translate object up/down/left/right in camera space

[Numa]

Hi there, 

I display labels (sprites) when I click on on objects in my scene.

I'd like those labels to always be displayed top-left of the object I click on, regardless of the camera position. (I use an arcRotateCamera).

How can I figure out what up/left is in camera space?

 

[Numa]

Ok I scratched my head and a little and came up with this:

ArcRotateCamera.prototype.CameraUpVector = function () {

    var xu = Math.cos(this.beta) * -Math.cos(this.alpha);
    var yu = Math.sin(this.beta);
    var zu = -Math.cos(this.beta) * Math.sin(this.alpha);
    return new BABYLON.Vector3(xu, yu, zu).normalize();
}

ArcRotateCamera.prototype.CameraLeftVector = function () {

    var xl = Math.sin(this.alpha);
    var yl = 0;
    var zl = -Math.cos(this.alpha);
    return new BABYLON.Vector3(xl, yl, zl).normalize();
}

It seems correct  ArcRotateCamera has a .upVector but it's just set to the world's up hehe.

[satguru]

see if this works

var cameraMatrix = camera.getWorldMatrix();
var pos = camera.position;
var cameraX = BABYLON.Vector3.TransformCoordinates(BABYLON.Axis.X, cameraMatrix).subtract(pos);
var cameraY = BABYLON.Vector3.TransformCoordinates(BABYLON.Axis.Y, cameraMatrix).subtract(pos);
var cameraZ = BABYLON.Vector3.TransformCoordinates(BABYLON.Axis.Z, cameraMatrix).subtract(pos);

 

[Numa]

Yep that works too