Unity Networking - [command] function executes when it is not supposed to

Question

I'm fairly new to unity networking and Networking itself.

Game: I have 2 players multiplayer game where each player can shoot.

Problem:

Code 1 makes both players shoot (in the host game only) when host player press spacebar. The client player cannot shoot from the client's game.

Note: the if (Input.GetKeyDown (KeyCode.Space)) is inside the CmdShoot method.

Code 2 executes correctly. Host can shoot in the host game and the client can shoot from the client's game.

Note: the if (Input.GetKeyDown (KeyCode.Space)) is outside the CmdShoot method for code 2.

Question: In code 1, why can't the client shoot and why does host makes both player shoot?

Code 1:

// Update is called once per frame
void Update () {
    if (!isLocalPlayer) {
        return;
    }

    CmdShoot ();
}

[Command]
void CmdShoot(){
    if (Input.GetKeyDown (KeyCode.Space)) {

        GameObject force_copy = GameObject.Instantiate (force) as GameObject;
        force_copy.transform.position = gameObject.transform.position + gameObject.transform.forward;
        force_copy.GetComponent<Rigidbody>().velocity = gameObject.transform.forward * force.GetComponent<Force>().getSpeed();

        NetworkServer.Spawn (force_copy);

        Destroy (force_copy, 5);
    }

}

Code 2:

// Update is called once per frame
void Update () {
    if (!isLocalPlayer) {
        return;
    }
    if (Input.GetKeyDown (KeyCode.Space)) {
        CmdShoot ();
    }
}

[Command]
void CmdShoot(){

    GameObject force_copy = GameObject.Instantiate (force) as GameObject;
    force_copy.transform.position = gameObject.transform.position + gameObject.transform.forward;
    force_copy.GetComponent<Rigidbody>().velocity = gameObject.transform.forward * force.GetComponent<Force>().getSpeed();

    NetworkServer.Spawn (force_copy);

    Destroy (force_copy, 5);

}

score 0 · Accepted Answer · answered Jun 28 '16 at 05:25

0

The [Command] tag tells that client wants to execute this function on a server.

In Code 1 case, your code calls the CmdShoot() to execute on server and then check if server is holding Space down (thus only host is able to shoot everything and client(s) not able to shoot at all).

In Code 2 case, your code first checks if local program is holding Space key down (independent of being host or client). If the local program is holding space key then it calls the CmdShoot() on server.

answered Jun 28 '16 at 05:25

LapisLazuli

406
4
8

That makes sense! However, in code 1, host AND client will shoot if the host is pressing the spacebar! The client doesn't shoot every time. The client shoots approximately every 5-7 spacebar presses. – Taimoor Rana Jun 28 '16 at 10:10
I believe network send rate is throttling the send rate of CmdShoot() on the client. For host it checks every time the Update() is called but client's CmdShoot() might be called every 25 ms or so on (don't remember the default value for network send rate). – LapisLazuli Jun 28 '16 at 10:35
But why is the client player shooting when the host presses the spacebar? I explicitly tell it to not run CmdShoot if it is not the local player with ' if (!isLocalPlayer) ' – Taimoor Rana Jun 28 '16 at 10:48
The isLocalPlayer is true if the instance is running locally (so both host and client will have the isLocalPlayer true on their instances of the program). Unity manual gives some insight on how various items work: [Unity - isLocalPlayer](https://docs.unity3d.com/ScriptReference/Networking.NetworkIdentity-isLocalPlayer.html) – LapisLazuli Jun 28 '16 at 12:21
Thank you very much for your help! – Taimoor Rana Jun 28 '16 at 13:40

Unity Networking - [command] function executes when it is not supposed to

1 Answers1