三个js如何手动将三角形添加到BufferGeometry

I've been trying to find the fastest way to change a mesh's vertices with three.js. I found that if I change parts of mesh.geometry.attributes.position.array, then set mesh.geometry.attributes.position.needsUpdate=true, it works well and doesn't have to rebuild arrays or recreate opengl buffers. I found that needsUpdate=true changes the version number of the attribute and that makes it resend the attributes vertices array to the opengl buffer.I've been trying to find the fastest way to cha