forked from: 万有引力
/**
* Copyright uwi ( http://wonderfl.net/user/uwi )
* MIT License ( http://www.opensource.org/licenses/mit-license.php )
* Downloaded from: http://wonderfl.net/c/1Nfj
*/
// forked from takenosin's 万有引力
// forked from takenosin's パーティクル
package {
import flash.display.Sprite;
import flash.events.Event;
[SWF(frameRate=60)]
public class ClassName extends Sprite {
private var Particles:Array;
private var numParticles:uint = 150;
public function ClassName() {
graphics.beginFill(0x0);
graphics.drawRect(0, 0, stage.stageWidth, stage.stageHeight);
graphics.endFill();
Particles = new Array();
for(var i:uint = 0; i < numParticles; i++){
var mass : Number = Math.random() * Math.random() * 10 + 1;
var Particle:Ball = new Ball(Math.pow(mass, 1/3) * 4, 0xff0000);
Particle.x = Math.random() * stage.stageWidth;
Particle.y = Math.random() * stage.stageHeight;
Particle.mass = mass;
Particle.alpha = mass / 15 + 0.1;
addChild(Particle);
Particles.push(Particle);
}
addEventListener(Event.ENTER_FRAME,onEnterFrame);
}
private function onEnterFrame(event:Event):void{
var gx : Number = 0;
var gy : Number = 0;
var smass : Number = 0;
for(var i:uint = 0; i < numParticles; i++){
var Particle:Ball = Particles[i];
Particle.x += Particle.vx;
Particle.y += Particle.vy;
gx += (Particle.x - stage.stageWidth / 2) * Particle.mass;
gy += (Particle.y - stage.stageHeight / 2) * Particle.mass;
smass += Particle.mass;
}
gx /= smass;
gy /= smass;
for(i = 0; i < numParticles; i++){
Particle = Particles[i];
Particle.x -= gx;
Particle.y -= gy;
}
for(i = 0; i < numParticles - 1; i++){
var PartA:Ball = Particles[i];
for(var j:uint = i + 1; j < numParticles; j++){
var PartB:Ball = Particles[j];
gravitate(PartA,PartB);
}
}
}
private function gravitate(PartA:Ball,PartB:Ball):void{
var dx:Number = PartB.x - PartA.x;
var dy:Number = PartB.y - PartA.y;
var distSQ:Number = dx * dx + dy * dy;
var dist:Number = Math.sqrt(distSQ);
if(dist < 50)dist = 50;
var force:Number = PartA.mass * PartB.mass / distSQ;
var ax:Number = force * dx / dist;
var ay:Number = force * dy / dist;
PartA.vx += ax / PartA.mass;
PartA.vy += ay / PartA.mass;
PartB.vx -= ax / PartB.mass;
PartB.vy -= ay / PartB.mass;
}
}
}
import flash.display.Sprite;
class Ball extends Sprite{
public var radius:Number;
private var color:uint;
public var vx:Number = 0;
public var vy:Number = 0;
public var mass:Number = 1;
public function Ball(radius:Number=40,color:uint=0x66ffff){
this.radius = radius;
this.color = color;
graphics.beginFill(color);
graphics.drawCircle(0,0,radius);
graphics.endFill();
}
}