ryujinx/Opentk
1
0
Fork 0
mirror of https://github.com/Ryujinx/Opentk.git synced 2024-12-27 18:15:34 +00:00
Code Issues Packages Projects Releases Wiki Activity
Opentk/Source/Bind/Specifications/Docs/ES20/glBlendFuncSeparate.xml
thefiddler 22a706e44f [Bind] Added documentation files for OpenGL ES
2014-03-28 20:06:55 +01:00

1072 lines
56 KiB
XML
Raw Blame History

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
<refentry id="glBlendFuncSeparate">
<refmeta>
<refmetainfo>
<copyright>
<year>1991-2006</year>
<holder>Silicon Graphics, Inc.</holder>
</copyright>
</refmetainfo>
<refentrytitle>glBlendFuncSeparate</refentrytitle>
<manvolnum>3G</manvolnum>
</refmeta>
<refnamediv>
<refname>glBlendFuncSeparate</refname>
<refpurpose>specify pixel arithmetic for RGB and alpha components separately</refpurpose>
</refnamediv>
<refsynopsisdiv><title>C Specification</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>glBlendFuncSeparate</function></funcdef>
<paramdef>GLenum <parameter>srcRGB</parameter></paramdef>
<paramdef>GLenum <parameter>dstRGB</parameter></paramdef>
<paramdef>GLenum <parameter>srcAlpha</parameter></paramdef>
<paramdef>GLenum <parameter>dstAlpha</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<!-- eqn: ignoring delim $$ -->
<refsect1 id="parameters"><title>Parameters</title>
<variablelist>
<varlistentry>
<term><parameter>srcRGB</parameter></term>
<listitem>
<para>
Specifies how the red, green, and blue blending factors are computed.
The following symbolic constants are accepted:
<constant>GL_ZERO</constant>,
<constant>GL_ONE</constant>,
<constant>GL_SRC_COLOR</constant>,
<constant>GL_ONE_MINUS_SRC_COLOR</constant>,
<constant>GL_DST_COLOR</constant>,
<constant>GL_ONE_MINUS_DST_COLOR</constant>,
<constant>GL_SRC_ALPHA</constant>,
<constant>GL_ONE_MINUS_SRC_ALPHA</constant>,
<constant>GL_DST_ALPHA</constant>,
<constant>GL_ONE_MINUS_DST_ALPHA</constant>,
<constant>GL_CONSTANT_COLOR</constant>,
<constant>GL_ONE_MINUS_CONSTANT_COLOR</constant>,
<constant>GL_CONSTANT_ALPHA</constant>,
<constant>GL_ONE_MINUS_CONSTANT_ALPHA</constant>, and
<constant>GL_SRC_ALPHA_SATURATE</constant>.
The initial value is <constant>GL_ONE</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dstRGB</parameter></term>
<listitem>
<para>
Specifies how the red, green, and blue destination blending factors are
computed. The following symbolic constants are accepted:
<constant>GL_ZERO</constant>,
<constant>GL_ONE</constant>,
<constant>GL_SRC_COLOR</constant>,
<constant>GL_ONE_MINUS_SRC_COLOR</constant>,
<constant>GL_DST_COLOR</constant>,
<constant>GL_ONE_MINUS_DST_COLOR</constant>,
<constant>GL_SRC_ALPHA</constant>,
<constant>GL_ONE_MINUS_SRC_ALPHA</constant>,
<constant>GL_DST_ALPHA</constant>,
<constant>GL_ONE_MINUS_DST_ALPHA</constant>.
<constant>GL_CONSTANT_COLOR</constant>,
<constant>GL_ONE_MINUS_CONSTANT_COLOR</constant>,
<constant>GL_CONSTANT_ALPHA</constant>, and
<constant>GL_ONE_MINUS_CONSTANT_ALPHA</constant>.
The initial value is <constant>GL_ZERO</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>srcAlpha</parameter></term>
<listitem>
<para>
Specified how the alpha source blending factor is computed. The same
symbolic constants are accepted as for <parameter>srcRGB</parameter>.
The initial value is <constant>GL_ONE</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>dstAlpha</parameter></term>
<listitem>
<para>
Specified how the alpha destination blending factor is computed. The same
symbolic constants are accepted as for <parameter>dstRGB</parameter>.
The initial value is <constant>GL_ZERO</constant>.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="description"><title>Description</title>
<para>
Pixels can be drawn using a function that blends
the incoming (source) RGBA values with the RGBA values
that are already in the frame buffer (the destination values).
Blending is initially disabled.
Use <citerefentry><refentrytitle>glEnable</refentrytitle></citerefentry> and <citerefentry><refentrytitle>glDisable</refentrytitle></citerefentry> with argument <constant>GL_BLEND</constant>
to enable and disable blending.
</para>
<para>
<function>glBlendFuncSeparate</function> defines the operation of blending when it is enabled.
<parameter>srcRGB</parameter> specifies which method is used to scale the
source RGB-color components.
<parameter>dstRGB</parameter> specifies which method is used to scale the
destination RGB-color components.
Likewise, <parameter>srcAlpha</parameter> specifies which method is used to scale the source alpha
color component, and <parameter>dstAlpha</parameter> specifies which method is used to scale the
destination alpha component.
The possible methods are described in the following table.
Each method defines four scale factors,
one each for red, green, blue, and alpha.
</para>
<para>
In the table and in subsequent equations, source and destination
color components are referred to as
<inlineequation><mml:math>
<!-- eqn: ( R sub s , G sub s , B sub s , A sub s ):-->
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:math></inlineequation>
and
<inlineequation><mml:math>
<!-- eqn: ( R sub d , G sub d , B sub d , A sub d ):-->
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:math></inlineequation>.
The color specified by <citerefentry><refentrytitle>glBlendColor</refentrytitle></citerefentry> is referred to as
<inlineequation><mml:math>
<!-- eqn: ( R sub c , G sub c , B sub c , A sub c ):-->
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:math></inlineequation>.
They are understood to have integer values between 0 and
<inlineequation><mml:math>
<!-- eqn: ( k sub R , k sub G , k sub B , k sub A ):-->
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">R</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">G</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">B</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:math></inlineequation>,
where
</para>
<para>
<para>
<inlineequation><mml:math>
<!-- eqn: k sub c = 2 sup {m sub c} - 1:-->
<mml:mrow>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:mo>=</mml:mo>
<mml:mrow>
<mml:msup><mml:mn>2</mml:mn>
<mml:mfenced open="" close="">
<mml:msub><mml:mi mathvariant="italic">m</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:msup>
<mml:mo>-</mml:mo>
<mml:mn>1</mml:mn>
</mml:mrow>
</mml:mrow>
</mml:math></inlineequation>
</para>
</para>
<para>
and
<inlineequation><mml:math>
<!-- eqn: ( m sub R , m sub G , m sub B , m sub A ):-->
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">m</mml:mi>
<mml:mi mathvariant="italic">R</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">m</mml:mi>
<mml:mi mathvariant="italic">G</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">m</mml:mi>
<mml:mi mathvariant="italic">B</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">m</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:math></inlineequation>
is the number of red,
green,
blue,
and alpha bitplanes.
</para>
<para>
Source and destination scale factors are referred to as
<inlineequation><mml:math>
<!-- eqn: ( s sub R , s sub G , s sub B , s sub A ):-->
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
<mml:mi mathvariant="italic">R</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
<mml:mi mathvariant="italic">G</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
<mml:mi mathvariant="italic">B</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">s</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:math></inlineequation>
and
<inlineequation><mml:math>
<!-- eqn: ( d sub R , d sub G , d sub B , d sub A ):-->
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
<mml:mi mathvariant="italic">R</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
<mml:mi mathvariant="italic">G</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
<mml:mi mathvariant="italic">B</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">d</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:math></inlineequation>.
All scale factors have range
<inlineequation><mml:math>
<!-- eqn: [0,1]:-->
<mml:mfenced open="[" close="]">
<mml:mn>0</mml:mn>
<mml:mn>1</mml:mn>
</mml:mfenced>
</mml:math></inlineequation>.
</para>
<para>
</para>
<informaltable frame="topbot">
<tgroup cols="3" align="left">
<colspec/>
<colspec/>
<colspec/>
<thead>
<row>
<entry rowsep="1" align="left"><emphasis role="bold">
Parameter
</emphasis></entry>
<entry rowsep="1" align="left"><emphasis role="bold">
RGB Factor
</emphasis></entry>
<entry rowsep="1" align="left"><emphasis role="bold">
Alpha Factor
</emphasis></entry>
</row>
</thead>
<tbody>
<row>
<entry align="left">
<constant>GL_ZERO</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( 0, 0, 0 ):-->
<mml:mfenced open="(" close=")">
<mml:mn>0</mml:mn>
<mml:mn>0</mml:mn>
<mml:mn>0</mml:mn>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: 0:-->
<mml:mn>0</mml:mn>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_ONE</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( 1, 1, 1 ):-->
<mml:mfenced open="(" close=")">
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: 1:-->
<mml:mn>1</mml:mn>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_SRC_COLOR</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( R sub s / k sub R , G sub s / k sub G , B sub s / k sub B ):-->
<mml:mfenced open="(" close=")">
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">R</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">G</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">B</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: A sub s / k sub A:-->
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_ONE_MINUS_SRC_COLOR</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( 1, 1, 1, 1 ) - ( R sub s / k sub R , G sub s / k sub G , B sub s / k sub B ):-->
<mml:mrow>
<mml:mfenced open="(" close=")">
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
</mml:mfenced>
<mml:mo>-</mml:mo>
<mml:mfenced open="(" close=")">
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">R</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">G</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">B</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mfenced>
</mml:mrow>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: 1 - A sub s / k sub A:-->
<mml:mrow>
<mml:mn>1</mml:mn>
<mml:mo>-</mml:mo>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mrow>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_DST_COLOR</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( R sub d / k sub R , G sub d / k sub G , B sub d / k sub B ):-->
<mml:mfenced open="(" close=")">
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">R</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">G</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">B</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: A sub d / k sub A:-->
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_ONE_MINUS_DST_COLOR</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( 1, 1, 1 ) - ( R sub d / k sub R , G sub d / k sub G , B sub d / k sub B ):-->
<mml:mrow>
<mml:mfenced open="(" close=")">
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
</mml:mfenced>
<mml:mo>-</mml:mo>
<mml:mfenced open="(" close=")">
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">R</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">G</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">B</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mfenced>
</mml:mrow>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: 1 - A sub d / k sub A:-->
<mml:mrow>
<mml:mn>1</mml:mn>
<mml:mo>-</mml:mo>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mrow>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_SRC_ALPHA</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( A sub s / k sub A , A sub s / k sub A , A sub s / k sub A ):-->
<mml:mfenced open="(" close=")">
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: A sub s / k sub A:-->
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_ONE_MINUS_SRC_ALPHA</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( 1, 1, 1 ) - ( A sub s / k sub A , A sub s / k sub A , A sub s / k sub A ):-->
<mml:mrow>
<mml:mfenced open="(" close=")">
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
</mml:mfenced>
<mml:mo>-</mml:mo>
<mml:mfenced open="(" close=")">
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mfenced>
</mml:mrow>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: 1 - A sub s / k sub A:-->
<mml:mrow>
<mml:mn>1</mml:mn>
<mml:mo>-</mml:mo>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mrow>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_DST_ALPHA</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( A sub d / k sub A , A sub d / k sub A , A sub d / k sub A ):-->
<mml:mfenced open="(" close=")">
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: A sub d / k sub A:-->
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_ONE_MINUS_DST_ALPHA</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( 1, 1, 1 ) - ( A sub d / k sub A , A sub d / k sub A , A sub d / k sub A ):-->
<mml:mrow>
<mml:mfenced open="(" close=")">
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
</mml:mfenced>
<mml:mo>-</mml:mo>
<mml:mfenced open="(" close=")">
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mfenced>
</mml:mrow>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: 1 - A sub d / k sub A:-->
<mml:mrow>
<mml:mn>1</mml:mn>
<mml:mo>-</mml:mo>
<mml:mfrac>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:mfrac>
</mml:mrow>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_CONSTANT_COLOR</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( R sub c, G sub c, B sub c ):-->
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: A sub c:-->
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_ONE_MINUS_CONSTANT_COLOR</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( 1, 1, 1 ) - ( R sub c, G sub c, B sub c ):-->
<mml:mrow>
<mml:mfenced open="(" close=")">
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
</mml:mfenced>
<mml:mo>-</mml:mo>
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">R</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">G</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">B</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:mrow>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: 1 - A sub c:-->
<mml:mrow>
<mml:mn>1</mml:mn>
<mml:mo>-</mml:mo>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
</mml:mrow>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_CONSTANT_ALPHA</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( A sub c, A sub c, A sub c ):-->
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: A sub c:-->
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_ONE_MINUS_CONSTANT_ALPHA</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( 1, 1, 1 ) - ( A sub c, A sub c, A sub c ):-->
<mml:mrow>
<mml:mfenced open="(" close=")">
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
<mml:mn>1</mml:mn>
</mml:mfenced>
<mml:mo>-</mml:mo>
<mml:mfenced open="(" close=")">
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:mrow>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: 1 - A sub c:-->
<mml:mrow>
<mml:mn>1</mml:mn>
<mml:mo>-</mml:mo>
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">c</mml:mi>
</mml:msub>
</mml:mrow>
</mml:math></inlineequation>
</entry>
</row>
<row>
<entry align="left">
<constant>GL_SRC_ALPHA_SATURATE</constant>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: ( i, i, i ):-->
<mml:mfenced open="(" close=")">
<mml:mi mathvariant="italic">i</mml:mi>
<mml:mi mathvariant="italic">i</mml:mi>
<mml:mi mathvariant="italic">i</mml:mi>
</mml:mfenced>
</mml:math></inlineequation>
</entry>
<entry align="left">
<inlineequation><mml:math>
<!-- eqn: 1:-->
<mml:mn>1</mml:mn>
</mml:math></inlineequation>
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
<para>
In the table,
</para>
<para>
<para>
<inlineequation><mml:math>
<!-- eqn: i = min (A sub s , 1 - {A sub d}):-->
<mml:mrow>
<mml:mi mathvariant="italic">i</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:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">s</mml:mi>
</mml:msub>
<mml:mrow>
<mml:mn>1</mml:mn>
<mml:mo>-</mml:mo>
<mml:mfenced open="" close="">
<mml:msub><mml:mi mathvariant="italic">A</mml:mi>
<mml:mi mathvariant="italic">d</mml:mi>
</mml:msub>
</mml:mfenced>
</mml:mrow>
</mml:mfenced>
</mml:mrow>
</mml:mrow>
</mml:math></inlineequation>
</para>
</para>
<para>
To determine the blended RGBA values of a pixel,
the system uses one of the equations set by
<citerefentry><refentrytitle>glBlendEquation</refentrytitle></citerefentry> or
<citerefentry><refentrytitle>glBlendEquationSeparate</refentrytitle></citerefentry>.
</para>
<para>
Despite the apparent precision of the above equations, blending arithmetic
is not exactly specified, because blending operates with imprecise integer
color values. However, a blend factor that should be equal to 1 is
guaranteed not to modify its multiplicand, and a blend factor equal to 0
reduces its multiplicand to 0.
</para>
</refsect1>
<refsect1 id="notes"><title>Notes</title>
<para>
Incoming (source) alpha is correctly thought of as a material opacity,
ranging from 1.0
(<inlineequation><mml:math>
<!-- eqn: K sub A:-->
<mml:msub><mml:mi mathvariant="italic">K</mml:mi>
<mml:mi mathvariant="italic">A</mml:mi>
</mml:msub>
</mml:math></inlineequation>),
representing complete opacity,
to 0.0 (0), representing complete
transparency.
</para>
</refsect1>
<refsect1 id="errors"><title>Errors</title>
<para>
<constant>GL_INVALID_ENUM</constant> is generated if
<parameter>srcRGB</parameter>, <parameter>dstRGB</parameter>,
<parameter>srcAlpha</parameter>, or <parameter>dstAlpha</parameter>
is not an accepted value.
</para>
</refsect1>
<refsect1 id="associatedgets"><title>Associated Gets</title>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_BLEND_SRC_RGB</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_BLEND_SRC_ALPHA</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_BLEND_DST_RGB</constant>
</para>
<para>
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_BLEND_DST_ALPHA</constant>
</para>
<para>
<citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_BLEND</constant>
</para>
<para>
</para>
</refsect1>
<refsect1 id="seealso"><title>See Also</title>
<para>
<citerefentry><refentrytitle>glBlendColor</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glBlendEquation</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glBlendEquationSeparate</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glBlendFunc</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glClear</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glEnable</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>glStencilFunc</refentrytitle></citerefentry>
</para>
</refsect1>
<refsect1 id="copyright"><title>Copyright</title>
<para>
Copyright <trademark class="copyright"></trademark> 1991-2006
Silicon Graphics, Inc. This document is licensed under the SGI
Free Software B License. For details, see
<ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
</para>
</refsect1>
</refentry>
Reference in a new issue View git blame Copy permalink