feat(homing): bullet_manager 受限角速度转向 + 锁定式目标重选 + bounce 协同; 删除无人消费的位置快照

_apply_homing 在位置积分前把速度矢量朝目标旋转，单帧转角上限 strength*delta，
rotated() 保持速率不变；wrapf 取最短转向方向。
目标仅在失效或首帧时经 _find_nearest_unvisited 重选，配 get_active_count()==0
空场守卫，避免 query_circle(r=400) 进入每帧热路径。
bounce 命中重定向时改写 homing_target_id，由 bounce 选目标 homing 追上去。
删除 _enemy_pos_snapshot 及 EnemyManager.fill_pos_snapshot（全项目唯一调用方）。

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/autoloads/bullet_manager.gd

@@ -18,9 +18,6 @@ var _active_count: int = 0
 # 冷数据（非热路径）
 var _bullet_contexts: Dictionary = {}
 
-# 敌人位置快照（homing 共用，由 _physics_process 帧头建立）
-var _enemy_pos_snapshot: PackedVector2Array = PackedVector2Array()
-
 var _cs_node: Node = null
 
 func _ready() -> void:
@@ -28,15 +25,17 @@ func _ready() -> void:
 	_data.fill(0.0)
 
 func _physics_process(delta: float) -> void:
-	EnemyManager.fill_pos_snapshot(_enemy_pos_snapshot)
 	if not _cs_node:
 		_gd_integrate(delta)
 
 # GDScript 回退路径（C# 未就绪时 / S0/S1 基线验证）
 func _gd_integrate(delta: float) -> void:
+	var has_cold: bool = not _bullet_contexts.is_empty()
 	var i: int = 0
 	while i < _active_count:
 		var base: int = i * BULLET_STRIDE
+		if has_cold and _bullet_contexts.has(i):
+			_apply_homing(i, base, delta)          # 转向须在位置积分之前，子弹当帧即沿新方向前进
 		_data[base + 0] += _data[base + 2] * delta  # x += vx * dt
 		_data[base + 1] += _data[base + 3] * delta  # y += vy * dt
 		_data[base + 2] += _data[base + 11] * delta # vx += accel * dt
@@ -116,6 +115,8 @@ func _check_collision(bullet_idx: int, base: int) -> bool:
 				_data[base + 2] = dir.x * spd
 				_data[base + 3] = dir.y * spd
 				_data[base + 7] *= float(cold.get("bounce_decay", 0.9))
+				if cold.has("homing_strength"):
+					cold["homing_target_id"] = next_id   # bounce 选目标，homing 接手追上去
 				cold["bounce_remaining"] = bounce - 1
 				cold["visited_targets"]  = visited
 				_bullet_contexts[bullet_idx] = cold
@@ -214,6 +215,37 @@ func _find_nearest_unvisited(origin: Vector2, radius: float, visited: Array) ->
 			best_id = eid
 	return best_id
 
+## 归航转向：以 homing_strength(弧度/秒) 为上限把速度矢量转向锁定目标，速率不变
+## 目标失效（死亡/未锁定）时重选一次；场上无敌人或射程内无目标则保持直行
+func _apply_homing(bullet_idx: int, base: int, delta: float) -> void:
+	var cold: Dictionary = _bullet_contexts[bullet_idx]
+	var strength: float = float(cold.get("homing_strength", 0.0))
+	if strength <= 0.0:
+		return
+	var pos: Vector2 = Vector2(_data[base + 0], _data[base + 1])
+	var tid: int = int(cold.get("homing_target_id", -1))
+	var tpos: Vector2 = Vector2(-9999.0, -9999.0)
+	if tid >= 0:
+		tpos = EnemyManager.get_pos_by_id(tid)
+	if tpos == Vector2(-9999.0, -9999.0):
+		# 目标失效或首帧：重选。空场守卫避免清场瞬间全体子弹集体 query_circle
+		if EnemyManager.get_active_count() == 0:
+			return
+		tid = _find_nearest_unvisited(pos, float(cold.get("homing_range", 400.0)), cold.get("visited_targets", []))
+		cold["homing_target_id"] = tid
+		_bullet_contexts[bullet_idx] = cold
+		if tid < 0:
+			return
+		tpos = EnemyManager.get_pos_by_id(tid)
+		if tpos == Vector2(-9999.0, -9999.0):
+			return
+	var vel: Vector2 = Vector2(_data[base + 2], _data[base + 3])
+	var diff: float = wrapf((tpos - pos).angle() - vel.angle(), -PI, PI)   # 最短转向方向
+	var max_step: float = strength * delta
+	var nv: Vector2 = vel.rotated(clampf(diff, -max_step, max_step))       # rotated 保持速率不变
+	_data[base + 2] = nv.x
+	_data[base + 3] = nv.y
+
 func get_nearest_enemy_pos(origin: Vector2, max_dist: float = 9999.0) -> Vector2:
 	return EnemyManager.get_nearest_pos(origin, max_dist)
 

scripts/autoloads/enemy_manager.gd

@@ -342,13 +342,6 @@ func get_nearest_pos(origin: Vector2, max_dist: float = 9999.0) -> Vector2:
 			best = Vector2(_data[base + 0], _data[base + 1])
 	return best
 
-## 建立敌人位置快照（BulletManager homing 共用）
-func fill_pos_snapshot(out_arr: PackedVector2Array) -> void:
-	out_arr.resize(_active_count)
-	for i in _active_count:
-		var base: int = i * ENEMY_STRIDE
-		out_arr[i] = Vector2(_data[base + 0], _data[base + 1])
-
 ## 同步 Node2D 显示位置（屏内 dirty sync）
 func sync_node_positions(enemy_nodes: Array) -> void:
 	for i in min(_active_count, enemy_nodes.size()):