forked from: forked from: with wind and gravity ff: IK Fiber

IKで糸の束っぽいもの（　少し重いです。　）

by francescotrillini 14 Apr 2013

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/**
 * Copyright francescotrillini ( http://wonderfl.net/user/francescotrillini )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/gh1f
 */

// forked from francescotrillini's forked from: with wind and gravity ff: IK Fiber
// forked from codeonwort's with wind and gravity ff: IK Fiber
// forked from whirlpower's IK Fiber
/**
* IKで糸の束っぽいもの（　少し重いです。　）
*/
package {
    import flash.display.Sprite;
    public class FlashTest extends Sprite {
        public function FlashTest() {
            // write as3 code here..
            stage.addChild( new TailLine() );           
        }
    }
}
        
        import flash.display.*;
    import flash.events.*;
    import flash.geom.*;
        
    internal class TailLine extends Bitmap
    {
        private var lines    :Array;
        
        public function TailLine():void
        {
            addEventListener( Event.ADDED_TO_STAGE, init );
        }
        
        private function init( e:Event ):void
        {
            removeEventListener( Event.ADDED_TO_STAGE, init );
            
            bitmapData = new BitmapData( stage.stageWidth, stage.stageHeight, true, 0x00000000 );
            
            lines = [];
            for (var i:int = 0; i < 50; i++)
            {
                var radius    :Number = Math.random() * 10;
                var radian    :Number = Math.random() * Math.PI*2;
                
                var line:IKline = new IKline(30, 16);
                line.x = Math.cos( radian ) * radius;
                line.y = Math.sin( radian ) * radius;
                line.gravity     = 0;    
                line.friction     = Math.random() * 0.2 + 0.7;    
                line.color = 0x123456//0x334422;
                lines.push( line );
            }
            
            addEventListener( Event.ENTER_FRAME, loop );
        }
        
        private var g:Number = 9.8, tg:Number = 9.8;
        private var wd:Number = 0, twd:Number = 10;
        private function loop( evt:Event ):void
        {
            var _x    :Number    = stage.mouseX;
            var _y    :Number    = stage.mouseY;
            
            bitmapData.lock();
            bitmapData.fillRect( bitmapData.rect, 0x00 );
            
            if(Math.random() < 0.1) tg = Math.random()*9.8;
            if(Math.random() < 0.1) twd = Math.random()*10;
            g += 0.1 * (tg - g)
            wd += 0.1 * (twd - wd);
            for each(var line:IKline in lines ) 
            {
                line.gravity = g;
                line.wind = wd;
                line.nextFrame( _x, _y );
                bitmapData.draw( drawLine( line ), new Matrix( 1,0,0,1,line.x,line.y ) );
            }
            bitmapData.unlock();
        }
        
        private function drawLine( line:IKline ):Shape
        {
            var segments:Array    = line.segments;
            var leng    :int    = segments.length;
            var shape    :Shape    = new Shape();
            var g        :Graphics = shape.graphics;
            
            g.moveTo( segments[0].x, segments[0].y );
            for ( var i :int = 0; i < leng-2; i++ )
            {
                var xc:Number = ( segments[i].x + segments[i + 1].x ) / 2;
                var yc:Number = ( segments[i].y + segments[i + 1].y ) / 2;
                
                g.lineStyle( 1-i/(leng-2), line.color, 1-i/(leng-2) );
                g.curveTo( segments[i].x, segments[i].y, xc, yc );
            }
            
            return shape;
        }
    }
     
    internal class IKline
    {
        public var segments /*Segment*/:Array = [];
        
        public var x            :Number = 0;
        public var y            :Number = 0;
        
        public var segmentLeng    :int = 90;
        public var segmentNum    :int = 8;
        public var wind:Number = 0
        public var gravity        :Number = 0;
        public var friction        :Number = 1;
        public var color        :uint = 0x888888;
        
        public function IKline(len:int, num:int):void
        {
            segmentLeng = len
            segmentNum = num
            
            var segment:Segment = new Segment( 0 * i );
            segments.push( segment );
            
            for (var i:int = 1; i < 10; i++) 
            {
                segment = new Segment( segmentLeng);
                segments.push( segment );
            }
        }
        
        public function nextFrame( _x:int, _y:int ):void
        {
            drag( segments[0], _x, _y );
            for ( var i:int = 1; i < 10; i++ )
            {
                var segmentA:Segment = segments[i];
                var segmentB:Segment = segments[i - 1];
                drag( segmentA, segmentB.x, segmentB.y );
            }
        }
        
        private function drag( segment:Segment, xpos:Number, ypos:Number ):void
        {
            segment.next();
            
            var dx        :Number = xpos - segment.x;
            var dy        :Number = ypos - segment.y;
            var radian    :Number = Math.atan2( dy, dx );
            segment.rotation = radian ;
            
            var pin    :Point    = segment.getPin();
            var w    :Number = pin.x - segment.x;
            var h    :Number = pin.y - segment.y;
            
            segment.x = xpos - w;
            segment.y = ypos - h;
            segment.setVector();
            
            segment.vx *= friction;
            segment.vy *= friction;
            segment.vx += wind
            segment.vy += gravity;
        }
    }
    
    internal class Segment extends Sprite
    {
        private var segmentLeng    :Number;
        public  var vx            :Number = 0;
        public  var vy            :Number = 0;
        
        private var prevX        :Number = 0;
        private var prevY        :Number = 0;
        
        public function Segment( segmentLeng:Number ):void
        {
            this.segmentLeng = segmentLeng;
        }
        
        public function next():void
        {
            x += vx;
            y += vy;
        }
        
        public function setVector():void
        {
            if( prevX ) vx = x - prevX;
            if( prevY ) vy = y - prevY;
            
            prevX = x;
            prevY = y;
        }
        
        public function getPin():Point
        {
            var angle    :Number = rotation ;
            var xpos    :Number = x + Math.cos( angle ) * segmentLeng;
            var ypos    :Number = y + Math.sin( angle ) * segmentLeng;
            
            return new Point( xpos, ypos );
        }
    }