FishNet Scene Manager should simulate the additional PhysicsScenes it creates

[kody-fields]

Noticed this after troubleshooting issues with a match-based game using scene stacking and multiple scenes for clients.

FishNet provides options to create additional PhysicsScenes and stack scenes but no built-in or automatic handling for ticking the scenes. I built a custom class to gather and simulate my additional PhysicsScenes, but if this can't be done in the library I'd at least like to see it called out very explicitly in the docs for those who may not be as familiar.

I know Unity docs suggest additional scenes will have to be manually ticked, but it feels like FishNet would handle them for you since it's creating and managing them otherwise.

Thanks!

[FirstGearGames]

This is intentional behavior. You write a script to tick the current scene using TimeManager OnPrePhysicsSimulation.

…

On Mon, Jul 17, 2023, 9:50 AM Kody Fields ***@***.***> wrote: Noticed this after troubleshooting issues with a match-based game using scene stacking and multiple scenes for clients. FishNet provides options to create additional PhysicsScenes and stack scenes but no built-in or automatic handling for ticking the scenes. I built a custom class to gather and simulate my additional scenes, but if this can't be done in the library I'd at least like to see it called out very explicitly in the docs for those who may not be as familiar. I know Unity docs suggest additional scenes will have to be manually ticked, but it feels like fishnet would handle them for you since it's creating and managing them otherwise. Thanks! — Reply to this email directly, view it on GitHub <#420>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGPJC3VTCTQLLYGYJ2CXBFDXQU7K7ANCNFSM6AAAAAA2M7GYVQ> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[kody-fields]

Do you think that suggestion should be called out in the docs? I did a quick search on that event OnPrePhysicsSimulation using the built-in search feature and it's only mentioned in the breaking changes section.

My concern is that for new users creating a game that relies on physics and using local physics options via the scene manager is effectively a "gotcha" in it's current state.

[FirstGearGames]

using FishNet.Object;
using System.Collections.Generic;
using UnityEngine;

/// <summary>
/// Synchronizes scene physics if not the default physics scene.
/// </summary>
public class PhysicsSceneSync : NetworkBehaviour
{
    /// <summary>
    /// True to synchronize physics 2d.
    /// </summary>
    private bool _synchronizePhysics2D;
    /// <summary>
    /// True to synchronize physics 3d.
    /// </summary>
    private bool _synchronizePhysics;
    /// <summary>
    /// Scenes which have physics handled by this script.
    /// </summary>
    private static HashSet<int> _synchronizedScenes = new HashSet<int>();

    public override void OnStartNetwork()
    {
        /* If scene is already synchronized do not take action.
         * This means the script was added twice to the same scene. */
        int sceneHandle = gameObject.scene.handle;
        if (_synchronizedScenes.Contains(sceneHandle))
            return;

        /* Set to synchronize the scene if either 2d or 3d
         * physics scene differ from the defaults. */
        _synchronizePhysics = (gameObject.scene.GetPhysicsScene() != Physics.defaultPhysicsScene);
        _synchronizePhysics2D = (gameObject.scene.GetPhysicsScene2D() != Physics2D.defaultPhysicsScene);

        /* If to synchronize 2d or 3d manually then
         * register to pre physics simulation. */
        if (_synchronizePhysics || _synchronizePhysics2D)
        {
            _synchronizedScenes.Add(sceneHandle);
            base.TimeManager.OnPrePhysicsSimulation += TimeManager_OnPrePhysicsSimulation;
        }
    }

    public override void OnStopNetwork()
    {
        //Check to unsubscribe.
        if (_synchronizePhysics || _synchronizePhysics2D)
        {
            _synchronizedScenes.Add(gameObject.scene.handle);
            base.TimeManager.OnPrePhysicsSimulation -= TimeManager_OnPrePhysicsSimulation;
        }
    }

    private void TimeManager_OnPrePhysicsSimulation(float delta)
    {
        /* If to simulate physics then do so on this objects
         * physics scene. If you know the object is not going to change
         * scenes you can cache the physics scenes
         * rather than look them up each time. */
        if (_synchronizePhysics)
            gameObject.scene.GetPhysicsScene().Simulate(delta);
        if (_synchronizePhysics2D)
            gameObject.scene.GetPhysicsScene2D().Simulate(delta);
    }

}

adding now

[kody-fields]

Looks good, pretty similar to what I'm doing in my code for this now. I have a few extra options like the ability to disable simulation when a scene is detected as empty (when using scene caching via FishNet SceneManagement). Thanks for taking a look at this issue.