Kick mines (real) (#8056)

Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Shared/StepTrigger/StepTriggerSystem.cs

@@ -0,0 +1,177 @@
+using System.Linq;
+using Robust.Shared.GameStates;
+using Robust.Shared.Physics.Dynamics;
+
+namespace Content.Shared.StepTrigger;
+
+public sealed class StepTriggerSystem : EntitySystem
+{
+    [Dependency] private readonly EntityLookupSystem _entityLookup = default!;
+
+    public override void Initialize()
+    {
+        SubscribeLocalEvent<StepTriggerComponent, ComponentGetState>(TriggerGetState);
+        SubscribeLocalEvent<StepTriggerComponent, ComponentHandleState>(TriggerHandleState);
+
+        SubscribeLocalEvent<StepTriggerComponent, StartCollideEvent>(HandleCollide);
+    }
+
+    public override void Update(float frameTime)
+    {
+        foreach (var (_, trigger) in EntityQuery<StepTriggerActiveComponent, StepTriggerComponent>())
+        {
+            if (!Update(trigger))
+                continue;
+
+            RemComp<StepTriggerActiveComponent>(trigger.Owner);
+        }
+    }
+
+    private bool Update(StepTriggerComponent component)
+    {
+        if (component.Deleted || !component.Active || component.Colliding.Count == 0)
+            return true;
+
+        foreach (var otherUid in component.Colliding.ToArray())
+        {
+            if (!otherUid.IsValid())
+            {
+                component.Colliding.Remove(otherUid);
+                component.CurrentlySteppedOn.Remove(otherUid);
+                component.Dirty();
+                continue;
+            }
+
+            // TODO: This shouldn't be calculating based on world AABBs.
+            var ourAabb = _entityLookup.GetWorldAABB(component.Owner);
+            var otherAabb = _entityLookup.GetWorldAABB(otherUid);
+
+            if (!TryComp(otherUid, out PhysicsComponent? otherPhysics) || !ourAabb.Intersects(otherAabb))
+            {
+                component.Colliding.Remove(otherUid);
+                component.CurrentlySteppedOn.Remove(otherUid);
+                component.Dirty();
+                continue;
+            }
+
+            if (component.CurrentlySteppedOn.Contains(otherUid))
+                continue;
+
+            if (!CanTrigger(component.Owner, otherUid, component))
+                continue;
+
+            if (otherPhysics.LinearVelocity.Length < component.RequiredTriggerSpeed)
+                continue;
+
+            var percentage = otherAabb.IntersectPercentage(ourAabb);
+            if (percentage < component.IntersectRatio)
+                continue;
+
+            var ev = new StepTriggeredEvent { Source = component.Owner, Tripper = otherUid };
+            RaiseLocalEvent(component.Owner, ref ev);
+
+            component.CurrentlySteppedOn.Add(otherUid);
+            component.Dirty();
+        }
+
+        return false;
+    }
+
+    private bool CanTrigger(EntityUid uid, EntityUid otherUid, StepTriggerComponent component)
+    {
+        if (!component.Active || component.CurrentlySteppedOn.Contains(otherUid))
+            return false;
+
+        var msg = new StepTriggerAttemptEvent { Source = uid, Tripper = otherUid };
+
+        RaiseLocalEvent(uid, ref msg);
+
+        return msg.Continue;
+    }
+
+    private void HandleCollide(EntityUid uid, StepTriggerComponent component, StartCollideEvent args)
+    {
+        var otherUid = args.OtherFixture.Body.Owner;
+
+        if (!CanTrigger(uid, otherUid, component))
+            return;
+
+        EnsureComp<StepTriggerActiveComponent>(uid);
+
+        component.Colliding.Add(otherUid);
+    }
+
+    private static void TriggerHandleState(EntityUid uid, StepTriggerComponent component, ref ComponentHandleState args)
+    {
+        if (args.Current is not StepTriggerComponentState state)
+            return;
+
+        component.RequiredTriggerSpeed = state.RequiredTriggerSpeed;
+        component.IntersectRatio = state.IntersectRatio;
+        component.CurrentlySteppedOn.Clear();
+
+        foreach (var slipped in state.CurrentlySteppedOn)
+        {
+            component.CurrentlySteppedOn.Add(slipped);
+        }
+    }
+
+    private static void TriggerGetState(EntityUid uid, StepTriggerComponent component, ref ComponentGetState args)
+    {
+        args.State = new StepTriggerComponentState(
+            component.IntersectRatio,
+            component.CurrentlySteppedOn.ToArray(),
+            component.RequiredTriggerSpeed);
+    }
+
+    public void SetIntersectRatio(EntityUid uid, float ratio, StepTriggerComponent? component = null)
+    {
+        if (!Resolve(uid, ref component))
+            return;
+
+        if (MathHelper.CloseToPercent(component.IntersectRatio, ratio))
+            return;
+
+        component.IntersectRatio = ratio;
+        Dirty(component);
+    }
+
+    public void SetRequiredTriggerSpeed(EntityUid uid, float speed, StepTriggerComponent? component = null)
+    {
+        if (!Resolve(uid, ref component))
+            return;
+
+        if (MathHelper.CloseToPercent(component.RequiredTriggerSpeed, speed))
+            return;
+
+        component.RequiredTriggerSpeed = speed;
+        Dirty(component);
+    }
+
+    public void SetActive(EntityUid uid, bool active, StepTriggerComponent? component = null)
+    {
+        if (!Resolve(uid, ref component))
+            return;
+
+        if (active == component.Active)
+            return;
+
+        component.Active = active;
+        Dirty(component);
+    }
+}
+
+[ByRefEvent]
+public struct StepTriggerAttemptEvent
+{
+    public EntityUid Source;
+    public EntityUid Tripper;
+    public bool Continue;
+}
+
+[ByRefEvent]
+public struct StepTriggeredEvent
+{
+    public EntityUid Source;
+    public EntityUid Tripper;
+}