State machine: Changing state by checking movement

Gowydot

Hello, I'm testing a state machine on Dodge the creep project. I can not properly change state by checking if the player is or is not moving by using velocity.x/z . Once it got to move state it will not go to Idle state even if I don't have any movement. This is the Print test after releasing input button for jump ("jump" > "idle" > "move")

		states.idle
			if !parent.is_on_floor():
				return states.jump
			elif parent.velocity.x !=0 and parent.velocity.z !=0:
				return states.move
		states.move:
			if !parent.is_on_floor():
				return states.jump
			elif parent.velocity.x ==0 and parent.velocity.z ==0:
				return states.idle
		states.jump:
			if parent.is_on_floor():
				return states.idle

So there is something wrong with checking of movement by velocity.x/z. Any suggestion?

ps. code for movements is

	if Input.is_action_pressed("move_right"):
		direction.x += 1
	...
	
	if direction != Vector3.ZERO:
		direction = direction.normalized()
	velocity.x = direction.x * speed
	velocity.z = direction.z * speed
	velocity = move_and_slide(velocity, Vector3.UP)

cybereality

So checking for zero almost never works due to floating point inaccuracy. Though a print statement will show 0, in the computer it might actually be 0.00000000014 or something like that which is not equal to 0. So you want to check like this:

const epsilon = 0.001

if abs(parent.velocity.x) < epsilon:
    # it's close enough to zero

Gowydot

		states.idle:
			if !parent.is_on_floor():
				return states.jump
			elif parent.velocity.x != 0 and parent.velocity.z != 0:
				return states.move
		states.move:
			if !parent.is_on_floor():
				return states.jump
			elif abs(parent.velocity.x) < epsilon and abs(parent.velocity.z) < epsilon:
				return states.idle

but now it's going Move<=>Idle constantly. I guess !=0 is also not working?

cybereality

You have to update the first if as well:

elif abs(parent.velocity.x) > epsilon and abs(parent.velocity.z) > epsilon:
    return states.move

Gowydot

Thank you so much!

		states.idle:
			if !parent.is_on_floor():
				return states.jump
			elif abs(parent.velocity.x) > epsilon :
				return states.move
			elif abs(parent.velocity.z) > epsilon :
				return states.move

cybereality

Yeah, no problem.

cybereality

You can also simplify the else if to this, it is slightly more optimized:

elif abs(parent.velocity.x) > epsilon or abs(parent.velocity.z) > epsilon:
    return states.move