Thrusters (shuttle go nyoom) (#5352)

Content.Server/Shuttles/EntitySystems/ShuttleSystem.cs

@@ -0,0 +1,117 @@
+using System.Collections.Generic;
+using Content.Server.Shuttles.Components;
+using JetBrains.Annotations;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Physics;
+
+namespace Content.Server.Shuttles.EntitySystems
+{
+    [UsedImplicitly]
+    internal sealed class ShuttleSystem : EntitySystem
+    {
+        private const float TileMassMultiplier = 4f;
+
+        public override void Initialize()
+        {
+            base.Initialize();
+            SubscribeLocalEvent<ShuttleComponent, ComponentAdd>(OnShuttleAdd);
+            SubscribeLocalEvent<ShuttleComponent, ComponentStartup>(OnShuttleStartup);
+            SubscribeLocalEvent<ShuttleComponent, ComponentShutdown>(OnShuttleShutdown);
+
+            SubscribeLocalEvent<GridInitializeEvent>(OnGridInit);
+            SubscribeLocalEvent<GridFixtureChangeEvent>(OnGridFixtureChange);
+        }
+
+        private void OnShuttleAdd(EntityUid uid, ShuttleComponent component, ComponentAdd args)
+        {
+            // Easier than doing it in the comp and they don't have constructors.
+            for (var i = 0; i < component.LinearThrusters.Length; i++)
+            {
+                component.LinearThrusters[i] = new List<ThrusterComponent>();
+            }
+        }
+
+        private void OnGridFixtureChange(GridFixtureChangeEvent args)
+        {
+            // Look this is jank but it's a placeholder until we design it.
+            if (args.NewFixtures.Count == 0) return;
+
+            foreach (var fixture in args.NewFixtures)
+            {
+                fixture.Mass = fixture.Area * TileMassMultiplier;
+                fixture.Restitution = 0.1f;
+            }
+        }
+
+        private void OnGridInit(GridInitializeEvent ev)
+        {
+            EntityManager.GetEntity(ev.EntityUid).EnsureComponent<ShuttleComponent>();
+        }
+
+        private void OnShuttleStartup(EntityUid uid, ShuttleComponent component, ComponentStartup args)
+        {
+            if (!component.Owner.HasComponent<IMapGridComponent>())
+            {
+                return;
+            }
+
+            if (!component.Owner.TryGetComponent(out PhysicsComponent? physicsComponent))
+            {
+                return;
+            }
+
+            if (component.Enabled)
+            {
+                Enable(physicsComponent);
+            }
+        }
+
+        public void Toggle(ShuttleComponent component)
+        {
+            if (!component.Owner.TryGetComponent(out PhysicsComponent? physicsComponent)) return;
+
+            component.Enabled = !component.Enabled;
+
+            if (component.Enabled)
+            {
+                Enable(physicsComponent);
+            }
+            else
+            {
+                Disable(physicsComponent);
+            }
+        }
+
+        private void Enable(PhysicsComponent component)
+        {
+            component.BodyType = BodyType.Dynamic;
+            component.BodyStatus = BodyStatus.InAir;
+            //component.FixedRotation = false; TODO WHEN ROTATING SHUTTLES FIXED.
+            component.FixedRotation = false;
+            component.LinearDamping = 0.2f;
+            component.AngularDamping = 0.3f;
+        }
+
+        private void Disable(PhysicsComponent component)
+        {
+            component.BodyType = BodyType.Static;
+            component.BodyStatus = BodyStatus.OnGround;
+            component.FixedRotation = true;
+        }
+
+        private void OnShuttleShutdown(EntityUid uid, ShuttleComponent component, ComponentShutdown args)
+        {
+            if (!component.Owner.TryGetComponent(out PhysicsComponent? physicsComponent))
+            {
+                return;
+            }
+
+            Disable(physicsComponent);
+
+            foreach (var fixture in physicsComponent.Fixtures)
+            {
+                fixture.Mass = 0f;
+            }
+        }
+    }
+}