Ways to detect 2D collision other than OnCollisionEnter2D

问题

This might come off as a stupid question, but in an if statement, is it possible to check if the object is currently colliding with another object?

Here is what I had thought of initially (in the code snipit bellow) but for some odd reason that I can't figure out, the variable onFloor is sometimes false when the object is being pushed upwards by the Platform.

void OnCollisionEnter2D(Collision2D c)
{
    switch(c.gameObject.tag)
    {
        case "Platform":
            onFloor = true;
            break;
        default:
            break;
    }
}

void OnCollisionExit2D(Collision2D c)
{
    switch(c.gameObject.tag)
    {
        case "Platform":
            onFloor = false;
            break;
        default:
            break;
    }
}

And for that reason, I am asking if there are any ways to detect if the circle collider of said object is colliding with box collider of intersecting object while in code. something like

if(CircleCollider2D.CollidingObject != null && CircleCollider2D.CollidingObject.tag == "Platform")
{ /*Code I'd like to do here*/ }

Now that's only my imagination trying to think of some way of it that could work but you get the point.

So, I ask, are there any solutions for my imagination?

After discussing with Programmer, IsTouching is underlined and giving the error: 'Collider2D' does not contain a definition for 'IsTouching' and no extension method 'IsTouching' accepting a first argument of type 'Collider2D' could be found (are you missing a using directive or an assembly reference?).

Here is the slimmed down code:

using UnityEngine;

public class Ball : MonoBehaviour
{ 
    Vector2 jumpVelocity;
    public Collision2D platform;

    // Use this for initialization
    void Start()
    {
        jumpVelocity = new Vector2(0, rigidbody2D.gravityScale * 100);
    }

    void FixedUpdate()
    {
        if (Input.GetKey(KeyCode.Space) && collider2D.IsTouching(platform))
        {
            rigidbody2D.AddForce(jumpVelocity, ForceMode2D.Force);
        }
    }
}

note that even changing collider2D to a Collision2D variable and taking that variable.collider.IsTouching results the same error.

回答1:

Are there different solutions than OnCollisionEnter2D

Yes. Many of them!

CircleCollider2D, other 2D colliders and its base class Collision2D, have built in functions to do this.

public bool IsTouching(Collider2D collider); //Check collision by the provided collider
public bool IsTouchingLayers(); //Check collision by any collision
public bool IsTouchingLayers(int layerMask); //Check collision by layer
public bool OverlapPoint(Vector2 point); //Check collision by position

The first function is more appropriate for this.

Simple Example:

Collision2D collider1;
Collision2D collider2;

void Update()
{
    //Checks if collider1 is touching with collider2
    if (collider1.collider.IsTouching(collider2.collider))
    {

    }
}

Example with the OnCollisionEnter2D function:

public CircleCollider2D myCircleCollider;

void OnCollisionEnter2D(Collision2D c)
{
    if (c.collider.IsTouching(myCircleCollider))
    {

    }
}

回答2:

Maybe what you are looking for is the OnCollisionStay method, this one will fire as long as they are touching each other.

There is some more info in the link here: https://docs.unity3d.com/ScriptReference/Collider2D.OnCollisionStay2D.html

来源：https://stackoverflow.com/questions/39897313/ways-to-detect-2d-collision-other-than-oncollisionenter2d

标签

unity3d

collider