Gravity (#841)

Content.Server/GameObjects/EntitySystems/GravitySystem.cs

@@ -0,0 +1,134 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Content.Server.GameObjects.Components.Gravity;
+using Content.Server.GameObjects.Components.Mobs;
+using JetBrains.Annotations;
+using Robust.Server.GameObjects.EntitySystems;
+using Robust.Server.Interfaces.Player;
+using Robust.Shared.GameObjects;
+using Robust.Shared.GameObjects.Systems;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Map;
+using Robust.Shared.Interfaces.Random;
+using Robust.Shared.IoC;
+using Robust.Shared.Map;
+using Robust.Shared.Maths;
+using Robust.Shared.Random;
+
+namespace Content.Server.GameObjects.EntitySystems
+{
+    [UsedImplicitly]
+    public class GravitySystem: EntitySystem
+    {
+#pragma warning disable 649
+        [Dependency] private readonly IMapManager _mapManager;
+        [Dependency] private readonly IPlayerManager _playerManager;
+        [Dependency] private readonly IEntitySystemManager _entitySystemManager;
+        [Dependency] private readonly IRobustRandom _random;
+#pragma warning restore 649
+
+        private const float GravityKick = 100.0f;
+
+        private const uint ShakeTimes = 10;
+
+        private Dictionary<GridId, uint> _gridsToShake;
+
+        private float internalTimer = 0.0f;
+
+        public override void Initialize()
+        {
+            EntityQuery = new TypeEntityQuery<GravityGeneratorComponent>();
+            _gridsToShake = new Dictionary<GridId, uint>();
+        }
+
+        public override void Update(float frameTime)
+        {
+            internalTimer += frameTime;
+            var gridsWithGravity = new List<GridId>();
+            foreach (var entity in RelevantEntities)
+            {
+                var generator = entity.GetComponent<GravityGeneratorComponent>();
+                if (generator.NeedsUpdate)
+                {
+                    generator.UpdateState();
+                }
+                if (generator.Status == GravityGeneratorStatus.On)
+                {
+                    gridsWithGravity.Add(entity.Transform.GridID);
+                }
+            }
+
+            foreach (var grid in _mapManager.GetAllGrids())
+            {
+                if (grid.HasGravity && !gridsWithGravity.Contains(grid.Index))
+                {
+                    grid.HasGravity = false;
+                    ScheduleGridToShake(grid.Index, ShakeTimes);
+                } else if (!grid.HasGravity && gridsWithGravity.Contains(grid.Index))
+                {
+                    grid.HasGravity = true;
+                    ScheduleGridToShake(grid.Index, ShakeTimes);
+                }
+            }
+
+            if (internalTimer > 0.2f)
+            {
+                ShakeGrids();
+                internalTimer = 0.0f;
+            }
+        }
+
+        private void ScheduleGridToShake(GridId gridId, uint shakeTimes)
+        {
+            if (!_gridsToShake.Keys.Contains(gridId))
+            {
+                _gridsToShake.Add(gridId, shakeTimes);
+            }
+            else
+            {
+                _gridsToShake[gridId] = shakeTimes;
+            }
+            // Play the gravity sound
+            foreach (var player in _playerManager.GetAllPlayers())
+            {
+                if (player.AttachedEntity == null
+                    || player.AttachedEntity.Transform.GridID != gridId) continue;
+                _entitySystemManager.GetEntitySystem<AudioSystem>().Play("/Audio/effects/alert.ogg", player.AttachedEntity);
+            }
+        }
+
+        private void ShakeGrids()
+        {
+            // I have to copy this because C# doesn't allow changing collections while they're
+            // getting enumerated.
+            var gridsToShake = new Dictionary<GridId, uint>(_gridsToShake);
+            foreach (var gridId in _gridsToShake.Keys)
+            {
+                if (_gridsToShake[gridId] == 0)
+                {
+                    gridsToShake.Remove(gridId);
+                    continue;
+                }
+                ShakeGrid(gridId);
+                gridsToShake[gridId] -= 1;
+            }
+            _gridsToShake = gridsToShake;
+        }
+
+        private void ShakeGrid(GridId gridId)
+        {
+            foreach (var player in _playerManager.GetAllPlayers())
+            {
+                if (player.AttachedEntity == null
+                    || player.AttachedEntity.Transform.GridID != gridId
+                    || !player.AttachedEntity.TryGetComponent(out CameraRecoilComponent recoil))
+                {
+                    continue;
+                }
+
+                recoil.Kick(new Vector2(_random.NextFloat(), _random.NextFloat()) * GravityKick);
+            }
+        }
+    }
+}