make fire spreading scale with mass (#27202)

* make fire spreading scale with mass

* realer

---------

Co-authored-by: deltanedas <@deltanedas:kde.org>

diff --git a/Content.Server/Atmos/EntitySystems/FlammableSystem.cs b/Content.Server/Atmos/EntitySystems/FlammableSystem.cs
index 53fcb720766f8ae98eb8b6720e063d9718afe778..058faf443ee110ddd294a67f8b278f620f20adc9 100644 (file)
--- a/Content.Server/Atmos/EntitySystems/FlammableSystem.cs
+++ b/Content.Server/Atmos/EntitySystems/FlammableSystem.cs
@@ -47,6 +47,8 @@ namespace Content.Server.Atmos.EntitySystems
         [Dependency] private readonly AudioSystem _audio = default!;
         [Dependency] private readonly IRobustRandom _random = default!;
 
+        private EntityQuery<PhysicsComponent> _physicsQuery;
+
         public const float MinimumFireStacks = -10f;
         public const float MaximumFireStacks = 20f;
         private const float UpdateTime = 1f;
@@ -62,6 +64,8 @@ namespace Content.Server.Atmos.EntitySystems
         {
             UpdatesAfter.Add(typeof(AtmosphereSystem));
 
+            _physicsQuery = GetEntityQuery<PhysicsComponent>();
+
             SubscribeLocalEvent<FlammableComponent, MapInitEvent>(OnMapInit);
             SubscribeLocalEvent<FlammableComponent, InteractUsingEvent>(OnInteractUsing);
             SubscribeLocalEvent<FlammableComponent, StartCollideEvent>(OnCollide);
@@ -203,7 +207,17 @@ namespace Content.Server.Atmos.EntitySystems
             if (flammable.OnFire && otherFlammable.OnFire)
             {
                 // Both are on fire -> equalize fire stacks.
-                var avg = (flammable.FireStacks + otherFlammable.FireStacks) / 2;
+                // Weight each thing's firestacks by its mass
+                var mass1 = 1f;
+                var mass2 = 1f;
+                if (_physicsQuery.TryComp(uid, out var physics) && _physicsQuery.TryComp(otherUid, out var otherPhys))
+                {
+                    mass1 = physics.Mass;
+                    mass2 = otherPhys.Mass;
+                }
+
+                var total = mass1 + mass2;
+                var avg = (flammable.FireStacks * mass1 + otherFlammable.FireStacks * mass2) / total;
                 flammable.FireStacks = flammable.CanExtinguish ? avg : Math.Max(flammable.FireStacks, avg);
                 otherFlammable.FireStacks = otherFlammable.CanExtinguish ? avg : Math.Max(otherFlammable.FireStacks, avg);
                 UpdateAppearance(uid, flammable);
@@ -212,25 +226,24 @@ namespace Content.Server.Atmos.EntitySystems
             }
 
             // Only one is on fire -> attempt to spread the fire.
-            if (flammable.OnFire)
+            var (srcUid, srcFlammable, destUid, destFlammable) = flammable.OnFire
+                ? (uid, flammable, otherUid, otherFlammable)
+                : (otherUid, otherFlammable, uid, flammable);
+
+            // if the thing on fire has less mass, spread less firestacks and vice versa
+            var ratio = 0.5f;
+            if (_physicsQuery.TryComp(srcUid, out var srcPhysics) && _physicsQuery.TryComp(destUid, out var destPhys))
             {
-                otherFlammable.FireStacks += flammable.FireStacks / 2;
-                Ignite(otherUid, uid, otherFlammable);
-                if (flammable.CanExtinguish)
-                {
-                    flammable.FireStacks /= 2;
-                    UpdateAppearance(uid, flammable);
-                }
+                ratio *= srcPhysics.Mass / destPhys.Mass;
             }
-            else
+
+            var lost = srcFlammable.FireStacks * ratio;
+            destFlammable.FireStacks += lost;
+            Ignite(destUid, srcUid, destFlammable);
+            if (srcFlammable.CanExtinguish)
             {
-                flammable.FireStacks += otherFlammable.FireStacks / 2;
-                Ignite(uid, otherUid, flammable);
-                if (otherFlammable.CanExtinguish)
-                {
-                    otherFlammable.FireStacks /= 2;
-                    UpdateAppearance(otherUid, otherFlammable);
-                }
+                srcFlammable.FireStacks -= lost;
+                UpdateAppearance(srcUid, srcFlammable);
             }
         }