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Flip Flop

Type: Branch (True / False)
Category: FLOW

Alternates between the True and False outputs on each call. The first call executes True, the second False, the third True, and so on. Useful for toggle mechanics.

Properties

None — the node only maintains a state flag.

Sockets

Socket Direction Type
In Input Exec
True Output Exec (odd calls: 1st, 3rd, 5th…)
False Output Exec (even calls: 2nd, 4th, 6th…)

Behavior

if not hasattr(self, '_ff_<name>'):
    self._ff_<name> = False
self._ff_<name> = not self._ff_<name>
if self._ff_<name>:
    # → True path
else:
    # → False path

The flag starts at False and is negated before the check, so:

Call State before Negated Path
1st False True True
2nd True False False
3rd False True True
… … … …

Typical usage

Door open/close

[OnCollision: button] → [Flip Flop]
                            ├── True  ──► [BTCustomTask: open_door()]
                            └── False ──► [BTCustomTask: close_door()]

Alternating attack animations (left/right)

[BT Condition: attack_requested]
    └── True ──► [Flip Flop]
                    ├── True  ──► [BT Play Animation: "AttackLeft"]
                    └── False ──► [BT Play Animation: "AttackRight"]

Blinking light (with Delay)

[OnUpdate] → [Delay: 0.5s, Repeat=True]
                 └── True ──► [Flip Flop]
                                 ├── True  ──► [BTCustomTask: light.energy = 10]
                                 └── False ──► [BTCustomTask: light.energy = 0]

Stealth mode toggle

[OnKeyboard: Tab] → [Flip Flop]
                        ├── True  ──► [BT Set Blackboard: stealth = True]
                        └── False ──► [BT Set Blackboard: stealth = False]

Notes

  • The state persists while the object exists. If the object is destroyed and recreated, Flip Flop starts from True again.
  • The node name determines the internal variable — give unique names if there are multiple Flip Flops in the same component.
  • Unlike Do Once, Flip Flop never ends — it always alternates indefinitely.
  • To reset to initial state: self._ff_NodeName = False.