205 lines
7.5 KiB
GDScript
205 lines
7.5 KiB
GDScript
class_name MPNavigationGraph
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extends Node2D
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# godot does not support types on dictionaries, actual type is Dictionary[NavigationNode, Array[NavigationNode]]
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var navigation_nodes: Dictionary = {}
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var latest_navigation_result: PathfindingResult = null
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var draw_nodes: bool = true
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var draw_edges: bool = true
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func all_nodes() -> Array[NavigationNode]:
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# i've had a problem where godot would not allow me to directly return navigation_nodes.keys()
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# because it wasn't able to cast the keys to Array[NavigationNode] directly because the type is not explicit
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# on the dictionary, so i had to do this workaround.
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var keys: Array = navigation_nodes.keys()
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var nodes: Array[NavigationNode] = []
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for key in keys:
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if key is NavigationNode:
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nodes.append(key)
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else:
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push_error("Key is not a NavigationNode: %s" % key)
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return nodes
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func get_connections(from: NavigationNode) -> Array[NavigationNode]:
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# the same problem as the all_nodes() function
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var connections: Array = navigation_nodes[from]
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var nodes: Array[NavigationNode] = []
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for connection in connections:
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if connection is NavigationNode:
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nodes.append(connection)
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else:
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push_error("Connection is not a NavigationNode: %s" % connection)
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return nodes
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func add_connection(from: NavigationNode, to: NavigationNode) -> void:
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if all_nodes().has(from):
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navigation_nodes[from].append(to)
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else:
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navigation_nodes[from] = [to]
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func add_node(x: float, y: float, merge_threshold: float = -1.0) -> NavigationNode:
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if merge_threshold > 0:
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var closest_node: NavigationNode = find_closest_node_with_threshold(Vector2(x, y), merge_threshold)
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if closest_node:
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closest_node.was_merged = true
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return closest_node
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var node: NavigationNode = NavigationNode.new()
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node.set_position(Vector2(x, y))
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navigation_nodes[node] = []
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return node
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func find_closest_node_with_threshold(position: Vector2, threshold: float) -> NavigationNode:
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var closest_node: NavigationNode = null
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var closest_distance: float = threshold
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for node in all_nodes():
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var distance: float = position.distance_to(node.position)
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if distance < closest_distance:
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closest_node = node
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closest_distance = distance
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return closest_node
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func remove_connection(from: NavigationNode, to: NavigationNode) -> void:
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if all_nodes().has(from):
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navigation_nodes[from].erase(to)
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func remove_node(node: NavigationNode) -> void:
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navigation_nodes.erase(node)
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for other_node in all_nodes():
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if other_node != node:
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remove_connection(other_node, node)
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func _draw() -> void:
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print("Drawing navigation graph")
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if draw_nodes or draw_edges:
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for from in all_nodes():
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if draw_edges:
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for to in get_connections(from):
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draw_line(local_to_world(from.position), local_to_world(to.position), Color.RED, 1, false)
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if draw_nodes:
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draw_circle(local_to_world(from.position), 5, Color.RED)
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if latest_navigation_result != null:
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if latest_navigation_result.path.size() > 1:
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for i in range(latest_navigation_result.path.size() - 1):
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draw_line(local_to_world(latest_navigation_result.path[i].position), local_to_world(latest_navigation_result.path[i + 1].position), Color.GREEN, 1, false)
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draw_circle(local_to_world(latest_navigation_result.next_position), 5, Color.GREEN)
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func local_to_world(location: Vector2) -> Vector2:
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return location * 32 + Vector2(16, 16)
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func draw_pathfinding_result(result: PathfindingResult) -> void:
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if latest_navigation_result and latest_navigation_result.is_identical_to(result):
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return
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latest_navigation_result = result
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queue_redraw()
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func determine_next_position(current_position: Vector2, target_position: Vector2) -> PathfindingResult:
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var result: PathfindingResult = PathfindingResult.new()
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# Find the closest node to the current position
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var start_node: NavigationNode = find_closest_node_with_threshold(current_position, INF)
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if start_node == null:
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# No nodes exist; cannot navigate
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result.is_next_target = true
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result.next_position = current_position
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return result
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# Find the closest node to the target position
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var end_node: NavigationNode = find_closest_node_with_threshold(target_position, INF)
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if end_node == null:
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# No nodes exist; cannot navigate
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result.is_next_target = true
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result.next_position = current_position
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return result
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# If the start and end nodes are the same, go directly to the target position
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if start_node == end_node:
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result.is_next_target = true
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result.next_position = target_position
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return result
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# Run Dijkstra's algorithm to find the path
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var path: Array[NavigationNode] = dijkstra(start_node, end_node)
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result.path = path
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# If a path is found, return the position of the next node in the path
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if path.size() > 1:
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# Next node in the path
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result.next_position = path[1].position
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return result
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elif path.size() == 1:
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# Directly reachable
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result.is_next_target = true
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result.next_position = target_position
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else:
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# No path found; return current position
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result.is_next_target = true
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result.next_position = current_position
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return result
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func array_contains_node(arr: Array, node: NavigationNode) -> bool:
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for item in arr:
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if item == node:
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return true
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return false
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func dijkstra(start_node: NavigationNode, end_node: NavigationNode) -> Array[NavigationNode]:
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var open_set: Array[NavigationNode] = []
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var closed_set: Array[NavigationNode] = []
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var distances: Dictionary = {}
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var previous_nodes: Dictionary = {}
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distances[start_node] = 0
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open_set.append(start_node)
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while open_set.size() > 0:
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# Find the node with the smallest tentative distance
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var current_node: NavigationNode = open_set[0]
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var current_distance: float = distances[current_node]
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for node in open_set:
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if distances[node] < current_distance:
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current_node = node
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current_distance = distances[node]
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# If the end node is reached, reconstruct the path
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if current_node == end_node:
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var path: Array[NavigationNode] = []
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var node: NavigationNode = end_node
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while node != null:
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path.insert(0, node)
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node = previous_nodes.get(node, null)
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return path
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open_set.erase(current_node)
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closed_set.append(current_node)
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# Examine neighbors of the current node
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var neighbors = get_connections(current_node)
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for neighbor in neighbors:
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if array_contains_node(closed_set, neighbor):
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continue
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var tentative_distance: float = distances[current_node] + current_node.position.distance_to(neighbor.position)
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if not array_contains_node(open_set, neighbor) or tentative_distance < distances.get(neighbor, INF):
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distances[neighbor] = tentative_distance
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previous_nodes[neighbor] = current_node
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if not array_contains_node(open_set, neighbor):
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open_set.append(neighbor)
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# No path found; return an empty array
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return []
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