.
        </para>
        <para>
            These equations use the source and destination blend factors
            specified by either <citerefentry><refentrytitle>glBlendFunc</refentrytitle></citerefentry> or
            <citerefentry><refentrytitle>glBlendFuncSeparate</refentrytitle></citerefentry>.
            See <citerefentry><refentrytitle>glBlendFunc</refentrytitle></citerefentry> or <citerefentry><refentrytitle>glBlendFuncSeparate</refentrytitle></citerefentry>
            for a description of the various blend factors.
        </para>
        <para>
            In the equations that follow, source and destination
            color components are referred to as
            <inlineequation><mml:math>
                <!-- eqn: ( R sub s, G sub s, B sub s, A sub s ):-->
                <mml:mfenced open="(" close=")">
                    <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
                    <mml:mi mathvariant="italic">s</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
                    <mml:mi mathvariant="italic">s</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
                    <mml:mi mathvariant="italic">s</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
                    <mml:mi mathvariant="italic">s</mml:mi>
                    </mml:msub>
                </mml:mfenced>
            </mml:math></inlineequation>
            and
            <inlineequation><mml:math>
                <!-- eqn: ( R sub d, G sub d, B sub d, A sub d ):-->
                <mml:mfenced open="(" close=")">
                    <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
                    <mml:mi mathvariant="italic">d</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
                    <mml:mi mathvariant="italic">d</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
                    <mml:mi mathvariant="italic">d</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
                    <mml:mi mathvariant="italic">d</mml:mi>
                    </mml:msub>
                </mml:mfenced>
            </mml:math></inlineequation>,
            respectively.
            The result color is referred to as
            <inlineequation><mml:math>
                <!-- eqn: ( R sub r, G sub r, B sub r, A sub r ):-->
                <mml:mfenced open="(" close=")">
                    <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
                    <mml:mi mathvariant="italic">r</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
                    <mml:mi mathvariant="italic">r</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
                    <mml:mi mathvariant="italic">r</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
                    <mml:mi mathvariant="italic">r</mml:mi>
                    </mml:msub>
                </mml:mfenced>
            </mml:math></inlineequation>.
            The source and destination blend factors are denoted
            <inlineequation><mml:math>
                <!-- eqn: ( s sub R, s sub G, s sub B, s sub A ):-->
                <mml:mfenced open="(" close=")">
                    <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
                    <mml:mi mathvariant="italic">R</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
                    <mml:mi mathvariant="italic">G</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
                    <mml:mi mathvariant="italic">B</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">s</mml:mi>
                    <mml:mi mathvariant="italic">A</mml:mi>
                    </mml:msub>
                </mml:mfenced>
            </mml:math></inlineequation>
            and
            <inlineequation><mml:math>
                <!-- eqn: ( d sub R, d sub G, d sub B, d sub A ):-->
                <mml:mfenced open="(" close=")">
                    <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
                    <mml:mi mathvariant="italic">R</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
                    <mml:mi mathvariant="italic">G</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
                    <mml:mi mathvariant="italic">B</mml:mi>
                    </mml:msub>
                    <mml:msub><mml:mi mathvariant="italic">d</mml:mi>
                    <mml:mi mathvariant="italic">A</mml:mi>
                    </mml:msub>
                </mml:mfenced>
            </mml:math></inlineequation>,
            respectively.
            For these equations all color components are understood to have values
            in the range 
            <inlineequation><mml:math>
                <!-- eqn: [0,1]:-->
                <mml:mfenced open="[" close="]">
                    <mml:mn>0</mml:mn>
                    <mml:mn>1</mml:mn>
                </mml:mfenced>
            </mml:math></inlineequation>.

        <informaltable frame="topbot">
            <tgroup cols="3" align="left">
                <colspec colwidth="1.1*" />
                <colspec colwidth="1*" />
                <colspec colwidth="1*" />
                <thead>
                    <row>
                        <entry rowsep="1" align="left"><emphasis role="bold">
                        Mode
                        </emphasis></entry>
                        <entry rowsep="1" align="left"><emphasis role="bold">
                        RGB Components
                        </emphasis></entry>
                        <entry rowsep="1" align="left"><emphasis role="bold">
                        Alpha Component
                        </emphasis></entry>
                    </row>
                </thead>
                <tbody>
                    <row>
                        <entry align="left">
                        <constant>GL_FUNC_ADD</constant>
                        </entry>
                        <entry align="left">
                        <informalequation><mml:math>
                            <!-- eqn: Rr  =      R sub s s sub R  +  R sub d d sub R :-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">Rr</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mrow>
									<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
									<mml:mi mathvariant="italic">s</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
									<mml:mi mathvariant="italic">R</mml:mi>
									</mml:msub>
									<mml:mo>+</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
									<mml:mi mathvariant="italic">d</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
									<mml:mi mathvariant="italic">R</mml:mi>
									</mml:msub>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></informalequation>
                        <informalequation><mml:math>
                            <!-- eqn: Gr  =    G sub s s sub G  +  G sub d d sub G :-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">Gr</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mrow>
									<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
									<mml:mi mathvariant="italic">s</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
									<mml:mi mathvariant="italic">G</mml:mi>
									</mml:msub>
									<mml:mo>+</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
									<mml:mi mathvariant="italic">d</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
									<mml:mi mathvariant="italic">G</mml:mi>
									</mml:msub>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></informalequation>
                        <informalequation><mml:math>
                            <!-- eqn: Br  =    B sub s s sub B  +  B sub d d sub B :-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">Br</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mrow>
									<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
									<mml:mi mathvariant="italic">s</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
									<mml:mi mathvariant="italic">B</mml:mi>
									</mml:msub>
									<mml:mo>+</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
									<mml:mi mathvariant="italic">d</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
									<mml:mi mathvariant="italic">B</mml:mi>
									</mml:msub>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></informalequation>
                        </entry>
                        <entry align="left">
                        <informalequation><mml:math>
                            <!-- eqn: Ar  =    A sub s s sub A  +  A sub d d sub A :-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">Ar</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mrow>
									<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
									<mml:mi mathvariant="italic">s</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
									<mml:mi mathvariant="italic">A</mml:mi>
									</mml:msub>
									<mml:mo>+</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
									<mml:mi mathvariant="italic">d</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
									<mml:mi mathvariant="italic">A</mml:mi>
									</mml:msub>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></informalequation>
                        </entry>
                    </row>
                    <row>
                        <entry align="left">
                        <constant>GL_FUNC_SUBTRACT</constant>
                        </entry>
                        <entry align="left">
                        <informalequation><mml:math>
                            <!-- eqn: Rr  =      R sub s s sub R  -  R sub d d sub R :-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">Rr</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mrow>
									<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
									<mml:mi mathvariant="italic">s</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
									<mml:mi mathvariant="italic">R</mml:mi>
									</mml:msub>
									<mml:mo>-</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
									<mml:mi mathvariant="italic">d</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
									<mml:mi mathvariant="italic">R</mml:mi>
									</mml:msub>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></informalequation>
                        <informalequation><mml:math>
                            <!-- eqn: Gr  =    G sub s s sub G  -  G sub d d sub G :-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">Gr</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mrow>
									<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
									<mml:mi mathvariant="italic">s</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
									<mml:mi mathvariant="italic">G</mml:mi>
									</mml:msub>
									<mml:mo>-</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
									<mml:mi mathvariant="italic">d</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
									<mml:mi mathvariant="italic">G</mml:mi>
									</mml:msub>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></informalequation>
                        <informalequation><mml:math>
                            <!-- eqn: Br  =    B sub s s sub B  -  B sub d d sub B :-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">Br</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mrow>
									<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
									<mml:mi mathvariant="italic">s</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
									<mml:mi mathvariant="italic">B</mml:mi>
									</mml:msub>
									<mml:mo>-</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
									<mml:mi mathvariant="italic">d</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
									<mml:mi mathvariant="italic">B</mml:mi>
									</mml:msub>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></informalequation>
                        </entry>
                        <entry align="left">
                        <informalequation><mml:math>
                            <!-- eqn: Ar  =    A sub s s sub A  -  A sub d d sub A :-->
                            <mml:mrow>
                                <mml:mi mathvariant="italic">Ar</mml:mi>
                                <mml:mo>=</mml:mo>
                                <mml:mrow>
									<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
									<mml:mi mathvariant="italic">s</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
									<mml:mi mathvariant="italic">A</mml:mi>
									</mml:msub>
									<mml:mo>-</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
									<mml:mi mathvariant="italic">d</mml:mi>
									</mml:msub>
									<mml:mo>&it;</mml:mo>
									<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
									<mml:mi mathvariant="italic">A</mml:mi>
									</mml:msub>
                                </mml:mrow>
                            </mml:mrow>
                        </mml:math></informalequation>
                        </entry>
                    </row>
                    <row>
                        <entry align="left">
                        <constant>GL_FUNC_REVERSE_SUBTRACT</constant>
                        </entry>
                        <entry align="left">
                            <informalequation><mml:math>
                                <!-- eqn: Rr  =      R sub d d sub R  -  R sub s s sub R :-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Rr</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
										<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
										<mml:mi mathvariant="italic">d</mml:mi>
										</mml:msub>
										<mml:mo>&it;</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
										<mml:mi mathvariant="italic">R</mml:mi>
										</mml:msub>
										<mml:mo>-</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
										<mml:mi mathvariant="italic">s</mml:mi>
										</mml:msub>
										<mml:mo>&it;</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
										<mml:mi mathvariant="italic">R</mml:mi>
										</mml:msub>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                            <informalequation><mml:math>
                                <!-- eqn: Gr  =    G sub d d sub G  -  G sub s s sub G :-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Gr</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
										<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
										<mml:mi mathvariant="italic">d</mml:mi>
										</mml:msub>
										<mml:mo>&it;</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
										<mml:mi mathvariant="italic">G</mml:mi>
										</mml:msub>
										<mml:mo>-</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
										<mml:mi mathvariant="italic">s</mml:mi>
										</mml:msub>
										<mml:mo>&it;</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
										<mml:mi mathvariant="italic">G</mml:mi>
										</mml:msub>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                            <informalequation><mml:math>
                                <!-- eqn: Br  =    B sub d d sub B  -  B sub s s sub B :-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Br</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
										<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
										<mml:mi mathvariant="italic">d</mml:mi>
										</mml:msub>
										<mml:mo>&it;</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
										<mml:mi mathvariant="italic">B</mml:mi>
										</mml:msub>
										<mml:mo>-</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
										<mml:mi mathvariant="italic">s</mml:mi>
										</mml:msub>
										<mml:mo>&it;</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
										<mml:mi mathvariant="italic">B</mml:mi>
										</mml:msub>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                        </entry>
                        <entry align="left">
                            <informalequation><mml:math>
                                <!-- eqn: Ar  =    A sub d d sub A  -  A sub s s sub A :-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Ar</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
										<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
										<mml:mi mathvariant="italic">d</mml:mi>
										</mml:msub>
										<mml:mo>&it;</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
										<mml:mi mathvariant="italic">A</mml:mi>
										</mml:msub>
										<mml:mo>-</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
										<mml:mi mathvariant="italic">s</mml:mi>
										</mml:msub>
										<mml:mo>&it;</mml:mo>
										<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
										<mml:mi mathvariant="italic">A</mml:mi>
										</mml:msub>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                        </entry>
                    </row>
                    <row>
                        <entry align="left">
                        <constant>GL_MIN</constant>
                        </entry>
                        <entry align="left">
                            <informalequation><mml:math>
                                <!-- eqn: Rr  =      min ( R sub s, R sub d):-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Rr</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">min</mml:mi>
                                        <mml:mo>&af;</mml:mo>
                                        <mml:mfenced open="(" close=")">
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
                                                <mml:mi mathvariant="italic">s</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
                                                <mml:mi mathvariant="italic">d</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                        </mml:mfenced>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                            <informalequation><mml:math>
                                <!-- eqn: Gr  =      min ( G sub s, G sub d):-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Gr</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">min</mml:mi>
                                        <mml:mo>&af;</mml:mo>
                                        <mml:mfenced open="(" close=")">
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
                                                <mml:mi mathvariant="italic">s</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
                                                <mml:mi mathvariant="italic">d</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                        </mml:mfenced>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                            <informalequation><mml:math>
                                <!-- eqn: Br  =      min ( B sub s, B sub d):-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Br</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">min</mml:mi>
                                        <mml:mo>&af;</mml:mo>
                                        <mml:mfenced open="(" close=")">
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
                                                <mml:mi mathvariant="italic">s</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
                                                <mml:mi mathvariant="italic">d</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                        </mml:mfenced>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                        </entry>
                        <entry align="left">
                            <informalequation><mml:math>
                                <!-- eqn: Ar  =      min ( A sub s, A sub d):-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Ar</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">min</mml:mi>
                                        <mml:mo>&af;</mml:mo>
                                        <mml:mfenced open="(" close=")">
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
                                                <mml:mi mathvariant="italic">s</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
                                                <mml:mi mathvariant="italic">d</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                        </mml:mfenced>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                        </entry>
                    </row>
                    <row>
                        <entry align="left">
                        <constant>GL_MAX</constant>
                        </entry>
                        <entry align="left">
                            <informalequation><mml:math>
                                <!-- eqn: Rr  =      max ( R sub s, R sub d):-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Rr</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">max</mml:mi>
                                        <mml:mo>&af;</mml:mo>
                                        <mml:mfenced open="(" close=")">
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
                                                <mml:mi mathvariant="italic">s</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">R</mml:mi>
                                                <mml:mi mathvariant="italic">d</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                        </mml:mfenced>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                            <informalequation><mml:math>
                                <!-- eqn: Gr  =      max ( G sub s, G sub d):-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Gr</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">max</mml:mi>
                                        <mml:mo>&af;</mml:mo>
                                        <mml:mfenced open="(" close=")">
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
                                                <mml:mi mathvariant="italic">s</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">G</mml:mi>
                                                <mml:mi mathvariant="italic">d</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                        </mml:mfenced>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                            <informalequation><mml:math>
                                <!-- eqn: Br  =      max ( B sub s, B sub d):-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Br</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">max</mml:mi>
                                        <mml:mo>&af;</mml:mo>
                                        <mml:mfenced open="(" close=")">
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
                                                <mml:mi mathvariant="italic">s</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">B</mml:mi>
                                                <mml:mi mathvariant="italic">d</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                        </mml:mfenced>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                        </entry>
                        <entry align="left">
                            <informalequation><mml:math>
                                <!-- eqn: Ar  =      max ( A sub s, A sub d):-->
                                <mml:mrow>
                                    <mml:mi mathvariant="italic">Ar</mml:mi>
                                    <mml:mo>=</mml:mo>
                                    <mml:mrow>
                                        <mml:mi mathvariant="italic">max</mml:mi>
                                        <mml:mo>&af;</mml:mo>
                                        <mml:mfenced open="(" close=")">
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
                                                <mml:mi mathvariant="italic">s</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                            <mml:mrow>
                                                <mml:msub><mml:mi mathvariant="italic">A</mml:mi>
                                                <mml:mi mathvariant="italic">d</mml:mi>
                                                </mml:msub>
                                            </mml:mrow>
                                        </mml:mfenced>
                                    </mml:mrow>
                                </mml:mrow>
                            </mml:math></informalequation>
                        </entry>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
        </para>
        <para>
            The results of these equations are clamped to the range 
                        <inlineequation><mml:math>
                            <!-- eqn: [0,1]:-->
                            <mml:mfenced open="[" close="]">
                                <mml:mn>0</mml:mn>
                                <mml:mn>1</mml:mn>
                            </mml:mfenced>
                        </mml:math></inlineequation>.
        </para>
        <para>
            The <constant>GL_MIN</constant> and <constant>GL_MAX</constant> equations are useful for applications
            that analyze image data (image thresholding against a constant color,
            for example).
            The <constant>GL_FUNC_ADD</constant> equation is useful
            for antialiasing and transparency, among other things.
        </para>
        <para>
            Initially, both the RGB blend equation and the alpha blend equation are set to <constant>GL_FUNC_ADD</constant>.
        </para>
        <para>
        </para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            The <constant>GL_MIN</constant>, and <constant>GL_MAX</constant> equations do not use
            the source or destination factors, only the source and destination colors.
        </para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>mode</parameter> is not one of
            <constant>GL_FUNC_ADD</constant>, <constant>GL_FUNC_SUBTRACT</constant>, <constant>GL_FUNC_REVERSE_SUBTRACT</constant>,
            <constant>GL_MAX</constant>, or <constant>GL_MIN</constant>.
        </para>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if <function>glBlendEquation</function> is executed
            between the execution of <citerefentry><refentrytitle>glBegin</refentrytitle></citerefentry> and the corresponding
            execution of <citerefentry><refentrytitle>glEnd</refentrytitle></citerefentry>.
        </para>
    </refsect1>
    <refsect1 id="associatedgets"><title>Associated Gets</title>
         <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with an argument of <constant>GL_BLEND_EQUATION_RGB</constant>
         </para>
         <para>
            <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with an argument of <constant>GL_BLEND_EQUATION_ALPHA</constant>
         </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glGetString</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glBlendColor</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glBlendFunc</refentrytitle></citerefentry>
            <citerefentry><refentrytitle>glBlendFuncSeparate</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
        </para>
    </refsect1>
</refentry>
