package app{
import flash.display.Sprite;
import flash.geom.Point;
import framework.game.Game;
import g.objs.MyObj;
/**
* var curve:Curve=Curve.create();
* var curvePoints:Vector.<Point>=curve.createCurve(originPoints);
* curve.draw(sprite,originPoints,curvePoints);
*/
public class Curve extends MyObj{
public static function create():Curve{
var game:Game=Game.getInstance();
var info:*={};
return game.createGameObj(new Curve(),info) as Curve;
}
public function Curve(){
super();
}
override protected function init(info:*=null):void{
super.init(info);
}
/**
* 创建曲线
* @param originPoint 曲线要经过的点列表
* @param curveRatio (0,1)曲线的疏密
* @param isCap 是否闭合曲线
* @return 返回曲线上的点列表
*/
public function createCurve(originPoint:Vector.<Point>,curveRatio:Number=0.1,isCap:Boolean=false):Vector.<Point>{
//控制点收缩系数 ，经调试0.6较好
const scale:Number=0.6;
const originCount:int=originPoint.length;
var midpoints:Vector.<Point>=new Vector.<Point>();
//生成中点
for(var i:int=0;i<originCount;i++){
var nexti:int=(i+1)%originCount;
midpoints[i]=new Point((originPoint[i].x + originPoint[nexti].x)/2.0,
(originPoint[i].y + originPoint[nexti].y)/2.0);
}
//平移中点
var extrapoints:Vector.<Point>=new Vector.<Point>(2 * originCount,true);
for(i=0;i<extrapoints.length;i++)extrapoints[i]=new Point();
for(i=0;i<originCount;i++){
nexti=(i+1)%originCount;
var backi:int=(i+originCount-1)%originCount;
var midinmid:Point=new Point((midpoints[i].x+midpoints[backi].x)/2.0,
(midpoints[i].y+midpoints[backi].y)/2.0);
var offsetx:int=originPoint[i].x-midinmid.x;
var offsety:int=originPoint[i].y-midinmid.y;
var extraindex:int=2*i;
extrapoints[extraindex].x=midpoints[backi].x+offsetx;
extrapoints[extraindex].y=midpoints[backi].y+offsety;
//朝 originPoint[i]方向收缩
var addx:int=(extrapoints[extraindex].x-originPoint[i].x)*scale;
var addy:int=(extrapoints[extraindex].y-originPoint[i].y)*scale;
extrapoints[extraindex].x=originPoint[i].x+addx;
extrapoints[extraindex].y=originPoint[i].y+addy;
var extranexti:int=(extraindex+1)%(2*originCount);
extrapoints[extranexti].x=midpoints[i].x+offsetx;
extrapoints[extranexti].y=midpoints[i].y+offsety;
//朝 originPoint[i]方向收缩
addx=(extrapoints[extranexti].x-originPoint[i].x)*scale;
addy=(extrapoints[extranexti].y-originPoint[i].y)*scale;
extrapoints[extranexti].x=originPoint[i].x+addx;
extrapoints[extranexti].y=originPoint[i].y+addy;
}
var curvePoint:Vector.<Point>=new Vector.<Point>();
var controlPoint:Vector.<Point>=new Vector.<Point>(4,true);
//生成4控制点，产生贝塞尔曲线
for(i=0;i<originCount;i++){
if(i>=originCount-1&&isCap==false)break;
controlPoint[0]=originPoint[i];
extraindex=2*i;
controlPoint[1]=extrapoints[extraindex + 1];
extranexti=(extraindex+2)%(2*originCount);
controlPoint[2]=extrapoints[extranexti];
nexti=(i+1)%originCount;
controlPoint[3]=originPoint[nexti];
var u:Number=1;
while(u>=0){
var px:int=bezier3funcX(u,controlPoint);
var py:int=bezier3funcY(u,controlPoint);
//u的步长决定曲线的疏密
u-=curveRatio;
var tempP:Point=new Point(px,py);
//存入曲线点
curvePoint.push(tempP);
}
}
return curvePoint;
}
//三次贝塞尔曲线
private function bezier3funcX(uu:Number,controlP:Vector.<Point>):Number{
var part0:Number=controlP[0].x*uu*uu*uu;
var part1:Number=3*controlP[1].x*uu*uu*(1-uu);
var part2:Number=3*controlP[2].x*uu*(1-uu)*(1-uu);
var part3:Number=controlP[3].x*(1-uu)*(1-uu)*(1-uu);
return part0+part1+part2+part3;
}
private function bezier3funcY(uu:Number,controlP:Vector.<Point>):Number{
var part0:Number=controlP[0].y*uu*uu*uu;
var part1:Number=3*controlP[1].y*uu*uu*(1-uu);
var part2:Number=3*controlP[2].y*uu*(1-uu)*(1-uu);
var part3:Number=controlP[3].y*(1-uu)*(1-uu)*(1-uu);
return part0+part1+part2+part3;
}
public function draw(sp:Sprite,originPoints:Vector.<Point>,curvePoints:Vector.<Point>,isDrawCurveDot:Boolean=true):void{
const color:uint=0xff0000;
sp.graphics.lineStyle(1,color);
for(var i:int=0;i<curvePoints.length;i++){
if(i>0){
sp.graphics.lineTo(curvePoints[i].x,curvePoints[i].y);
}else{
sp.graphics.moveTo(curvePoints[i].x,curvePoints[i].y);
}
//
if(isDrawCurveDot){
sp.graphics.drawCircle(curvePoints[i].x,curvePoints[i].y,3);
}
}
//draw dot
sp.graphics.lineStyle(1,0x0000ff,0.5);
sp.graphics.beginFill(0x0000ff,0.5);
for(i=0;i<originPoints.length;i++){
sp.graphics.drawCircle(originPoints[i].x,originPoints[i].y,3);
}
sp.graphics.endFill();
}
};
}
https://blog.csdn.net/hzsjun/article/details/24958773