UnityFrustum

This little library implements frustum in a form of a mesh. It consists of a mesh generator, and components that use it.

Why this

Many selection solutions on the market use techniques like bounds checking or unity event system and PhysicsRaycaster. Both have limitations, it one case you would have to iterate over all objects in view, and then check against bounds, which can be imprecise and require screen space convertion. Other approach is tied to unity event system and it's workflow, requiring you to use additional logic for reception of events. This solution simply uses collider which is the most basic generic way without any additional logic.

Example usage:

• Create visible unit field of view
• Create actual field of view collider using FrustumCollider
• Use frustum collider + FrustumCameraSelector to select objects in the world by dragging on the screen the selection box (the original requirement of this lib)
• Other uses.

Usage

The frustum is defined by several parameters:

• Vertical FOV
• Horizontal FOV
• Near plane distance
• Far plane distance

Additionally you shrink the current frustum in its area using

• Extent min (from lower left corner, a 0-1 float value)
• Extent max

Using selection system

Selection system consists of a FrustumCollider and FrustumCameraSelector working in tandem. Instructions:

1. Attach FrustumCameraSelector to camera
2. It will auto setup the parameters in Reset()
3. Add FrustumMeshCollider to that camera so it can receive physics events.
4. Drag FrustumCameraSelector into TakeParametersFrom field of FrustumMeshCollider, this will make it sample the mesh generator settings from it.
5. Make both UpdateInRealtime.
6. Any object you wish to be able to select must have a rigidbody (kinematic will do)

Now select camera, play and watch the selection mesh when you drag on the screen. Couple of things to note:

• Collider must be a convex trigger
• Generator should not be set to split vertex, this improves performance
• Both selector and meshcollider work in fixed update due to it being tied to physics, meaning the selection itself is running at the physics framerate, it may be an issue in the future.

If you get errors while clicking, with collider generation , from PhysX its due to the excessive thinning of the collider, when its converted to convex. To solve it you have to use these: * Minimal Extents Dimensions value, make it higher * Move camera near plane further * Move camera far plane closer

All in all its due to near plane being super thin, ill fix it in future releases.