Context3DBlendFactor - Adobe ActionScript® 3 (AS3 ) API Reference

Package	flash.display3D
Class	public final class Context3DBlendFactor
Inheritance	Context3DBlendFactor Object

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 11, 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.

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

Context3D.setBlendFactors()

Public Properties

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	Property		Defined By
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object

Public Methods

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	Method		Defined By
		hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined.	Object
		isPrototypeOf(theClass:Object):Boolean Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.	Object
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions.	Object
		toString():String Returns the string representation of the specified object.	Object
		valueOf():Object Returns the primitive value of the specified object.	Object

Public Constants

	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

Constant Detail

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 (D_a,D_a,D_a,D_a), where D_a 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 (D_r,D_g,D_b,D_a), where D_r/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-D_a,1-D_a,1-D_a,1-D_a), where D_a 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-D_r,1-D_g,1-D_b,1-D_a), where D_r/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-S_a,1-S_a,1-S_a,1-S_a), where S_a 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-S_r,1-S_g,1-S_b,1-S_a), where S_r/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 (S_a,S_a,S_a,S_a), where S_a 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 (S_r,S_g,S_b,S_a), where S_r/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).

Context3DBlendFactor - AS3

Classes x

DESTINATION_ALPHA

DESTINATION_COLOR

ONE

ONE_MINUS_DESTINATION_ALPHA

ONE_MINUS_DESTINATION_COLOR

ONE_MINUS_SOURCE_ALPHA

ONE_MINUS_SOURCE_COLOR

SOURCE_ALPHA

SOURCE_COLOR

ZERO

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