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MassComponent

MassComponent stores an entity's mass, which CollisionSystem uses to scale both the positional nudge and knockback speed on player–enemy contact. Heavier entities are harder to move — they receive a smaller nudge and a slower knockback impulse.

public struct MassComponent: Component {
    public var mass: Int  // Default: 10
}

The player defaults to mass 10. Enemy masses are set per EnemyType in EnemyEntityFactory:

EnemyMass
.ranger5
.mummy10
.charger15
.tower20

How Mass Is Used​

On a player–enemy collision, CollisionSystem reads both entities' MassComponent values and derives:

Positional nudge — each entity is displaced by its share of the MTV, weighted by the other entity's mass:

player nudge = MTV × (enemyMass / totalMass)
enemy nudge  = MTV × (playerMass / totalMass)

A heavier enemy pushes the player further away, and vice versa.

Knockback speed — each entity's knockback speed is inversely proportional to its own mass:

knockbackSpeed = baseKnockbackSpeed (1500) / mass

A lighter entity (e.g. .ranger, mass 5) receives a faster knockback impulse than a heavier one (e.g. .tower, mass 20).

Fallback​

If an entity has no MassComponent, CollisionSystem falls back to a default mass of 10 to avoid division by zero.