Table of Contents

Class NavigationAgent2D

A 2D agent used to pathfind to a position while avoiding obstacles.

Inheritance
NavigationAgent2D

A 2D agent used to pathfind to a position while avoiding static and dynamic obstacles. The calculation can be used by the parent node to dynamically move it along the path. Requires navigation data to work correctly.

Dynamic obstacles are avoided using RVO collision avoidance. Avoidance is computed before physics, so the pathfinding information can be used safely in the physics step.

Note: After setting the target_position property, the get_next_path_position method must be used once every physics frame to update the internal path logic of the navigation agent. The vector position it returns should be used as the next movement position for the agent's parent node.

See Also

Using NavigationAgents

Properties

If true the agent is registered for an RVO avoidance callback on the NavigationServer2D. When velocity is used and the processing is completed a safe_velocity Vector2 is received with a signal connection to NavigationAgent2D.velocity_computed. Avoidance processing with many registered agents has a significant performance cost and should only be enabled on agents that currently require it.

var avoidance_enabled : bool = false

Property Value

bool
  • void set_avoidance_enabled(bool value)
  • bool get_avoidance_enabled

A bitfield determining the avoidance layers for this NavigationAgent. Other agents with a matching bit on the avoidance_mask will avoid this agent.

var avoidance_layers : int = 1

Property Value

int
  • void set_avoidance_layers(int value)
  • int get_avoidance_layers

A bitfield determining what other avoidance agents and obstacles this NavigationAgent will avoid when a bit matches at least one of their avoidance_layers.

var avoidance_mask : int = 1

Property Value

int
  • void set_avoidance_mask(int value)
  • int get_avoidance_mask

The agent does not adjust the velocity for other agents that would match the avoidance_mask but have a lower avoidance_priority. This in turn makes the other agents with lower priority adjust their velocities even more to avoid collision with this agent.

var avoidance_priority : float = 1.0

Property Value

float
  • void set_avoidance_priority(float value)
  • float get_avoidance_priority

If true shows debug visuals for this agent.

var debug_enabled : bool = false

Property Value

bool
  • void set_debug_enabled(bool value)
  • bool get_debug_enabled

If debug_use_custom is true uses this color for this agent instead of global color.

var debug_path_custom_color : Color = Color(1, 1, 1, 1)

Property Value

Color
  • void set_debug_path_custom_color(Color value)
  • Color get_debug_path_custom_color

If debug_use_custom is true uses this line width for rendering paths for this agent instead of global line width.

var debug_path_custom_line_width : float = -1.0

Property Value

float
  • void set_debug_path_custom_line_width(float value)
  • float get_debug_path_custom_line_width

If debug_use_custom is true uses this rasterized point size for rendering path points for this agent instead of global point size.

var debug_path_custom_point_size : float = 4.0

Property Value

float
  • void set_debug_path_custom_point_size(float value)
  • float get_debug_path_custom_point_size

If true uses the defined debug_path_custom_color for this agent instead of global color.

var debug_use_custom : bool = false

Property Value

bool
  • void set_debug_use_custom(bool value)
  • bool get_debug_use_custom

The maximum number of neighbors for the agent to consider.

var max_neighbors : int = 10

Property Value

int
  • void set_max_neighbors(int value)
  • int get_max_neighbors

The maximum speed that an agent can move.

var max_speed : float = 100.0

Property Value

float
  • void set_max_speed(float value)
  • float get_max_speed

A bitfield determining which navigation layers of navigation regions this agent will use to calculate a path. Changing it during runtime will clear the current navigation path and generate a new one, according to the new navigation layers.

var navigation_layers : int = 1

Property Value

int
  • void set_navigation_layers(int value)
  • int get_navigation_layers

The distance to search for other agents.

var neighbor_distance : float = 500.0

Property Value

float
  • void set_neighbor_distance(float value)
  • float get_neighbor_distance

The distance threshold before a path point is considered to be reached. This allows agents to not have to hit a path point on the path exactly, but only to reach its general area. If this value is set too high, the NavigationAgent will skip points on the path, which can lead to it leaving the navigation mesh. If this value is set too low, the NavigationAgent will be stuck in a repath loop because it will constantly overshoot the distance to the next point on each physics frame update.

var path_desired_distance : float = 20.0

Property Value

float
  • void set_path_desired_distance(float value)
  • float get_path_desired_distance

The maximum distance the agent is allowed away from the ideal path to the final position. This can happen due to trying to avoid collisions. When the maximum distance is exceeded, it recalculates the ideal path.

var path_max_distance : float = 100.0

Property Value

float
  • void set_path_max_distance(float value)
  • float get_path_max_distance

Additional information to return with the navigation path.

var path_metadata_flags : int = 7

Property Value

int
  • void set_path_metadata_flags(int value)
  • int get_path_metadata_flags

The path postprocessing applied to the raw path corridor found by the pathfinding_algorithm.

var path_postprocessing : int = 0

Property Value

int
  • void set_path_postprocessing(int value)
  • int get_path_postprocessing

The pathfinding algorithm used in the path query.

var pathfinding_algorithm : int = 0

Property Value

int
  • void set_pathfinding_algorithm(int value)
  • int get_pathfinding_algorithm

The radius of the avoidance agent. This is the "body" of the avoidance agent and not the avoidance maneuver starting radius (which is controlled by neighbor_distance).

Does not affect normal pathfinding. To change an actor's pathfinding radius bake NavigationMesh resources with a different agent_radius property and use different navigation maps for each actor size.

var radius : float = 10.0

Property Value

float

The path simplification amount in worlds units.

var simplify_epsilon : float = 0.0

Property Value

float
  • void set_simplify_epsilon(float value)
  • float get_simplify_epsilon

If true a simplified version of the path will be returned with less critical path points removed. The simplification amount is controlled by simplify_epsilon. The simplification uses a variant of Ramer-Douglas-Peucker algorithm for curve point decimation.

Path simplification can be helpful to mitigate various path following issues that can arise with certain agent types and script behaviors. E.g. "steering" agents or avoidance in "open fields".

var simplify_path : bool = false

Property Value

bool
  • void set_simplify_path(bool value)
  • bool get_simplify_path

The distance threshold before the target is considered to be reached. On reaching the target, target_reached is emitted and navigation ends (see is_navigation_finished and navigation_finished).

You can make navigation end early by setting this property to a value greater than path_desired_distance (navigation will end before reaching the last waypoint).

You can also make navigation end closer to the target than each individual path position by setting this property to a value lower than path_desired_distance (navigation won't immediately end when reaching the last waypoint). However, if the value set is too low, the agent will be stuck in a repath loop because it will constantly overshoot the distance to the target on each physics frame update.

var target_desired_distance : float = 10.0

Property Value

float
  • void set_target_desired_distance(float value)
  • float get_target_desired_distance

If set, a new navigation path from the current agent position to the target_position is requested from the NavigationServer.

var target_position : Vector2 = Vector2(0, 0)

Property Value

Vector2

The minimal amount of time for which this agent's velocities, that are computed with the collision avoidance algorithm, are safe with respect to other agents. The larger the number, the sooner the agent will respond to other agents, but less freedom in choosing its velocities. A too high value will slow down agents movement considerably. Must be positive.

var time_horizon_agents : float = 1.0

Property Value

float
  • void set_time_horizon_agents(float value)
  • float get_time_horizon_agents

The minimal amount of time for which this agent's velocities, that are computed with the collision avoidance algorithm, are safe with respect to static avoidance obstacles. The larger the number, the sooner the agent will respond to static avoidance obstacles, but less freedom in choosing its velocities. A too high value will slow down agents movement considerably. Must be positive.

var time_horizon_obstacles : float = 0.0

Property Value

float
  • void set_time_horizon_obstacles(float value)
  • float get_time_horizon_obstacles

Sets the new wanted velocity for the agent. The avoidance simulation will try to fulfill this velocity if possible but will modify it to avoid collision with other agents and obstacles. When an agent is teleported to a new position, use NavigationAgent2D.set_velocity_forced as well to reset the internal simulation velocity.

var velocity : Vector2 = Vector2(0, 0)

Property Value

Vector2

Methods

Qualifiers: const

Returns the distance to the target position, using the agent's global position. The user must set target_position in order for this to be accurate.

float distance_to_target

get_avoidance_layer_value(int)

Qualifiers: const

Returns whether or not the specified layer of the avoidance_layers bitmask is enabled, given a layer_number between 1 and 32.

bool get_avoidance_layer_value(int layer_number)

Parameters

layer_number int

get_avoidance_mask_value(int)

Qualifiers: const

Returns whether or not the specified mask of the avoidance_mask bitmask is enabled, given a mask_number between 1 and 32.

bool get_avoidance_mask_value(int mask_number)

Parameters

mask_number int

Qualifiers: const

Returns this agent's current path from start to finish in global coordinates. The path only updates when the target position is changed or the agent requires a repath. The path array is not intended to be used in direct path movement as the agent has its own internal path logic that would get corrupted by changing the path array manually. Use the intended get_next_path_position once every physics frame to receive the next path point for the agents movement as this function also updates the internal path logic.

PackedVector2Array get_current_navigation_path

Qualifiers: const

Returns which index the agent is currently on in the navigation path's PackedVector2Array.

int get_current_navigation_path_index

Qualifiers: const

Returns the path query result for the path the agent is currently following.

NavigationPathQueryResult2D get_current_navigation_result

Returns the reachable final position of the current navigation path in global coordinates. This position can change if the agent needs to update the navigation path which makes the agent emit the path_changed signal.

Vector2 get_final_position

get_navigation_layer_value(int)

Qualifiers: const

Returns whether or not the specified layer of the navigation_layers bitmask is enabled, given a layer_number between 1 and 32.

bool get_navigation_layer_value(int layer_number)

Parameters

layer_number int

Qualifiers: const

Returns the RID of the navigation map for this NavigationAgent node. This function returns always the map set on the NavigationAgent node and not the map of the abstract agent on the NavigationServer. If the agent map is changed directly with the NavigationServer API the NavigationAgent node will not be aware of the map change. Use NavigationAgent2D.set_navigation_map to change the navigation map for the NavigationAgent and also update the agent on the NavigationServer.

RID get_navigation_map

Returns the next position in global coordinates that can be moved to, making sure that there are no static objects in the way. If the agent does not have a navigation path, it will return the position of the agent's parent. The use of this function once every physics frame is required to update the internal path logic of the NavigationAgent.

Vector2 get_next_path_position

Qualifiers: const

Returns the RID of this agent on the NavigationServer2D.

RID get_rid

Returns true if the agent's navigation has finished. If the target is reachable, navigation ends when the target is reached. If the target is unreachable, navigation ends when the last waypoint of the path is reached.

Note: While true prefer to stop calling update functions like get_next_path_position. This avoids jittering the standing agent due to calling repeated path updates.

bool is_navigation_finished

Returns true if get_final_position is within target_desired_distance of the target_position.

bool is_target_reachable

Qualifiers: const

Returns true if the agent reached the target, i.e. the agent moved within target_desired_distance of the target_position. It may not always be possible to reach the target but it should always be possible to reach the final position. See get_final_position.

bool is_target_reached

set_avoidance_layer_value(int, bool)

Based on value, enables or disables the specified layer in the avoidance_layers bitmask, given a layer_number between 1 and 32.

void set_avoidance_layer_value(int layer_number, bool value)

Parameters

layer_number int
value bool

set_avoidance_mask_value(int, bool)

Based on value, enables or disables the specified mask in the avoidance_mask bitmask, given a mask_number between 1 and 32.

void set_avoidance_mask_value(int mask_number, bool value)

Parameters

mask_number int
value bool

set_navigation_layer_value(int, bool)

Based on value, enables or disables the specified layer in the navigation_layers bitmask, given a layer_number between 1 and 32.

void set_navigation_layer_value(int layer_number, bool value)

Parameters

layer_number int
value bool

set_navigation_map(RID)

Sets the RID of the navigation map this NavigationAgent node should use and also updates the agent on the NavigationServer.

void set_navigation_map(RID navigation_map)

Parameters

navigation_map RID

set_velocity_forced(Vector2)

Replaces the internal velocity in the collision avoidance simulation with velocity. When an agent is teleported to a new position this function should be used in the same frame. If called frequently this function can get agents stuck.

void set_velocity_forced(Vector2 velocity)

Parameters

velocity Vector2

Events

link_reached(Dictionary)

Signals that the agent reached a navigation link. Emitted when the agent moves within path_desired_distance of the next position of the path when that position is a navigation link.

The details dictionary may contain the following keys depending on the value of path_metadata_flags:

  • position: The start position of the link that was reached.

  • type: Always NavigationPathQueryResult2D.PATH_SEGMENT_TYPE_LINK.

  • rid: The RID of the link.

  • owner: The object which manages the link (usually NavigationLink2D).

  • link_entry_position: If owner is available and the owner is a NavigationLink2D, it will contain the global position of the link's point the agent is entering.

  • link_exit_position: If owner is available and the owner is a NavigationLink2D, it will contain the global position of the link's point which the agent is exiting.

signal link_reached(Dictionary details)

Parameters

details Dictionary

Signals that the agent's navigation has finished. If the target is reachable, navigation ends when the target is reached. If the target is unreachable, navigation ends when the last waypoint of the path is reached. This signal is emitted only once per loaded path.

This signal will be emitted just after target_reached when the target is reachable.

signal navigation_finished

Emitted when the agent had to update the loaded path:

  • because path was previously empty.

  • because navigation map has changed.

  • because agent pushed further away from the current path segment than the path_max_distance.

signal path_changed

Signals that the agent reached the target, i.e. the agent moved within target_desired_distance of the target_position. This signal is emitted only once per loaded path.

This signal will be emitted just before navigation_finished when the target is reachable.

It may not always be possible to reach the target but it should always be possible to reach the final position. See get_final_position.

signal target_reached

velocity_computed(Vector2)

Notifies when the collision avoidance velocity is calculated. Emitted every update as long as avoidance_enabled is true and the agent has a navigation map.

signal velocity_computed(Vector2 safe_velocity)

Parameters

safe_velocity Vector2

waypoint_reached(Dictionary)

Signals that the agent reached a waypoint. Emitted when the agent moves within path_desired_distance of the next position of the path.

The details dictionary may contain the following keys depending on the value of path_metadata_flags:

  • position: The position of the waypoint that was reached.

  • type: The type of navigation primitive (region or link) that contains this waypoint.

  • rid: The RID of the containing navigation primitive (region or link).

  • owner: The object which manages the containing navigation primitive (region or link).

signal waypoint_reached(Dictionary details)

Parameters

details Dictionary