IK Fiber
IKで糸の束っぽいもの（ 少し重いです。 ）
/**
* Copyright whirlpower ( http://wonderfl.net/user/whirlpower )
* MIT License ( http://www.opensource.org/licenses/mit-license.php )
* Downloaded from: http://wonderfl.net/c/n4OB
*/
/**
* 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();
line.x = Math.cos( radian ) * radius;
line.y = Math.sin( radian ) * radius;
line.segmentLeng = 20;
line.segmentNum = 8;
line.gravity = 0;
line.friction = Math.random() * 0.2 + 0.7;
line.color = 0x334422;
lines.push( line );
}
addEventListener( Event.ENTER_FRAME, loop );
}
private function loop( evt:Event ):void
{
var _x :Number = stage.mouseX;
var _y :Number = stage.mouseY;
bitmapData.lock();
bitmapData.fillRect( bitmapData.rect, 0x00 );
for each(var line:IKline in lines )
{
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 = 20;
public var segmentNum :int = 8;
public var gravity :Number = 0;
public var friction :Number = 1;
public var color :uint = 0x888888;
public function IKline():void
{
this.gravity = gravity;
this.friction = friction;
var segment:Segment = new Segment( 0 * i );
segments.push( segment );
for (var i:int = 1; i < segmentNum; i++)
{
segment = new Segment( segmentLeng-0.5 * i );
segments.push( segment );
}
}
public function nextFrame( _x:int, _y:int ):void
{
drag( segments[0], _x, _y );
for ( var i:int = 1; i < segmentNum; 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 * 180 / Math.PI;
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.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 * Math.PI / 180;
var xpos :Number = x + Math.cos( angle ) * segmentLeng;
var ypos :Number = y + Math.sin( angle ) * segmentLeng;
return new Point( xpos, ypos );
}
}