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package com.senocular.gyro {
import flash.geom.Point;
/**
* Seekers follow target at a constant acceleration
TODO: option for constant vector acceleration for x/y instead of individually
option for matching if lower? do automatically?
*/
public class SeekProjectile extends Seek {
protected var _acceleration:Number = .5;
protected var _orient:Boolean = true;
protected var vector:Point = new Point(0, 0);
private static const TO_DEGREES:Number = (180/Math.PI);
/**
* A value between 0 and 1 representing how quickly
* a seeker accelerationes the target with every step
*/
public function get acceleration():Number {
return _acceleration;
}
public function set acceleration(n:Number):void {
_acceleration = n;
}
/**
* When true, rotation is set to point to the target
*/
public function get orient():Boolean {
return _orient;
}
public function set orient(b:Boolean):void {
_orient = b;
}
/**
* Constructor
*/
public function SeekProjectile(acceleration:Number = .5, orient:Boolean = true){
super([]);
this.acceleration = acceleration;
this.orient = orient;
}
/**
* Seek method; matches seeker properties
* to target properties based on the properties list
*/
public override function follow(target:*, seeker:*):void {
if (!_acceleration) return;
var dx:Number = target.x - seeker.x;
var dy:Number = target.y - seeker.y;
var dist:Number = Math.sqrt(dx*dx + dy*dy);
var angle:Number = Math.atan2(dy, dx);
if (_orient) {
seeker.rotation = angle*TO_DEGREES;
}
vector.x += _acceleration * Math.cos(angle);
vector.y += _acceleration * Math.sin(angle);
seeker.x += vector.x;
seeker.y += vector.y;
}
}
}
