How to find the angle of a collided piece..?

Dad3353

I can get, from the Node, its transform basis.y...

func _on_area_3d_area_shape_entered(_area_rid, area, area_shape_index, _local_shape_index):
	print("Touched")
	print("Self Degrees : ",self.global_transform.basis.y)
	var other_shape_owner = area.shape_find_owner(area_shape_index)
	var other_shape_node = area.shape_owner_get_owner(other_shape_owner)
	print("Node Degrees : ",other_shape_node.global_transform.basis.y)

...The result is always the same, whatever the angle of the two pieces; here's a screenshot...

The Red piece is 'Self', the Green piece 'Node'. More is needed to get the angles, but what..?

It's always at 10, whatever its orientation.

Rainfollower

Dad3353 ...The result is always the same, whatever the angle of the two pieces; here's a screenshot...

Here I noticed this. And here's from my experience: if you get always the same number regardless of rotation (or movement), then this number comes from the wrong system of coordinates. Totally looks like this.

Please check that you rotate the thing (change rotation angles) in that same system, where you get your transform from.
Transforming coordinates from global to local and between local systems is one of the places where it is very easy to make error.

DaveTheCoder

Print out more stuff.

For example, print the name property or the result of the get_path() method so that you know you're looking at the right nodes.

Or with the debugger, you can set a break point and view all of the nodes' properties at the same time.

Dad3353

DaveTheCoder

Ok. Tomorrow, as it's late here in France. To be continued... :-)

Rainfollower

Hey! Sorry to go a bit off the track, but maybe the standard Godot collision will be easier?..

PhysicsBody2D and PhysicsBody3D have this move_and_collide() method that returns an object of KinematicCollision2D or KinematicCollision3D type respectively. And that object contains information about the collision that object had: angle, shape, normal vector at the point of collision...

Here's for 3D (but there is the same for 2D just in case):
https://docs.godotengine.org/en/4.5/classes/class_physicsbody3d.html
https://docs.godotengine.org/en/4.5/classes/class_kinematiccollision3d.html

Dad3353

Rainfollower

Easier..? Maybe, but it's confused me even more..! I can't seem to be able to create a PhysicsBody3D at all, as it's greyed out in the list of Nodes to create. I suppose there's an explanation, but I couldn't find one in the official docs. Should I ignore this avenue of research, or have I missed something..?

DaveTheCoder

Dad3353 I can't seem to be able to create a PhysicsBody3D at all, as it's greyed out in the list of Nodes to create.

It's an abstract class. You can't create an instance of an abstract class because the class definition doesn't implement all of its members. You create an instance of a concrete (fully implemented) class that inherits from PhysicsBody3D: CharacterBody3D, PhysicalBone3D, RigidBody3D, StaticBody3D or a class that inherits from one of those.

Rainfollower

Dad3353

Dad3353 Easier..?

Well, you won't have to invent your own collision detection and processing, at least, it is already done in there.

Dad3353

DaveTheCoder

OK,, it's abstract; I understand that, now. However, this brings up another difficulty. An Area3D can have a Collision signal, but a StaticBody3D cannot. How can I collect this collision angle without a collision signal..? I have found no example of doing this (or I'm being particularly obtuse...). We're getting closer, I feel, but there is still a wide gap in my knowledge that I can't see how to jump.
If I use 'Area3D', the 'get_angle' is not recognised.
If I use 'StaticBody3D', there is no signal to set off my 'Print' statements. Here's the code I'm trying out...

func _on_area_3d_area_shape_entered(_area_rid, area, area_shape_index, _local_shape_index):
	print("Touched")
	print("Self Degrees : ",self.global_transform.basis.y)
	var other_shape_owner = area.shape_find_owner(area_shape_index)
	var other_shape_node = area.shape_owner_get_owner(other_shape_owner)
	var angle = other_shape_node.get_angle(other_shape_owner,Vector3(0, 1, 0))
	print("Node Degrees : ",other_shape_node.global_transform.basis.y)
	print("Angle Degrees : ",rad_to_deg(angle))

Dad3353

Dad3353 func on_area_3d_area_shape_entered(area_rid, area, area_shape_index, _local_shape_index):
print("Touched")
print("Self Degrees : ",self.global_transform.basis.y)
var other_shape_owner = area.shape_find_owner(area_shape_index)
var other_shape_node = area.shape_owner_get_owner(other_shape_owner)
var angle = other_shape_node.get_angle(other_shape_owner,Vector3(0, 1, 0))
print("Node Degrees : ",other_shape_node.global_transform.basis.y)
print("Angle Degrees : ",rad_to_deg(angle))

I'm really not understanding something as (seemingly...) simple in plain English.
From the collision I could capture, using an Area3D, there seems to be no way of reading an angle (the code above is rejected at 'get_angle', as it's not a PhysicalBody3D. Whether it's the Red or Green one makes no difference; they are both Area3D, so : no 'angle'. I know which is which, and whatever their relative angles on screen, their collision, as I'm reading it, doesn't give me angle information.
Now, if these objects have to be StaticBody3D, in order to have 'angle' information collectable, I don't know how to get collision information. It can't come from a collision signal, as there does not seem to be one for this type of object. If something else has to happen, I don't know what that 'something' is. I'm sure that, whatever that 'something' turns out to be, I would be able to recognise which of these pieces has to rotate (in the original screenshot above, it has to be the 'Red' one, as that's the piece I've offered up to the Green one to 'snap' to...). The issue, for me, is not so much knowing which piece is which, as having some way of establishing the angle the Red piece has to pivot through to match the Green one. There's still a lot of fog, and smoke obscuring my dim eyes.

DaveTheCoder

If you're calling the PhysicsBody3D method move_and_collide(), it returns a KinematicCollision3D, which has the get_angle() method.

https://docs.godotengine.org/en/4.6/classes/class_physicsbody3d.html#class-physicsbody3d-method-move-and-collide
https://docs.godotengine.org/en/4.6/classes/class_kinematiccollision3d.html#class-kinematiccollision3d-method-get-angle

Dad3353

DaveTheCoder

That's not how I'm moving the pieces, though (maybe I should..?). As seen in the script I posted above ^^, I have a raycast from the mouse position to detect the piece beneath it, and I move the piece to follow the mouse position. If there's a better way of following the mouse, using move_and_collide, maybe that would help..? We're edging closer...

DaveTheCoder

I was just answering your question. I don't know if move_and_collide() is better than the approach you're currently using. If you want to stick to that approach: https://godotforums.org/d/43919-how-to-find-the-angle-of-a-collided-piece/8

Dad3353

DaveTheCoder

Hmm... this circular reference is unlikely to advance my knowledge by much. I can set a break point alright, then squint mole-like at node properties seeking enlightenment. I'm obviously severely off-track somehow, so maybe I need to re-think a lot of things. Thanks; off for some introspection, then. To be continued... :-ı

DaveTheCoder

The point of the reply I linked is that you determined that two objects seem to have the same angle. But since you didn't print the names or node paths of the objects, you don't know if those two objects are the red and green railroad track pieces.

DaveTheCoder

If you're going to ignore my suggestions, I can't help further.

Dad3353

DaveTheCoder

I'm not sure that I've fully understood your suggestions, but... Thanks for trying.