unity OnTriggerEnter2D 未注册

Question

I am new to using unity and am having a real problem getting trigger collisions to register.

public void  OnTriggerEnter2D(Collider2D other)
{
    print("collide");
    if (other.CompareTag("Fish"))
    {
        print("Caught");
    }
}

I have 2D polygon colliders and a rigid body on both items. I have also got 1 set a trigger(have tried having both as trigger). However one UI item is a sprite and the other is an image. Both items are also tagged with "fish"

Would really appreciate any help. Thanks

Answer 1

There are four things I can think of which need to happen so that OnTriggerEnter gets called:

1. The two objects' colliders need to actually be overlapping. Just because their rendered pixels are overlapping, doesn't mean their colliders are overlapping. This can be checked in the editor. Their colliders are indicated with a green outline in the Scene tab. If you don't see anything, make sure the button labeled Gizmos is turned on.

2. The two objects need to be in physics layers which are set to collide with each other. You can check this in Edit > Settings > Physics2D > Layer Collision Matrix .

3. Both objects need to have Rigidbody2D components attached. Make sure these aren't Rigidbody components, as those are for 3D physics.

4. The object which contains the OnTriggerEnter2D event needs to have isTrigger = true .

Answer 2

I've tried several things to do. First I've checked recommendations from another post. In nutshell:

1. Checked if I have rigid body at least for one of objects
2. Checked layers
3. Checked tags
4. Played with "is trigger".

Finally, the solution was to add script to object via create and add component button and not to drop written script to it. Have no idea, but for me that was the solution. Even it was same script.

Answer 3

Both a Sprite and an Image can collide with another Image. What might be wrong is that your sprite may look like touching the image however in the scene the canvas might be far away, so camera may deceive you. Here is the sample code for my tests:

Script that moves the Sprite:

    private Rigidbody2D _rigidbody;
    private void Awake() => _rigidbody = GetComponent<Rigidbody2D>();

        private void FixedUpdate()
    {
        if (Input.GetKey(KeyCode.A))
        {
            var movement = -transform.right * Time.fixedDeltaTime * 250;
            _rigidbody.MovePosition(transform.position + movement);
        }
        
        if (Input.GetKey(KeyCode.D))
        {
            var movement = transform.right * Time.fixedDeltaTime * 250;
            _rigidbody.MovePosition(transform.position + movement);
        }
    }

Trigger script on image:

    private void OnTriggerEnter2D(Collider2D other)
    {
        Debug.Log(other.name);
    }

Answer 4

Nothing helps for me, but in my case I didn't know there was a place in code that breaks collision layers (that is do not change the collision matrix settings visually):

Physics2D.IgnoreLayerCollision( ...

Check that too and make sure it is not called.