用aframe改变glb 3D模型的不透明度

<script src="https://aframe.io/releases/1.2.0/aframe.min.js"></script>
<script src="https://cdn.rawgit.com/donmccurdy/aframe-extras/v6.1.0/dist/aframe-extras.min.js"></script>

<a-scene>
  <a-assets>
    <a-asset-item id="model" src="path/to/model.glb"></a-asset-item>
  </a-assets>
  <a-entity gltf-model="#model"></a-entity>
</a-scene>

<a-entity gltf-model-opacity></a-entity>

AFRAME.registerComponent('gltf-model-opacity', {
  init: function () {
    var el = this.el;
    el.addEventListener('model-loaded', function () {
      var model = el.getObject3D('mesh');
      if (model) {
        model.traverse(function (node) {
          if (node.isMesh) {
            node.material.transparent = true; // 设置材质为透明
            node.material.opacity = 0.5; // 设置透明度（0-1之间的值）
          }
        });
      }
    });
  }
});