docs: function drawBufferInfo(gl, bufferInfo, primitiveType, count, offset) {
      var indices = bufferInfo.indices;
      primitiveType = primitiveType === undefined ? gl.TRIANGLES : primitiveType;
      var numElements = count === undefined ? bufferInfo.numElements : count;
      offset = offset === undefined ? offset : 0;
      if (indices) {
        gl.drawElements(primitiveType, numElements, gl.UNSIGNED_SHORT, offset);
      } else {
        gl.drawArrays(primitiveType, offset, numElements);
      }
    }