FloodPath Class Reference

Floods the area completely for easy computation of any path to a single point. More...

Inheritance diagram for FloodPath:

Collaboration diagram for FloodPath:

Public Member Functions
	FloodPath (Vector3 start, OnPathDelegate callbackDelegate)
	Creates a new FloodPath instance.
override void	CalculateStep (long targetTick)
	Opens nodes until there are none left to search (or until the max time limit has been exceeded)
Node	GetParent (Node node)
bool	HasPathTo (Node node)
override void	Initialize ()
	Initializes the path.
override void	Prepare ()
override void	Reset ()
	Reset all values to their default values.
Public Member Functions inherited from Path
void	AdvanceState (PathState s)
	Threadsafe increment of the state.
bool	CanTraverse (Node node)
	Returns if the node can be traversed.
void	Claim (System.Object o)
	Claim this path.
virtual string	DebugString (PathLog logMode)
	Returns a debug string for this path.
void	Error ()
	Aborts the path because of an error.
void	ForceLogError (string msg)
	Logs an error and calls Error() to true.
PathState	GetState ()
	Returns the state of the path in the pathfinding pipeline.
uint	GetTagPenalty (int tag)
	Returns penalty for the given tag.
float	GetTotalLength ()
	Total Length of the path.
bool	IsDone ()
	Returns if this path is done calculating.
void	Log (string msg)
	Appends a message to the errorLog.
void	LogError (string msg)
	Appends msg to errorLog and logs msg to the console.
virtual void	OnEnterPool ()
	Called when the path enters the pool.
void	PrepareBase (NodeRunData runData)
	Prepares low level path variables for calculation.
void	Release (System.Object o)
	Releases a path claim.
void	ReleaseSilent (System.Object o)
	Releases the path silently.
virtual void	ReturnPath ()
	Calls callback to return the calculated path.
virtual void	Trace (NodeRun from)
	Traces the calculated path from the end node to the start.

Static Public Member Functions
static FloodPath	Construct (Vector3 start, OnPathDelegate callback=null)

Public Attributes
Vector3	originalStartPoint
Node	startNode
Vector3	startPoint
Public Attributes inherited from Path
OnPathDelegate	callback
	Callback to call when the path is complete.
System.DateTime	callTime
	When the call was made to start the pathfinding for this path.
float	duration
	The duration of this path in ms.
int	enabledTags = -1
	Which graph tags are traversable.
int	height
	Height of the character.
Heuristic	heuristic
	Determines which heuristic to use.
float	heuristicScale = 1F
	Scale of the heuristic values.
Path	next
	The next path to be searched.
NNConstraint	nnConstraint = PathNNConstraint.Default
	Constraint for how to search for nodes.
List< Node >	path
	Holds the path as a Node array.
ushort	pathID
	ID of this path.
int	radius
	Radius for the unit searching for the path.
bool	recycled = false
	True if the path is currently recycled (i.e in the path pool).
NodeRunData	runData
int	searchedNodes
	Number of nodes this path has searched.
int	searchIterations = 0
int	speed
	Speed of the character.
int	turnRadius
	Turning radius of the character.
List< Vector3 >	vectorPath
	Holds the (perhaps post processed) path as a Vector3 array.
int	walkabilityMask = -1
	A mask for defining what type of ground a unit can traverse, not used in any default standard graph.

Protected Member Functions
override void	Recycle ()
	Recycle the path.
void	Setup (Vector3 start, OnPathDelegate callback)
Protected Member Functions inherited from Path
bool	HasExceededTime (int searchedNodes, long targetTime)

Protected Attributes
Dictionary< Node, Node >	parents
Protected Attributes inherited from Path
int[]	_tagPenalties = new int[0]
	Penalties for each tag.
NodeRun	currentR
	The node currently being processed.
bool	hasBeenReset = false
	True if the Reset function has been called.
float	maxFrameTime
	The max number of milliseconds per iteration (frame, in case of non-multithreading)

Additional Inherited Members
Properties inherited from Path
PathCompleteState	CompleteState [get, set]
bool	error [get]
	If the path failed, this is true.
string	errorLog [get]
	Log messages with info about eventual errors.
int[]	tagPenalties [get, set]
	Penalties for each tag.

Detailed Description

Floods the area completely for easy computation of any path to a single point.

This path is a bit special, because it does not do anything useful by itself. What it does is that it calculates paths to all nodes it can reach, floods it. This data will remain stored in the path. Then you can call a FloodPathTracer path, that path will trace the path from it's starting point all the way to where this path started flooding and thus generating a path extremely quickly.
It is very useful in for example TD (Tower Defence) games where all your AIs will walk to the same point, but from different places, and you do not update the graph or change the target point very often, what changes is their positions and new AIs spawn all the time (which makes it hard to use the MultiTargetPath).

With this path type, it can all be handled easily.

• At start, you simply start ONE FloodPath and save the reference (it will be needed later).
• Then when a unit is spawned or needs it's path recalculated, start a FloodPathTracer path from it's position. It will then find the shortest path to the point specified when you called the FloodPath extremely quickly.
• If you update the graph (for example place a tower in a TD game) or need to change the target point, you simply call a new FloodPath (and store it's reference).

Version

From 3.2 and up, path traversal data is now stored in the path class. So you can now use other path types in parallel with this one.

Here follows some example code of the above list of steps:

public static FloodPath fpath;

public void Start () {
    fpath = new FloodPath (someTargetPosition, null);
    AstarPath.StartPath (fpath);
}

When searching for a new path to someTargetPosition from let's say transform.position, you do

FloodPathTracer fpathTrace = new FloodPathTracer (transform.position,fpath,null);
seeker.StartPath (fpathTrace,OnPathComplete);

Where OnPathComplete is your callback function.

Note

This path type relies on pathIDs being stored in the graph, but pathIDs are only 16 bits, meaning they will overflow after 65536 paths. When that happens all pathIDs in the graphs will be cleared, so at that point you will also need to recalculate the FloodPath.
To do so, register to the AstarPath::On65KOverflow callback:

public void Start () {
    AstarPath.On65KOverflow += MyCallbackFunction;
}

public void MyCallbackFunction () {
    //The callback is nulled every time it is called, so we need to register again
    AstarPath.On65KOverflow += MyCallbackFunction;
    
    //Recalculate the path
} 

This will happen after a very long time into the game, but it will happen eventually (look at the 'path number' value on the log messages when paths are completed for a hint about when)

Anothing thing to note is that if you are using NNConstraints on the FloodPathTracer, they must always inherit from Pathfinding::PathIDConstraint.
The easiest is to just modify the instance of PathIDConstraint which is created as the default one.

A* Pro Feature:

This is an A* Pathfinding Project Pro feature only. This function/class/variable might not exist in the Free version of the A* Pathfinding Project or the functionality might be limited
The Pro version can be bought here

Member Function Documentation

override void Initialize ( )

virtual

Initializes the path.

Sets up the open list and adds the first node to it

Implements Path.

Here is the call graph for this function:

override void Recycle ( )

protectedvirtual

Recycle the path.

Calling this means that the path and any variables on it are not needed anymore and the path can be pooled. All path data will be reset. Implement this in inheriting path types to support recycling of paths.

public override void Recycle () {
    //Recycle the Path (<Path> should be replaced by the path type it is implemented in)
    PathPool<Path>.Recycle (this);
}

Note

Do not call this function directly, instead use the Claim and Release functions.

See Also

Pathfinding.PathPool

Reset

Claim

Release

Implements Path.

override void Reset ( )

virtual

Reset all values to their default values.

All inheriting path types must implement this function, resetting ALL their variables to enable recycling of paths. Call this base function in inheriting types with base.Reset ();

Reimplemented from Path.

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

• /Users/aron/Unity/AstarPathfindingGIT/Assets/AstarPathfindingProject/Pathfinders/FloodPath.cs