The infinite expanse of space on your computer! Click to place the black hole.
Document Class:
package com.elegantactionscript.fxpression09 {
import flash.display.Sprite;
import flash.display.Shape;
import flash.display.Graphics;
import flash.events.MouseEvent;
public class CursorGravity extends Sprite {
public static const G:Number = 0.0000000000667;
public static var meter:Number;
public static var cursorMass:Number; // kg
public static var massMultiplier:Number;
public static var blackHole:Shape;
public function CursorGravity():void {
meter = 5;
cursorMass = 100000;
massMultiplier = 700;
blackHole = new Shape();
blackHole.x = stage.stageWidth / 2
blackHole.y = stage.stageHeight / 2;
var g:Graphics = blackHole.graphics;
with (g) {
lineStyle(1, 0xffff00, 0.5);
beginFill(0x000000);
drawCircle(0, 0, 10);
}
addChild(blackHole);
stage.frameRate = 30;
var satellites:Array = [[100, 30, 60, -0.5, 1], [350, 430, 40, 1, -1], [20, 110, 30, 0, 1], [150, 20, 20, 1, 0], [200, 200, 10, 0.2, -0.5], [250, 70, 25, -0.8, 0.2], [300, 300, 5, 0, -0.2], [275, 150, 10, -0.5, 0]];
var l:int = satellites.length;
for (var i:uint = 0; i<l; i++) {
var satellite:Satellite = new Satellite(satellites*[2]);
satellite.x = satellites*[0]
satellite.y = satellites*[1]
satellite.xSpeed = satellites*[3];
satellite.ySpeed = satellites*[4];
addChild(satellite);
satellite.setup();
}
stage.addEventListener(MouseEvent.CLICK, placeBlackHole, false, 0, true);
}
private function placeBlackHole(evt:MouseEvent):void {
blackHole.x = evt.stageX;
blackHole.y = evt.stageY;
}
}
}
Satellite:
package com.elegantactionscript.fxpression09 {
import flash.display.Sprite;
import flash.display.Graphics;
import flash.events.Event;
public class Satellite extends Sprite {
private var radius:Number;
private var mass:Number;
public var xSpeed:Number;
public var ySpeed:Number;
private var xAcc:Number;
private var yAcc:Number;
public function Satellite(radius:Number):void {
this.radius = radius;
mass = (Math.PI * radius * radius) / 2 * CursorGravity.massMultiplier;
xSpeed = 0;
ySpeed = 0;
xAcc = 0;
yAcc = 0;
var g:Graphics = this.graphics;
with (g) {
lineStyle(2, 0xffffff, 0.5);
beginFill(0x000022);
drawCircle(0, 0, radius);
}
}
public function setup():void {
stage.addEventListener(Event.ENTER_FRAME, updateScreen, false, 0, true);
}
private function updateScreen(evt:Event):void {
var gravityForce = (CursorGravity.G * CursorGravity.cursorMass * this.mass) / (getDistance());
var cursorAngle = Math.atan2( (y - CursorGravity.blackHole.y), (x - CursorGravity.blackHole.x) );
xAcc = -gravityForce * Math.cos(cursorAngle);
yAcc = -gravityForce * Math.sin(cursorAngle);
xSpeed += xAcc;
ySpeed += yAcc;
x += xSpeed;
y += ySpeed;
}
private function getDistance():Number {
return Math.sqrt( (x - CursorGravity.blackHole.x) * (x - CursorGravity.blackHole.x) + (y - CursorGravity.blackHole.y) * (y - CursorGravity.blackHole.y) ) * CursorGravity.meter;
}
}
}
It’s either calming and serene or very slow, depending on how you look at it. It think it is the epitome of tranquility…
