Is there a way for Physics.CheckSphere to have OnEnter and OnExit?

Questions & Answers
1

I was wondering if there’s a way to call functions like OnEnter and OnExit, which only get called once, using the Physics sphere. Right now I can only find a function CheckSphere() which returns true or false every frame its called. Mine is in the Update function right now, checking for the layer which the player collider is on.

so – how can I call a method just ONCE when the player enters the sphere region, and call another method ONCE when the player exits the sphere region?

PS – I’m not using rigidbodies or character controllers on these “trigger” regions. So don’t waste your time telling me “just add a rigidbody”. I don’t want them.
These sphere regions handle things on the game map, like for example, a player walks near a door and the door lights up signaling that the player can enter. Or for chatting with NPCs, entering a battle with a monster, etc a large variety of things.
The player does have a character controller attached to him though.

2

A potential solution is to just have a bool variable that holds the last value of the CheckSphere() and use that to call code on enter or exit. For example:

bool oldCheckSphere;

void FixedUpdate (){
    // Add parameters here
    bool checkSphere = Physics.CheckSphere(...);
    
    if(oldCheckSphere == false && checkSphere == true){
        // OnEnter

    } else if (oldCheckSphere == true && checkSphere == false){
        // OnExit

    }

    oldCheckSphere = checkSphere;
}

Just input whatever parameters into the Physics.CheckSphere(…) and I believe it should work.

Hope this helped!