Raycast 2d在Unity3d中不起作用

Question

I'm new to Unity and blocked 2nd day with a simple try to raycast. This is the script which I use to raycast:

void Update () {
    Debug.DrawLine(transform.position, transform.position - transform.up);
    RaycastHit2D[] hits = Physics2D.RaycastAll(transform.position, transform.position - transform.up, Mathf.Infinity);
    if(hits.Length > 0)
    {
        Debug.Log("Hit");
    }
}

I have attached this script to a square and put near it another square which acts like a target, also added a 2d box collider to the target. I have disabled the "hit itself" feature like is described here: http://answers.unity3d.com/questions/756380/raycast-ignore-itself.html After performing all this steps the raycast hits nothing, the collider of the hit object is always null (checked this in debug mode, also nothing is written in console) . I drew a debug line, and indeed it points to the target square like in screenshots.

Please help me figure out what I'm doing wrong.

Answer 1

Physics.Raycast is for 3D Colliders and this includes Box Collider, Sphere Collider and others. No 2D in their names.

Physics2D.Raycast is for 2D colliders. You need a Box Collider 2D since this is a Sprite Renderer which is a 2D Object.

EDIT :

With your edit, the problem is that the direction of the raycast is too short. You have to multiply it by a number. The value of 100 should be fine.

public float distance = 100f;

void Update()
{
    Debug.DrawLine(transform.position, transform.position + transform.right);
    RaycastHit2D hit = Physics2D.Raycast(transform.position, transform.position + transform.right * distance, Mathf.Infinity);
    if (hit.collider != null)
    {
        Debug.Log("hit: " + hit.collider.name);
    }
}