Acceleration / Deacceleration in PathFollow

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:bust_in_silhouette: Asked By Alex Pires

Hi guys!

I trying to make a 3D train over rails, so it will begin slow, then gain velocity when the user press right key, when the player release the key, the train slow down then stop.

I don’t know how to make use of lerp in this case (using PathFollow and offset value).

Any suggestions? Maybe an alternative way of doing this.

Thank you in advance!

Path
—|_PathFollow
-------------|_KinematicBody

obs.: I’m increasing the offset value of PathFollow, but I’d preffer use move_and_slide and avoid making use of offset (loss of gravity and etc), but if this works with offset it’s okay. When I use move_and_slide acceleration/deacceleration and gravity is okay, but how does the train follow the path (x+z axis) and turn along the rail?

P.S.: Sorry about my english

—UPDATE—

I got this to work, but I’m not happy with the results.

Issues:

  • The train(hero) isn’t starting in the first point of the path.
  • The train is not standing still.It’s moving backwards when stopped.
  • The camera is also a crap when child of train or Path Follow. Seems to be unstable, trembling.
  • Plus, the path created in Godot doesn’t seem to works well, had to create a new one in Blender then import.

Download my project [Godot 3.1]: https://yadi.sk/d/egenpGXWtAEA8Q (Yandex disk cloud)

Here is the code:

extends Spatial

var velocity = 0 
var tempo =0
var acceleration = 0

onready var hero = $Path/PathFollow/hero
onready var pathf = $Path/PathFollow
   
func _process(delta):
	
	tempo+=1*delta
	velocity += (acceleration/tempo)*delta
	pathf.offset += velocity*delta
	
    # Stop it!
	if velocity <= 0:
		velocity=0
		acceleration=0
    # Set max velocity
	elif velocity >=8:
		velocity=8
	
	if Input.is_action_pressed("ui_right"):

		acceleration+=0.5
	else: #release
		acceleration-=16