mirror of
https://github.com/Ryujinx/Opentk.git
synced 2024-12-29 11:15:38 +00:00
1115 lines
61 KiB
XML
1115 lines
61 KiB
XML
<!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="glBlendFunc">
|
|
<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>glBlendFunc</refentrytitle>
|
|
<manvolnum>3G</manvolnum>
|
|
</refmeta>
|
|
<refnamediv>
|
|
<refname>glBlendFunc</refname>
|
|
<refpurpose>specify pixel arithmetic</refpurpose>
|
|
</refnamediv>
|
|
<refsynopsisdiv><title>C Specification</title>
|
|
<funcsynopsis>
|
|
<funcprototype>
|
|
<funcdef>void <function>glBlendFunc</function></funcdef>
|
|
<paramdef>GLenum <parameter>sfactor</parameter></paramdef>
|
|
<paramdef>GLenum <parameter>dfactor</parameter></paramdef>
|
|
</funcprototype>
|
|
</funcsynopsis>
|
|
</refsynopsisdiv>
|
|
<refsect1 xml:id="parameters"><title>Parameters</title>
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><parameter>sfactor</parameter></term>
|
|
<listitem>
|
|
<para>
|
|
Specifies how the red, green, blue,
|
|
and alpha source blending factors are computed.
|
|
The initial value is <constant>GL_ONE</constant>.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><parameter>dfactor</parameter></term>
|
|
<listitem>
|
|
<para>
|
|
Specifies how the red, green, blue,
|
|
and alpha 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>
|
|
</variablelist>
|
|
</refsect1>
|
|
<refsect1 xml: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>glBlendFunc</function> defines the operation of blending when it is enabled.
|
|
<parameter>sfactor</parameter> specifies which method is used to scale the
|
|
source color components.
|
|
<parameter>dfactor</parameter> specifies which method is used to scale the
|
|
destination color components.
|
|
Both parameters must be one of the following symbolic constants:
|
|
<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>,
|
|
<constant>GL_SRC_ALPHA_SATURATE</constant>,
|
|
The possible methods are described in the following table.
|
|
Each method defines four scale factors,
|
|
one each for red, green, blue, and alpha.
|
|
In the table and in subsequent equations, 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 color specified by <citerefentry><refentrytitle>glBlendColor</refentrytitle></citerefentry> is referred to as
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- 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>.
|
|
</para>
|
|
<para>
|
|
Source and destination scale factors are referred to as
|
|
<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>.
|
|
The scale factors described in the table,
|
|
denoted
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( f sub R , f sub G , f sub B , f sub A ): -->
|
|
<mml:mfenced open="(" close=")">
|
|
<mml:msub><mml:mi mathvariant="italic">f</mml:mi>
|
|
<mml:mi mathvariant="italic">R</mml:mi>
|
|
</mml:msub>
|
|
<mml:msub><mml:mi mathvariant="italic">f</mml:mi>
|
|
<mml:mi mathvariant="italic">G</mml:mi>
|
|
</mml:msub>
|
|
<mml:msub><mml:mi mathvariant="italic">f</mml:mi>
|
|
<mml:mi mathvariant="italic">B</mml:mi>
|
|
</mml:msub>
|
|
<mml:msub><mml:mi mathvariant="italic">f</mml:mi>
|
|
<mml:mi mathvariant="italic">A</mml:mi>
|
|
</mml:msub>
|
|
</mml:mfenced>
|
|
</mml:math></inlineequation>,
|
|
represent either source or destination factors.
|
|
All scale factors have 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>
|
|
Prior to blending, unsigned normalized fixed-point color components undergo
|
|
an implied conversion to floating-point using equation 2.1. This conversion must
|
|
leave the values 0 and 1 invariant. Blending computations are treated as if carried
|
|
out in floating-point and will be performed with a precision and dynamic range no
|
|
lower than that used to represent destination components.
|
|
If the value of <constant>GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING</constant> for the
|
|
framebuffer attachment corresponding to the destination buffer is <constant>GL_SRGB</constant>,
|
|
the R, G, and B destination color values (after conversion from fixed-point
|
|
to floating-point) are considered to be encoded for the sRGB color space and
|
|
hence must be linearized prior to their use in blending. Each R, G, and B component
|
|
is converted in the same fashion described for sRGB texture components.
|
|
</para>
|
|
<para>
|
|
</para>
|
|
<informaltable>
|
|
<tgroup cols="2" align="left">
|
|
<colspec/>
|
|
<colspec/>
|
|
<thead>
|
|
<row>
|
|
<entry>
|
|
<emphasis role="bold"> Parameter </emphasis>
|
|
</entry>
|
|
<entry>
|
|
<emphasis role="bold">
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( f sub R , f sub G , f sub B , f sub A ): -->
|
|
<mml:mfenced open="(" close=")">
|
|
<mml:msub><mml:mi mathvariant="italic">f</mml:mi>
|
|
<mml:mi mathvariant="italic">R</mml:mi>
|
|
</mml:msub>
|
|
<mml:msub><mml:mi mathvariant="italic">f</mml:mi>
|
|
<mml:mi mathvariant="italic">G</mml:mi>
|
|
</mml:msub>
|
|
<mml:msub><mml:mi mathvariant="italic">f</mml:mi>
|
|
<mml:mi mathvariant="italic">B</mml:mi>
|
|
</mml:msub>
|
|
<mml:msub><mml:mi mathvariant="italic">f</mml:mi>
|
|
<mml:mi mathvariant="italic">A</mml:mi>
|
|
</mml:msub>
|
|
</mml:mfenced>
|
|
</mml:math></inlineequation>
|
|
</emphasis>
|
|
</entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_ZERO</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( 0, 0, 0, 0 ): -->
|
|
<mml:mfenced open="(" close=")">
|
|
<mml:mn>0</mml:mn>
|
|
<mml:mn>0</mml:mn>
|
|
<mml:mn>0</mml:mn>
|
|
<mml:mn>0</mml:mn>
|
|
</mml:mfenced>
|
|
</mml:math></inlineequation>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_ONE</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( 1, 1, 1, 1 ): -->
|
|
<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:math></inlineequation>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_SRC_COLOR</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( R sub s / k sub R , G sub s / k sub G , B sub s / k sub B , A sub s / k sub A ): -->
|
|
<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: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>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_ONE_MINUS_SRC_COLOR</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( 1, 1, 1, 1 ) - (R sub s / k sub R , G sub s / k sub G , B sub s / k sub B , 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: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: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>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_DST_COLOR</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( R sub d / k sub R , G sub d / k sub G , B sub d / k sub B , A sub d / k sub A ): -->
|
|
<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: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>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_ONE_MINUS_DST_COLOR</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( 1, 1, 1, 1 ) - (R sub d / k sub R , G sub d / k sub G , B sub d / k sub B , 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: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: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>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_SRC_ALPHA</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( A sub s / k sub A , 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: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>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_ONE_MINUS_SRC_ALPHA</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( 1, 1, 1, 1 ) - (A sub s / k sub A , 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: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: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>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_DST_ALPHA</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( A sub d / k sub A , 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: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>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_ONE_MINUS_DST_ALPHA</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( 1, 1, 1, 1 ) - ( A sub d / k sub A , 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: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: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>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_CONSTANT_COLOR</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- 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>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_ONE_MINUS_CONSTANT_COLOR</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( 1, 1, 1, 1 ) - ( R sub c, G sub c, B 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: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: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>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_CONSTANT_ALPHA</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( A sub c, 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:msub><mml:mi mathvariant="italic">A</mml:mi>
|
|
<mml:mi mathvariant="italic">c</mml:mi>
|
|
</mml:msub>
|
|
</mml:mfenced>
|
|
</mml:math></inlineequation>
|
|
</entry>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_ONE_MINUS_CONSTANT_ALPHA</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( 1, 1, 1, 1 ) - ( A sub c, 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: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: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>
|
|
</row>
|
|
<row>
|
|
<entry>
|
|
<constant>GL_SRC_ALPHA_SATURATE</constant>
|
|
</entry>
|
|
<entry>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: ( i, i, i, 1 ): -->
|
|
<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:mn>1</mml:mn>
|
|
</mml:mfenced>
|
|
</mml:math></inlineequation>
|
|
</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</informaltable>
|
|
<para>
|
|
In the table,
|
|
</para>
|
|
<para>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: i = min (A sub s , k sub A - A sub d ) / k sub A: -->
|
|
<mml:mrow>
|
|
<mml:mi mathvariant="italic">i</mml:mi>
|
|
<mml:mo>=</mml:mo>
|
|
<mml:mfrac>
|
|
<mml:mrow>
|
|
<mml:mi mathvariant="italic">min</mml:mi>
|
|
<mml:mo>⁡</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:msub><mml:mi mathvariant="italic">k</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:mrow>
|
|
</mml:mfenced>
|
|
</mml:mrow>
|
|
<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>
|
|
</para>
|
|
<para>
|
|
To determine the blended RGBA values of a pixel,
|
|
the system uses the following equations:
|
|
</para>
|
|
<para>
|
|
<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- eqn: R sub d = min ( k sub R, R sub s s sub R + R sub d d sub R ): -->
|
|
<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:mrow>
|
|
<mml:mi mathvariant="italic">min</mml:mi>
|
|
<mml:mo>⁡</mml:mo>
|
|
<mml:mfenced open="(" close=")">
|
|
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
|
|
<mml:mi mathvariant="italic">R</mml:mi>
|
|
</mml:msub>
|
|
<mml:mrow>
|
|
<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:mo>+</mml:mo>
|
|
<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: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: G sub d = min ( k sub G, G sub s s sub G + G sub d d sub G ): -->
|
|
<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:mrow>
|
|
<mml:mi mathvariant="italic">min</mml:mi>
|
|
<mml:mo>⁡</mml:mo>
|
|
<mml:mfenced open="(" close=")">
|
|
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
|
|
<mml:mi mathvariant="italic">G</mml:mi>
|
|
</mml:msub>
|
|
<mml:mrow>
|
|
<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:mo>+</mml:mo>
|
|
<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: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: B sub d = min ( k sub B, B sub s s sub B + B sub d d sub B ): -->
|
|
<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:mrow>
|
|
<mml:mi mathvariant="italic">min</mml:mi>
|
|
<mml:mo>⁡</mml:mo>
|
|
<mml:mfenced open="(" close=")">
|
|
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
|
|
<mml:mi mathvariant="italic">B</mml:mi>
|
|
</mml:msub>
|
|
<mml:mrow>
|
|
<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:mo>+</mml:mo>
|
|
<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: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: A sub d = min ( k sub A, A sub s s sub A + A sub d d sub A ): -->
|
|
<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:mrow>
|
|
<mml:mi mathvariant="italic">min</mml:mi>
|
|
<mml:mo>⁡</mml:mo>
|
|
<mml:mfenced open="(" close=")">
|
|
<mml:msub><mml:mi mathvariant="italic">k</mml:mi>
|
|
<mml:mi mathvariant="italic">A</mml:mi>
|
|
</mml:msub>
|
|
<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:mfenced>
|
|
</mml:mrow>
|
|
</mml:mrow>
|
|
</mml:math></inlineequation>
|
|
</para>
|
|
<para>
|
|
If the value of <constant>GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING</constant> for the framebuffer
|
|
attachment corresponding to the destination buffer is <constant>GL_SRGB</constant>, the R, G, and B
|
|
values after blending are converted into the non-linear sRGB color space by computing
|
|
<!-- Missing equation! -->
|
|
where cl is the R, G, or B element and cs is the result (effectively converted into an
|
|
sRGB color space).
|
|
If <constant>GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING</constant> is not <constant>GL_SRGB</constant>, then
|
|
cs = cl:
|
|
The resulting cs values for R, G, and B, and the unmodified A form a new
|
|
RGBA color value. If the color buffer is fixed-point, each component is clamped
|
|
to the range [0; 1] and then converted to a fixed-point value using equation
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 xml:id="examples"><title>Examples</title>
|
|
<para>
|
|
</para>
|
|
<para>
|
|
Transparency is best implemented using blend function
|
|
(<constant>GL_SRC_ALPHA</constant>, <constant>GL_ONE_MINUS_SRC_ALPHA</constant>)
|
|
with primitives sorted from farthest to nearest.
|
|
Note that this transparency calculation does not require
|
|
the presence of alpha bitplanes in the frame buffer.
|
|
</para>
|
|
<para>
|
|
Blend function
|
|
(<constant>GL_SRC_ALPHA</constant>, <constant>GL_ONE_MINUS_SRC_ALPHA</constant>)
|
|
is also useful for rendering antialiased points and lines
|
|
in arbitrary order.
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 xml:id="notes"><title>Notes</title>
|
|
<para>
|
|
Incoming (source) alpha is correctly thought of as a material opacity,
|
|
ranging from 1.0
|
|
(<inlineequation><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
|
|
<!-- 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>
|
|
<para>
|
|
When more than one color buffer is enabled for drawing,
|
|
the GL performs blending separately for each enabled buffer,
|
|
using the contents of that buffer for destination color.
|
|
(See <citerefentry><refentrytitle>glDrawBuffers</refentrytitle></citerefentry>.)
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 xml:id="errors"><title>Errors</title>
|
|
<para>
|
|
<constant>GL_INVALID_ENUM</constant> is generated if either <parameter>sfactor</parameter>
|
|
or <parameter>dfactor</parameter> is not an accepted value.
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 xml:id="associatedgets"><title>Associated Gets</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_BLEND_SRC</constant>
|
|
</para>
|
|
<para>
|
|
<citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with argument <constant>GL_BLEND_DST</constant>
|
|
</para>
|
|
<para>
|
|
<citerefentry><refentrytitle>glIsEnabled</refentrytitle></citerefentry> with argument <constant>GL_BLEND</constant>
|
|
</para>
|
|
<para>
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 xml:id="versions">
|
|
<title>API Version Support</title>
|
|
<informaltable>
|
|
<tgroup cols="3" align="left">
|
|
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
|
|
<tbody>
|
|
<row>
|
|
<entry>glBlendFunc</entry>
|
|
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='es20']/*)"/>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</informaltable>
|
|
</refsect1>
|
|
<refsect1 xml:id="seealso"><title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>glBlendColor</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glBlendEquation</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glBlendFuncSeparate</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glClear</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glDrawBuffers</refentrytitle></citerefentry>,
|
|
<citerefentry><refentrytitle>glEnable</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>
|