Raycast to an area, not a point

Questions & Answers
1

I am trying to get a AI character detection working. I have a character and a CCTV camera that should detect him.

The camera has a sphere collider on itself and when this triggers, I do a raycast from the camera towards the hit object and see if it is the player. But there is a problem with this approach. The transform.position of the character is at its feet. So if the whole player is visible, except his feet, he will not get detected.

Is there a way to cast from the camera towards an area, not just a single point? That would ensure that whenever any part of the player is visible, it will get detected.

Thanks

2

Doesn’t sound right. Raycasts work against colliders.

Anyway, you can CapsuleCast, SphereCast or even OverlapSphere from the point of your first Raycast hit on the floor.

3

You could check if the game objects bounding box is within the viewspace or screenspace of that camera.

[Here’s a class I made][1] for another answer that you may use and modify to suit your needs. For example you may want to use a different camera than Camera.main and you may want to use viewspace instead of screenspace. In particular, you could make a new method based on BoundsToScreenRect that uses [WorldToViewportPoint][2] and immediately tests overlap with a new Rect(0, 0, 1, 1)

I [updated the class][3] (

[4]) to include `OverlapsViewport` methods.

*It's possible there's another way to see if the object is within a frustum of a camera. This is just one way to do it. In such case, please do add a comment on how to approach the problem with your idea.*


  [1]: https://github.com/devmelon/Answers/blob/c84139bc1c013c40fd6dcd511bb5af346910395f/Assets/Answers/newGuyInThat/SelectionUtil.cs
  [2]: http://docs.unity3d.com/ScriptReference/Camera.WorldToViewportPoint.html
  [3]: https://github.com/devmelon/Answers/blob/aa99ec49cdef536611d2a213349bd78cc9416e4f/Assets/Answers/newGuyInThat/SelectionUtil.cs
  [4]: https://github.com/devmelon/Answers/commit/aa99ec49cdef536611d2a213349bd78cc9416e4f#diff-6230b0471c79c206f9cd05648aad86aa
4

There is sphere cast… it may be what you are looking for…or you could get your distance between the cam and player …instantiate a trigger collision object there and see if you characters in it…