flash on 2010-3-14

by john0 14 Mar 2010

Embed

/**
 * Copyright john0 ( http://wonderfl.net/user/john0 )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/AgFm
 */

package
{
	import flash.display.Sprite
	import flash.events.Event;
	import flash.geom.Vector3D;
	[SWF(frameRate = "30")]
	public class Main extends Sprite
	{
		private var canvas:Sprite;
		private var cylinder:Cylinder;
		
		public function Main():void
		{	
			canvas = new Sprite();
			cylinder = new Cylinder(10, 10);
			canvas.graphics.beginFill(0xFF0000);
			canvas.graphics.drawCircle(100, 100, 10);
			canvas.graphics.endFill();
 
			addChild(canvas);
			addEventListener(Event.ENTER_FRAME, OnEnterFrame);
		}
		
		private function OnEnterFrame(event:Event):void
		{
			cylinder.SetForce(new Vector3D(0.0, -10.0, 0.0));
			cylinder.Update();
			canvas.x += 2
			canvas.y = 0
			
		}
	}
}

 

import flash.geom.Vector3D;
class RigidBody
{
    		// constant quantities---------------
    		// mass
    		protected var _mass:Number;
    		protected var _massinv:Number;
    		
    		// moment of inertia
    		protected var _I:Number;
    		protected var _Iinv:Number;
    		
    		// state variables-------------------
    		// positio  of center of mass
    		protected var _x:Vector3D = new Vector3D(0.0, 0.0, 0.0);
    		public function GetPos():Vector3D
    		{
    			return _x;
    		}
    		
    		// angle
    		protected var _a:Number;
    		
    		// liner momentum
    		protected var _p:Vector3D = new Vector3D(0.0, 0.0, 0.0);;
    		
    		// angular momentum
    		protected var _L:Number;
    		
    		// computed quantities---------------
    		protected var _force:Vector3D = new Vector3D(0.0, 0.0, 0.0);
    		public function SetForce(force:Vector3D) : void { _force = force; }
    		protected var _torque:Vector3D = new Vector3D(0.0, 0.0, 0.0);
}

class Cylinder extends RigidBody
{
	public function Cylinder(mass:Number, radius:Number) : void
	{
		_mass = mass;
		_massinv = 1 / mass;
	
		// compute moment of inertia of cylinder
		_I = 0.5 * mass * radius * radius;
		_Iinv = 1 / _I;
	}
	
	public function Update() : void
	{
		
		var p:Vector3D = new Vector3D();
		p = _p;
		var force:Vector3D = new Vector3D();
		force = _force;
		
		// p1  = p0 + force * dt
		force.scaleBy(1.0);
		//p += force;
		_p = p;
		/*
		// v = p/m = mv / m
		p.scaleBy(_massinv);
		var v:Vector3D = p;
		
		// x1 = x0 + v *dt
		v.scaleBy(1.0);
		_x += v;
		*/
	}
	

}