How to use collisions with a tag

Ladislav_Uherkovich · January 7, 2022, 12:19pm

Hello there,

when I try to use OnCollisionEnter2D without tags, it works:

void OnCollisionEnter2D(Collision2D other)
{
    moveSpeed = slowSpeed;
    Debug.Log("You damaged your car!");
}

but when trying to use it with tags (as I want the car to slow down only when colliding with houses which are tagged House but to not slow down otherwise):

void OnCollisionEnter2D(Collision2D other)
{
    if (other.tag == "House")
    {
        moveSpeed = slowSpeed;
        Debug.Log("You damaged your car!");
    }
}

I will get an error message:

Compiler Error CS1061
‘Collision2D’ does not contain a definition for ‘tag’ and no accessible extension method ‘tag’ accepting a first argument of type ‘Collision2D’ could be found (are you missing a using directive or an assembly reference?).
This error occurs when you try to call a method or access a class member that does not exist.

How can I set up different behaviour when colliding with objects with different tags?

Btw. great course, I changed the behaviour a little so that you will cannot run over the customer as he has a rigid body but he has another collider around him so you just need to get close to him and also customer will point out that you do not have a package when you have none and also the game will be declared a victory when you deliver 3 packages.

Thanks

Laco

Nina · January 7, 2022, 8:29pm

Hi Ladislav,

It’s great to see that you are already implementing your own ideas. The solution for your problem is relatively easy, and I’m sure you’ll be able to figure it out yourself. So I’m just leaving a little tip for you: Check the Collision2D class in the Unity API to see what you are able to access. Then find a way to access the tag. One little “step” is missing in your current if-condition.

If you cannot figure it out yourself, please let me know what you did.

And in case you are in a hurry or just want to know the solution, click here for the solution.

other.gameObject.tag == "House"

How can I set up different behaviour when colliding with objects with different tags?

Like you did in your code: with if-blocks.

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