AS3 算法，菱形分8份三角形，检测点在哪个个三角形中

今天，由于公事，研究了一下，算法：

简单的三角形类：

package{import flash.display.Sprite;import flash.geom.Point;/** * 三角形 * @author Jave.Lin */public class Triangle extends Sprite{private var _p1:Point;private var _p2:Point;private var _p3:Point;private var _c:uint;public function get p1():Point{return _p1;}public function get p2():Point{return _p2;}public function get p3():Point{return _p3;}public function get c():uint{return _c;}public function set p1(value:Point):void{if(value.x!=_p1.x && value.y!=_p1.y){_p1=value;redraw();}}public function set p2(value:Point):void{if(value.x!=_p2.x && value.y!=_p2.y){_p2=value;redraw();}}public function set p3(value:Point):void{if(value.x!=_p3.x && value.y!=_p3.y){_p3=value;redraw();}}public function Triangle($p1:Point,$p2:Point,$p3:Point,$c:uint=0xff0000){super();setPointsRedraw($p1,$p2,$p3,$c);}public function setPointsRedraw($p1:Point,$p2:Point,$p3:Point,$c:uint=0xff0000):void{_p1=$p1;_p2=$p2;_p3=$p3;_c=$c;redraw();}private function redraw():void{// clearthis.graphics.clear();// begine and set stylethis.graphics.beginFill(_c,0.5);this.graphics.lineStyle(1,_c,0.5);// start positionthis.graphics.moveTo(_p1.x,_p1.y);// draw linesthis.graphics.lineTo(_p2.x,_p2.y);this.graphics.lineTo(_p3.x,_p3.y);this.graphics.lineTo(_p1.x,_p1.y);// end drawthis.graphics.endFill();}}}

菱形类：

package{import flash.display.Sprite;/** * 菱形类 * @author Jave.Lin */public class Diamond extends Sprite{protected var _xR:Number;protected var _yR:Number;public function get xR():Number{return _xR;}public function set xR(value:Number):void{if(value!=_xR){_xR=value;redraw();}}public function get yR():Number{return _yR;}public function set yR(value:Number):void{if(value!=_yR){_yR=value;redraw();}}public function Diamond($xR:Number,$yR:Number){setXYRAndRedraw($xR,$yR);}public function setXYRAndRedraw($xR:Number,$yR:Number):void{_xR=$xR;_yR=$yR;redraw();}private function redraw():void{// clearthis.graphics.clear();// begine and set stylethis.graphics.beginFill(0xff0000,0.5);this.graphics.lineStyle(1,0xff0000,0.5);// start positionthis.graphics.moveTo(_xR,0);// draw linesthis.graphics.lineTo(0,_yR);this.graphics.lineTo(-_xR,0);this.graphics.lineTo(0,-_yR);this.graphics.lineTo(_xR,0);// end drawthis.graphics.endFill();}}}

菱形扩展类：

package{import flash.geom.Point;import flash.utils.getTimer;/** * 菱形的一个扩展类 * @author Jave.Lin */public class DiamondExt extends Diamond{private var _triangles:Vector.<Triangle>=new Vector.<Triangle>();private var _angle1:Number;private var _angle2:Number;public function DiamondExt($xR:Number, $yR:Number){super($xR, $yR);generateTriangle();}private function generateTriangle():void{//_angle1=Math.abs(Math.tan(_yR/_xR));//有误差？_angle1=Math.abs(Math.atan2((-_yR-0),((0-(-_xR)))));if(_angle1>(Math.PI/2))_angle1-=(Math.PI/2);_angle2=Math.PI/2-_angle1;_triangles[0]=new Triangle(new Point(0,0),new Point(_xR,0),new Point(_xR/2,_yR/2));_triangles[1]=new Triangle(new Point(0,0),new Point(_xR/2,_yR/2),new Point(0,_yR));_triangles[2]=new Triangle(new Point(0,0),new Point(0,_yR),new Point(-(_xR/2),_yR/2));_triangles[3]=new Triangle(new Point(0,0),new Point(-(_xR/2),_yR/2),new Point(-_xR,0));_triangles[4]=new Triangle(new Point(0,0),new Point(-_xR,0),new Point(-(_xR/2),-(_yR/2)));_triangles[5]=new Triangle(new Point(0,0),new Point(0,-_yR),new Point(-(_xR/2),-(_yR/2)));_triangles[6]=new Triangle(new Point(0,0),new Point(_xR/2,-(_yR/2)),new Point(0,-_yR));_triangles[7]=new Triangle(new Point(0,0),new Point(_xR,0),new Point(_xR/2,-(_yR/2)));for (var i:int = 0; i < _triangles.length; i++) {addChild(_triangles[i]);}}public function checkPointAndLightTheTriangle(point:Point):void{var tempA:Number=Math.atan2(point.y,point.x);resetTriangles();if(tempA>=0 && tempA<_angle1){_triangles[0].alpha=0.5;}else if(tempA>=_angle1 && tempA<(_angle1+_angle2)){_triangles[1].alpha=0.5;}else if(tempA>=Math.PI/2 && tempA<(Math.PI/2+_angle2)){_triangles[2].alpha=0.5;}else if(tempA>=(Math.PI/2+_angle2) && tempA<Math.PI){_triangles[3].alpha=0.5;}else if(tempA>=-Math.PI && tempA<(-Math.PI+_angle1)){_triangles[4].alpha=0.5;}else if(tempA>=(-Math.PI+_angle1) && tempA<-Math.PI/2){_triangles[5].alpha=0.5;}else if(tempA>=-Math.PI/2 && tempA<-_angle1){_triangles[6].alpha=0.5;}else if(tempA>=-_angle1 && tempA<0){_triangles[7].alpha=0.5;}}public function testLargeNumSummaryPerformancea(point:Point,num:int=100000):void{var num1Right:Number=_angle1+_angle2;var num2Right:Number=Math.PI/2+_angle2;var num3Right:Number=Math.PI;var num4Left:Number=-Math.PI;var num4Right:Number=-Math.PI+_angle1;var num5Right:Number=-Math.PI/2;var num6Right:Number=-_angle1;var startTime:int=getTimer();var triangleNum:int=0;var tempA:Number=Math.atan2(point.y,point.x);for (var i:int = 0; i < num; i++) {if(tempA>=0 && tempA<_angle1){triangleNum=0;}else if(tempA>=_angle1 && tempA<num1Right){triangleNum=1;}else if(tempA>=num1Right && tempA<num2Right){triangleNum=2;}else if(tempA>=num2Right && tempA<num3Right){triangleNum=3;}else if(tempA>=num4Left && tempA<num4Right){triangleNum=4;}else if(tempA>=num4Right && tempA<num5Right){triangleNum=5;}else if(tempA>=num5Right && tempA<num6Right){triangleNum=6;}else if(tempA>=num6Right && tempA<0){triangleNum=7;}}var endTime:int=getTimer();trace("run "+num+" times elpasedTime:"+(endTime-startTime));// run 1000000 times elpasedTime : 26 ms 左右}public function resetTriangles():void{for (var i:int = 0; i < _triangles.length; i++) {_triangles[i].alpha=1;}}}}

应用示例：

package{import flash.display.Sprite;import flash.events.MouseEvent;import flash.geom.Point;public class DiamondTest extends Sprite{private var _diamond:Diamond;private var _triangle:Triangle;private var _diamondExt:DiamondExt;public function DiamondTest(){super();_diamond=new Diamond(50,25);addChild(_diamond);_diamond.x=200;_diamond.y=200;_diamond.addEventListener(MouseEvent.MOUSE_OVER,onDiamondOverHandler);_diamond.addEventListener(MouseEvent.MOUSE_OUT,onDiamondOutHandler);_triangle=new Triangle(new Point(0,0),new Point(25,-25),new Point(-25,-25),0x00ffff);addChild(_triangle);_triangle.x=50;_triangle.y=200;_diamondExt=new DiamondExt(50,25);addChild(_diamondExt);_diamondExt.x=400;_diamondExt.y=200;_diamondExt.addEventListener(MouseEvent.MOUSE_MOVE,onDiamondExtMoveHandler);_diamondExt.addEventListener(MouseEvent.MOUSE_OUT,onDiamondExtOutHandler);}private function onDiamondExtOutHandler(e:MouseEvent):void{_diamondExt.resetTriangles();}private function onDiamondExtMoveHandler(e:MouseEvent):void{_diamondExt.checkPointAndLightTheTriangle(new Point(mouseX-_diamondExt.x,mouseY-_diamondExt.y));_diamondExt.testLargeNumSummaryPerformancea(new Point(mouseX-_diamondExt.x,mouseY-_diamondExt.y));//,1000000);}private function onDiamondOverHandler(e:MouseEvent):void{trace("over");}private function onDiamondOutHandler(e:MouseEvent):void{trace("out");}}}

设计前草稿图：

运行效果，用鼠标经过带有三角形的菱形，分别移动不同的三角形位置上，即可看到效果。

可以把这个扩展的菱形，长度弄大一些。

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