Why is my double jump code not working correctly?

Question

In max_jumps I set the maximum number of jumps. But in the end he jumps 3 times, that is, he will always jump 1 time more than specified in max_jumps. Wtf?

Print output if I pressed UP button 3 times:

1
1
2

Player script:

extends KinematicBody2D

var motion = Vector2()
var player = {
    "speed": 20000,
    "gravity": 2500,
    "jump": -40000,
    "count_jumps": 0,
    "max_jumps": 2
}

func _physics_process(delta):
    # movement
    if Input.is_action_pressed("ui_left"):
        motion.x = -player.speed * delta
    elif Input.is_action_pressed("ui_right"):
        motion.x = player.speed * delta
    else:
        motion.x = 0

    # jump
    if Input.is_action_just_pressed("ui_up") && player.count_jumps < player.max_jumps:
        player.count_jumps += 1
        motion.y = player.jump * delta
        print(player.count_jumps)

    if is_on_floor():
        player.count_jumps = 0

    #gravity    
    motion.y += player.gravity * delta
    motion = move_and_slide(motion, Vector2.UP)

Answer 1

The fact that you get 2 1's in your output is a clue to the problem. Looking at your code, I assume this is what's happening...

• count_jumps starts as 0
• You jump...
• count_jumps increments to 1 (and prints the first 1 in the output)
• Next, you check is_on_floor(). But, that's only updated after calling move_and_slide, which you haven't done yet). So, I'd guess that returns true and you reset count_jumps to 0.
• Now, you call move_and_slide(), which updates is_on_floor() to return false
• Now, you jump again
• That increments count_jumps to 1 (again, and prints 1 again)
• The next is_on_floor() check (correctly) returns false, so you don't reset count_jumps. From this point forward, things work as you expect, but you've already gotten an extra, first jump due to the incorrect call order of move_and_slide() and is_on_floor().

Bottom line, you need to call move_and_slide() before the result of is_on_floor() is accurate. So, you'll need to refactor / reorder some of your code.

Comments

thank! while I was waiting for an answer, I already guessed this myself, moved the section with the code is_on_floor() higher than the jump check code and everything worked =)