wave5-collision-filter-layer-masking

Filter Unity DOTS physics collision layers by applying symmetric bitmasks using CollisionFilter.BelongsTo and CollisionFilter.CollidesWith. This ensures raycasts and spatial queries only hit intended layers, preventing false positives and incorrect body interactions.

Spatial queries return false positives in high-density Unity Physics simulations when default filters are used. Tightening collision filters with specific BelongsTo and CollidesWith bitmasks reduces broadphase candidate pairs and eliminates inaccurate query results.

Optimize Unity DOTS physics performance by tightening CollisionFilter bitmasks instead of using defaults. Precise BelongsTo and CollidesWith settings reduce broadphase candidate pairs and narrowphase evaluations in dense scenes, saving CPU time.

Set up CollisionFilter bitmasks by assigning BelongsTo on colliders to define their layer and CollidesWith on queries to define target layers. Use shared 1u << layerIndex constants to align both sides of the filtering rule.

GroupIndex affects collision filter masking in Unity DOTS and must be handled intentionally. When configuring BelongsTo and CollidesWith bitmasks, GroupIndex overrides standard layer logic to maintain correct gameplay semantics during spatial queries.

Use collision layer masking to prevent friendly fire by setting projectile raycasts to CollidesWith enemy and ground layers only. Assigning BelongsTo layers correctly ensures projectiles bypass allies, reducing physics noise and wasted query evaluations.