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785 lines
45 KiB
XML
785 lines
45 KiB
XML
<!DOCTYPE refentry [ <!ENTITY % mathent SYSTEM "math.ent"> %mathent; ]>
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<!-- Converted by db4-upgrade version 1.1 -->
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<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glBlendEquation">
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<info>
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<copyright>
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<year>1991-2006</year>
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<holder>Silicon Graphics, Inc.</holder>
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</copyright>
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<copyright>
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<year>2010-2013</year>
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<holder>Khronos Group</holder>
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</copyright>
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</info>
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<refmeta>
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<refentrytitle>glBlendEquation</refentrytitle>
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<manvolnum>3G</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>glBlendEquation</refname>
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<refpurpose>specify the equation used for both the RGB blend equation and the Alpha blend equation</refpurpose>
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</refnamediv>
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<refsynopsisdiv><title>C Specification</title>
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<funcsynopsis>
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<funcprototype>
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<funcdef>void <function>glBlendEquation</function></funcdef>
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<paramdef>GLenum <parameter>mode</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>void <function>glBlendEquationi</function></funcdef>
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<paramdef>GLuint <parameter>buf</parameter></paramdef>
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<paramdef>GLenum <parameter>mode</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1 xml:id="parameters"><title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><parameter>buf</parameter></term>
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<listitem>
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<para>
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for <function>glBlendEquationi</function>, specifies the index of the draw buffer
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for which to set the blend equation.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>mode</parameter></term>
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<listitem>
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<para>
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specifies how source and destination colors are combined.
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It must be <constant>GL_FUNC_ADD</constant>, <constant>GL_FUNC_SUBTRACT</constant>,
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<constant>GL_FUNC_REVERSE_SUBTRACT</constant>, <constant>GL_MIN</constant>, <constant>GL_MAX</constant>.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1 xml:id="description"><title>Description</title>
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<para>
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The blend equations determine how a new pixel (the ''source'' color)
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is combined with a pixel already in the framebuffer (the ''destination''
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color). This function sets both the RGB blend equation and the alpha
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blend equation to a single equation. <function>glBlendEquationi</function>
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specifies the blend equation for a single draw buffer whereas <function>glBlendEquation</function>
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sets the blend equation for all draw buffers.
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</para>
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<para>
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These equations use the source and destination blend factors
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specified by either <citerefentry><refentrytitle>glBlendFunc</refentrytitle></citerefentry> or
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<citerefentry><refentrytitle>glBlendFuncSeparate</refentrytitle></citerefentry>.
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See <citerefentry><refentrytitle>glBlendFunc</refentrytitle></citerefentry> or <citerefentry><refentrytitle>glBlendFuncSeparate</refentrytitle></citerefentry>
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for a description of the various blend factors.
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</para>
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<para>
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In the equations that follow, source and destination
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color components are referred to as
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: ( R sub s, G sub s, B sub s, A sub s ): -->
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<mml:mfenced open="(" close=")">
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<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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</mml:mfenced>
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</mml:math></inlineequation>
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and
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: ( R sub d, G sub d, B sub d, A sub d ): -->
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<mml:mfenced open="(" close=")">
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<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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</mml:mfenced>
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</mml:math></inlineequation>,
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respectively.
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The result color is referred to as
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: ( R sub r, G sub r, B sub r, A sub r ): -->
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<mml:mfenced open="(" close=")">
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<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
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<mml:mi mathvariant="italic">r</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
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<mml:mi mathvariant="italic">r</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
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<mml:mi mathvariant="italic">r</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
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<mml:mi mathvariant="italic">r</mml:mi>
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</mml:msub>
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</mml:mfenced>
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</mml:math></inlineequation>.
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The source and destination blend factors are denoted
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: ( s sub R, s sub G, s sub B, s sub A ): -->
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<mml:mfenced open="(" close=")">
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">R</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">G</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">B</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">A</mml:mi>
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</mml:msub>
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</mml:mfenced>
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</mml:math></inlineequation>
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and
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: ( d sub R, d sub G, d sub B, d sub A ): -->
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<mml:mfenced open="(" close=")">
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">R</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">G</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">B</mml:mi>
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</mml:msub>
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">A</mml:mi>
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</mml:msub>
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</mml:mfenced>
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</mml:math></inlineequation>,
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respectively.
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For these equations all color components are understood to have values
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in the range
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: [0,1]: -->
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<mml:mfenced open="[" close="]">
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<mml:mn>0</mml:mn>
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<mml:mn>1</mml:mn>
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</mml:mfenced>
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</mml:math></inlineequation>.
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<informaltable>
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<tgroup cols="3" align="left">
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<colspec colwidth="1.1*"/>
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<colspec colwidth="1*"/>
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<colspec colwidth="1*"/>
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<thead>
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<row>
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<entry>
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<emphasis role="bold"> Mode </emphasis>
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</entry>
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<entry>
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<emphasis role="bold"> RGB Components </emphasis>
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</entry>
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<entry>
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<emphasis role="bold"> Alpha Component </emphasis>
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</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>
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<constant>GL_FUNC_ADD</constant>
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</entry>
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<entry>
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: Rr = R sub s s sub R + R sub d d sub R : -->
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<mml:mrow>
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<mml:mi mathvariant="italic">Rr</mml:mi>
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<mml:mo>=</mml:mo>
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<mml:mrow>
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<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">R</mml:mi>
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</mml:msub>
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<mml:mo>+</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">R</mml:mi>
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</mml:msub>
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</mml:mrow>
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</mml:mrow>
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</mml:math></inlineequation>
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: Gr = G sub s s sub G + G sub d d sub G : -->
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<mml:mrow>
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<mml:mi mathvariant="italic">Gr</mml:mi>
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<mml:mo>=</mml:mo>
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<mml:mrow>
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<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">G</mml:mi>
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</mml:msub>
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<mml:mo>+</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">G</mml:mi>
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</mml:msub>
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</mml:mrow>
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</mml:mrow>
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</mml:math></inlineequation>
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: Br = B sub s s sub B + B sub d d sub B : -->
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<mml:mrow>
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<mml:mi mathvariant="italic">Br</mml:mi>
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<mml:mo>=</mml:mo>
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<mml:mrow>
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<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">B</mml:mi>
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</mml:msub>
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<mml:mo>+</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">B</mml:mi>
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</mml:msub>
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</mml:mrow>
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</mml:mrow>
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</mml:math></inlineequation>
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</entry>
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<entry>
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: Ar = A sub s s sub A + A sub d d sub A : -->
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<mml:mrow>
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<mml:mi mathvariant="italic">Ar</mml:mi>
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<mml:mo>=</mml:mo>
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<mml:mrow>
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<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">A</mml:mi>
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</mml:msub>
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<mml:mo>+</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">A</mml:mi>
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</mml:msub>
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</mml:mrow>
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</mml:mrow>
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</mml:math></inlineequation>
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</entry>
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</row>
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<row>
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<entry>
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<constant>GL_FUNC_SUBTRACT</constant>
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</entry>
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<entry>
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: Rr = R sub s s sub R - R sub d d sub R : -->
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<mml:mrow>
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<mml:mi mathvariant="italic">Rr</mml:mi>
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<mml:mo>=</mml:mo>
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<mml:mrow>
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<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">R</mml:mi>
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</mml:msub>
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<mml:mo>-</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">R</mml:mi>
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</mml:msub>
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</mml:mrow>
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</mml:mrow>
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</mml:math></inlineequation>
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: Gr = G sub s s sub G - G sub d d sub G : -->
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<mml:mrow>
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<mml:mi mathvariant="italic">Gr</mml:mi>
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<mml:mo>=</mml:mo>
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<mml:mrow>
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<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">G</mml:mi>
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</mml:msub>
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<mml:mo>-</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">G</mml:mi>
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</mml:msub>
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</mml:mrow>
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</mml:mrow>
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</mml:math></inlineequation>
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- eqn: Br = B sub s s sub B - B sub d d sub B : -->
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<mml:mrow>
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<mml:mi mathvariant="italic">Br</mml:mi>
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<mml:mo>=</mml:mo>
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<mml:mrow>
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<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
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<mml:mi mathvariant="italic">s</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
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<mml:mi mathvariant="italic">B</mml:mi>
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</mml:msub>
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<mml:mo>-</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
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<mml:mi mathvariant="italic">d</mml:mi>
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</mml:msub>
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<mml:mo>⁢</mml:mo>
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<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
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<mml:mi mathvariant="italic">B</mml:mi>
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</mml:msub>
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</mml:mrow>
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</mml:mrow>
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</mml:math></inlineequation>
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</entry>
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<entry>
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<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
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<!-- 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>⁢</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>⁢</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>⁢</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>⁢</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>⁢</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>⁢</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>⁢</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>⁢</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>⁢</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>⁢</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>⁡</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>⁡</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>⁡</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>⁡</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>⁡</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>⁡</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>⁡</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>⁡</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="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"/> 2010-2013 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>.
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</para>
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</refsect1>
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</refentry>
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