Destructible

How to make an entity destructible

Making an entity destructible is done by adding the Damageable and Destructible components to it in YAML. The Destructible component is responsible for defining a list of thresholds that it has, each with a trigger (when it will activate) and a list of behaviors (what happens when it activates).

- type: entity
  id: Wall
  name: wall
  description: Keeps the air in and the greytide out.
  components:
  - type: Damageable
    resistances: metallicResistances
  - type: Destructible
    thresholds: # List of thresholds that this entity can reach
    # First and only threshold, defining a trigger and a list of behaviors
    - trigger: # This threshold's trigger
        !type:DamageTrigger # Triggers at a total amount of damage...
        damage: 300 # ... equal to or above 300
      behaviors: # This threshold's behaviors
      - !type:SpawnEntitiesBehavior # First behavior, spawns entities
        spawn:
          Girder: # Spawn girders...
            min: 1 # ... from a minimum of 1...
            max: 1 # ... up to a maximum of 1
      - !type:DoActsBehavior # Second behavior, activates a list of acts
        acts: ["Destruction"] # In this case the Destruction act

How to add a new destructible trigger

All triggers implement the IThresholdTrigger interface. New ones can be defined like so:

[DataDefinition]
public partial class DamageTrigger : IThresholdTrigger
{
    /// <summary>
    ///     The amount of damage at which this threshold will trigger.
    /// </summary>
    [DataField]
    public int Damage { get; set; }

    public bool Reached(IDamageableComponent damageable, DestructibleSystem system)
    {
        return damageable.TotalDamage >= Damage;
    }
}

How to add a new destructible behavior

All behaviors implement the IThresholdBehavior interface. New ones can be defined like so:

[DataDefinition]
public partial class PlaySoundBehavior : IThresholdBehavior
{
    /// <summary>
    ///     Sound played upon destruction.
    /// </summary>
    [DataField]
    public string Sound { get; set; } = string.Empty;

    public void Execute(IEntity owner, DestructibleSystem system)
    {
        if (string.IsNullOrEmpty(Sound))
        {
            return;
        }

        var pos = owner.Transform.Coordinates;
        SoundSystem.Play(Filter.Pvs(pos), Sound, pos, AudioHelpers.WithVariation(0.125f));
    }
}