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Collision Detection System

Source: client/engine/systems/SystemsFunctions/CollisionDetectionSystem.cpp

Purpose: Detect collisions between hitboxes and resolve penetrations (separation) for solid entities.

Components used:

  • Transform
  • HitBox
  • Solid
  • GameWorld (context)

Behavior​

  • Compute origin offsets via GetOffsetFromTransform.
  • Perform AABB tests to detect intersection between two hitboxes (IsCollidingFromOffset).
  • On collision, compute penetration in X and Y and separate along the smallest penetration axis.
  • Use isSolid and isLocked flags to decide which entities can be moved to resolve the collision.

Main signature​

void CollisionDetectionSystem(Eng::registry &reg,
    Rtype::Client::GameWorld &game_world,
    Eng::sparse_array<Com::Transform> &transforms,
    Eng::sparse_array<Com::HitBox> const &hitBoxes,
    Eng::sparse_array<Com::Solid> const &solids);

Notes​

  • Collision resolution accounts for scale (trans.scale) and computed offsets.
  • If both entities are isLocked, no resolution occurs.
  • If both are solid and movable, separation can be shared (implementation-specific).