Module bevy_picking_core::backend

This module provides a simple interface for implementing a picking backend.

Because bevy_picking_core is very loosely coupled with its backends, you can mix and match as many backends as you want. For example, You could use the rapier backend to raycast against physics objects, a picking shader backend to pick non-physics meshes, and a custom backend for your UI. The PointerHitss produced by these various backends will be combined, sorted, and used as a homogeneous input for the picking systems that consume these events.

Implementation

• A picking backend only has one job: reading PointerLocation components, checking Pickable entities for hits, and producing PointerHits events. In plain English, a backend is provided the location of pointers, and is asked to provide a list of entities under those pointers.

• The PointerHits events produced by a backend do not need to be sorted or filtered, all that is needed is an unordered list of entities and their HitData.

• Backends do not need to consider the Pickable component, though they may use it for optimization purposes. For example, a backend that traverses a spatial hierarchy may want to early exit if it intersects an entity that blocks lower entities from being picked.

Modules

• prelude
  Common imports for implementing a picking backend.

Structs

• HitData
  Holds data from a successful pointer hit test.
• PointerHits
  An event produced by a picking backend after it has run its hit tests, describing the entities under a pointer.