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https://github.com/Relintai/godot-steering-ai-framework.git
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134 lines
3.7 KiB
GDScript
134 lines
3.7 KiB
GDScript
# Represents a path made up of Vector3 waypoints, split into segments path
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# follow behaviors can use.
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# @category - Base types
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class_name GSAIPath
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extends Reference
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# If `false`, the path loops.
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var is_open: bool
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# Total length of the path.
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var length: float
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var _segments: Array
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var _nearest_point_on_segment: Vector3
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var _nearest_point_on_path: Vector3
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func _init(waypoints: Array, _is_open := false) -> void:
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self.is_open = _is_open
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create_path(waypoints)
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_nearest_point_on_segment = waypoints[0]
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_nearest_point_on_path = waypoints[0]
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# Creates a path from a list of waypoints.
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func create_path(waypoints: Array) -> void:
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if not waypoints or waypoints.size() < 2:
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printerr("Waypoints cannot be null and must contain at least two (2) waypoints.")
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return
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_segments = []
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length = 0
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var current: Vector3 = waypoints.front()
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var previous: Vector3
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for i in range(1, waypoints.size(), 1):
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previous = current
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if i < waypoints.size():
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current = waypoints[i]
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elif is_open:
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break
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else:
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current = waypoints[0]
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var segment := GSAISegment.new(previous, current)
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length += segment.length
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segment.cumulative_length = length
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_segments.append(segment)
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# Returns the distance from `agent_current_position` to the next waypoint.
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func calculate_distance(agent_current_position: Vector3) -> float:
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if _segments.size() == 0:
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return 0.0
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var smallest_distance_squared: float = INF
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var nearest_segment: GSAISegment
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for i in range(_segments.size()):
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var segment: GSAISegment = _segments[i]
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var distance_squared := _calculate_point_segment_distance_squared(
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segment.begin, segment.end, agent_current_position
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)
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if distance_squared < smallest_distance_squared:
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_nearest_point_on_path = _nearest_point_on_segment
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smallest_distance_squared = distance_squared
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nearest_segment = segment
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var length_on_path := (
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nearest_segment.cumulative_length
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- _nearest_point_on_path.distance_to(nearest_segment.end)
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)
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return length_on_path
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# Calculates a target position from the path's starting point based on the `target_distance`.
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func calculate_target_position(target_distance: float) -> Vector3:
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if is_open:
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target_distance = clamp(target_distance, 0, length)
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else:
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if target_distance < 0:
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target_distance = length + fmod(target_distance, length)
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elif target_distance > length:
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target_distance = fmod(target_distance, length)
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var desired_segment: GSAISegment
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for i in range(_segments.size()):
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var segment: GSAISegment = _segments[i]
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if segment.cumulative_length >= target_distance:
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desired_segment = segment
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break
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if not desired_segment:
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desired_segment = _segments.back()
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var distance := desired_segment.cumulative_length - target_distance
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return (
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((desired_segment.begin - desired_segment.end) * (distance / desired_segment.length))
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+ desired_segment.end
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)
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# Returns the position of the first point on the path.
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func get_start_point() -> Vector3:
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return _segments.front().begin
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# Returns the position of the last point on the path.
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func get_end_point() -> Vector3:
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return _segments.back().end
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func _calculate_point_segment_distance_squared(start: Vector3, end: Vector3, position: Vector3) -> float:
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_nearest_point_on_segment = start
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var start_end := end - start
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var start_end_length_squared := start_end.length_squared()
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if start_end_length_squared != 0:
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var t = (position - start).dot(start_end) / start_end_length_squared
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_nearest_point_on_segment += start_end * clamp(t, 0, 1)
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return _nearest_point_on_segment.distance_squared_to(position)
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class GSAISegment:
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var begin: Vector3
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var end: Vector3
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var length: float
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var cumulative_length: float
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func _init(_begin: Vector3, _end: Vector3) -> void:
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self.begin = _begin
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self.end = _end
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length = _begin.distance_to(_end)
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