openlayers6加载天地图混乱问题

按照之前的加载百度地图的方式切片排版会错误
修改resouce为下边任意一种：baidu_source 或者baidusource都可以正常加载百度地图
<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no" />
    <title>Test Map</title> 
    <style>
      html,
      body,
      #viewDiv {
        margin: 0;
        padding: 0;
        width: 100%;
        height: 100%;
      }
    </style>   <link href="./v6.3.1-dist/ol.css" rel="stylesheet" type="text/css" />
    <script src="./v6.3.1-dist/ol.js"></script>
    
  </head>
  <body class="claro">
    <div id="viewDiv"></div>
    <script type="text/javascript">
    var projection = ol.proj.get("EPSG:3857");
    var resolutions = [];
    for(var i=0; i<19; i++){
        resolutions[i] = Math.pow(2, 18-i);
    }
    var tilegrid  = new ol.tilegrid.TileGrid({
        origin: [0,0],
        resolutions: resolutions
    });

    var baidu_source = new ol.source.TileImage({
        projection: projection,
        tileGrid: tilegrid,
        tileUrlFunction: function(tileCoord, pixelRatio, proj){
            if(!tileCoord){
                return "";
            }
            var z = tileCoord[0];
            var x = tileCoord[1];
            var y = tileCoord[2];

            if(x<0){
                x = "M"+(-x);
            }
             
                y =  (-y);
            

            return "http://online3.map.bdimg.com/onlinelabel/?qt=tile&x="+x+"&y="+y+"&z="+z+"&styles=pl&udt=20151021&scaler=1&p=1";
        }
    });
    var  baidusource= new ol.source.XYZ({
       projection: 'baidu',
       maxZoom: 18,
       tileUrlFunction: function(tileCoord,ss,e) {
         var x = tileCoord[1];
         var y = tileCoord[2];
         var z = tileCoord[0];
         console.log(x,y,z,ss,e)
         y = -y 
         return "http://online3.map.bdimg.com/tile/?qt=vtile&x="+x+"&y="+y+"&z="+z+"&styles=pl&udt=udt=20170908&scaler=1&p=1" 
       },
       tileGrid: new ol.tilegrid.TileGrid({
         resolutions: resolutions,
         origin: [0, 0],
         //extent: ol.extent.applyTransform(extent, projzh.ll2bmerc),
         tileSize: [256, 256]
       })
     })

    var baidu_layer = new ol.layer.Tile({
        source: baidu_source
    });

    var map = new ol.Map({
        target: 'viewDiv',
        layers: [baidu_layer],
        view: new ol.View({
            center:  [12959773,4853101],
            zoom: 5
        })
    }); 
</script> 
  </body>
</html>