Adds enemies

demo/ai/tasks/pursue.gd

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+#*
+#* pursue.gd
+#* =============================================================================
+#* Copyright (c) 2023-present Serhii Snitsaruk and the LimboAI contributors.
+#*
+#* Use of this source code is governed by an MIT-style
+#* license that can be found in the LICENSE file or at
+#* https://opensource.org/licenses/MIT.
+#* =============================================================================
+#*
+@tool
+extends BTAction
+## Move towards the target until the agent is flanking it. [br]
+## Returns [code]RUNNING[/code] while moving towards the target but not yet at the desired position. [br]
+## Returns [code]SUCCESS[/code] when at the desired position relative to the target (flanking it). [br]
+## Returns [code]FAILURE[/code] if the target is not a valid [Node2D] instance. [br]
+
+## How close should the agent be to the desired position to return SUCCESS.
+const TOLERANCE := 30.0
+
+## Blackboard variable that stores our target (expecting Node2D).
+@export var target_var: StringName = &"target"
+
+## Blackboard variable that stores desired speed.
+@export var speed_var: StringName = &"speed"
+
+## Desired distance from target.
+@export var approach_distance: float = 100.0
+
+var _waypoint: Vector2
+
+
+# Display a customized name (requires @tool).
+func _generate_name() -> String:
+	return "Pursue %s" % [LimboUtility.decorate_var(target_var)]
+
+
+# Called each time this task is entered.
+func _enter() -> void:
+	var target: Node2D = blackboard.get_var(target_var, null)
+	if is_instance_valid(target):
+		# Movement is performed in smaller steps.
+		# For each step, we select a new waypoint.
+		_select_new_waypoint(_get_desired_position(target))
+
+
+# Called each time this task is ticked (aka executed).
+func _tick(_delta: float) -> Status:
+	var target: Node2D = blackboard.get_var(target_var, null)
+	if not is_instance_valid(target):
+		return FAILURE
+
+	var desired_pos: Vector2 = _get_desired_position(target)
+	if agent.global_position.distance_to(desired_pos) < TOLERANCE:
+		return SUCCESS
+
+	if agent.global_position.distance_to(_waypoint) < TOLERANCE:
+		_select_new_waypoint(desired_pos)
+
+	var speed: float = blackboard.get_var(speed_var, 200.0)
+	var desired_velocity: Vector2 = agent.global_position.direction_to(_waypoint) * speed
+	agent.move(desired_velocity)
+	agent.update_facing()
+	return RUNNING
+
+
+## Get the closest flanking position to target.
+func _get_desired_position(target: Node2D) -> Vector2:
+	var side: float = signf(agent.global_position.x - target.global_position.x)
+	var desired_pos: Vector2 = target.global_position
+	desired_pos.x += approach_distance * side
+	return desired_pos
+
+
+## Select an intermidiate waypoint towards the desired position.
+func _select_new_waypoint(desired_position: Vector2) -> void:
+	var distance_vector: Vector2 = desired_position - agent.global_position
+	var angle_variation: float = randf_range(-0.2, 0.2)
+	_waypoint = agent.global_position + distance_vector.limit_length(150.0).rotated(angle_variation)