微信小程序中使用three.js加载出来的半透明模型不正常

这张图是浏览器中查看的

下面这张是在小程序中加载出来的 同一个模型
loader.load('https://资源地址手动屏蔽1313689111.tcb.qcloud.la/%E9%80%8F%E6%98%8E.glb', function (gltf) {
model = gltf.scene;
createGUI(model, gltf.animations)
model.traverse(function (child) {
if (child.isMesh) {
child.material.transparent = true;
child.material.opacity = 0.5;
}
});
scene.add(model);
}, undefined, function (e) {
console.error(e);
});
renderer = new THREE.WebGLRenderer({ antialias: true },{ alpha: true });
renderer.setPixelRatio(wx.getSystemInfoSync().pixelRatio);
renderer.setSize(canvas.width, canvas.height);
renderer.gammaOutput = true;
renderer.gammaFactor = 2.2;
const { OrbitControls } = registerOrbit(THREE)
controls = new OrbitControls( camera, renderer.domElement );
camera.position.set( 5, 5, 10 );
controls.update();