Collider2D.callbackLayers

Description

The Layers that this Collider2D will report collision or trigger callbacks for during a contact with another Collider2D.

When a contact occurs between two Collider2D, each Collider2D will get a collision or trigger callback. This options allows you to select which layer(s) will produce a callback.

The ability to limit which layers will result in a callback can reduce the complexity of the script inside the callback so that it can safely assume only specific layers will be reported. There is also a performance benefit in not performing callbacks that are not required.

These are all the physics callbacks which are affected by callback layers:

• OnCollisionEnter2D
• OnCollisionStay2D
• OnCollisionExit2D
• OnTriggerEnter2D
• OnTriggerStay2D
• OnTriggerExit2D

NOTES:

• This does not control whether the Collider2D will come into contact or not but simply if the resultant callback will happen.
• Even if all callback layers are selected, only contacts captured via Collider2D.contactCaptureLayers, will be reported.
• The other Collider2D involved in any contact callback disabled here will still receive callbacks defined by its own callbackLayers property.
• Normally both the Collider2D and the Rigidbody2D it is attached to receive a callback therefore this option controls both those component callbacks.
• When enabling callback layers where callbacks already exist, those contacts will not be reported as new contacts i.e. there will not be an OnCollisionEnter2D or OnTriggerEnter2D callback produced.

Additional resources: LayerMask.