最近开发也遇到了同样的问题，看了看源码，是因为gltf-loader.js中引用了Blob和URL两个Web API，但小程序是不支持的。官方提供的demo之所以可以加载那个机器人，是因为他的模型不包含纹理（Texture）数据。而只有在加载加载纹理的时候，才会调用这两个不支持的API。

不要使用Blob、URL的polyfill，因为createObjectURL这个api不能被polyfill。

其实加载Texture只是一段内存buffer数据。除了createObjectURL，还可以用base64。我简单改了代码，可以参考下这里的代码

URL和blob需要模拟；建议使用gltf模型，glb纹理都需要blob

// Blob文件
export default class $Blob {
  constructor(parts, options) {
    this.parts = parts;
    this.options = options;


    // 目前仅适配如下
    // var blob = new Blob([bufferView], { type: source.mimeType });
    // sourceURI = URL.createObjectURL(blob);


    // var base64 = ArrayBufferToBase64(bufferView);
    // var url = `data:${options.type};base64,${base64}`;
  }
}
// url文件
import Blob from './Blob';
import { encode as ArrayBufferToBase64 } from './base64-arraybuffer';


export default class $URL {
  createObjectURL(obj) {
    if (obj instanceof Blob) {
      // TODO: use wasm to improve decode performance
      // 经测试主要耗时在于字符串拼接，使用assemblyscript的字符串拼接比js拼接慢非常多


      // 组长找到更好的方式，使用wx.fileSystemManager写入临时文件来获取url，但是需要手动管理临时文件


      // const t = Date.now();
      const base64 = ArrayBufferToBase64(obj.parts[0]);
      const url = `data:${obj.options.type};base64,${base64}`;
      // console.log('createObjectURL', Date.now() - t);
      return url;
    }


    return '';
  }


  revokeObjectURL() {}
}
// base64-arraybuffer文件
/*
 * base64-arraybuffer
 * https://github.com/niklasvh/base64-arraybuffer
 *
 * Copyright (c) 2012 Niklas von Hertzen
 * Licensed under the MIT license.
 */


var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';


// Use a lookup table to find the index.
var lookup = new Uint8Array(256);
for (var i = 0; i < chars.length; i++) {
  lookup[chars.charCodeAt(i)] = i;
}


// 有点慢
// export function encode(arraybuffer) {
//   var bytes = new Uint8Array(arraybuffer),
//     i,
//     len = bytes.length,
//     base64 = '';


//   for (i = 0; i < len; i += 3) {
//     base64 += chars[bytes[i] >> 2];
//     base64 += chars[((bytes[i] & 3) << 4) | (bytes[i + 1] >> 4)];
//     base64 += chars[((bytes[i + 1] & 15) << 2) | (bytes[i + 2] >> 6)];
//     base64 += chars[bytes[i + 2] & 63];
//   }


//   if (len % 3 === 2) {
//     base64 = base64.substring(0, base64.length - 1) + '=';
//   } else if (len % 3 === 1) {
//     base64 = base64.substring(0, base64.length - 2) + '==';
//   }


//   return base64;
// }


// 快一点
export function encode(arrayBuffer) {
  var base64 = '';


  var bytes = new Uint8Array(arrayBuffer);
  var byteLength = bytes.byteLength;
  var byteRemainder = byteLength % 3;
  var mainLength = byteLength - byteRemainder;


  var a, b, c, d;
  var chunk;


  // Main loop deals with bytes in chunks of 3
  for (var i = 0; i < mainLength; i = i + 3) {
    // Combine the three bytes into a single integer
    chunk = (bytes[i] << 16) | (bytes[i + 1] << 8) | bytes[i + 2];


    // Use bitmasks to extract 6-bit segments from the triplet
    a = (chunk & 16515072) >> 18; // 16515072 = (2^6 - 1) << 18
    b = (chunk & 258048) >> 12; // 258048   = (2^6 - 1) << 12
    c = (chunk & 4032) >> 6; // 4032     = (2^6 - 1) << 6
    d = chunk & 63; // 63       = 2^6 - 1


    // Convert the raw binary segments to the appropriate ASCII encoding
    base64 += chars[a] + chars[b] + chars[c] + chars[d];
  }


  // Deal with the remaining bytes and padding
  if (byteRemainder == 1) {
    chunk = bytes[mainLength];


    a = (chunk & 252) >> 2; // 252 = (2^6 - 1) << 2


    // Set the 4 least significant bits to zero
    b = (chunk & 3) << 4; // 3   = 2^2 - 1


    base64 += chars[a] + chars[b] + '==';
  } else if (byteRemainder == 2) {
    chunk = (bytes[mainLength] << 8) | bytes[mainLength + 1];


    a = (chunk & 64512) >> 10; // 64512 = (2^6 - 1) << 10
    b = (chunk & 1008) >> 4; // 1008  = (2^6 - 1) << 4


    // Set the 2 least significant bits to zero
    c = (chunk & 15) << 2; // 15    = 2^4 - 1


    base64 += chars[a] + chars[b] + chars[c] + '=';
  }


  return base64;
}


export function decode(base64) {
  var bufferLength = base64.length * 0.75,
    len = base64.length,
    i,
    p = 0,
    encoded1,
    encoded2,
    encoded3,
    encoded4;


  if (base64[base64.length - 1] === '=') {
    bufferLength--;
    if (base64[base64.length - 2] === '=') {
      bufferLength--;
    }
  }


  var arraybuffer = new ArrayBuffer(bufferLength),
    bytes = new Uint8Array(arraybuffer);


  for (i = 0; i < len; i += 4) {
    encoded1 = lookup[base64.charCodeAt(i)];
    encoded2 = lookup[base64.charCodeAt(i + 1)];
    encoded3 = lookup[base64.charCodeAt(i + 2)];
    encoded4 = lookup[base64.charCodeAt(i + 3)];


    bytes[p++] = (encoded1 << 2) | (encoded2 >> 4);
    bytes[p++] = ((encoded2 & 15) << 4) | (encoded3 >> 2);
    bytes[p++] = ((encoded3 & 3) << 6) | (encoded4 & 63);
  }


  return arraybuffer;
}

兄弟们 我也遇到了 解决了

报错了是 “Blob is not defined”

解决方案：

glb模型建的不对 ，找UI同学重新生成了模型，某种规格的，就可以了，代码没有改动就能渲染glb模型了。

同问

问

同问

你是在小程序环境下的canvas开发小游戏吗？