Best ground 2D ground check strategy? How to detect if a object is touching the top of a layer?

Questions & Answers
1

Heya.

Im currently making a basic 2D platformer. Up until i have been using the Collider2D IsTouchingLayer function but just realised that i can get away with infinite jumps while touching the bottom of platforms. How would i detect if the player is just touching the TOP of the ground?
Thanks in advance.

2

You can check if it is under you, but you will need OnCollissionX or OnTriggerX methods. For example (non tested, but should work).

if (coll.gameObject.transform.position.y <= transform.position.y)
    // Object colliding with is under you

In reality, you’ll want to check with (coll.gameObject.transform.position.y + coll.gameObject.renderer.bounds.extents.y) and (transform.position.y - renderer.bounds.extents.y).
This will give you the exact “bottom” of your character and “top” of platform.
Hope this helps.