Need help with some vector math

Armory Engine General
1

I have this peace of code:

var physics = PhysicsWorld.active;

                // Start from cone location
                var from = object.transform.world.getLoc();

                // Cast ray in the direction cone points to
                var to = object.transform.look();

                // 1000 units long
                to.mult(1000);

                // End position
                to.add(from);
                
                var rb = physics.rayCast(from, to);
                if (rb != null) {
                    trace(physics.hitPointWorld);
                }

Now I got from and got hitpoint. I want to transform and scale cylinder so that it goes from from to hitpoint. Any suggestions?

Thank you

2

If your cylinder’s origin is at one extreme end of the cylinder, and your cylinder’s size is 1 unit long when it’s scale is 1, then you could try something like this ( I haven’t tested it, but it should give you the idea ):

var dist = Vec4.distance(from, physics.hitPointWorld); // Get the distance to the hit point
object.transform.scale = new Vec4(1, 1, dist); // Set the scale of the cylinder to match the distance to the hit point
object.buildMatrix(); // Update transform matrix with modified scale
object.local.applyQuat(new Quat().fromTo(from, physics.hitPointWorld)); // Rotate object to point at hit point
3

Did not know of this. Sadly id does nothing for me. :confused:

4

Ah, I forgot that the inputs to Quat.fromTo needs to be normalized.

Try this code from the LookAt node to do the rotation:

v1 = new Vec4();
v2 = new Vec4();
v1.set(0, 0, 1);
v2.setFrom(physics.hitPointWorld).sub(from).normalize();

var q = new Quat().fromTo(v1, v2);
object.local.applyQuat(q);

Another thing to note is the cylinder can’t be the child of another object or the rotation won’t work because the rotation is set in the local space.

5

Ok tnx. Scale, rot is in place, now I have to figure out location :wink:

1 Like
6

laser.transform.local.applyQuat(q);

this still did nothing, but

laser.transform.rot = q;

7

Did that work to rotate it?

8

Kind of, its hard to tell without right location