proposal: BufferAttribute.copyVector( )

I was doing some computation on a buffer attribute where I needed to fetch each normal to create a new attribute, so I was looking for a way to copy the values of the attr to a vector, but I see we only have single fetches getX, getY, getZ.

What about adding a copyVector method to BufferAttribute that would do the work?

const myVector = new Vector3()
for (let i = 0; etc etc) {
	bufferAttribute // itemSize 3
		.copyVector(index, myVector)
}

This could be implemented as

copyVector( index, vector ) {
   const x = this.getX( index )
   const y = this.getY( index ) 

   // either check the vector or check the buffer's itemSize
   if ( vector.isVector3 ) {
     vector.z = this.getZ( index )
  }

  if ( vector.isVector4 ) {
    vector.w = this.getW( index );
  }
}

Of course this is trivially done in userland, but it’s such a small snippet that it could be nice to have. I did a quick search and we also use this pattern in some examples and lib code: https://github.com/mrdoob/three.js/search?q=.getX (not all of these results apply )

[donmccurdy]

@Mugen87 perhaps a sentence like https://github.com/mrdoob/three.js/pull/23772 would not be too intrusive?

[Mugen87]

Why are you not using fromBufferAttribute()?

myVector.fromBufferAttribute( bufferAttribute, index );

That is the intended way of extracting attribute data into vectors.