// forked from sake's 階段を上るやつ2
/*
   階段を上るやつ2。
   定数kの値を変更すると、ジャンプする高さが変更できます。
*/

package
{
	import flash.display.Graphics;
	import flash.display.Sprite;
	import flash.events.Event;
	import flash.geom.Matrix3D;
	[SWF(width="465", height="465", backgroundColor="0xFFFFFF", frameRate="40")]

public class stair2 extends Sprite
	{
		private var container:Sprite;
		private var cube:Sprite;
		private var xx:Number
		private var nn:int;
		
		// ジャンプする度合いを制御する定数
		private const k:Number = 6;

public function stair2()
		{
			container=new Sprite();
			container.x=465 / 2;
			container.y=465 / 2;
			addChild(container);
			container.scaleX=container.scaleY=container.scaleZ=1.8;
			nn=xx=0;

cube=new Sprite;
			container.addChild(cube);
			cube.name="sp" + nn.toString();
			nn++;

// Cubeを作る
			var sp0:Sprite=new Sprite();
			draw(sp0.graphics);
			sp0.rotationY=90;
			sp0.x=5;
			cube.addChild(sp0);
			sp0.name="plane0";

var sp1:Sprite=new Sprite();
			draw(sp1.graphics);
			sp1.rotationY=-90;
			sp1.x=-5;
			cube.addChild(sp1);
			sp1.name="plane1";

var sp2:Sprite=new Sprite();
			draw(sp2.graphics);
			sp2.rotationX=-90;
			sp2.y=-5;
			cube.addChild(sp2);
			sp2.name="plane2";

var sp3:Sprite=new Sprite();
			draw(sp3.graphics);
			sp3.rotationX=90;
			sp3.y=5;
			cube.addChild(sp3);
			sp3.name="plane3";

var sp4:Sprite=new Sprite();
			draw(sp4.graphics);
			sp4.z=-5;
			cube.addChild(sp4);
			sp4.name="plane4";

var sp5:Sprite=new Sprite();
			draw(sp5.graphics);
			sp5.z=5;
			cube.addChild(sp5);
			sp5.name="plane5";

// 階段を作る
                                /*			
                                for(var i:int=-200; i < 200; i+=10)
			{
				var sp6:Sprite=new Sprite;
				draw(sp6.graphics);
				container.addChild(sp6);
				sp6.x=i;
				sp6.y=-(i - 5);
				sp6.rotationX=90;
				sp6.name="sp" + nn.toString();
				nn++;

var sp7:Sprite=new Sprite;
				draw(sp7.graphics);
				container.addChild(sp7);
				sp7.x=i + 5;
				sp7.y=-i;
				sp7.rotationY=90;
				sp7.name="sp" + nn.toString();
				nn++;
			}
                            */
			addEventListener(Event.ENTER_FRAME, onFrame);
		}

private function draw(g:Graphics):void
		{
			g.beginFill(0xFFFFFF * Math.random(), 0.6);
			g.drawRect(-5, -5, 10, 10);
			g.endFill();
		}

private function onFrame(e:Event):void
		{
			container.rotationY+=0.5;

// ここでCubeの座標を計算
			cube.x=10 * xx;
			cube.y = -10 *( -1*(2*k-1+2*Math.sqrt(k*k-k))*(xx - k + Math.sqrt(k*k-k)-Math.floor(xx))*(xx - k + Math.sqrt(k*k-k)-Math.floor(xx)) + k + Math.floor(xx));
			xx+=0.1;
			if (xx >= 18) xx=-18;

var array:Array=[];
			for(var i:int=0; i < 6; i++)
			{
				var sp:Sprite=cube.getChildByName("plane" + i.toString())as Sprite;
				var mat:Matrix3D=sp.transform.getRelativeMatrix3D(this);
				array.push({sp:sp, z:mat.position.z});
			}
			array.sortOn("z", Array.NUMERIC | Array.DESCENDING);
			for(var i:int=0; i < 6; i++)
			{
				var sp:Sprite=array[i].sp as Sprite;
				cube.setChildIndex(sp, i);
			}

array=[];
			for(var i:int=0; i < nn; i++)
			{
				var sp:Sprite=container.getChildByName("sp" + i.toString())as Sprite;
				var mat:Matrix3D=sp.transform.getRelativeMatrix3D(this);
				array.push({sp:sp, z:mat.position.z});
			}
			array.sortOn("z", Array.NUMERIC | Array.DESCENDING);
			for(var i:int=0; i < nn; i++)
			{
				var sp:Sprite=array[i].sp as Sprite;
				container.setChildIndex(sp, i);
			}
		}
	}
}

forked from: 階段を上るやつ2