godot-steering-ai-framework/godot/addons/com.gdquest.godot-steering-ai-framework/Behaviors/GSAIAvoidCollisions.gd
2023-01-13 20:08:32 +01:00

64 lines
2.3 KiB
GDScript

# Steers the agent to avoid obstacles in its path. Approximates obstacles as
# spheres.
# @category - Group behaviors
class_name GSAIAvoidCollisions
extends GSAIGroupBehavior
var _first_neighbor: GSAISteeringAgent
var _shortest_time : float = 0.0
var _first_minimum_separation : float = 0.0
var _first_distance : float = 0.0
var _first_relative_position : Vector3
var _first_relative_velocity : Vector3
func _calculate_steering(acceleration: GSAITargetAcceleration) -> void:
_shortest_time = INF
_first_neighbor = null
_first_minimum_separation = 0
_first_distance = 0
var neighbor_count : int = proximity.find_neighbors(_callback)
if neighbor_count == 0 or not _first_neighbor:
acceleration.set_zero()
else:
if (_first_minimum_separation <= 0 || _first_distance < agent.bounding_radius + _first_neighbor.bounding_radius):
acceleration.linear = _first_neighbor.position - agent.position
else:
acceleration.linear = (_first_relative_position+ (_first_relative_velocity * _shortest_time))
acceleration.linear = (acceleration.linear.normalized() * -agent.linear_acceleration_max)
acceleration.angular = 0
# Callback for the proximity to call when finding neighbors. Keeps track of every `neighbor`
# that was found but only keeps the one the owning agent will most likely collide with.
# @tags - virtual
func _report_neighbor(neighbor: GSAISteeringAgent) -> bool:
var relative_position : Vector3 = neighbor.position - agent.position
var relative_velocity : Vector3 = neighbor.linear_velocity - agent.linear_velocity
var relative_speed_squared : float = relative_velocity.length_squared()
if relative_speed_squared == 0:
return false
else:
var time_to_collision : float = -relative_position.dot(relative_velocity) / relative_speed_squared
if time_to_collision <= 0 || time_to_collision >= _shortest_time:
return false
else:
var distance = relative_position.length()
var minimum_separation: float = (distance - sqrt(relative_speed_squared) * time_to_collision)
if minimum_separation > agent.bounding_radius + neighbor.bounding_radius:
return false
else:
_shortest_time = time_to_collision
_first_neighbor = neighbor
_first_minimum_separation = minimum_separation
_first_distance = distance
_first_relative_position = relative_position
_first_relative_velocity = relative_velocity
return true