mvbg

VM_ACTOR_DEACTIVATE

VM_ACTOR_DEACTIVATE is a GBVM instruction used to make an actor (a character or object in your game world) inactive and invisible, effectively removing it from active gameplay and rendering.

Purpose: Deactivating actors is crucial for optimizing game performance and managing the presence of entities in your game world. VM_ACTOR_DEACTIVATE is essential for:

• Removing actors from play: Making an NPC disappear from a scene, or a collectible item vanish after being picked up.
• Disabling actor behavior: Once deactivated, an actor typically stops executing its associated scripts, stops moving, animating, and interacting with other game elements, saving CPU cycles.
• Dynamic scene management: Controlling which actors are present and active in a scene at any given time, which can be useful for managing memory or creating dynamic environments (e.g., enemies that only appear under certain conditions).

When an actor is deactivated, it typically becomes invisible on screen and its associated behaviors are paused or stopped. It remains in memory but is no longer actively processed by the game engine.

Syntax:

VM_ACTOR_DEACTIVATE ACTOR

• ACTOR: A variable that contains the actor number (ID) of the actor to be deactivated. This actor number is typically assigned when the actor is created or defined in your game project.

Usage Example: Removing a Collected Item

Imagine your player picks up a key. Once the key is collected, it should disappear from the screen and no longer be interactive. You can achieve this by deactivating the key actor.

; In your script, when the player interacts with a key:

; Assume KEY_ACTOR_ID is the actor ID for the key
KEY_ACTOR_ID:
  .R_INT8 5 ; Example Actor ID for the key

; Assume VAR_HAS_KEY is a flag that gets set when the key is collected
VAR_HAS_KEY:
  .R_INT8 0

; ... code for player interaction with the key ...

; Set flag that player has the key
VM_SET_CONST VAR_HAS_KEY, 1

; Deactivate the key actor so it disappears and is no longer interactive
VM_ACTOR_DEACTIVATE KEY_ACTOR_ID

VM_LOAD_TEXT TEXT_KEY_COLLECTED
VM_DISPLAY_TEXT
VM_IDLE 60

; ... continue script ...

TEXT_KEY_COLLECTED:
  .TEXT "You found a key!"
  .TEXT_END

In this example, VM_ACTOR_DEACTIVATE KEY_ACTOR_ID makes the key actor disappear from the game world and stops its processing. This is a clean way to remove temporary objects or characters from the active scene once their purpose is fulfilled.

Analogy to other programming languages: This is analogous to disabling or setting an object’s active or visible property to false in a game engine like Unity (gameObject.SetActive(false)) or Godot (node.hide()). It’s about controlling the lifecycle and presence of game entities within the active scene, often for performance or gameplay reasons.