<!DOCTYPE refentry [ <!ENTITY % mathent SYSTEM "math.ent"> %mathent; ]>

<!-- Converted by db4-upgrade version 1.1 -->

<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glBlendEquation">
    <info>
        <copyright>
            <year>1991-2006</year>
            <holder>Silicon Graphics, Inc.</holder>
        </copyright>
        <copyright>
            <year>2010-2014</year>
            <holder>Khronos Group</holder>
        </copyright>
    </info>
    <refmeta>
        <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>
            <funcprototype>
                <funcdef>void <function>glBlendEquationi</function></funcdef>
                <paramdef>GLuint <parameter>buf</parameter></paramdef>
                <paramdef>GLenum <parameter>mode</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 xml:id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>buf</parameter></term>
            <listitem>
                <para>
                    for <function>glBlendEquationi</function>, specifies the index of the draw buffer
                    for which to set the blend equation.
                </para>
            </listitem>
        </varlistentry>
        <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 xml: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. <function>glBlendEquationi</function>
            specifies the blend equation for a single draw buffer whereas <function>glBlendEquation</function>
            sets the blend equation for all draw buffers.
        </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 xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- 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 xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- 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 xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- 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 xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- 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 xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- 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 xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                <!-- eqn: [0,1]: -->
                <mml:mfenced open="[" close="]">
                    <mml:mn>0</mml:mn>
                    <mml:mn>1</mml:mn>
                </mml:mfenced>
            </mml:math></inlineequation>.

        <informaltable>
            <tgroup cols="3" align="left">
                <colspec colwidth="1.1*"/>
                <colspec colwidth="1*"/>
                <colspec colwidth="1*"/>
                <thead>
                    <row>
                        <entry>
                            <emphasis role="bold"> Mode </emphasis>
                        </entry>
                        <entry>
                            <emphasis role="bold"> RGB Components </emphasis>
                        </entry> 
                        <entry>
                            <emphasis role="bold"> Alpha Component </emphasis>
                        </entry>
                    </row>
                </thead>
                <tbody>
                    <row>
                        <entry>
                        <constant>GL_FUNC_ADD</constant>
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- 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></inlineequation>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- 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></inlineequation>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- 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></inlineequation>
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- 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></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_FUNC_SUBTRACT</constant>
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- 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></inlineequation>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- 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></inlineequation>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- 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></inlineequation>
                        </entry>
                        <entry>
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- 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></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_FUNC_REVERSE_SUBTRACT</constant>
                        </entry>
                        <entry>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                        </entry>
                        <entry>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_MIN</constant>
                        </entry>
                        <entry>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                        </entry>
                        <entry>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                        </entry>
                    </row>
                    <row>
                        <entry>
                        <constant>GL_MAX</constant>
                        </entry>
                        <entry>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                        </entry>
                        <entry>
                            <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                                <!-- 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></inlineequation>
                        </entry>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
        </para>
        <para>
            The results of these equations are clamped to the range
                        <inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
                            <!-- 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 xml: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 xml: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_VALUE</constant> is generated by <function>glBlendEquationi</function> if <parameter>buf</parameter> is greater
            than or equal to the value of <constant>GL_MAX_DRAW_BUFFERS</constant>.
        </para>
    </refsect1>
    <refsect1 xml: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 xml:id="versions"><title>Version Support</title>
        <informaltable>
            <tgroup cols="13" align="left">
                <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
                <tbody>
                    <row>
                        <entry><function>glBlendEquation</function></entry>
                        <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='20']/*)"/>
                    </row>
                    <row>
                        <entry><function>glBlendEquationi</function></entry>
                        <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='40']/*)"/>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
    </refsect1>
    <refsect1 xml:id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glBlendColor</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glBlendFunc</refentrytitle></citerefentry>
            <citerefentry><refentrytitle>glBlendFuncSeparate</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 xml:id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"/> 1991-2006 Silicon Graphics, Inc.
            Copyright <trademark class="copyright"/> 2010-2014 Khronos Group.
            This document is licensed under the SGI Free Software B License.
            For details, see
            <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</link>.
        </para>
    </refsect1>
</refentry>
