DR-042 Phase C (legibility, part 2): walls block enemies (C5) — restore the fortress fantasy

Player-built structures now physically block enemies (husks walked straight through walls before). Dedicated
"Structure" physics layer (slot 9) so the player passes its own walls while enemies are stopped:

- New WorldCollisionConfig.StructureMask, baked from the "Structure" layer in WorldCollisionAuthoring (mirrors
  EnvironmentMask). EnemyAISystem ORs it into the movement sweep filter (CollidesWith = envMask | structMask) —
  no new system, same 1-2 SphereCasts per enemy.
- Wall/Turret/Pylon prefabs get a cell-sized BoxCollider on the Structure layer (Wall's existing one relayered).
- Physics matrix: Default x Structure unchecked, so the kinematic player CC (Default) passes its own walls while
  the enemy's explicit cast still hits them. Despawn frees collision for free (collider dies with the entity).

Play-verified baked filters: StructMask=512; structure colliders BelongsTo=512, CollidesWith=0xFFFFFFFE
(includes Environment for the enemy cast, EXCLUDES bit 0 so the player passes). 389/389 EditMode, no exceptions.
Server-only/static colliders -> deterministic, no client divergence. SaveData stays v5.

Phase C complete (C5-C7). A visual fun-gate (husk stops at wall, player walks through) is the operator's eyes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/_Project/Prefabs/Pylon.prefab

@@ -102,7 +102,8 @@ GameObject:
   - component: {fileID: 9053853372340598254}
   - component: {fileID: 6834786618115927220}
   - component: {fileID: 7685488391646220227}
-  m_Layer: 0
+  - component: {fileID: 1225369404710843925}
+  m_Layer: 9
   m_Name: Pylon
   m_TagString: Untagged
   m_Icon: {fileID: 0}
@@ -177,3 +178,24 @@ MonoBehaviour:
   m_EditorClassIdentifier: ProjectM.Authoring::ProjectM.Authoring.StructureAuthoring
   Kind: 6
   MaxHp: 150
+--- !u!65 &1225369404710843925
+BoxCollider:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 3885353946372160549}
+  m_Material: {fileID: 0}
+  m_IncludeLayers:
+    serializedVersion: 2
+    m_Bits: 0
+  m_ExcludeLayers:
+    serializedVersion: 2
+    m_Bits: 0
+  m_LayerOverridePriority: 0
+  m_IsTrigger: 0
+  m_ProvidesContacts: 0
+  m_Enabled: 1
+  serializedVersion: 3
+  m_Size: {x: 1.6, y: 2, z: 1.6}
+  m_Center: {x: 0, y: 1, z: 0}

Assets/_Project/Prefabs/Turret.prefab

@@ -378,7 +378,8 @@ GameObject:
   - component: {fileID: 9053853372340598254}
   - component: {fileID: 6834786618115927220}
   - component: {fileID: 1794795016809289889}
-  m_Layer: 0
+  - component: {fileID: 9049467567705961987}
+  m_Layer: 9
   m_Name: Turret
   m_TagString: Untagged
   m_Icon: {fileID: 0}
@@ -455,6 +456,27 @@ MonoBehaviour:
   CooldownTicks: 30
   Damage: 12
   MaxHp: 120
+--- !u!65 &9049467567705961987
+BoxCollider:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 3885353946372160549}
+  m_Material: {fileID: 0}
+  m_IncludeLayers:
+    serializedVersion: 2
+    m_Bits: 0
+  m_ExcludeLayers:
+    serializedVersion: 2
+    m_Bits: 0
+  m_LayerOverridePriority: 0
+  m_IsTrigger: 0
+  m_ProvidesContacts: 0
+  m_Enabled: 1
+  serializedVersion: 3
+  m_Size: {x: 1.6, y: 2, z: 1.6}
+  m_Center: {x: 0, y: 1, z: 0}
 --- !u!1 &4051895978514069616
 GameObject:
   m_ObjectHideFlags: 0

Assets/_Project/Prefabs/Wall.prefab

@@ -103,7 +103,7 @@ GameObject:
   - component: {fileID: 6834786618115927220}
   - component: {fileID: 8793146551006314905}
   - component: {fileID: 7779358222264100756}
-  m_Layer: 0
+  m_Layer: 9
   m_Name: Wall
   m_TagString: Untagged
   m_Icon: {fileID: 0}

Assets/_Project/Scripts/Authoring/World/WorldCollisionAuthoring.cs

@@ -15,6 +15,9 @@ namespace ProjectM.Authoring
     {
         [Tooltip("Name of the Unity layer carrying the static world colliders (boundary ring + landmarks).")]
         public string EnvironmentLayerName = "Environment";
+        [Tooltip("DR-042 C5: Unity layer carrying player-built structure colliders (Wall/Turret/Pylon) that block enemies.")]
+        public string StructureLayerName = "Structure";
+
 
         private class WorldCollisionBaker : Baker<WorldCollisionAuthoring>
         {
@@ -23,7 +26,9 @@ namespace ProjectM.Authoring
                 int layer = LayerMask.NameToLayer(authoring.EnvironmentLayerName);
                 uint mask = layer >= 0 ? 1u << layer : 0u;
                 var entity = GetEntity(TransformUsageFlags.None);
-                AddComponent(entity, new WorldCollisionConfig { EnvironmentMask = mask });
+                int structLayer = LayerMask.NameToLayer(authoring.StructureLayerName);
+                uint structMask = structLayer >= 0 ? 1u << structLayer : 0u;
+                AddComponent(entity, new WorldCollisionConfig { EnvironmentMask = mask, StructureMask = structMask });
             }
         }
     }

Assets/_Project/Scripts/Server/Combat/EnemyAISystem.cs

@@ -100,8 +100,9 @@ namespace ProjectM.Server
             var ecb = new EntityCommandBuffer(Allocator.Temp);
             bool havePhysics = SystemAPI.TryGetSingleton<PhysicsWorldSingleton>(out var physics);
             uint envMask = SystemAPI.TryGetSingleton<WorldCollisionConfig>(out var worldCol) ? worldCol.EnvironmentMask : 0u;
-            var envFilter = new CollisionFilter { BelongsTo = ~0u, CollidesWith = envMask, GroupIndex = 0 };
+            uint sweepMask = envMask | worldCol.StructureMask; // DR-042 C5: also collide enemies against player-built walls
-            bool sweep = havePhysics && envMask != 0u;
+            var envFilter = new CollisionFilter { BelongsTo = ~0u, CollidesWith = sweepMask, GroupIndex = 0 };
+            bool sweep = havePhysics && sweepMask != 0u;
             const float SweepRadius = 0.5f; // collide-and-slide sphere radius for Husk movement
 
             foreach (var (xform, stats, cooldown, knockback, windup, region) in

Assets/_Project/Scripts/Simulation/World/WorldCollisionComponents.cs

@@ -11,7 +11,14 @@ namespace ProjectM.Simulation
     /// </summary>
     public struct WorldCollisionConfig : IComponentData
     {
+        /// <summary>BelongsTo bitmask of the Environment physics layer (<c>1u &lt;&lt; layerIndex</c>).</summary>
         /// <summary>BelongsTo bitmask of the Environment physics layer (<c>1u &lt;&lt; layerIndex</c>).</summary>
         public uint EnvironmentMask;
+
+        /// <summary>DR-042 C5: BelongsTo bitmask of the "Structure" physics layer (player-built Wall/Turret/Pylon
+        /// colliders). OR'd into the enemy-movement sweep filter so husks collide-and-slide against walls. 0 if the
+        /// layer is absent (feature inert). The layer matrix excludes Structure&times;the player layer so the player CC
+        /// passes through its own walls.</summary>
+        public uint StructureMask;
     }
 }

ProjectSettings/DynamicsManager.asset

@@ -3,10 +3,11 @@
 --- !u!55 &1
 PhysicsManager:
   m_ObjectHideFlags: 0
-  serializedVersion: 13
+  serializedVersion: 23
   m_Gravity: {x: 0, y: -9.81, z: 0}
   m_DefaultMaterial: {fileID: 0}
   m_BounceThreshold: 2
+  m_DefaultMaxDepenetrationVelocity: 10
   m_SleepThreshold: 0.005
   m_DefaultContactOffset: 0.01
   m_DefaultSolverIterations: 6
@@ -16,11 +17,11 @@ PhysicsManager:
   m_EnableAdaptiveForce: 0
   m_ClothInterCollisionDistance: 0.1
   m_ClothInterCollisionStiffness: 0.2
-  m_ContactsGeneration: 1
+  m_LayerCollisionMatrix: fffdfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffeffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
-  m_LayerCollisionMatrix: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
+  m_SimulationMode: 0
-  m_AutoSimulation: 1
   m_AutoSyncTransforms: 0
   m_ReuseCollisionCallbacks: 1
+  m_InvokeCollisionCallbacks: 1
   m_ClothInterCollisionSettingsToggle: 0
   m_ClothGravity: {x: 0, y: -9.81, z: 0}
   m_ContactPairsMode: 0
@@ -31,6 +32,14 @@ PhysicsManager:
   m_WorldSubdivisions: 8
   m_FrictionType: 0
   m_EnableEnhancedDeterminism: 0
-  m_EnableUnifiedHeightmaps: 1
+  m_ImprovedPatchFriction: 0
+  m_GenerateOnTriggerStayEvents: 1
   m_SolverType: 0
   m_DefaultMaxAngularSpeed: 50
+  m_ScratchBufferChunkCount: 4
+  m_CurrentBackendId: 4072204805
+  m_FastMotionThreshold: 3.4028235e+38
+  m_SceneBuffersReleaseInterval: 0
+  m_ReleaseSceneBuffers: 0
+  m_LogVerbosity: 3
+  m_IncrementalStaticBroadphase: 1

ProjectSettings/TagManager.asset

@@ -14,7 +14,7 @@ TagManager:
   - 
   - 
   - Environment
-  - 
+  - Structure
   - 
   - 
   -