The Emitter class manages the creation and ongoing state of particles. It uses a number of
utility classes to customise its behaviour.
An emitter uses Initializers to customise the initial state of particles
that it creates, their position, velocity, color etc. These are added to the
emitter using the addInitializer method.
An emitter uses Actions to customise the behaviour of particles that
it creates, to apply gravity, drag, fade etc. These are added to the emitter
using the addAction method.
An emitter uses Activities to customise its own behaviour in an ongoing manner, to
make it move or rotate.
An emitter uses a Counter to know when and how many particles to emit.
An emitter uses a Renderer to display the particles on screen.
All timings in the emitter are based on actual time passed, not on frames.
Most functionality is best added to an emitter using Actions,
Initializers, Activities, Counters and Renderers. This offers greater
flexibility to combine behaviours witout needing to subclass
the Emitter itself.
The emitter also has position properties - x, y, rotation - that can be used to directly
affect its location in the particle system.
counter:Counter [read-write]
The Counter for the Emitter. The counter defines when and
with what frequency the emitter emits particles.
Implementation
public function get counter():Counter
public function set counter(value:Counter):void
maximumFrameTime:Number [read-write]
The maximum duration, in seconds, for a single update frame, in seconds.
Under some circumstances related to the Flash player (e.g. on MacOSX, when the
user right-clicks on the flash movie) the flash movie will freeze for a period. When the
freeze ends, the current frame of the particle system will be calculated as the time since
the previous frame, which encompases the duration of the freeze. This could cause the
system to generate a single frame update that compensates for a long period of time and
hence moves the particles an unexpected long distance in one go. The result is usually
visually unacceptable and certainly unexpected.
This property sets a maximum duration for a frame such that any frames longer than
this duration are ignored. The default value is 0.5 seconds. Developers don't usually
need to change this from the default value.
Implementation
public function get maximumFrameTime():Number
public function set maximumFrameTime(value:Number):void
particleFactory:ParticleFactory [read-write]
This is the particle factory used by the emitter to create and dispose of particles.
The default value is an instance of the ParticleCreator class that is shared by all
emitters. You don't usually need to alter this unless you are not using the default
particle type. Any custom particle factory should implement the ParticleFactory class.
Implementation
public function get particleFactory():ParticleFactory
public function set particleFactory(value:ParticleFactory):void
See also
particles:Array [read-only]
The array of all particles created by this emitter.
Implementation
public function get particles():Array
renderer:Renderer [read-write]
The Renderer for the Emitter. The renderer draws the particles.
Implementation
public function get renderer():Renderer
public function set renderer(value:Renderer):void
rotation:Number [read-write]
Indicates the rotation of the Emitter, in degrees, within the particle system's coordinate space.
Implementation
public function get rotation():Number
public function set rotation(value:Number):void
rotRadians:Number [read-write]
Indicates the rotation of the Emitter, in radians, within the particle system's
coordinate space.
Implementation
public function get rotRadians():Number
public function set rotRadians(value:Number):void
public var spaceSort:Boolean = false
Identifies whether the particles should be arranged
into spacially sorted arrays - this speeds up proximity
testing for those actions that need it.
public var spaceSortedX:Array
The array of particle indices sorted based on the particles' horizontal positions.
To persuade the emitter to create this array you should set the spaceSort property
to true. Usually, actions that need this set to true will do so in their addedToEmitter
method.
x:Number [read-write]
Indicates the x coordinate of the Emitter within the particle system's coordinate space.
Implementation
public function get x():Number
public function set x(value:Number):void
y:Number [read-write]
Indicates the y coordinate of the Emitter within the particle system's coordinate space.
Implementation
public function get y():Number
public function set y(value:Number):void
public function Emitter()
The constructor creates an emitter.
public function addAction(action:Action, priority:Number):void
Adds an Action to the Emitter. Actions set the behaviour
of particles created by the emitter.
Parameters
| action:Action — The Action to add
|
| |
| priority:Number — Indicates the sequencing of the actions. Higher numbers cause
an action to be run before other actions. All actions have a default priority
which is used if no value is passed in this parameter. The default priority is usually
the one you want so this parameter is only used when you need to override the default.
|
public function addActivity(activity:Activity, priority:Number):void
Adds an Activity to the Emitter. Activities set the behaviour
of the Emitter.
Parameters
| activity:Activity — The activity to add
|
| |
| priority:Number — Indicates the sequencing of the activities. Higher numbers cause
an activity to be run before other activities. All activities have a default priority
which is used if no value is passed in this parameter. The default priority is usually
the one you want so this parameter is only used when you need to override the default.
|
public function addDisplayObjects(... objects):void
Adds existing display objects as particles to the emitter. This allows you, for example,
to take an existing image and subject it to the actions of the emitter.
This method moves all the display objects into the emitter's renderer,
removing them from their current position within the display list. It will
only work if a renderer has been defined for the emitter and the renderer has
been added to the display list.
Parameters
| ... objects — Each parameter is another display object for adding to the emitter.
If you pass an array as the parameter, each item in the array should be another
display object for adding to the emitter.
|
public function addInitializer(initializer:Initializer, priority:Number):void
Adds an Initializer object to the Emitter. Initializers set the
initial properties of particles created by the emitter.
Parameters
| initializer:Initializer — The Initializer to add
|
| |
| priority:Number — Indicates the sequencing of the initializers. Higher numbers
cause an initializer to be run before other initialzers. All initializers
have a default priority which is used if no value is passed in this
parameter. The default priority is usually the one you want so this
parameter is only used when you need to override the default.
|
protected function createParticle():Particle
Returns
public function dispose():void
Cleans up the emitter prior to removal. If you don't call this method,
the garbage collector will clean up all the particles in teh usual way.
If you use this method, the particles will be returned to the particle
factory for reuse.
protected function frameUpdate(time:Number):void
Used internally and in derived classes to update the emitter.
Parameters
| time:Number — The duration, in seconds, of the current frame.
|
public function pause():void
Pauses the emitter.
public function removeAction(action:Action):void
Removes an Action from the Emitter.
Parameters
| action:Action — The Action to remove
|
See also
addAction()
public function removeActivity(activity:Activity):void
Removes an Activity from the Emitter.
Parameters
| activity:Activity — The Activity to remove
|
See also
addActivity()
public function removeInitializer(initializer:Initializer):void
Removes an Initializer from the Emitter.
Parameters
See also
addInitializer()
public function rendererGlobalToLocal(p:Point):Point
If the emitter's renderer is a display object, this method will
calculate a localToGlobal on the point with respect to the renderer.
The new point is returned. If the renderer is not a display object then
the original point is returned.
Parameters
Returns
public function rendererLocalToGlobal(p:Point):Point
If the emitter's renderer is a display object, this method will
calculate a localToGlobal on the point with respect to the renderer.
The new point is returned. If the renderer is not a display object then
the original point is returned.
Parameters
Returns
public function resume():void
Resumes the emitter after a pause.
public function runAhead(time:Number, frameRate:Number = 10):void
Makes the emitter skip forwards a period of time with a single update.
Used when you want the emitter to look like it's been running for a while.
Parameters
| time:Number — The time, in seconds, to skip ahead.
|
| |
| frameRate:Number (default = 10) |
public function start():void
Starts the emitter. Until start is called, the emitter will not emit any particles.
Event object type: org.flintparticles.events.FlintEvent
Dispatched when an emitter attempts to update the particles' state but it
contains no particles. This event will be dispatched every time the update
occurs and there are no particles in the emitter. The update does not occur
when the emitter has not yet been started, when the emitter is paused, and
after the emitter has been disposed. So the event will not be dispatched
at these times.
See the firework
example for an example that uses this event.
See also
pause();
dispose();
Event object type: org.flintparticles.events.FlintEvent
Dispatched when a particle is created and has just been added to the system.
Event object type: org.flintparticles.events.FlintEvent
Dispatched when a particle dies and is about to be removed from the system.
As soon as the event has been handled the particle will be removed but at the
time of the event it still exists so its properties (e.g. its location) can be
read from it.
© Big Room Ventures Ltd. 2008
flash.events.EventDispatcher