How to find out if an object points down

CaribaLedon

Hey there! I would like to find out if an object in my scene points down. In my case this object a gun, that needs to be pointed at the floor to reload (it's a VR game).

I tried the following piece of code:

var angle = get_global_transform().basis.get_euler().angle_to(Vector3.DOWN)
if(angle < 20):
    reload()

My idea was t get the object's global orientation vector and compare it to the world's global DOWN vector. If the angle between both vectors iy smaller than 20 degrees, the gun must be pointing at the floor.

But actually this code does not what I thought it would do. It just returns a constant value, now matter how I rotate my object. Also I might have mixed up degrees and radians, bt that is a different problem ;-)

Can anyone give me ahint on how to get the global orientation vector of a node?

TwistedTwigleg

You probably do not want to use the Euler angles, as its a Vector3 that represents the rotation but is not necessarily the direction the node is in. I’m not sure what direction (0, 0, 0) rotation is in Euler angles, nor if it would be consistent.

I’d check to see which of the three axes is “forward” for your weapon. Once you figure that out, you can then get its global-space direction from the basis. If your weapon faces the -Z axes, then -$weapon.global_transform.basis.z.normalized() should give you its current direction. Then I think you should just be able to use a dot product to figure out the angle difference between the weapon direction and Vector3.DOWN.

Something like this should work, I think (untested):

# assuming -Z is “forward” for your weapon
var direction = global_transform.basis.z.normalized()
var angle = Vector3.DOWN.dot(direction)
# In Godot, most every function uses radians (with a few exceptions)
var angle_needed = deg2rad(20)
if (angle <= angle_needed):
	reload()