Put dead matadors on a corpse collision layer

A killed matador's ragdoll shared the WORLD layer with the bull, so the
bull collided with the bodies and spazzed out on them. Give corpses a
dedicated CORPSE layer masked to itself, and tag the ground/walls with
CORPSE too (at level load, so it also reaches colliders baked into the
instanced GLB arenas). The corpse still rests on the arena, but the bull
— which only masks WORLD — passes straight through the bodies.

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

levels/game_shell.gd

@@ -4,6 +4,8 @@ extends Node3D
 ## spawners, lighting, colliders) into LevelRoot. Switching levels frees the whole
 ## previous module first, so no old mesh or collider can survive into the next fight.
 
+const PhysicsLayers = preload("res://physics_layers.gd")
+
 @onready var _level_root: Node3D = $LevelRoot
 @onready var _camera: IsoCamera = $Player/Camera3D
 
@@ -25,4 +27,16 @@ func load_active_level() -> void:
 		push_warning("game_shell: active level has no level_scene")
 		return
 	_camera.set_framing_scale(level.camera_zoom)
-	_level_root.add_child(level.level_scene.instantiate())
+	var module := level.level_scene.instantiate()
+	_tag_environment_for_corpses(module)
+	_level_root.add_child(module)
+
+
+## Ground and walls stay on WORLD so the bull and live matadors collide with them; here
+## we add CORPSE too. A killed matador's ragdoll is masked to CORPSE alone, so it rests
+## on the arena while the bull — which only collides with WORLD — passes through the body
+## instead of spazzing out on it. Done at load so it also reaches colliders baked into
+## the instanced GLB arenas, not just the level module's own floor box.
+func _tag_environment_for_corpses(module: Node) -> void:
+	for body: StaticBody3D in module.find_children("*", "StaticBody3D", true, false):
+		body.collision_layer |= PhysicsLayers.CORPSE

matador_ragdoll.gd

@@ -4,6 +4,8 @@ extends RefCounted
 ## limited swing/twist (DP-tunable) so the corpse keeps its silhouette instead of
 ## folding into a flat "deflated" pile; the cape stays free (PIN) so it drapes.
 
+const PhysicsLayers = preload("res://physics_layers.gd")
+
 # [bone, radius] → sphere collider; [bone, radius, height] → capsule.
 const _BONES: Array = [
 	["matador",       0.18],
@@ -53,10 +55,15 @@ static func build(skeleton: Skeleton3D) -> PhysicalBoneSimulator3D:
 		pb.bone_name       = bname
 		pb.mass            = 0.4
 		pb.linear_damp     = 0.1
-		pb.collision_layer = 1
-		pb.collision_mask  = 1
+		# The ragdoll only simulates once the matador is dead, so it lives on the CORPSE
+		# layer and masks to CORPSE alone: it rests on the ground/walls (which also carry
+		# CORPSE) but the bull — which collides only with WORLD — passes straight through
+		# the bodies instead of tripping over them.
+		pb.collision_layer = PhysicsLayers.CORPSE
+		pb.collision_mask  = PhysicsLayers.CORPSE
 		if bname.begins_with("Bone"):
-			# Cape: floppy cloth — free swing, light, draggy, one-way collision.
+			# Cape: floppy cloth — free swing, light, draggy, one-way collision (layer 0
+			# so nothing collides with it; it still drapes on the CORPSE-masked ground).
 			pb.joint_type      = PhysicalBone3D.JOINT_TYPE_PIN
 			pb.mass            = 0.15
 			pb.linear_damp     = 0.5

physics_layers.gd

@@ -0,0 +1,11 @@
+## Central registry of the 3D physics collision-layer bits. These mirror the
+## layer_names in project.godot so the editor's layer picker reads the same words.
+##
+## The bull only collides with WORLD, so a killed matador is lifted off WORLD onto
+## CORPSE alone (see matador_ragdoll.gd). The ground and walls carry WORLD | CORPSE
+## (tagged at level load in game_shell.gd), so the ragdoll still rests on the arena
+## while the bull passes through the bodies instead of tripping over them.
+
+const WORLD:  int = 1  # layer 1 — environment + live actors (bull, matadors, spears)
+const BULL:   int = 2  # layer 2 — the bull's own body
+const CORPSE: int = 4  # layer 3 — ragdolled matadors; ground/walls also carry this

physics_layers.gd.uid

@@ -0,0 +1 @@
+uid://d01o2ul83waw5

project.godot

@@ -118,6 +118,12 @@ ability_roll={
 
 pointing/emulate_touch_from_mouse=true
 
+[layer_names]
+
+3d_physics/layer_1="world"
+3d_physics/layer_2="bull"
+3d_physics/layer_3="corpse"
+
 [physics]
 
 3d/physics_engine="Jolt Physics"