Package | flash.display3D |
Class | public final class Context3DBlendFactor |
Inheritance | Context3DBlendFactor Object |
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
A blend factor represents a particular four-value vector that is multiplied with the source or destination color in the blending formula. The blending formula is:
result = source * sourceFactor + destination * destinationFactor
In the formuls, the source color is the output color of the pixel shader program. The destination color is the color that currently exists in the color buffer, as set by previous clear and draw operations.
For example, if the source color is (.6, .6, .6, .4) and the source blend factor is Context3DBlendFactor.ONE_MINUS_SOURCE_ALPHA
,
then the source part of the blending equation is calculated as:
(.6, .6, .6, .4) * (1-0.4, 1-0.4, 1-0.4, 1-0.4) = (.36, .36, .36, .24)
The final calculation is clamped to the range [0,1].
Examples
The following examples demonstrate the blending math using source color = (.6,.4,.2,.4), destination color = (.8,.8,.8,.5), and various blend factors.
Purpose | Source factor | Destination factor | Blend formula | Result |
---|---|---|---|---|
No blending | ONE | ZERO | (.6,.4,.2,.4) * ( 1, 1, 1, 1) + (.8,.8,.8,.5) * ( 0, 0, 0, 0) | ( .6, .4, .2, .4) |
Alpha | SOURCE_ALPHA | ONE_MINUS_SOURCE_ALPHA | (.6,.4,.2,.4) * (.4,.4,.4,.4) + (.8,.8,.8,.5) * (.6,.6,.6,.6) | (.72,.64,.56,.46) |
Additive | ONE | ONE | (.6,.4,.2,.4) * ( 1, 1, 1, 1) + (.8,.8,.8,.5) * ( 1, 1, 1, 1) | ( 1, 1, 1, .9) |
Multiply | DESTINATION_COLOR | ZERO | (.6,.4,.2,.4) * (.8,.8,.8,.5) + (.8,.8,.8,.5) * ( 0, 0, 0, 0) | (.48,.32,.16, .2) |
Screen | ONE | ONE_MINUS_SOURCE_COLOR | (.6,.4,.2,.4) * ( 1, 1, 1, 1) + (.8,.8,.8,.5) * (.4,.6,.8,.6) | (.92,.88,.68, .7) |
Note that not all combinations of blend factors are useful and that you can sometimes achieve the same effect in different ways.
Related API Elements
Constant | Defined By | ||
---|---|---|---|
DESTINATION_ALPHA : String = "destinationAlpha" [static]
The blend factor is (Da,Da,Da,Da), where Da is
the alpha component of the fragment color computed by the pixel program. | Context3DBlendFactor | ||
DESTINATION_COLOR : String = "destinationColor" [static]
The blend factor is (Dr,Dg,Db,Da), where Dr/g/b/a is
the corresponding component of the current color in the color buffer. | Context3DBlendFactor | ||
ONE : String = "one" [static]
The blend factor is (1,1,1,1). | Context3DBlendFactor | ||
ONE_MINUS_DESTINATION_ALPHA : String = "oneMinusDestinationAlpha" [static]
The blend factor is (1-Da,1-Da,1-Da,1-Da), where Da is
the alpha component of the current color in the color buffer. | Context3DBlendFactor | ||
ONE_MINUS_DESTINATION_COLOR : String = "oneMinusDestinationColor" [static]
The blend factor is (1-Dr,1-Dg,1-Db,1-Da), where Dr/g/b/a is
the corresponding component of the current color in the color buffer. | Context3DBlendFactor | ||
ONE_MINUS_SOURCE_ALPHA : String = "oneMinusSourceAlpha" [static]
The blend factor is (1-Sa,1-Sa,1-Sa,1-Sa), where Sa is
the alpha component of the fragment color computed by the pixel program. | Context3DBlendFactor | ||
ONE_MINUS_SOURCE_COLOR : String = "oneMinusSourceColor" [static]
The blend factor is (1-Sr,1-Sg,1-Sb,1-Sa), where Sr/g/b/a is
the corresponding component of the fragment color computed by the pixel program. | Context3DBlendFactor | ||
SOURCE_ALPHA : String = "sourceAlpha" [static]
The blend factor is (Sa,Sa,Sa,Sa), where Sa is
the alpha component of the fragment color computed by the pixel program. | Context3DBlendFactor | ||
SOURCE_COLOR : String = "sourceColor" [static]
The blend factor is (Sr,Sg,Sb,Sa), where Sr/g/b/a is
the corresponding component of the fragment color computed by the pixel program. | Context3DBlendFactor | ||
ZERO : String = "zero" [static]
The blend factor is (0,0,0,0). | Context3DBlendFactor |
DESTINATION_ALPHA | Constant |
public static const DESTINATION_ALPHA:String = "destinationAlpha"
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
The blend factor is (Da,Da,Da,Da)
, where Da
is
the alpha component of the fragment color computed by the pixel program.
DESTINATION_COLOR | Constant |
public static const DESTINATION_COLOR:String = "destinationColor"
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
The blend factor is (Dr,Dg,Db,Da)
, where Dr/g/b/a
is
the corresponding component of the current color in the color buffer.
ONE | Constant |
public static const ONE:String = "one"
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
The blend factor is (1,1,1,1)
.
ONE_MINUS_DESTINATION_ALPHA | Constant |
public static const ONE_MINUS_DESTINATION_ALPHA:String = "oneMinusDestinationAlpha"
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
The blend factor is (1-Da,1-Da,1-Da,1-Da)
, where Da
is
the alpha component of the current color in the color buffer.
ONE_MINUS_DESTINATION_COLOR | Constant |
public static const ONE_MINUS_DESTINATION_COLOR:String = "oneMinusDestinationColor"
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
The blend factor is (1-Dr,1-Dg,1-Db,1-Da)
, where Dr/g/b/a
is
the corresponding component of the current color in the color buffer.
ONE_MINUS_SOURCE_ALPHA | Constant |
public static const ONE_MINUS_SOURCE_ALPHA:String = "oneMinusSourceAlpha"
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
The blend factor is (1-Sa,1-Sa,1-Sa,1-Sa)
, where Sa
is
the alpha component of the fragment color computed by the pixel program.
ONE_MINUS_SOURCE_COLOR | Constant |
public static const ONE_MINUS_SOURCE_COLOR:String = "oneMinusSourceColor"
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
The blend factor is (1-Sr,1-Sg,1-Sb,1-Sa)
, where Sr/g/b/a
is
the corresponding component of the fragment color computed by the pixel program.
SOURCE_ALPHA | Constant |
public static const SOURCE_ALPHA:String = "sourceAlpha"
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
The blend factor is (Sa,Sa,Sa,Sa)
, where Sa
is
the alpha component of the fragment color computed by the pixel program.
SOURCE_COLOR | Constant |
public static const SOURCE_COLOR:String = "sourceColor"
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
The blend factor is (Sr,Sg,Sb,Sa)
, where Sr/g/b/a
is
the corresponding component of the fragment color computed by the pixel program.
ZERO | Constant |
public static const ZERO:String = "zero"
Language Version: | ActionScript 3.0 |
Runtime Versions: | Flash Player 11, AIR 3 |
The blend factor is (0,0,0,0)
.
Wed Nov 21 2018, 06:34 AM -08:00