flash.display.ShaderJob - Adobe® Flex® 4 Language Reference (Flex 4)

Package	flash.display
Class	public class ShaderJob
Inheritance	ShaderJob EventDispatcher Object

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

A ShaderJob instance is used to execute a shader operation in stand-alone mode. The shader operation executes and returns its result data. It is up to the developer to determine how to use the result.

There are two primary reasons for using a shader in stand-alone mode:

Processing non-image data: Using a ShaderJob instance you have control over input values and over how the shader result is used. The shader can return the result as binary data or number data instead of image data.
Background processing: Some shaders are complex and require a notable amount of time to execute. Executing a complex shader in the main execution of an application could slow down other parts of the application such as user interaction or updating the screen. Using a ShaderJob instance, you can execute the shader in the background. When the shader is executed in this way, the shader operation runs separate from the main execution of the application.

The shader property (or constructor parameter) specifies the Shader instance representing the shader that is used for the operation. You provide any parameter or input that the shader expects using the associated ShaderParameter or ShaderInput instance.

Before execution a ShaderJob operation, you provide an object into which the result is written, by setting it as the value of the target property. When the shader operation completes the result is written into the target object.

To begin a background shader operation, call the start() method. When the operation finishes the result is written into the target object. At that point the ShaderJob instance dispatches a complete event, notifying listeners that the result is available.

To execute a shader synchronously (that is, not running in the background), call the start() method and pass true as an argument. The shader runs in the main execution thread and your code pauses until the operation completes. When it finishes the result is written into the target object. At that point the application continues running at the next line of code.

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
		height : int The height of the result data in the target if it is a ByteArray or Vector.<Number> instance.	ShaderJob
		progress : Number [read-only] The progress of a running shader.	ShaderJob
		prototype : Object [static] A reference to the prototype object of a class or function object.	Object
		shader : Shader The shader that's used for the operation.	ShaderJob
		target : Object The object into which the result of the shader operation is written.	ShaderJob
		width : int The width of the result data in the target if it is a ByteArray or Vector.<Number> instance.	ShaderJob

Public Methods

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	Method		Defined By
		ShaderJob(shader:Shader = null, target:Object = null, width:int = 0, height:int = 0)	ShaderJob
		addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event.	EventDispatcher
		cancel():void Cancels the currently running shader operation.	ShaderJob
		dispatchEvent(event:Event):Boolean Dispatches an event into the event flow.	EventDispatcher
		hasEventListener(type:String):Boolean Checks whether the EventDispatcher object has any listeners registered for a specific type of event.	EventDispatcher
		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
		removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes a listener from the EventDispatcher object.	EventDispatcher
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		start(waitForCompletion:Boolean = false):void Starts a shader operation in synchronous or asynchronous mode, according to the value of the waitForCompletion parameter.	ShaderJob
		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
		willTrigger(type:String):Boolean Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.	EventDispatcher

Events

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	Summary	Defined By
activate	[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active.	EventDispatcher
complete	Dispatched when a ShaderJob that executes asynchronously finishes processing the data using the shader.	ShaderJob
deactivate	[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive.	EventDispatcher

Property Detail

height

property

height:int

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

The height of the result data in the target if it is a ByteArray or Vector.<Number> instance. The size of the ByteArray or Vector.<Number> instance is enlarged if necessary and existing data is overwritten.

Implementation
public function get height():int
public function set height(value:int):void

progress

property

progress:Number [read-only]

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

The progress of a running shader. This property is a value from 0 through 1. Zero is the initial value (0% complete). One indicates that the shader has completed its operation.

If the cancel() method is called this property becomes undefined, and its value cannot be used reliably until the shader operation starts again.

Implementation
public function get progress():Number

shader

property

shader:Shader

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

The shader that's used for the operation. Any input or parameter that the shader expects must be provided using the ShaderInput or ShaderParameter property of the Shader instance's data property. An input must be provided using its corresponding ShaderInput even if it is the same as the target object.

To process a ByteArray containing a linear array of data (as opposed to image data) set the corresponding ShaderInput instance's height to 1 and width to the number of 32-bit floating-point values in the ByteArray. In that case, the input in the shader must be defined with the image1 data type.

Implementation
public function get shader():Shader
public function set shader(value:Shader):void

target

property

target:Object

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

The object into which the result of the shader operation is written. This object must be a BitmapData, ByteArray, or Vector.<Number> instance.

Implementation
public function get target():Object
public function set target(value:Object):void

width

property

width:int

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

The width of the result data in the target if it is a ByteArray or Vector.<Number> instance. The size of the ByteArray or Vector.<Number> instance is enlarged if necessary and existing data is overwritten.

Implementation
public function get width():int
public function set width(value:int):void

Constructor Detail

ShaderJob

()

Constructor

public function ShaderJob(shader:Shader = null, target:Object = null, width:int = 0, height:int = 0)

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Parameters

	`shader:Shader` (default = `null`) — The shader to use for the operation.

	`target:Object` (default = `null`) — The object into which the result of the shader operation is written. This argument must be a BitmapData, ByteArray, or Vector.<Number> instance.

	`width:int` (default = `0`) — The width of the result data in the `target` if it is a ByteArray or Vector.<Number> instance. The size of the ByteArray or Vector.<Number> instance is enlarged if necessary and existing data is overwritten.

	`height:int` (default = `0`) — The height of the result data in the `target` if it is a ByteArray or Vector.<Number> instance. The size of the ByteArray or Vector.<Number> instance is enlarged if necessary and existing data is overwritten.

Method Detail

cancel

()

method

public function cancel():void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Cancels the currently running shader operation. Any result data that is already computed is discarded. The complete event is not dispatched.

Calling cancel() multiple times has no additional effect.

start

()

method

public function start(waitForCompletion:Boolean = false):void

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Starts a shader operation in synchronous or asynchronous mode, according to the value of the waitForCompletion parameter.

In asynchronous mode (when waitForCompletion is false), which is the default, the ShaderJob execution runs in the background. The shader operation does not affect the responsiveness of the display or other operations. In asynchronous mode the start() call returns immediately and the program continues with the next line of code. When the asynchronous shader operation finishes, the result is available and the complete event is dispatched.

Only one background ShaderJob operation executes at a time. Shader operations are held in a queue until they execute. If you call the start() method while a shader operation is executing, the additional operation is added to the end of the queue. Later, when its turn comes, it executes.

To execute a shader operation in synchronous mode, call start() with a true value for the waitForCompletion parameter (the only parameter). Your code pauses at the point where start() is called until the shader operation completes. At that point the result is available and execution continues with the next line of code.

When you call the start() method the Shader instance in the shader property is copied internally. The shader operation uses that internal copy, not a reference to the original shader. Any changes made to the shader, such as changing a parameter value, input, or bytecode, are not applied to the copied shader that's used for the shader processing. To incorporate shader changes into the shader processing, call the cancel() method (if necessary) and call the start() method again to restart the shader processing.

While a shader operation is executing, the target object's value is not changed. When the operation finishes (and the complete event is dispatched in asynchronous mode) the entire result is written to the target object at one time. If the target object is a BitmapData instance and its dispose() method is called before the operation finishes, the complete event is still dispatched in asynchronous mode. However, the result data is not written to the BitmapData object because it is in a disposed state.

Parameters

waitForCompletion:Boolean (default = false) — Specifies whether to execute the shader in the background (false, the default) or in the main program execution (true).

Events

complete:ShaderEvent — Dispatched when the operation finishes, if the start() method is called with a waitForCompletion argument of true.

Throws

	`ArgumentError` — When the `target` property is `null` or is not a BitmapData, ByteArray, or Vector.<Number> instance.

	`ArgumentError` — When the shader specifies an image input that isn't provided.

	`ArgumentError` — When a ByteArray or Vector.<Number> instance is used as an input and the `width` and `height` properties aren't specified for the ShaderInput, or the specified values don't match the amount of data in the input object. See the `ShaderInput.input` property for more information.

Event Detail

complete

Event

Event Object Type: flash.events.ShaderEvent
property ShaderEvent.type = flash.events.ShaderEvent.COMPLETE

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Dispatched when a ShaderJob that executes asynchronously finishes processing the data using the shader. A ShaderJob instance executes asynchronously when the start() method is called with a false value for the waitForCompletion parameter.

Defines the value of the type property of a complete event object.

This event has the following properties:

Property	Value
`bubbles`	`false`
`bitmapData`	The BitmapData object containing the result of the operation that finished (or `null` if the target wasn't a BitmapData object).
`byteArray`	The ByteArray object containing the result of the operation that finished (or `null` if the target wasn't a ByteArray object).
`cancelable`	`false`; there is no default behavior to cancel.
`currentTarget`	The object that is actively processing the event object with an event listener.
`target`	The ShaderJob object reporting completion.
`vector`	The Vector.<Number> instance containing the result of the operation that finished (or `null` if the target wasn't a Vector.<Number> instance).