javascript实现多边形碰撞检测

const app = new PIXI.Application({ antialias: true });
document.body.appendChild(app.view);

const graphics = new PIXI.Graphics();


// draw polygon
const path = [600, 370, 700, 460, 780, 420, 730, 570, 590, 520];

graphics.lineStyle(0);
graphics.beginFill(0x3500FA, 1);
graphics.drawPolygon(path);
graphics.endFill();

app.stage.addChild(graphics);

 var xuanzhuan = PIXI.Sprite.from("/moban/images/share.jpg");
 xuanzhuan.width=120;
 xuanzhuan.height=120;
 xuanzhuan.x=13;
 xuanzhuan.y=33;
  app.stage.addChild(xuanzhuan);


  xuanzhuan.interactive = true;

  xuanzhuan.buttOnMode= true;
   xuanzhuan
    .on("pointerdown", onDragStart)
    .on("pointerup", onDragEnd)
    .on("pointerupoutside", onDragEnd)
    .on("pointermove", onDragMove);

  function onDragStart(event) {
  // store a reference to the data
  // the reason for this is because of multitouch
  // we want to track the movement of this particular touch
  this.data = event.data;
  this.alpha = 0.5;
  this.dragging = true;
}

function onDragEnd() {
  this.alpha = 1;
  this.dragging = false;
  // set the interaction data to null
  this.data = null;
}
   var  posPolygon=[];
     var dianlist={};
    dianlist["x"]=600;
    dianlist["y"]=370; 
    posPolygon.push(dianlist)
  var dianlist={};
    dianlist["x"]=700;
    dianlist["y"]=460; 
    posPolygon.push(dianlist)  
  var dianlist={};
    dianlist["x"]=780;
    dianlist["y"]=420; 
    posPolygon.push(dianlist)   
  var dianlist={};
    dianlist["x"]=730;
    dianlist["y"]=570; 
   posPolygon.push(dianlist) 
  var dianlist={};
    dianlist["x"]=590;
    dianlist["y"]=520; 
    posPolygon.push(dianlist)
function onDragMove() {
  if (this.dragging) {
    const newPosition = this.data.getLocalPosition(this.parent);
    this.x = newPosition.x;
    this.y = newPosition.y;

    var baoweihe=this.getBounds();
    var youxiajiaox=baoweihe.x+baoweihe.width;
    var youxiajiaoy=baoweihe.y+baoweihe.height;

    var poslist=[];
     var pos={};
    pos["x"]=baoweihe.x;
    pos["y"]=baoweihe.y;    
    poslist.push(pos);      

  var pos={};
    pos["x"]=youxiajiaox;
    pos["y"]=baoweihe.y;    
    poslist.push(pos);      
    var pos={};
    pos["x"]=youxiajiaox;
    pos["y"]=youxiajiaoy;    
    poslist.push(pos);

    var pos={};
    pos["x"]=baoweihe.x;
    pos["y"]=youxiajiaoy;    
    poslist.push(pos);    

     
  
    var ispengzhuang=PolygonInPolygon(poslist, posPolygon,5);
    if(ispengzhuang){
      alert("碰撞了");
    }


  }
}

function PolygonInPolygon(posPolygonA, posPolygonB, count){
  console.log(posPolygonA);
    var count1=posPolygonA.length;
   for(var i=0;i Math.max( p1.y, p2.y ) )
      continue;
      
    // 计算交点 X 左边 ： (p2.y - p1.y)/(p2.x - p1.x) = (y - p1.y)/(x - p1.x)
    // 直线 K 值相等， 交点y = pos.y
    let x = (pos.y - p1.y) * (p2.x - p1.x) / (p2.y - p1.y) + p1.x
    // 只统计单边交点，即点的正向方向
    if(x > pos.x)
      cross ++;
  }
 
  return cross % 2 == 1;
}