Fix gravity shenanigans (#12866)

Content.Client/Gravity/GravitySystem.Shake.cs

@@ -0,0 +1,59 @@
+using Content.Shared.Camera;
+using Content.Shared.Gravity;
+using Robust.Client.Player;
+using Robust.Shared.Audio;
+using Robust.Shared.Player;
+using Robust.Shared.Random;
+
+namespace Content.Client.Gravity;
+
+public sealed partial class GravitySystem
+{
+    [Dependency] private readonly IPlayerManager _playerManager = default!;
+    [Dependency] private readonly IRobustRandom _random = default!;
+    [Dependency] private readonly SharedAudioSystem _audio = default!;
+    [Dependency] private readonly SharedCameraRecoilSystem _sharedCameraRecoil = default!;
+
+    private void InitializeShake()
+    {
+        SubscribeLocalEvent<GravityShakeComponent, ComponentInit>(OnShakeInit);
+    }
+
+    private void OnShakeInit(EntityUid uid, GravityShakeComponent component, ComponentInit args)
+    {
+        var localPlayer = _playerManager.LocalPlayer?.ControlledEntity;
+
+        if (!TryComp<TransformComponent>(localPlayer, out var xform) ||
+            xform.GridUid != uid && xform.MapUid != uid)
+        {
+            return;
+        }
+
+        if (Timing.IsFirstTimePredicted && TryComp<GravityComponent>(uid, out var gravity))
+        {
+            _audio.PlayGlobal(gravity.GravityShakeSound, Filter.Local(), true, AudioParams.Default.WithVolume(-2f));
+        }
+    }
+
+    protected override void ShakeGrid(EntityUid uid, GravityComponent? gravity = null)
+    {
+        base.ShakeGrid(uid, gravity);
+
+        if (!Resolve(uid, ref gravity) || !Timing.IsFirstTimePredicted)
+            return;
+
+        var localPlayer = _playerManager.LocalPlayer?.ControlledEntity;
+
+        if (!TryComp<TransformComponent>(localPlayer, out var xform))
+            return;
+
+        if (xform.GridUid != uid ||
+            xform.GridUid == null && xform.MapUid != uid)
+        {
+            return;
+        }
+
+        var kick = new Vector2(_random.NextFloat(), _random.NextFloat()) * GravityKick;
+        _sharedCameraRecoil.KickCamera(localPlayer.Value, kick);
+    }
+}