feat: add remote avatar detection and scene-aware trigger areas

- Add TriggerDetector collision to avatars for trigger area detection
- Track avatar entity IDs via metadata (dcl_entity_id, dcl_scene_id)
- Implement scene-awareness: only fire events for entities in active scene
- Separate physical state (entities_inside) from logical state (entities_entered)
- Generate synthetic ENTER/EXIT events when entities change scenes while
  physically inside trigger areas
- Query avatar current scene via metadata to handle remote avatar scene changes

Author: kuruk-mm

godot/project.godot

@@ -185,7 +185,7 @@ pointing/emulate_touch_from_mouse=true
 3d_render/layer_20="OUTLINE_SYSTEM_DEPTH"
 3d_physics/layer_1="CL_POINTER"
 3d_physics/layer_2="CL_PHYSICS"
-3d_physics/layer_3="CL_RESERVED1"
+3d_physics/layer_3="CL_PLAYER"
 3d_physics/layer_4="CL_RESERVED2"
 3d_physics/layer_5="CL_RESERVED3"
 3d_physics/layer_6="CL_RESERVED4"

godot/src/decentraland_components/avatar/avatar.gd

@@ -13,6 +13,11 @@ const WEARABLE_NAME_PREFIX = "__"
 @export var hide_name: bool = false
 @export var non_3d_audio: bool = false
 
+# Entity info for trigger area detection (set by avatar_shape.rs for scene avatars)
+var dcl_scene_id: int = -1
+var dcl_entity_id: int = -1
+var is_local_player: bool = false
+
 # Public
 var avatar_id: String = ""
 var hidden: bool = false
@@ -53,6 +58,7 @@ var wearable_promises = null
 
 @onready var avatar_modifier_area_detector = $avatar_modifier_area_detector
 @onready var click_area = $ClickArea
+@onready var trigger_detector = %TriggerDetector
 
 
 func _ready():
@@ -90,6 +96,41 @@ func _ready():
 	click_area.set_meta("is_avatar", true)
 	click_area.set_meta("avatar_id", avatar_id)
 
+	# Connect to scene change signal for trigger area tracking
+	# This signal is emitted by DclAvatar (Rust side) when the avatar changes parcels
+	change_scene_id.connect(self._on_avatar_scene_changed)
+
+	# Trigger detection is setup later via setup_trigger_detection() when entity info is available
+
+
+## Setup trigger detection for this avatar.
+## Call this after the avatar is created with the appropriate entity info.
+## - For local player: scene_id=-1, entity_id=SceneEntityId.PLAYER (0x10000)
+## - For remote avatars: scene_id=-1, entity_id=assigned entity from avatar_scene.rs
+## - For scene avatars (NPCs): scene_id and entity_id from the scene
+func setup_trigger_detection(p_scene_id: int, p_entity_id: int) -> void:
+	dcl_scene_id = p_scene_id
+	dcl_entity_id = p_entity_id
+
+	# Set metadata on TriggerDetector so trigger_area.rs can identify this avatar
+	trigger_detector.set_meta("dcl_scene_id", dcl_scene_id)
+	trigger_detector.set_meta("dcl_entity_id", dcl_entity_id)
+
+	# Initialize current scene metadata (will be updated via _on_avatar_scene_changed)
+	# For scene NPCs, this stays at dcl_scene_id; for remote avatars, it will be updated
+	trigger_detector.set_meta("dcl_avatar_current_scene_id", dcl_scene_id)
+
+	# Enable the collision shape
+	trigger_detector.get_node("CollisionShape3D").disabled = false
+
+
+## Called when the avatar changes parcel scenes (signal from DclAvatar/Rust)
+func _on_avatar_scene_changed(new_scene_id: int, _prev_scene_id: int) -> void:
+	# Update the current scene metadata on TriggerDetector
+	# This allows trigger_area.rs to know which scene this avatar is currently in
+	if trigger_detector:
+		trigger_detector.set_meta("dcl_avatar_current_scene_id", new_scene_id)
+
 
 func on_chat_message(address: String, message: String, _timestamp: float):
 	if avatar_id != address:

godot/src/decentraland_components/avatar/avatar.tscn

@@ -360,6 +360,10 @@ height = 0.1
 
 [sub_resource type="CapsuleShape3D" id="CapsuleShape3D_mwwx3"]
 
+[sub_resource type="CapsuleShape3D" id="CapsuleShape3D_trigger"]
+radius = 0.25
+height = 1.5
+
 [node name="Avatar" type="DclAvatar"]
 script = ExtResource("1_mwwx3")
 
@@ -899,6 +903,16 @@ bus = &"Scene"
 
 [node name="Avatar_SFXs" parent="." instance=ExtResource("7_xt6ge")]
 
+[node name="TriggerDetector" type="StaticBody3D" parent="."]
+unique_name_in_owner = true
+collision_layer = 4
+collision_mask = 0
+
+[node name="CollisionShape3D" type="CollisionShape3D" parent="TriggerDetector"]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1.2, 0)
+shape = SubResource("CapsuleShape3D_trigger")
+disabled = true
+
 [node name="ClickArea" type="Area3D" parent="."]
 unique_name_in_owner = true
 collision_layer = 536870912

godot/src/logic/player/player.gd

@@ -135,6 +135,10 @@ func _ready():
 	if own_click_area:
 		own_click_area.queue_free()
 
+	# Setup trigger detection for local player's avatar
+	# scene_id=-1 (not a scene NPC), entity_id=1 (SceneEntityId::PLAYER)
+	avatar.setup_trigger_detection(-1, 1)
+
 
 func _on_player_profile_changed(new_profile: DclUserProfile):
 	var new_version = new_profile.get_profile_version()

lib/src/avatars/avatar_scene.rs

@@ -208,6 +208,16 @@ impl AvatarScene {
         new_avatar.connect("emote_triggered".into(), emote_triggered_callable);
 
         self.base_mut().add_child(new_avatar.clone().upcast());
+
+        // Setup trigger detection with the assigned entity_id
+        // scene_id=-1 means this is a remote avatar (not a scene NPC)
+        // NOTE: This must be called AFTER add_child so that _ready() has been called
+        // and the @onready trigger_detector variable is initialized
+        new_avatar.call(
+            "setup_trigger_detection".into(),
+            &[(-1_i32).to_variant(), entity_id.as_i32().to_variant()],
+        );
+
         self.avatar_godot_scene
             .insert(entity_id, new_avatar.clone());
 

lib/src/scene_runner/components/avatar_shape.rs

@@ -126,6 +126,13 @@ pub fn update_avatar_shape(scene: &mut Scene, crdt_state: &mut SceneCrdtState) {
                     new_avatar_shape.set_name(GString::from("AvatarShape"));
                     node_3d.add_child(new_avatar_shape.clone().upcast());
 
+                    // Setup trigger detection for scene avatar (NPC)
+                    // scene_id from the scene, entity_id from the entity
+                    new_avatar_shape.call(
+                        "setup_trigger_detection".into(),
+                        &[scene.scene_id.0.to_variant(), entity.as_i32().to_variant()],
+                    );
+
                     new_avatar_shape.call_deferred(
                         "async_update_avatar".into(),
                         &[new_avatar_data.to_variant(), avatar_name.to_variant()],