flash on 2011-10-28

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license : see code comments
modified : 2011-10-28 02:37:19

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package
{
    import com.bit101.components.HUISlider;
    import flash.display.Sprite;
    import flash.events.Event;
 
    public class Main extends Sprite
    {
        private var vehicles:Vector.<SteeredVehicle> = new Vector.<SteeredVehicle>();
        private var distSlider:HUISlider;
        private var radiusSlider:HUISlider;
        
        public function Main()
        {
            distSlider = new HUISlider(this, 0, 400, "Distance", distSliderHandler);
            radiusSlider = new HUISlider(this, 0, 420, "Radius", radiusSliderHandler);
            
            distSlider.minimum = 0.0, distSlider.maximum = 200.0, distSlider.value = 50.0;
            radiusSlider.minimum = 0.0, radiusSlider.maximum = 100.0, radiusSlider.value = 25.0;
            
            vehicles.push(addChild(new SteeredVehicle(230, 230)));
            
            addEventListener(Event.ENTER_FRAME, onEnterFrame);
        }
        
        private function distSliderHandler(event:Event):void 
        {
            for each (var vehicle:SteeredVehicle in vehicles)
            {
                vehicle.wanderDist = distSlider.value;
            }
        }
        
        private function radiusSliderHandler(event:Event):void 
        {
            for each (var vehicle:SteeredVehicle in vehicles)
            {
                vehicle.wanderRadius = radiusSlider.value;
            }
        }
 
        private function onEnterFrame(event:Event):void 
        {    
            for each (var vehicle:SteeredVehicle in vehicles)
            {
                vehicle.wander();
                vehicle.update();
            }
        }
    }
}

class Vector2D
{
    public var x:Number;
    public var y:Number;

public function Vector2D(x:Number, y:Number)
    {
        this.x = x;
        this.y = y;
    }

public static function get ZERO():Vector2D
    {
        return new Vector2D(0, 0);
    }

public function add(vec:Vector2D):Vector2D
    {
        this.x += vec.x;
        this.y += vec.y;

return this;
    }

public function subtract(vec:Vector2D):Vector2D
    {
        this.x -= vec.x;
        this.y -= vec.y;

return this;
    }

public function multiply(value:Number):Vector2D
    {
        this.x *= value;
        this.y *= value;

return this;
    }

public function divide(value:Number):Vector2D
    {
        this.x /= value;
        this.y /= value;

return this;
    }

public function get length():Number
    {
        return Math.sqrt(x * x + y * y);
    }

public function set length(value:Number):void
    {
        var a:Number = angle;
        x = Math.cos(a) * value;
        y = Math.sin(a) * value;
    }

public function dot(vec:Vector2D):Number
    {
        return this.x * vec.x + this.y * vec.y;
    }
    
    public function normalize(thickness:Number = 1.0):Vector2D
    {
        if (length == 0)
        {
            this.x = 1.0;
            return this;
        }

var scale:Number = thickness / length;
        this.x *= scale;
        this.y *= scale;

return this;
    }

public function distance(vec:Vector2D):Number
    {
        return Math.sqrt(distanceSquared(vec));
    }

public function distanceSquared(vec:Vector2D):Number
    {
        var tx:Number = this.x - vec.x;
        var ty:Number = this.y - vec.y;

return tx * tx + ty * ty;
    }

public function truncate(max:Number):Vector2D
    {
        length = Math.min(length, max);

return this;
    }

public function clone():Vector2D
    {
        return new Vector2D(x, y);
    }
    
    public function get angle():Number
    {
        return Math.atan2(y, x);
    }

public function set angle(radian:Number):void
    {
        var len:Number = length;
        x = Math.cos(radian) * len;
        y = Math.sin(radian) * len;
    }
}

import flash.display.Sprite;

class Vehicle extends Sprite
{
    public static const WRAP:String = "wrap";
    public static const BOUNCE:String = "bounce";
    public var edgeBehavior:String = WRAP;
    public var velocity:Vector2D;
    public var maxSpeed:Number = 10.0;
    public var mass:Number = 1.0;

public function Vehicle(x:Number, y:Number) 
    {
        this.x = x;
        this.y = y;
        velocity = Vector2D.ZERO;
    }

public function update():void
    {
        velocity.truncate(maxSpeed);
        
        this.x += velocity.x;
        this.y += velocity.y;
        
        if (edgeBehavior == WRAP) wrap();
        else if (edgeBehavior == BOUNCE) bounce();

rotation = velocity.angle * 180 / Math.PI;
        draw();
    }
    
    private function wrap():void
    {
        if (this.x < 0)
        {
            this.x = stage.stageWidth - 1;
        }
        else if (stage.stageWidth <= this.x)
        {
            this.x = 0;
        }
        
        if (this.y < 0)
        {
            this.y = stage.stageHeight - 1;
        }
        else if (stage.stageHeight <= this.y)
        {
            this.y = 0;
        }
    }
    
    private function bounce():void
    {
        if (this.x < 0)
        {
            velocity.x = -velocity.x;
            this.x = 0;
        }
        else if (stage.stageWidth <= this.x)
        {
            velocity.x = -velocity.x;
            this.x = stage.stageWidth - 1;
        }
        
        if (this.y < 0)
        {
            velocity.y = -velocity.y;
            this.y = 0;
        }
        else if (stage.stageHeight <= this.y)
        {
            velocity.y = -velocity.y;
            this.y = stage.stageHeight - 1;
        }
    }

public function get position():Vector2D
    {
        return new Vector2D(x, y);
    }

protected function draw():void 
    {
        graphics.clear();
        graphics.lineStyle(2.0, 0x0);
        graphics.moveTo(5, 0);
        graphics.lineTo(-10, -5);
        graphics.lineTo(-10, 5);
        graphics.lineTo(5, 0);
    }
}

class SteeredVehicle extends Vehicle 
{
    public var force:Vector2D;
    public var maxForce:Number = 1.0;
    public var arriveDist:Number = 100.0;
    public var wanderDist:Number = 50.0;
    public var wanderRadius:Number = 20.0;
    public var wanderAngle:Number = 0.0;
    public var wanderAngleRange:Number = 0.5;

public function SteeredVehicle(x:Number, y:Number) 
    {
        super(x, y);
        force = Vector2D.ZERO;
    }

public function seek(target:Vector2D):void
    {
        var desiredVelocity:Vector2D = target.subtract(position);
        desiredVelocity.normalize().multiply(maxSpeed).subtract(velocity);
        force.add(desiredVelocity);
    }
    
    public function flee(target:Vector2D):void
    {
        var desiredVelocity:Vector2D = target.subtract(position);
        desiredVelocity.normalize().multiply(maxSpeed).subtract(velocity);
        force.subtract(desiredVelocity);
    }
    
    public function arrive(target:Vector2D):void
    {
        var desiredVelocity:Vector2D = target.subtract(position);
        var dist:Number = desiredVelocity.length;
        desiredVelocity.normalize().multiply(maxSpeed);
        if (dist < arriveDist) desiredVelocity.multiply(dist / arriveDist);
        desiredVelocity.subtract(velocity);
        force.add(desiredVelocity);
    }
    
    public function pursue(target:Vehicle):void
    {
        var frame:Number = target.position.distance(position) / maxSpeed;
        var predictedTarget:Vector2D = target.position.clone().add(target.velocity.clone().multiply(frame));
        seek(predictedTarget);
    }
    
    public function evade(target:Vehicle):void
    {
        var frame:Number = target.position.distance(position) / maxSpeed;
        var predictedTarget:Vector2D = target.position.clone().add(target.velocity.clone().multiply(frame));
        flee(predictedTarget);
    }
    
    public function wander():void
    {
        var center:Vector2D = velocity.clone().normalize().multiply(wanderDist);
        var offset:Vector2D = Vector2D.ZERO;
        offset.length = wanderRadius;
        offset.angle = wanderAngle;
        center.add(offset).subtract(velocity);
        force.add(center);
        
        wanderAngle += Math.random() * wanderAngleRange - wanderAngleRange / 2;
    }

override public function update():void 
    {    
        force.truncate(maxForce);
        force.divide(mass);
        velocity.add(force);
        force = Vector2D.ZERO;
        super.update();
    }
    
    override protected function draw():void 
    {
        super.draw();
        var center:Vector2D = velocity.clone().normalize().multiply(wanderDist);
        center.angle -= velocity.angle;
        graphics.drawCircle(center.x, center.y, wanderRadius);
        var offset:Vector2D = Vector2D.ZERO;
        offset.length = wanderRadius;
        offset.angle = wanderAngle;
        center.add(offset);
        
        graphics.beginFill(0xED1A3D);
        graphics.drawCircle(center.x, center.y, 5);
        graphics.endFill();
    }
}

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