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alecmcealecmce
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It's late and parabolas are broken
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8 files changed

+390
-1
lines changed

8 files changed

+390
-1
lines changed

‎src/alecmce/invalidation/InvalidatesVO.as‎

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this.isInvalidated = false;
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}
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public function resolve():void
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{
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isInvalidated = false;
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target.resolve();
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}
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}
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}

‎src/as3geometry/geom2D/line/VertexProjectedToLine.as‎

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package as3geometry.geom2D.line
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{
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import as3geometry.AS3GeometryContext;
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import as3geometry.abstract.Mutable;
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import as3geometry.geom2D.Line;
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import as3geometry.geom2D.SpatialVector;
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import as3geometry.geom2D.Vertex;
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public class VertexProjectedToLine extends Mutable implements Vertex
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{
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private var _line:Line;
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private var _vertex:Vertex;
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private var _x:Number;
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private var _y:Number;
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public function VertexProjectedToLine(context:AS3GeometryContext, line:Line, vertex:Vertex)
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{
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super(context);
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addDefinien(_vertex = vertex);
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addDefinien(_line = line);
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resolve();
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}
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public function get line():Line
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{
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return _line;
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}
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public function set line(value:Line):void
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{
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if (_line == value)
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return;
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removeDefinien(_line);
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_line = value;
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addDefinien(_line);
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invalidate();
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}
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public function get vertex():Vertex
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{
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return _vertex;
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}
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public function set vertex(value:Vertex):void
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{
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if (_vertex == value)
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return;
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removeDefinien(_vertex);
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_vertex = value;
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addDefinien(_vertex);
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invalidate();
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}
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public function get x():Number
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{
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return _x;
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}
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public function get y():Number
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{
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return _y;
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}
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override public function resolve():void
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{
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super.resolve();
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var a:Vertex = _line.a;
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var v:SpatialVector = _line.vector;
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var x:Number = _vertex.x;
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var y:Number = _vertex.y;
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var i:Number = v.i;
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var j:Number = v.j;
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var n:Number = x - a.x;
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var m:Number = y - a.y;
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var delta:Number = (j * n - i * m) / (i * i + j * j);
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_x = x - j * delta;
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_y = y + i * delta;
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}
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}
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}

‎src/as3geometry/geom2D/parabola/ImmutableParabola.as‎

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package as3geometry.geom2D.parabola
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{
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import as3geometry.abstract.Mutable;
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import as3geometry.errors.MutabilityError;
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import as3geometry.geom2D.Line;
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import as3geometry.geom2D.Parabola;

‎src/as3geometry/geom2D/parabola/MutableParabola.as‎

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package as3geometry.geom2D.parabola
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{
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import as3geometry.AS3GeometryContext;
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import as3geometry.abstract.Mutable;
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import as3geometry.geom2D.Line;
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import as3geometry.geom2D.Parabola;
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import as3geometry.geom2D.Vertex;
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public class MutableParabola extends Mutable implements Parabola
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{
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private var _focus:Vertex;
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private var _directrix:Line;
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public function MutableParabola(context:AS3GeometryContext, focus:Vertex, directrix:Line)
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{
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super(context);
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addDefinien(_focus = focus);
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addDefinien(_directrix = directrix);
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invalidate(true);
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}
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public function getVertex(n:Number):Vertex
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{
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// TODO: Auto-generated method stub
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return null;
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}
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public function get focus():Vertex
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{
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return _focus;
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}
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public function get directrix():Line
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{
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return _directrix;
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}
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}
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}

‎src/as3geometry/geom2D/ui/ParabolaDrawer/ParabolaDrawer.as‎

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package as3geometry.geom2D.ui.ParabolaDrawer
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{
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import as3geometry.AS3GeometryContext;
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import as3geometry.geom2D.Line;
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import as3geometry.geom2D.Parabola;
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import as3geometry.geom2D.Vertex;
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import as3geometry.geom2D.ui.generic.UIDrawer;
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import as3geometry.geom2D.util.ParabolaHelper;
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import ui.Paint;
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import flash.events.Event;
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public class ParabolaDrawer extends UIDrawer
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{
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private var _parabola:Parabola;
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private var _diagonal:Number;
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private var _drawPending:Boolean;
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private var _helper:ParabolaHelper;
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public function ParabolaDrawer(context:AS3GeometryContext, parabola:Parabola, paint:Paint = null)
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{
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super(context, paint);
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addDefinien(_parabola = parabola);
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_drawPending = false;
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_helper = new ParabolaHelper();
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addEventListener(Event.ADDED_TO_STAGE, onAddedToStage);
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}
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private function onAddedToStage(event:Event):void
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{
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removeEventListener(Event.ADDED_TO_STAGE, onAddedToStage);
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_diagonal = calculateDiagonal();
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if (_drawPending)
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draw();
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}
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private function calculateDiagonal():Number
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{
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var w:int = stage.stageWidth;
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var h:int = stage.stageHeight;
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return Math.sqrt(w * w + h * h);
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}
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public function get parabola():Parabola
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{
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return _parabola;
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}
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public function set parabola(value:Parabola):void
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{
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if (_parabola == value)
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return;
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removeDefinien(_parabola);
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addDefinien(_parabola = value);
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invalidate();
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}
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override protected function draw():void
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{
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if (!stage)
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{
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_drawPending = true;
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return;
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}
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_drawPending = false;
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var line:Line = _parabola.directrix;
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// the line registration point a
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var a:Vertex = line.a;
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var ax:Number = a.x;
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var ay:Number = a.y;
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// the line registraion point b
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var b:Vertex = line.b;
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var bx:Number = b.x;
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var by:Number = b.y;
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// the parabola focus
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var c:Vertex = _parabola.focus;
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var cx:Number = c.x;
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var cy:Number = c.y;
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// the vector from a to be that defines the direction of the line
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var bx_ax:Number = bx - ax;
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var by_ay:Number = by - ay;
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var abSqrd:Number = (bx_ax * bx_ax + by_ay * by_ay);
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var abInv:Number = 1 / Math.sqrt(abSqrd);
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// we want to get the vector from c to the point closest to it on the
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// line ab. Call that point d. We know that the vector cd is perpendicular
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// to the vector ab. delta is the amount we have to scale the vector ab to
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// get the right length for cd.
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var cx_ax:Number = cx - ax;
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var cy_ay:Number = cy - ay;
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var delta:Number = (by_ay * cx_ax - bx_ax * cy_ay) / abSqrd;
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// the vector cd defined
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var dx_cx:Number = -by_ay * delta;
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var dy_cy:Number = bx_ax * delta;
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// the point d defined, along with the length of cd. This is the 'focal
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// parameter' of the parabola, which is an important value.
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var dx:Number = cx + dx_cx;
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var dy:Number = cy + dy_cy;
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var cd:Number = Math.sqrt(dx_cx * dx_cx + dy_cy * dy_cy);
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var cdInv:Number = 1 / cd;
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var cdHalf:Number = cd * 0.5;
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// the point e defined, which lies between the focus and directrix
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// where the parametric value is 0 (the closest point to both the focus
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// and directrix)
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var ex:Number = cx + dx_cx * 0.5;
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var ey:Number = cy + dy_cy * 0.5;
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// the strategy now is to use the parametric form of the parabola equation
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// to work out where if you project a and b onto the parabola, they would
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// be positioned. To do this I need to tranlsate the coordinate system of
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// the parameteric equations into the real coordinate sytem...
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// (mx,my) is a unit vector along the line ab, which will be my x-vector.
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// my y-vector will be it's perpendicular: (-my,mx)
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var mx:Number = bx_ax * abInv;
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var my:Number = by_ay * abInv;
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// work out how far a is away from d anormx, which in the normal parametric
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// form is my x coordinate. This lets me derive the parameter
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// T which lets me derive the normal parametric coordinate anormy.
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var dx_ax:Number = dx - ax;
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var dy_ay:Number = dy - ay;
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var anormx:Number = -Math.sqrt(dx_ax * dx_ax + dy_ay * dy_ay);
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var aT:Number = anormx * cdInv;
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var anormy:Number = cdHalf * aT * aT;
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// do the same thing as just described for b as well
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var dx_bx:Number = dx - bx;
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var dy_by:Number = dy - by;
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var bnormx:Number = Math.sqrt(dx_bx * dx_bx + dy_by * dy_by);
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var bT:Number = bnormx * cdInv;
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var bnormy:Number = cdHalf * bT * bT;
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// now convert that into real-world coordinates by translating (dx,dy)
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// along the axes (mx,my) and (-my,mx) by the magnitudes [amx,amy] and
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// [bmx,bmy].
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var fx:Number = ex + anormx * mx - anormy * my;
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var fy:Number = ey + anormx * my + anormy * mx;
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var tx:Number = ex + bnormx * mx - bnormy * my;
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var ty:Number = ey + bnormx * my + bnormy * mx;
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graphics.moveTo(fx, fy);
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graphics.curveTo(dx, dy, tx, ty);
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}
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}
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}

‎src/as3geometry/geom2D/util/ParabolaHelper.as‎

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package as3geometry.geom2D.util
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{
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public class ParabolaHelper
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{
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public function yOnVerticalParabola(x:Number, directrixY:Number):Number
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{
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return (x * x) / (4 * -directrixY);
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}
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public function xOnVerticalParabola(y:Number, directrixY:Number):Number
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{
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var value:Number = 4 * y * -directrixY;
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if (value < 0)
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return Number.NaN;
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return Math.sqrt(value);
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}
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}
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}

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