Absolute Object3D.lookAt?

while working on #1535, and revising #1188, I realized the need to understand converting between global <–> local coordinates.

in THREE.Object3D.lookAt, a TODO is commented

// TODO: Add hierarchy  support

do we want the behavior to be object.lookAt(absolutePosition)? Would anyone like to check if these calculations are correct?

// Insert right after lookAt: function ( vector ) {
// Make sure scene matrix are updated
// scene.updateMatrixWorld();
var targetMatrix = new THREE.Matrix4().setPosition(vector);
var objMatrixWorldInverse = new THREE.Matrix4().getInverse(this.parent.matrixWorld);

targetMatrix.multiply(targetMatrix, objMatrixWorldInverse);
vector.getPositionFromMatrix( targetMatrix );

[netsider]

idk… but the behavior of this method is weird.

[mrdoob]

Not sure…

If it had to sit in the application layer it would look like this:

var matrix = new THREE.Matrix4().getInverse( object1.matrixWorld );
var vector = matrix.multiplyVector3( object2.matrixWorld.getPosition() );
object1.lookAt( vector );

And with the new method:

object1.lookAt( object1.worldToLocal( object2.matrixWorld.getPosition() ) );