NetworkPuristPlus Cable Alignment and Rotation

NetworkPuristPlus v1.1.0 is a server-authoritative mod (via BepInEx + Harmony + LaunchPad networking) that strips long-piece variants and optionally aligns straight cables to a canonical rotation orientation. The AlignStraightCables setting is the suspect in multiplayer cable rotation desync: it rotates cables post-placement without explicit server-only gating at the rotation point.

Harmony patches

The mod registers five patches via new Harmony("net.networkpuristplus").PatchAll() (line 148):

1. [HarmonyPatch(typeof(World), "OnLoadingFinished")] (line 659)
2. Class: ReplaceLongPiecesOnLoadPatch
3. Type: Postfix

4. Purpose: Rebuilds placed long pieces into single-tile segments on world load.

5. [HarmonyPatch(typeof(World), "OnLoadingFinished")] (line 873)

6. Class: NormalizeCableRollOnLoadPatch
7. Type: Postfix

8. Purpose: Aligns all straight cables on world load when Settings.CableAlignmentEnabled.

9. [HarmonyPatch(typeof(Cable), "OnRegistered")] (line 852)

10. Class: NormalizeCableRollOnRegisterPatch
11. Type: Postfix

12. Purpose: Aligns freshly-placed cables immediately post-registration when Settings.CableAlignmentEnabled.

13. [HarmonyPatch(typeof(Constructor), "SpawnConstruct")] (line 926)

14. Class: RewriteLongVariantOnConstructPatch
15. Type: Prefix (returns bool, can skip base)

16. Purpose: Rewrites long-piece builds into single-tile spawns at build time.

17. [HarmonyPatch(typeof(SPDADataHandler), "HandleThingPageOverrides")] (line 986)

18. Class: HideLongVariantsStationpediaPatch
19. Type: Postfix
20. Purpose: Re-hides long-variant prefabs from the Stationpedia after page-override passes.

The AlignStraightCables config setting

Config name: AlignStraightCables, bound via config.Bind<bool>("Server - Cables", "Align Straight Cables", true, ...) (line 316). Binding is in static Settings class, called once in Awake() at line 132.

Where it is read:

1. CableAlignmentEnabled property (lines 283-294): gated by master Enabled toggle.
2. Join validation (lines 180, 222): broadcasted and validated on client join.
3. Patch guards (lines 859, 878): checked before alignment.

Cable rotation mechanics: CableRoll class

Rotation logic in CableRoll static utility class (lines 779-851):

Canonical orientation mapping

internal static Quaternion Canonical(Quaternion rotation)
{
    Vector3 val = rotation * Vector3.forward;
    float num = Mathf.Abs(val.x);
    float num2 = Mathf.Abs(val.y);
    float num3 = Mathf.Abs(val.z);
    if (num >= num2 && num >= num3)
        return CanonX;
    if (num2 >= num3)
        return CanonY;
    return CanonZ;
}

Deterministic: transforms forward vector, classifies by axis dominance.

Normalization (lines 821-850)

internal static bool Normalise(Cable c)
{
    if (!IsNormalisableStraight(c))
        return false;
    Quaternion thingTransformRotation = ((Thing)c).ThingTransformRotation;
    Quaternion val = Canonical(thingTransformRotation);
    if (Quaternion.Angle(thingTransformRotation, val) < 1f)
        return false;
    ((Thing)c).ThingTransform.rotation = val;               // line 842: ROTATION SET
    ((Thing)c).RegisteredRotation = val;                   // line 843
    ((Structure)c).Direction = val;                        // line 844
    if (NetworkManager.IsServer)                           // line 845: SERVER CHECK (too late)
    {
        ((Thing)c).NetworkUpdateFlags = (ushort)(((Thing)c).NetworkUpdateFlags | 1);
    }
    return true;
}

Critical issue: Rotation assignments (lines 842-844) execute BEFORE server-only check (line 845).

The cable registration patch

[HarmonyPatch(typeof(Cable), "OnRegistered")]
internal static class NormalizeCableRollOnRegisterPatch
{
    private static void Postfix(Cable __instance)
    {
        if (!Settings.CableAlignmentEnabled || !GameManager.RunSimulation || (int)GameManager.GameState == 4)
        {
            return;
        }
        try
        {
            CableRoll.Normalise(__instance);
        }
        catch (Exception arg)
        {
            NetworkPuristPlusPlugin.PlayerWarn($"could not align a just-built cable: {arg}");
        }
    }
}

No explicit server-only guard. Cable.OnRegistered fires on both server AND client.

Verdict on Task 4

YES. NetworkPuristPlus mutates cable rotation after Cable.OnRegistered runs on BOTH server AND client without server-only gating at the rotation-setting point.

Method: CableRoll.Normalise(Cable c) (line 821)

Rotation mutations: - Line 842: ((Thing)c).ThingTransform.rotation = val; - Line 843: ((Thing)c).RegisteredRotation = val; - Line 844: ((Structure)c).Direction = val;

Problem: These execute unconditionally. The server check at line 845 only gates NetworkUpdateFlags, not the transform mutation.

Called from: NormalizeCableRollOnRegisterPatch.Postfix (line 865), which patches Cable.OnRegistered with no explicit server-only guard.

Verification history

• 2026-05-17: page created. Decompiled NetworkPuristPlus.dll (Workshop 3724874914) via ilspycmd. Verdict: YES, cable rotation mutated on both sides without server-only gating at rotation point (lines 842-844 before server check at 845).

Open questions

• Does Cable.DeserializeOnJoin invoke OnRegistered synchronously?
• Multi-frame delay between local rotation and network replication?
• Floating-point context near axis-dominance boundaries causing divergent canonical selection?