docs: function createAttribsFromArrays(gl, arrays, opt_mapping) {
      var mapping = opt_mapping || createMapping(arrays);
      var attribs = {};
      Object.keys(mapping).forEach(function(attribName) {
        var bufferName = mapping[attribName];
        var array = makeTypedArray(arrays[bufferName], bufferName);
        attribs[attribName] = {
          buffer:        createBufferFromTypedArray(gl, array),
          numComponents: array.numComponents || guessNumComponentsFromName(bufferName),
          type:          getGLTypeForTypedArray(gl, array),
          normalize:     getNormalizationForTypedArray(array),
        };
      });
      return attribs;
    }