="text/javascript"></script>
  <script src="js/gltf-loader.js" type="text/javascript"></script>
  <script src="js/earcut.min.js" type="text/javascript"></script>
  <script src="js/dat.gui.min.js" type="text/javascript"></script>
  <body>
    <canvas id="canvas" width=800 height=800 class="container" style="border : 1px solid;float: left;"></canvas>
    <div style = "width:400px;height: 800px;position: absolute;left: 800px;">
        <input type="button" class="btn" value="测距" id = "distance"/>
        <