Internal agent for the RVO system. More...

Detailed Description

Internal agent for the RVO system.

Usually you will interface with the IAgent interface instead.

See also: IAgent

Classes
struct	VO
	Velocity Obstacle. More...

class	VOBuffer
	Very simple list. More...

Public Member Functions
	Agent (Vector2 pos, float elevationCoordinate)

void	BufferSwitch ()
	Reads public properties and stores them in internal fields. More...

void	CalculateNeighbours ()
	Populate the neighbours and neighbourDists lists with the closest agents to this agent. More...

void	ForceSetVelocity (Vector2 velocity)
	Set the current velocity of the agent. More...

void	PostCalculation ()

void	PreCalculation ()

void	SetCollisionNormal (Vector2 normal)
	Set the normal of a wall (or something else) the agent is currently colliding with. More...

void	SetTarget (Vector2 targetPoint, float desiredSpeed, float maxSpeed)
	Point towards which the agent should move. More...

Package Functions
void	CalculateVelocity (Pathfinding.RVO.Simulator.WorkerContext context)

float	InsertAgentNeighbour (Agent agent, float rangeSq)
	Used by the Quadtree. More...

Package Attributes
bool	locked = false

Agent	next
	Used internally for a linked list. More...

Vector2	position

float	radius

Simulator	simulator
	Simulator which handles this agent. More...

Properties
float	AgentTimeHorizon `[get, set]`
	Max number of estimated seconds to look into the future for collisions with agents. More...

float	CalculatedSpeed `[get, private set]`
	Optimal speed of the agent to avoid collisions. More...

Vector2	CalculatedTargetPoint `[get, private set]`
	Optimal point to move towards to avoid collisions. More...

RVOLayer	CollidesWith `[get, set]`
	Layer mask specifying which layers this agent will avoid. More...

bool	DebugDraw `[get, set]`
	Draw debug information. More...

float	ElevationCoordinate `[get, set]`
	Coordinate which separates characters in the height direction. More...

float	Height `[get, set]`
	Height of the agent in world units. More...

RVOLayer	Layer `[get, set]`
	Specifies the avoidance layer for this agent. More...

bool	Locked `[get, set]`
	Locked agents will be assumed not to move. More...

int	MaxNeighbours `[get, set]`
	Max number of agents to take into account. More...

int	NeighbourCount `[get, private set]`
	Number of neighbours that the agent took into account during the last simulation step. More...

List< ObstacleVertex >	NeighbourObstacles `[get]`

float	ObstacleTimeHorizon `[get, set]`
	Max number of estimated seconds to look into the future for collisions with obstacles. More...

Vector2	Position `[get, set]`
	Position of the agent. More...

System.Action	PreCalculationCallback `[set, private get]`
	Callback which will be called right before avoidance calculations are started. More...

float	Priority `[get, set]`
	How strongly other agents will avoid this agent. More...

float	Radius `[get, set]`
	Radius of the agent in world units. More...

Properties inherited from IAgent
float	AgentTimeHorizon `[get, set]`
	Max number of estimated seconds to look into the future for collisions with agents. More...

float	CalculatedSpeed `[get]`
	Optimal speed of the agent to avoid collisions. More...

Vector2	CalculatedTargetPoint `[get]`
	Optimal point to move towards to avoid collisions. More...

RVOLayer	CollidesWith `[get, set]`
	Layer mask specifying which layers this agent will avoid. More...

bool	DebugDraw `[get, set]`
	Draw debug information. More...

float	ElevationCoordinate `[get, set]`
	Coordinate which separates characters in the height direction. More...

float	Height `[get, set]`
	Height of the agent in world units. More...

RVOLayer	Layer `[get, set]`
	Specifies the avoidance layer for this agent. More...

bool	Locked `[get, set]`
	Locked agents will be assumed not to move. More...

int	MaxNeighbours `[get, set]`
	Max number of agents to take into account. More...

int	NeighbourCount `[get]`
	Number of neighbours that the agent took into account during the last simulation step. More...

List< ObstacleVertex >	NeighbourObstacles `[get]`
	List of obstacle segments which were close to the agent during the last simulation step. More...

float	ObstacleTimeHorizon `[get, set]`
	Max number of estimated seconds to look into the future for collisions with obstacles. More...

Vector2	Position `[get, set]`
	Position of the agent. More...

System.Action	PreCalculationCallback `[set]`
	Callback which will be called right before avoidance calculations are started. More...

float	Priority `[get, set]`
	How strongly other agents will avoid this agent. More...

float	Radius `[get, set]`
	Radius of the agent in world units. More...

Private Member Functions
Vector2	EvaluateGradient (VOBuffer vos, Vector2 p, out float value)
	Evaluate gradient and value of the cost function at velocity p. More...

void	GenerateNeighbourAgentVOs (VOBuffer vos)

void	GenerateObstacleVOs (VOBuffer vos)

Vector2	GradientDescent (VOBuffer vos, Vector2 sampleAround1, Vector2 sampleAround2)

Vector2	To2D (Vector3 p, out float elevation)
	Converts a 3D vector to a 2D vector in the movement plane. More...

Vector2	Trace (VOBuffer vos, Vector2 p, out float score)
	Traces the vector field constructed out of the velocity obstacles. More...

Static Private Member Functions
static bool	BiasDesiredVelocity (VOBuffer vos, ref Vector2 desiredVelocity, ref Vector2 targetPointInVelocitySpace, float maxBiasRadians)
	Bias towards the right side of agents. More...

static void	DrawVO (Vector2 circleCenter, float radius, Vector2 origin)

static Vector3	FromXZ (Vector2 p)
	(x, 0, y) More...

static Color	Rainbow (float v)

static float	Sqr (float x)
	Square a number. More...

static Vector2	ToXZ (Vector3 p)
	(x, z) More...

Private Attributes
float	agentTimeHorizon

float	calculatedSpeed

Vector2	calculatedTargetPoint

RVOLayer	collidesWith

Vector2	collisionNormal

Vector2	currentVelocity

bool	debugDraw

float	desiredSpeed

Vector2	desiredTargetPointInVelocitySpace
	Desired target point - position. More...

Vector2	desiredVelocity

const float	DesiredVelocityWeight = 0.1f

float	elevationCoordinate

float	height

RVOLayer	layer

bool	manuallyControlled

int	maxNeighbours

float	maxSpeed

List< float >	neighbourDists = new List<float>()

List< Agent >	neighbours = new List<Agent>()

float	nextDesiredSpeed

float	nextMaxSpeed

Vector2	nextTargetPoint

List< ObstacleVertex >	obstacles = new List<ObstacleVertex>()

List< ObstacleVertex >	obstaclesBuffered = new List<ObstacleVertex>()

float	obstacleTimeHorizon

const float	WallWeight = 5
	Extra weight that walls will have. More...

Constructor & Destructor Documentation

◆ Agent()

Agent	(	Vector2	pos,
		float	elevationCoordinate
	)

Member Function Documentation

◆ BiasDesiredVelocity()

static bool BiasDesiredVelocity	(	VOBuffer	vos,
		ref Vector2	desiredVelocity,
		ref Vector2	targetPointInVelocitySpace,
		float	maxBiasRadians
	)

staticprivate

Bias towards the right side of agents.

Rotate desiredVelocity at most [value] number of radians. 1 radian ≈ 57° This breaks up symmetries.

The desired velocity will only be rotated if it is inside a velocity obstacle (VO). If it is inside one, it will not be rotated further than to the edge of it

The targetPointInVelocitySpace will be rotated by the same amount as the desired velocity

Returns: True if the desired velocity was inside any VO

◆ BufferSwitch()

void BufferSwitch ( )

Reads public properties and stores them in internal fields.

This is required because multithreading is used and if another script updated the fields at the same time as this class used them in another thread weird things could happen.

Will also set CalculatedTargetPoint and CalculatedSpeed to the result which was last calculated.

◆ CalculateNeighbours()

void CalculateNeighbours ( )

Populate the neighbours and neighbourDists lists with the closest agents to this agent.

◆ CalculateVelocity()

void CalculateVelocity ( Pathfinding.RVO.Simulator.WorkerContext context )

package

◆ DrawVO()

static void DrawVO	(	Vector2	circleCenter,
		float	radius,
		Vector2	origin
	)

staticprivate

◆ EvaluateGradient()

Vector2 EvaluateGradient	(	VOBuffer	vos,
		Vector2	p,
		out float	value
	)

private

Evaluate gradient and value of the cost function at velocity p.

◆ ForceSetVelocity()

void ForceSetVelocity ( Vector2 velocity )

Set the current velocity of the agent.

This will override the local avoidance input completely. It is useful if you have a player controlled character and want other agents to avoid it.

Calling this method will mark the agent as being externally controlled for 1 simulation step. Local avoidance calculations will be skipped for the next simulation step but will be resumed after that unless this method is called again.

Implements IAgent.

◆ FromXZ()

static Vector3 FromXZ ( Vector2 p )

staticprivate

(x, 0, y)

◆ GenerateNeighbourAgentVOs()

void GenerateNeighbourAgentVOs ( VOBuffer vos )

private

◆ GenerateObstacleVOs()

void GenerateObstacleVOs ( VOBuffer vos )

private

◆ GradientDescent()

Vector2 GradientDescent	(	VOBuffer	vos,
		Vector2	sampleAround1,
		Vector2	sampleAround2
	)

private

◆ InsertAgentNeighbour()

float InsertAgentNeighbour	(	Agent	agent,
		float	rangeSq
	)

package

Used by the Quadtree.

See also: CalculateNeighbours

◆ PostCalculation()

void PostCalculation ( )

◆ PreCalculation()

void PreCalculation ( )

◆ Rainbow()

static Color Rainbow ( float v )

staticprivate

◆ SetCollisionNormal()

void SetCollisionNormal ( Vector2 normal )

Set the normal of a wall (or something else) the agent is currently colliding with.

This is used to make the RVO system aware of things like physics or an agent being clamped to the navmesh. The velocity of this agent that other agents observe will be modified so that there is no component into the wall. The agent will however not start to avoid the wall, for that you will need to add RVO obstacles.

This value will be cleared after the next simulation step, normally it should be set every frame when the collision is still happening.

Implements IAgent.

◆ SetTarget()

void SetTarget	(	Vector2	targetPoint,
		float	desiredSpeed,
		float	maxSpeed
	)

Point towards which the agent should move.

Usually you set this once per frame. The agent will try move as close to the target point as possible. Will take effect at the next simulation step.

Note: The system assumes that the agent will stop when it reaches the target point so if you just want to move the agent in a particular direction, make sure that you set the target point a good distance in front of the character as otherwise the system may not avoid colisions that well. What would happen is that the system (in simplified terms) would think that the agents would stop before the collision and thus it wouldn't slow down or change course. See the image below. In the image the desiredSpeed is the length of the blue arrow and the target point is the point where the black arrows point to. In the upper case the agent does not avoid the red agent (you can assume that the red agent has a very small velocity for simplicity) while in the lower case it does.
If you are following a path a good way to pick the target point is to set it to
targetPoint = directionToNextWaypoint.normalized * remainingPathDistance
Where remainingPathDistance is the distance until the character would reach the end of the path. This works well because at the end of the path the direction to the next waypoint will just be the direction to the last point on the path and remainingPathDistance will be the distance to the last point in the path, so targetPoint will be set to simply the last point in the path. However when remainingPathDistance is large the target point will be so far away that the agent will essentially be told to move in a particular direction, which is precisely what we want.

Parameters

targetPoint	Target point in world space (XZ plane or XY plane depending on if the simulation is configured for 2D or 3D). Note that this is a Vector2, not a Vector3 since the system simulates everything internally in 2D. So if your agents move in the XZ plane you will have to supply it as a Vector2 with (x,z) coordinates.
desiredSpeed	Desired speed of the agent. In world units per second. The agent will try to move with this speed if possible.
maxSpeed	Max speed of the agent. In world units per second. If necessary (for example if another agent is on a collision trajectory towards this agent) the agent can move at this speed. Should be at least as high as desiredSpeed, but it is recommended to use a slightly higher value than desiredSpeed (for example desiredSpeed*1.2).

Implements IAgent.

◆ Sqr()

static float Sqr ( float x )

staticprivate

Square a number.

◆ To2D()

Vector2 To2D	(	Vector3	p,
		out float	elevation
	)

private

Converts a 3D vector to a 2D vector in the movement plane.

If movementPlane is XZ it will be projected onto the XZ plane and the elevation coordinate will be the Y coordinate otherwise it will be projected onto the XY plane and elevation will be the Z coordinate.

◆ ToXZ()

static Vector2 ToXZ ( Vector3 p )

staticprivate

(x, z)

◆ Trace()

Vector2 Trace	(	VOBuffer	vos,
		Vector2	p,
		out float	score
	)

private

Traces the vector field constructed out of the velocity obstacles.

Returns the position which gives the minimum score (approximately).

See also: https://en.wikipedia.org/wiki/Gradient_descent

private

◆ desiredTargetPointInVelocitySpace

Vector2 desiredTargetPointInVelocitySpace

Agent next

Used by this script as a reference and to prevent adding this agent to multiple simulations.

◆ WallWeight

const float WallWeight = 5

private

Extra weight that walls will have.

Property Documentation

◆ AgentTimeHorizon

float AgentTimeHorizon

getset

Max number of estimated seconds to look into the future for collisions with agents.

As it turns out, this variable is also very good for controling agent avoidance priorities. Agents with lower values will avoid other agents less and thus you can make 'high priority agents' by giving them a lower value.

◆ CalculatedSpeed

float CalculatedSpeed

getprivate set

Optimal speed of the agent to avoid collisions.

The movement script should move towards CalculatedTargetPoint with this speed.

◆ CalculatedTargetPoint

Vector2 CalculatedTargetPoint

getprivate set

Optimal point to move towards to avoid collisions.

The movement script should move towards this point with a speed of CalculatedSpeed.

Note: This is a Vector2, not a Vector3 as that is what the SetTarget method accepts.

See also: RVOController.CalculateMovementDelta.

◆ CollidesWith

RVOLayer CollidesWith

getset

Layer mask specifying which layers this agent will avoid.

You can set it as CollidesWith = RVOLayer.DefaultAgent | RVOLayer.Layer3 | RVOLayer.Layer6 ...

See also: http://en.wikipedia.org/wiki/Mask_(computing)

◆ DebugDraw

bool DebugDraw

getset

Draw debug information.

Note: Will always draw debug info in the XZ plane even if Pathfinding.RVO.Simulator.movementPlane is set to XY.; Ignored if multithreading on the simulator component has been enabled since Unity's Debug API can only be called from the main thread.

◆ ElevationCoordinate

float ElevationCoordinate

getset

Coordinate which separates characters in the height direction.

Since RVO can be used either in 2D or 3D, it is not as simple as just using the y coordinate of the 3D position. In 3D this will most likely be set to the y coordinate, but in 2D (top down) it should in most cases be set to 0 since all characters are always in the same plane, however it may be set to some other value, for example if the game is 2D isometric.

The position is assumed to be at the base of the character (near the feet).

◆ Height

float Height

getset

Height of the agent in world units.

Agents are modelled as circles/cylinders.

◆ Layer

RVOLayer Layer

getset

Specifies the avoidance layer for this agent.

The CollidesWith mask on other agents will determine if they will avoid this agent.

◆ Locked

bool Locked

getset

Locked agents will be assumed not to move.

◆ MaxNeighbours

int MaxNeighbours

getset

Max number of agents to take into account.

Decreasing this value can lead to better performance, increasing it can lead to better quality of the simulation.

◆ NeighbourCount

int NeighbourCount

getprivate set

Number of neighbours that the agent took into account during the last simulation step.

◆ NeighbourObstacles

List<ObstacleVertex> NeighbourObstacles

get

◆ ObstacleTimeHorizon

float ObstacleTimeHorizon

getset

Max number of estimated seconds to look into the future for collisions with obstacles.

◆ Position

Vector2 Position

getset

Position of the agent.

The agent does not move by itself, a movement script has to be responsible for reading the CalculatedTargetPoint and CalculatedSpeed properties and move towards that point with that speed. This property should ideally be set every frame.

Note that this is a Vector2, not a Vector3 since the RVO simulates everything internally in 2D. So if your agents move in the XZ plane you may have to convert it to a Vector3 like this.

Vector3 position3D = new Vector3(agent.Position.x, agent.ElevationCoordinate, agent.Position.y);

◆ PreCalculationCallback

System.Action PreCalculationCallback

setprivate get

Callback which will be called right before avoidance calculations are started.

Used to update the other properties with the most up to date values

◆ Priority

float Priority

getset

How strongly other agents will avoid this agent.

Usually a value between 0 and 1. Agents with similar priorities will avoid each other with an equal strength. If an agent sees another agent with a higher priority than itself it will avoid that agent more strongly. In the extreme case (e.g this agent has a priority of 0 and the other agent has a priority of 1) it will treat the other agent as being a moving obstacle. Similarly if an agent sees another agent with a lower priority than itself it will avoid that agent less.

In general the avoidance strength for this agent is:

if this.priority > 0 or other.priority > 0:
    avoidanceStrength = other.priority / (this.priority + other.priority);
else:
    avoidanceStrength = 0.5

◆ Radius

float Radius

getset

Radius of the agent in world units.

Agents are modelled as circles/cylinders.

The documentation for this class was generated from the following file:

/Users/arong/Unity/a-pathfinding-project/Assets/AstarPathfindingProject/Core/RVO/RVOAgent.cs

Detailed Description

Classes

Public Member Functions

Package Functions

Package Attributes

Properties

Private Member Functions

Static Private Member Functions

Private Attributes

Constructor & Destructor Documentation

◆ Agent()

Member Function Documentation

◆ BiasDesiredVelocity()

◆ BufferSwitch()

◆ CalculateNeighbours()

◆ CalculateVelocity()

◆ DrawVO()

◆ EvaluateGradient()

◆ ForceSetVelocity()

◆ FromXZ()

◆ GenerateNeighbourAgentVOs()

◆ GenerateObstacleVOs()

◆ GradientDescent()

◆ InsertAgentNeighbour()

◆ PostCalculation()

◆ PreCalculation()

◆ Rainbow()

◆ SetCollisionNormal()

◆ SetTarget()

◆ Sqr()

◆ To2D()

◆ ToXZ()

◆ Trace()

Member Data Documentation

◆ agentTimeHorizon

◆ calculatedSpeed

◆ calculatedTargetPoint

◆ collidesWith

◆ collisionNormal

◆ currentVelocity

◆ debugDraw

◆ desiredSpeed

◆ desiredTargetPointInVelocitySpace

◆ desiredVelocity

◆ DesiredVelocityWeight

◆ elevationCoordinate

◆ height

◆ layer

◆ locked

◆ manuallyControlled

◆ maxNeighbours

◆ maxSpeed

◆ neighbourDists

◆ neighbours

◆ next

◆ nextDesiredSpeed

◆ nextMaxSpeed

◆ nextTargetPoint

◆ obstacles

◆ obstaclesBuffered

◆ obstacleTimeHorizon

◆ position

◆ radius

◆ simulator

◆ WallWeight

Property Documentation

◆ AgentTimeHorizon

◆ CalculatedSpeed

◆ CalculatedTargetPoint

◆ CollidesWith

◆ DebugDraw

◆ ElevationCoordinate

◆ Height

◆ Layer

◆ Locked

◆ MaxNeighbours

◆ NeighbourCount

◆ NeighbourObstacles

◆ ObstacleTimeHorizon

◆ Position