避免自我冲突

Question

I'm firing lasers from a cannon in a 2d space game in unity using the following method:

[Command]
private void CmdFire()
{
    GameObject laser = (GameObject)Instantiate(LaserPrefab, leftShot ? leftCannon.position : rightCannon.position, leftShot ? leftCannon.rotation * Quaternion.Euler(0, 0, 90) : rightCannon.rotation * Quaternion.Euler(0, 0, 90));
    Physics2D.IgnoreCollision(laser.GetComponent<Collider2D>(), transform.FindChild("PlayerShip").GetComponent<Collider2D>());
    Physics2D.IgnoreCollision(laser.GetComponent<Collider2D>(), transform.FindChild("PlayerShip").FindChild(leftShot?"LeftCannon":"RightCannon").GetComponent<Collider2D>());
    laser.GetComponent<SpriteRenderer>().sortingOrder = 0;
    laser.GetComponent<Rigidbody2D>().velocity = laser.transform.right * 10;
    NetworkServer.Spawn(laser);
    leftShot = !leftShot;
    Destroy(laser, 2f);
}

The important bit being the Physics2D.IgnoreCollision() sections that are designed to stop them shooting themselves. This works exactly as expected on the host (you can shoot the other ships but not yourself) but the lasers constantly hit their own ship on the client machines.

As you can see here:

This is my first attempt at making a multiplayer game in Unity so any help would be appreciated.

Answer 1

Alternatively, you could add a tag to your player, like "Player" and check in OnCollisionEnter2D whether or not the bullet is colliding with the player that way:

void OnCollisionEnter2D (Collision2D coll) {
    // If the tag of the thing we collide with is "Player"...
    if (coll.gameObject.tag == "Player")
        Debug.Log("Player hit!");

    // Ignore the collision with the player.
    Physics2D.IgnoreCollision(player.collider, collider);
}

Another way is to give the player a different layer to the bullets and ignore collisions between the player and bullet layers:

Physics2D.IgnoreLayerCollision(PlayerLayer, BulletLayer, true);

Or go to Edit > Project Settings > Physics 2D and choose which layers collide with each other there:

You would probably want to add your own custom layers for Player and Bullets.

Answer 2

在激光的OnCollisionEnter2D中，通过比较ID检查gameObject是否为“自己”

If( collider.gameObject.GetInstanceID() != yourself.gameObject.GetInstanceID() )

Answer 3

go to Edit > Project Settings > Physics 2D and choose which layers collide with each other there: