Local Avoidance Simulator. More...

Detailed Description

Local Avoidance Simulator.

This class handles local avoidance simulation for a number of agents using Reciprocal Velocity Obstacles (RVO) and Optimal Reciprocal Collision Avoidance (ORCA).

This class will handle calculation of velocities from desired velocities supplied by a script. It is, however, not responsible for moving any objects in a Unity Scene. For that there are other scripts (see below).

Obstacles can be added and removed from the simulation, agents can also be added and removed at any time.

See Also: RVOSimulator RVOAgent Pathfinding.RVO.IAgent

The implementation is based on the RVO2 Library (http://gamma.cs.unc.edu/RVO2/) extended with many new features.

You will most likely mostly use the wrapper class RVOSimulator.

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Classes
class	Worker

class	WorkerContext

Public Types
enum	SamplingAlgorithm { AdaptiveSampling, GradientDescent }

Public Member Functions
	Simulator (int workers, bool doubleBuffering)
	Create a new simulator.

IAgent	AddAgent (IAgent agent)
	Add a previously removed agent to the simulation.

IAgent	AddAgent (Vector3 position)
	Add an agent at the specified position.

ObstacleVertex	AddObstacle (ObstacleVertex v)
	Adds a previously removed obstacle.

ObstacleVertex	AddObstacle (Vector3[] vertices, float height)
	Adds an obstacle described by the vertices.

ObstacleVertex	AddObstacle (Vector3[] vertices, float height, Matrix4x4 matrix, RVOLayer layer=RVOLayer.DefaultObstacle)
	Adds an obstacle described by the vertices.

ObstacleVertex	AddObstacle (Vector3 a, Vector3 b, float height)
	Adds a line obstacle with a specified height.

void	ClearAgents ()
	Removes all agents from the simulation.

List< Agent >	GetAgents ()
	Get a list of all agents.

List< ObstacleVertex >	GetObstacles ()
	Get a list of all obstacles.

void	OnDestroy ()

void	RemoveAgent (IAgent agent)
	Removes a specified agent from this simulation.

void	RemoveObstacle (ObstacleVertex v)
	Removes the obstacle identified by the vertex.

void	Update ()
	Should be called once per frame.

void	UpdateObstacle (ObstacleVertex obstacle, Vector3[] vertices, Matrix4x4 matrix)
	Updates the vertices of an obstacle.

void	UpdateObstacles ()
	Rebuilds the obstacle tree at next simulation frame.

Public Attributes
SamplingAlgorithm	algorithm = SamplingAlgorithm.AdaptiveSampling
	What sampling algorithm to use.

List< ObstacleVertex >	obstacles
	Obstacles in this simulation.

float	qualityCutoff = 0.05f

float	stepScale = 1.5f

Properties
float	DeltaTime `[get]`

float	DesiredDeltaTime `[get, set]`
	Time in seconds between each simulation step.

bool	Interpolation `[get, set]`
	Use Interpolation.

KDTree	KDTree `[get]`
	KDTree for this simulation.

bool	Multithreading `[get]`
	Is using multithreading.

bool	Oversampling `[get, set]`

float	PrevDeltaTime `[get]`

RVOQuadtree	Quadtree `[get]`
	Quadtree for this simulation.

float	WallThickness `[get, set]`

Private Member Functions
	~Simulator ()
	Terminates any worker threads.

void	BuildQuadtree ()

void	CleanObstacles ()

void	ScheduleCleanObstacles ()

Private Attributes
List< Agent >	agents
	Agents in this simulation.

WorkerContext	coroutineWorkerContext = new WorkerContext()

float	deltaTime

float	desiredDeltaTime = 0.05f
	Inverse desired simulation fps.

bool	doCleanObstacles = false

bool	doubleBuffering = true
	Use Double Buffering.

bool	doUpdateObstacles = false

bool	interpolation = true
	Use Interpolation.

KDTree	kdTree
	KDTree for this simulation.

float	lastStep = -99999

float	lastStepInterpolationReference = -9999

bool	oversampling = false

float	prevDeltaTime = 0

RVOQuadtree	quadtree = new RVOQuadtree()

float	wallThickness = 1

Worker[]	workers
	Worker threads.

Member Enumeration Documentation

enum SamplingAlgorithm

Enumerator:

AdaptiveSampling
GradientDescent

Constructor & Destructor Documentation

Simulator	(	int	workers,
		bool	doubleBuffering
	)

Create a new simulator.

Parameters

workers	Use the specified number of worker threads. When the number zero is specified, no multithreading will be used. A good number is the number of cores on the machine.
doubleBuffering	Use Double Buffering for calculations. Testing done with 5000 agents and 0.1 desired delta time showed that with double buffering enabled the game ran at 50 fps for most frames, dropping to 10 fps during calculation frames. But without double buffering it ran at around 10 fps all the time. This will let threads calculate while the game progresses instead of waiting for the calculations to finish.

Note: Will only have effect if using multithreading

See Also: Multithreading

~Simulator ( )

private

Terminates any worker threads.

Member Function Documentation

IAgent AddAgent ( IAgent agent )

Add a previously removed agent to the simulation.

An agent can only be in one simulation at a time, any attempt to add an agent to two simulations or multiple times to the same simulation will result in an exception being thrown.

See Also: RemoveAgent

IAgent AddAgent ( Vector3 position )

Add an agent at the specified position.

You can use the returned interface to read several parameters such as position and velocity and set for example radius and desired velocity.

See Also: RemoveAgent

ObstacleVertex AddObstacle ( ObstacleVertex v )

Adds a previously removed obstacle.

This does not check if the obstacle is already added to the simulation, so please do not add an obstacle multiple times.

It is assumed that this is a valid obstacle.

ObstacleVertex AddObstacle	(	Vector3[]	vertices,
		float	height
	)

Adds an obstacle described by the vertices.

See Also: RemoveObstacle

ObstacleVertex AddObstacle	(	Vector3[]	vertices,
		float	height,
		Matrix4x4	matrix,
		RVOLayer	layer = `RVOLayer.DefaultObstacle`
	)

Adds an obstacle described by the vertices.

See Also: RemoveObstacle

ObstacleVertex AddObstacle	(	Vector3	a,
		Vector3	b,
		float	height
	)

Adds a line obstacle with a specified height.

See Also: RemoveObstacle

void BuildQuadtree ( )

private

void CleanObstacles ( )

private

void ClearAgents ( )

Removes all agents from the simulation.

List<Agent> GetAgents ( )

Get a list of all agents.

This is an internal list. I'm not going to be restrictive so you may access it since it is better for performance but please do not modify it since that can cause errors in the simulation.

Warning: Do not modify this list!

List<ObstacleVertex> GetObstacles ( )

Get a list of all obstacles.

This is a list of obstacle vertices. Each vertex is part of a doubly linked list loop forming an obstacle polygon.

Warning: Do not modify this list!

See Also: AddObstacle; RemoveObstacle

void OnDestroy ( )

void RemoveAgent ( IAgent agent )

Removes a specified agent from this simulation.

The agent can be added again later by using AddAgent.

See Also: AddAgent(IAgent); ClearAgents

void RemoveObstacle ( ObstacleVertex v )

Removes the obstacle identified by the vertex.

This must be the same vertex as the one returned by the AddObstacle call.

See Also: AddObstacle

void ScheduleCleanObstacles ( )

private

void Update ( )

Should be called once per frame.

void UpdateObstacle	(	ObstacleVertex	obstacle,
		Vector3[]	vertices,
		Matrix4x4	matrix
	)

Updates the vertices of an obstacle.

Parameters

obstacle	Obstacle to update
vertices	New vertices for the obstacle, must have at least the number of vertices in the original obstacle
matrix	Matrix to multiply vertices with before updating obstacle

The number of vertices in an obstacle cannot be changed, existing vertices can only be moved.

void UpdateObstacles ( )

Rebuilds the obstacle tree at next simulation frame.

Add and remove obstacle functions call this automatically.

Member Data Documentation

List<Agent> agents

private

Agents in this simulation.

SamplingAlgorithm algorithm = SamplingAlgorithm.AdaptiveSampling

What sampling algorithm to use.

See Also: "Reciprocal Velocity Obstacles for Real-Time Multi-Agent Navigation"; https://en.wikipedia.org/wiki/Gradient_descent; http://digestingduck.blogspot.se/2010/04/adaptive-rvo-sampling.html; http://digestingduck.blogspot.se/2010/10/rvo-sample-pattern.html

WorkerContext coroutineWorkerContext = new WorkerContext()

private

float deltaTime

private

float desiredDeltaTime = 0.05f

private

Inverse desired simulation fps.

See Also: DesiredDeltaTime

bool doCleanObstacles = false

private

bool doubleBuffering = true

private

Use Double Buffering.

See Also: DoubleBuffering

bool doUpdateObstacles = false

private

bool interpolation = true

private

Use Interpolation.

See Also: Interpolation

KDTree kdTree

private

KDTree for this simulation.

float lastStep = -99999

private

float lastStepInterpolationReference = -9999

private

List<ObstacleVertex> obstacles

Obstacles in this simulation.

bool oversampling = false

private

float prevDeltaTime = 0

private

RVOQuadtree quadtree = new RVOQuadtree()

private

float qualityCutoff = 0.05f

float stepScale = 1.5f

float wallThickness = 1

private

Worker [] workers

private

Worker threads.

Property Documentation

float DeltaTime

get

float DesiredDeltaTime

getset

Time in seconds between each simulation step.

This is the desired delta time, the simulation will never run at a higher fps than the rate at which the Update function is called.

bool Interpolation

getset

Use Interpolation.

If interpolation is enabled, agent positions will be interpolated on frames when no rvo calculation is done. This has a very small overhead, but usually yields much smoother looking movement.

KDTree KDTree

get

KDTree for this simulation.

Used internally by the simulation. Please only read from this tree, do not rebuild it since that can interfere with the simulation. It is rebuilt when needed.

bool Multithreading

get

Is using multithreading.

bool Oversampling

getset

float PrevDeltaTime

get

RVOQuadtree Quadtree

get

Quadtree for this simulation.

Used internally by the simulation to perform fast neighbour lookups for each agent. Please only read from this tree, do not rebuild it since that can interfere with the simulation. It is rebuilt when needed.

float WallThickness

getset

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

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

Detailed Description

Classes

Public Types

Public Member Functions

Public Attributes

Properties

Private Member Functions

Private Attributes

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

Property Documentation