Looking to improve throwing objects in VR?

Dismantled

I am looking to improve my throwing mechanic in VR. I want to be able to have more control over the feel and smoothness of the throw. Currently using the windows mixed reality platform with open VR.

I have a simple scene.

I got the hand to throw the red triangular cube and it works. sometimes when testing I can't figure out why i get weird directional changes when throwing in some scenarios? how does the impulse/velocity choose a direction on button press? I used the vr starter tutorial on the docs and

Thank you Bastiaan Olij for making such an awesome tutorial!

I tried to find a way to average the velocity but I could never get it to work better then just this basic velocity function. '''func _process(delta): controller_velocity = (global_transform.origin - last_position) /delta last_position = global_transform.origin'''

Here is the code for the VR controller/3darea.

extends Area
var impulse_factor = .4


var object_in_area = Array()
var picked_up_object = null
var last_position = Vector3(0.0,0.0,0.0)
export var velocity = Vector3(0.0,0.0,0.0)
var controller_velocity = Vector3(0, 0, 0)
var prior_controller_position = Vector3(0, 0, 0)
var prior_controller_velocities = []

func _on_Area_body_entered(body):
	if body.has_method('pickup') and object_in_area.find(body) == -1:
		object_in_area.push_back(body)
		print(object_in_area)
		print(body)

func _on_Area_body_exited(body):
	if object_in_area.find(body) != -1:
		object_in_area.erase(body)
		print(object_in_area)

func _on_button_pressed(button):
	print(button)
	if button == 2:
		if picked_up_object:
			picked_up_object.let_go(controller_velocity * impulse_factor)
			picked_up_object = null
		elif !object_in_area.empty():
			picked_up_object = object_in_area[0]
			picked_up_object.pickup(self)

func _ready():
	get_parent().connect("button_pressed",self,"_on_button_pressed")
	

func _process(delta):
	
	
		#this section was me trying to find a way to average velocities?
#		controller_velocity = Vector3(0, 0, 0)
#
#		if prior_controller_velocities.size() > 0:
#	        for vel in prior_controller_velocities:
#	            controller_velocity += vel
#
#		controller_velocity += (global_transform.origin - prior_controller_position) / delta
#
#		prior_controller_velocities.append((global_transform.origin - prior_controller_position) / delta)
#		prior_controller_position = global_transform.origin
#
#		if prior_controller_velocities.size() > 15: 
#			prior_controller_velocities.remove(0)
##
#		controller_velocity = controller_velocity / prior_controller_velocities.size()
##
#
	controller_velocity = (global_transform.origin - last_position) /delta
	last_position = global_transform.origin

Here is what i got for the triangular cube.

extends RigidBody

onready var original_parent = get_parent()

var  original_collision_layer 

var  original_collision_mask 

var picked_up_by = null

onready var triangle_block_start_postion = self.global_transform.origin

func pickup(by):
	if picked_up_by == by:
		return # quit function if body is already picked up?
	
	if picked_up_by:
		let_go()
	
	picked_up_by = by
	
	mode = RigidBody.MODE_STATIC
	collision_layer = 0
	collision_mask = 0
	
	original_parent.remove_child(self)
	picked_up_by.add_child(self)
	
	transform = Transform()

func let_go(impulse = Vector3(0.0,0.0,0.0)):
	if picked_up_by:
		var t = global_transform
		picked_up_by.remove_child(self)
		original_parent.add_child(self)
		global_transform = t
		mode = RigidBody.MODE_RIGID
		collision_layer = original_collision_layer 
		collision_mask = original_collision_mask 
		apply_impulse(Vector3(0.0,0.0,0.0), impulse)
		yield(get_tree().create_timer(5.0),"timeout")
		global_transform.origin  = triangle_block_start_postion
		picked_up_by = null
		
func _ready():
	original_collision_layer = collision_layer
	original_collision_mask = collision_layer
	print(original_parent)
	print(picked_up_by)

hopefully this helps explain everything .. I will try to find out how to save my scene if more info is needed.

TwistedTwigleg

Yeah, I couldn't find a good way to get the velocity of the controllers either. I'm not sure how other game engines/frameworks do it, but I'm pretty sure there is something that makes it easier and/or more consistent.

I think OpenVR exposes the velocity of the controls, but I think when I asked about it there was a technical reason why it wasn't exposed to Godot.

If I think/find anything, I'll add it here, as I am also curious to know if there is a way to improve throwing/velocity-tracking in VR.

Dismantled

Thanks for the response TwistedTwigleg! I was thinking that the velocity i got from

 extends Area  
 var controller_velocity = Vector3(0, 0, 0)
 var prior_controller_position = Vector3(0, 0, 0)
 var prior_controller_velocities = []
 func _process(delta):
	controller_velocity = (global_transform.origin - last_position) /delta
        last_position = global_transform.origin

might be good enough if i am able to to smooth out how it applies the impulse and the direction from hand through some other code? Even in unity i had still gotten bad results using get_velocity function based on the direction i was facing and how i move the controller. i found Godot for it to be working much better lol.. but when I was using unity i was using visual code. In Godot i am actually coding lol.

I will look into open vr some more? I guess I need to get better with how transforms and impulses work? learn how to transfer the velocity smoothly in correct direction after button press? I might be completely off on this?

TwistedTwigleg

@Dismantled said: Thanks for the response TwistedTwigleg! I was thinking that the velocity i got from ... might be good enough if i am able to to smooth out how it applies the impulse and the direction from hand through some other code? Even in unity i had still gotten bad results using get_velocity function based on the direction i was facing and how i move the controller. i found Godot for it to be working much better lol.. but when I was using unity i was using visual code. In Godot i am actually coding lol.

Smoothing the velocity will definetly probably help, though I don't know what the best method for it would be. I think I experimented with velocity smoothing for the VR tutorial, but I think I had an issue with it, though right now I cannot remember what it was.

I have not done any VR in Unity, but I want to look at it some time for a prototype, so it is good to know that in Unity I will need to probably find a way to smooth controller velocity for things like throwing.

I guess I need to get better with how transforms and impulses work? learn how to transfer the velocity smoothly in correct direction after button press? I might be completely off on this?

That is probably a good idea, though I've only done a few VR development experiments so I do not know for sure. It likely will not hurt though, the knowledge of transforms and impulses might be helpful for other game projects even if it isn't helpful for VR.

Dismantled

I am thinking about making a standard fps throwing mechanic might help me understand things better. any tutorials on that? I guess it does get more complicated in VR because the throw can be lot more realistic and you can move the hand anywhere and release at any point.

TwistedTwigleg

The Godot documentation's FPS tutorial, part 5, shows how to make a pickup/throw system using Godot that might be helpful. Disclaimer: I authored the tutorial

I looked around and couldn't find another tutorial covering FPS throwing in Godot when searching "Godot FPS Throw" or "Godot FPS Throwing", though I only did a quick look. I am sure there are more tutorials and material out there, I just don't know where to look.

Dismantled

Thanks! I will check out the FPS tutorial in the docs.