Game development in Godot often involves intricate character animations, particularly for actions like attacking. Utilizing the AnimationPlayer and AnimationTree nodes is a common approach to manage these animations and transitions. However, developers occasionally encounter unexpected behavior, such as an animation method being called multiple times when it should execute only once. This article explores a specific case reported by a user within the Godot community, where a method triggered at the end of an attack animation played back multiple times, despite the animation state changing.
The user described a setup involving a KinematicBody2D character with a simple state machine managed within the _physics_process() function. Character animations for different states (e.g., AttackUp, RunDown, IdleLeft) were handled by an AnimationPlayer, driven by an AnimationTree. When the player pressed the spacebar, the character transitioned to an ATTACK state.
Inside the attack_state() method, the character’s velocity was set to Vector2.ZERO, and the AnimationTree was used to travel() to the appropriate attack animation track (e.g., “Attack”).
func _physics_process(delta):
match(state):
MOVE:
move_state(delta)
ROLL:
pass
ATTACK:
attack_state()
func attack_state():
print("Inside attack_state()")
velocity = Vector2.ZERO
animation_state.travel("Attack")
func attack_animation_finished():
print("Inside attack_animation_finished()")
state = MOVEA crucial part of this setup was using a call_method track within each attack animation in the AnimationPlayer. This track was configured to call a method named attack_animation_finished() precisely when the animation concluded. The purpose of attack_animation_finished() was to change the player’s state back to MOVE, allowing normal movement and subsequent attacks.
Godot AnimationPlayer dock showing various character attack animations configured.
The expected behavior was that pressing space would call attack_state(), which in turn would trigger the animation via the AnimationTree. Once the animation finished, attack_animation_finished() would be called once, resetting the state.
However, upon running the game and triggering an attack, the user observed an anomaly in the console output. While the “Inside attack_state()” message appeared multiple times (which was somewhat understood to be related to _physics_process frequency while the state was ATTACK), the “Inside attack_animation_finished()” message was printed twice for each single attack action.
Godot console output showing ‘Inside attack_state()’ printed multiple times and ‘Inside attack_animation_finished()’ printed twice.
This duplicate method call was perplexing because the attack_animation_finished() method explicitly changes the state back to MOVE. If it were called once and successfully changed the state, the game should exit the ATTACK state, preventing a second call to attack_state() and subsequently, theoretically, preventing the AnimationPlayer from attempting to call the method again. Yet, the method was clearly executing twice. The user questioned why the AnimationPlayer or AnimationTree would trigger the method call twice, especially given the state change logic.
Initial community responses speculated that the repeated calls to “Inside attack_state()” were indeed due to the method being inside _physics_process, which runs at a fixed rate independent of animation length. However, this didn’t fully explain the duplicate call to attack_animation_finished().
Further debugging revealed that the second unexpected call to attack_animation_finished() occurred immediately after the _process() callback in a global singleton script. This observation hinted that the issue might be related to the interaction between different process loops (_physics_process, _process) and how the AnimationTree manages playback and signal/method triggering across frames.
Another theory suggested by the community was related to diagonal attacks. If the setup involved blending or attempting to play multiple attack animations simultaneously (e.g., for combining right and up directions), this could potentially lead to the finish method being triggered by more than one animation track. However, the user’s setup seemed to imply traveling to a single appropriate attack animation track, making this less likely the primary cause for a straightforward state machine setup.
Other developers following similar tutorials (specifically mentioning HeartBeast’s) reported experiencing similar issues, with methods sometimes being called 3-4 times, leading to unexpected behaviors like timers triggering prematurely. This reinforced the idea that this wasn’t an isolated incident but potentially a common pitfall or nuance when using AnimationTree‘s call_method track for animation completion detection.
A suggested workaround that proved helpful for some facing this issue was adjusting the timing of the call_method track. Instead of placing the keyframe exactly at the very end of the animation track, setting it slightly earlier (e.g., 0.1 or 0.2 seconds before the absolute end) seemed to mitigate the multiple call issue for some users. This suggests the problem might be related to how AnimationTree evaluates the end of a track and potentially re-evaluates it across frames if the playback position hovers exactly at the endpoint.
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In summary, while the exact root cause for the duplicate attack_animation_finished() calls when using AnimationTree‘s call_method track remains somewhat debated within the community discussion, the observations point towards potential interactions between game loops (_physics_process, _process), AnimationTree evaluation logic, and the precise timing of method calls at the very end of animation tracks. For developers encountering this specific problem, the suggested workaround of placing the call_method keyframe slightly before the animation’s absolute end offers a practical solution, although understanding the underlying mechanism requires deeper investigation into Godot’s animation system processing. This case highlights the value of community forums in identifying and discussing common development challenges and potential workarounds.
