enableAttributeArray_(attribName, size, type, stride, offset) {
    const location = this.getAttributeLocation(attribName);
    // the attribute has not been found in the shaders or is not used; do not enable it
    if (location < 0) {
      return;
    }
    this.gl_.enableVertexAttribArray(location);
    this.gl_.vertexAttribPointer(location, size, type, false, stride, offset);
  }
Will set the currently bound buffer to an attribute of the shader program. Used by `#enableAttributes`
internally.
@param {string} attribName Attribute name
@param {number} size Number of components per attributes
@param {number} type UNSIGNED_INT, UNSIGNED_BYTE, UNSIGNED_SHORT or FLOAT
@param {number} stride Stride in bytes (0 means attribs are packed)
@param {number} offset Offset in bytes
@private