// forked from makc3d's Galaxy
package
{
    import flash.filters.GlowFilter;

import org.papervision3d.cameras.CameraType;
    import org.papervision3d.core.geom.Pixels;
    import org.papervision3d.core.geom.renderables.Pixel3D;
    import org.papervision3d.objects.DisplayObject3D;
    import org.papervision3d.view.layer.BitmapEffectLayer; 
    import org.papervision3d.view.layer.ViewportLayer; 
    import org.papervision3d.view.BasicView;

[SWF (width=465, height=465, backgroundColor=0x0, frameRate=20)]
    public class Galaxy extends BasicView
    {
        private var pixels:Pixels;

public function Galaxy()
        {
            super(0,0,true,false,CameraType.TARGET);
            camera.z = -150;

var layer:BitmapEffectLayer =
                new BitmapEffectLayer (viewport, 465, 465, true, 0, "clear_pre", false, true);
            viewport.containerSprite.addLayer (layer);

pixels = new Pixels (layer);
            scene.addChild (pixels);

var stars:Array = [];
            // we can use far more pixels than particles ;)
            generate (stars); generate (stars); generate (stars);
            generate (stars); generate (stars); generate (stars);

for each (var obj:Object in stars) {
                var p:Pixel3D = new Pixel3D(obj.c + 0x1000000 * obj.a, obj.x, obj.y, obj.z);
                pixels.addPixel3D (p);
            }

startRendering();
            addEventListener("enterFrame", onEnterFrame);

filters = [ new GlowFilter (0x007fff, 0.5, 30, 30, 10) ];
        }

private function onEnterFrame(e:*):void {
            pixels.yaw (2); pixels.pitch (1);
        }

private function generate (stars:Array):void {
            // I wrote this code back in late '90s in TurboPascal
            // By now, I have no idea how it works, and what those magic numbers are :)

var I:Number, J:Number, K:Number,
            s:Number, L:Number, d:Number, R:Number,
            dX:Number, dY:Number, dZ:Number,
            c2:Number;
            var Rm:Number = 20, A:Number = 0.3;

var clr:Array = [0x0080FF, 0x8080E4, 0xB0B0FF];

for (I = 0; I < 101; I++)
            {
                A = A + 0.03;
                R = A * Rm;
                for (J = 0; J < 5 - Math.floor(I / 20); J++)
                {
                    for (K = 0; K < 5; K++)
                    {
                        L = clr[(R > 3 * Rm * Math.random()) ? 0 : 1];
                        c2 = (R > 2 * Rm * Math.random()) ? 1 : 2;
                        if (A < 0.6) L = clr[2];
                        s = Math.max (2, Rm - R / 3);

dX = R * Math.cos(A + K * 2 * Math.PI / 5) +
                            0.2 * ((100 - I) * Math.random() + I / 2);
                        dY = R * Math.sin(A + K * 2 * Math.PI / 5) +
                            0.2 * ((100 - I) * Math.random() + I / 2);
                        dZ = s * (Math.random() - Math.random());

stars.push ({ x: dX, y: dY, z: dZ, c: L, a: (255 - 120 * c2) });
                    }
                }
            }
        }
    }
}

Galaxy (Pixels)