forked from: 線分の交差判定

/**
 * Copyright hemingway ( http://wonderfl.net/user/hemingway )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/bq31
 */

// forked from Mae_ITR's 線分の交差判定
package  
{
    //http://hakuhin.hp.infoseek.co.jp/main/as/collision.html
    //参考にしました　てか、まんまです
    import flash.display.Sprite;
    import flash.geom.Point;
    import flash.events.Event;
    import flash.events.MouseEvent;
    
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    
    import com.bit101.components.*;

    public class LineCrossTest extends Sprite
    {
        private var a:Point;
        private var b:Point;
        private var c:Point;
        private var d:Point;        
        private var OldMouse:Point;
        
        private var ballA:Ball;
        private var ballB:Ball;
        private var ballC:Ball;
        
        private var txt:Label;
        
        public function LineCrossTest() 
        {
            this.stage.align = StageAlign.TOP_LEFT;
            this.stage.scaleMode = StageScaleMode.NO_SCALE;
            
            init();
        }
        
        private function init():void
        {
            a = new Point(stage.stageWidth*Math.random(),stage.stageHeight*Math.random());
            b = new Point(stage.stageWidth*Math.random(),stage.stageHeight*Math.random());
            c = new Point();
            d = new Point(mouseX,mouseY);
            OldMouse = d.clone();
            
            ballA = new Ball(5, 0x999999);
            ballA.x = a.x;
            ballA.y = a.y;
            
            ballA.addEventListener(MouseEvent.MOUSE_DOWN, onPress);
            ballA.addEventListener(MouseEvent.MOUSE_UP, onRelease);    
            
            ballB = new Ball(5, 0x999999);
            ballB.x = b.x;
            ballB.y = b.y;
            
            ballB.addEventListener(MouseEvent.MOUSE_DOWN, onPress);
            ballB.addEventListener(MouseEvent.MOUSE_UP, onRelease);    
            
            ballC = new Ball(3, 0x00FF99);
            ballC.x = c.x;
            ballC.y = c.y;
            
            txt = new Label(this, 6, 6);
            
            addChild(ballC);
            addChild(ballB);
            addChild(ballA);
            
            draw();
            addEventListener(Event.ENTER_FRAME, onEnterFrame);
        }
        
        private function onEnterFrame(e:Event):void 
        {
            d.x = mouseX - OldMouse.x;
            d.y = mouseY - OldMouse.y;
            
            draw();
            calculation();
            
            OldMouse.x = mouseX;
            OldMouse.y = mouseY;
        }
        
        private function calculation():void {
            var ab:Point = new Point(b.x - a.x, b.y - a.y);
            var n:Point = new Point( -ab.y, ab.x);
            n.normalize(1);
            var dd:Number = -(a.x * n.x + a.y * n.y);
            if (d.x != 0 || d.y != 0) {
                var t:Number = -(n.x * OldMouse.x + n.y * OldMouse.y + dd) / (n.x * d.x + n.y * d.y);
                if (t > 0 && t <= 1) {
                    c.x = OldMouse.x + d.x * t;
                    c.y = OldMouse.y + d.y * t;
                    var ac:Point = new Point(c.x - a.x, c.y - a.y);
                    var bc:Point = new Point(c.x - b.x, c.y - b.y);
                    var doc:Number = (ac.x * bc.x) + (ac.y * bc.y);
                    if (doc < 0) {
                        ballC.x = c.x;
                        ballC.y = c.y;
                        txt.text = "x : " + c.x + "\n" + "y : " + c.y + "\n";
                    }                    
                }
            }
        }
        
        private function onPress(e:MouseEvent):void 
        {
            e.target.startDrag();
            stage.addEventListener(MouseEvent.MOUSE_MOVE, onMove);
            
        }
        
        private function onMove(e:MouseEvent):void 
        {
            a.x = ballA.x;
            a.y = ballA.y;
            b.x = ballB.x; 
            b.y = ballB.y; 
        }
        
        private function onRelease(e:MouseEvent):void 
        {
            e.target.stopDrag();
            stage.removeEventListener(MouseEvent.MOUSE_MOVE, onMove);            
        }
        
        private function draw():void
        {
            this.graphics.clear();
            this.graphics.lineStyle(1, 0xCCCCCC);
            this.graphics.moveTo(a.x, a.y);
            this.graphics.lineTo(b.x, b.y);    
            this.graphics.lineStyle(1, 0x00FF99, 0.5);
            this.graphics.moveTo(OldMouse.x, OldMouse.y);
            this.graphics.lineTo(mouseX, mouseY);
        }
        
    }
    
}

import flash.display.Sprite

class Ball extends Sprite {
    
    private var radius:Number;
    private var color:uint;
    
    public function Ball(radius:Number = 40, color:uint = 0xff0000) {
        this.radius = radius;
        this.color = color;
        init();
    }
    
    public function init():void {
        graphics.beginFill(color);
        graphics.drawCircle(0, 0, radius);
        graphics.endFill();
    }
    
}