Packageflash.display3D
Classpublic final class Context3DBlendFactor
InheritanceContext3DBlendFactor Inheritance Object

Language version: ActionScript 3.0
Runtime version: AIR 3

Defines the values to use for specifying the source and destination blend factors.

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.

PurposeSource factorDestination factorBlend formulaResult
No blendingONEZERO (.6,.4,.2,.4) * ( 1, 1, 1, 1) + (.8,.8,.8,.5) * ( 0, 0, 0, 0)( .6, .4, .2, .4)
AlphaSOURCE_ALPHAONE_MINUS_SOURCE_ALPHA(.6,.4,.2,.4) * (.4,.4,.4,.4) + (.8,.8,.8,.5) * (.6,.6,.6,.6)(.72,.64,.56,.46)
AdditiveONEONE (.6,.4,.2,.4) * ( 1, 1, 1, 1) + (.8,.8,.8,.5) * ( 1, 1, 1, 1)( 1, 1, 1, .9)
MultiplyDESTINATION_COLORZERO (.6,.4,.2,.4) * (.8,.8,.8,.5) + (.8,.8,.8,.5) * ( 0, 0, 0, 0)(.48,.32,.16, .2)
ScreenONEONE_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.

See also

Context3D.setBlendFactors()

Public Properties
 PropertyDefined by
 Inheritedconstructor : Object
A reference to the class object or constructor function for a given object instance.
Object
 Inheritedprototype : Object
[static] A reference to the prototype object of a class or function object.
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Public Methods
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hasOwnProperty(name:String):Boolean
Indicates whether an object has a specified property defined.
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 Inherited
isPrototypeOf(theClass:Object):Boolean
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 Inherited
propertyIsEnumerable(name:String):Boolean
Indicates whether the specified property exists and is enumerable.
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 Inherited
setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void
Sets the availability of a dynamic property for loop operations.
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 Inherited
toLocaleString():String
Returns the string representation of this object, formatted according to locale-specific conventions.
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 Inherited
toString():String
Returns the string representation of the specified object.
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 Inherited
valueOf():Object
Returns the primitive value of the specified object.
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Public Constants
 ConstantDefined 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
Constant detail
DESTINATION_ALPHAconstant
public static const DESTINATION_ALPHA:String = "destinationAlpha"

Language version: ActionScript 3.0
Runtime version: 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_COLORconstant 
public static const DESTINATION_COLOR:String = "destinationColor"

Language version: ActionScript 3.0
Runtime version: 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.

ONEconstant 
public static const ONE:String = "one"

Language version: ActionScript 3.0
Runtime version: AIR 3

The blend factor is (1,1,1,1).

ONE_MINUS_DESTINATION_ALPHAconstant 
public static const ONE_MINUS_DESTINATION_ALPHA:String = "oneMinusDestinationAlpha"

Language version: ActionScript 3.0
Runtime version: 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_COLORconstant 
public static const ONE_MINUS_DESTINATION_COLOR:String = "oneMinusDestinationColor"

Language version: ActionScript 3.0
Runtime version: 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_ALPHAconstant 
public static const ONE_MINUS_SOURCE_ALPHA:String = "oneMinusSourceAlpha"

Language version: ActionScript 3.0
Runtime version: 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_COLORconstant 
public static const ONE_MINUS_SOURCE_COLOR:String = "oneMinusSourceColor"

Language version: ActionScript 3.0
Runtime version: 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_ALPHAconstant 
public static const SOURCE_ALPHA:String = "sourceAlpha"

Language version: ActionScript 3.0
Runtime version: 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_COLORconstant 
public static const SOURCE_COLOR:String = "sourceColor"

Language version: ActionScript 3.0
Runtime version: 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.

ZEROconstant 
public static const ZERO:String = "zero"

Language version: ActionScript 3.0
Runtime version: AIR 3

The blend factor is (0,0,0,0).




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