A* Pathfinding Project
4.1.7
The A* Pathfinding Project for Unity 3D
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A path which searches from one point to a number of different targets in one search or from a number of different start points to a single target. More...
A path which searches from one point to a number of different targets in one search or from a number of different start points to a single target.
This is faster than searching with an ABPath for each target if pathsForAll is true. This path type can be used for example when you want an agent to find the closest target of a few different options.
When pathsForAll is true, it will calculate a path to each target point, but it can share a lot of calculations for the different paths so it is faster than requesting them separately.
When pathsForAll is false, it will perform a search using the heuristic set to None and stop as soon as it finds the first target. This may be faster or slower than requesting each path separately. It will run a Dijkstra search where it searches all nodes around the start point until the closest target is found. Note that this is usually faster if some target points are very close to the start point and some are very far away, but it can be slower if all target points are relatively far away because then it will have to search a much larger region since it will not use any heuristics.
Public Types | |
enum | HeuristicMode { None, Average, MovingAverage, Midpoint, MovingMidpoint, Sequential } |
Public Member Functions | |
MultiTargetPath () | |
Default constructor. More... | |
Public Member Functions inherited from ABPath | |
ABPath () | |
Default constructor. More... | |
Public Member Functions inherited from Path | |
void | BlockUntilCalculated () |
Blocks until this path has been calculated and returned. More... | |
void | Claim (System.Object o) |
Claim this path (pooling). More... | |
void | Error () |
Aborts the path because of an error. More... | |
PathState | GetState () |
Returns the state of the path in the pathfinding pipeline. More... | |
float | GetTotalLength () |
Total Length of the path. More... | |
bool | IsDone () |
Returns if this path is done calculating. More... | |
void | Release (System.Object o, bool silent=false) |
Releases a path claim (pooling). More... | |
IEnumerator | WaitForPath () |
Waits until this path has been calculated and returned. More... | |
Static Public Member Functions | |
static MultiTargetPath | Construct (Vector3[] startPoints, Vector3 target, OnPathDelegate[] callbackDelegates, OnPathDelegate callback=null) |
static MultiTargetPath | Construct (Vector3 start, Vector3[] targets, OnPathDelegate[] callbackDelegates, OnPathDelegate callback=null) |
Static Public Member Functions inherited from ABPath | |
static ABPath | Construct (Vector3 start, Vector3 end, OnPathDelegate callback=null) |
Construct a path with a start and end point. More... | |
Public Attributes | |
OnPathDelegate [] | callbacks |
Callbacks to call for each individual path. More... | |
int | chosenTarget = -1 |
The closest target index (if any target was found) More... | |
HeuristicMode | heuristicMode = HeuristicMode.Sequential |
How to calculate the heuristic. More... | |
List< GraphNode > [] | nodePaths |
Stores all paths to the targets. More... | |
Vector3 [] | originalTargetPoints |
Target points specified when creating the path. More... | |
bool | pathsForAll = true |
If true, a path to all targets will be returned, otherwise just the one to the closest one. More... | |
GraphNode [] | targetNodes |
Nearest nodes to the targetPoints. More... | |
Vector3 [] | targetPoints |
Target points specified when creating the path. More... | |
bool [] | targetsFound |
Indicates if the target has been found. More... | |
List< Vector3 > [] | vectorPaths |
Stores all vector paths to the targets. More... | |
Public Attributes inherited from ABPath | |
bool | calculatePartial |
Calculate partial path if the target node cannot be reached. More... | |
GraphNode | endNode |
End node of the path. More... | |
Vector3 | endPoint |
End point of the path. More... | |
Vector3 | originalEndPoint |
End Point exactly as in the path request. More... | |
Vector3 | originalStartPoint |
Start Point exactly as in the path request. More... | |
Int3 | startIntPoint |
Start point in integer coordinates. More... | |
GraphNode | startNode |
Start node of the path. More... | |
Vector3 | startPoint |
Start point of the path. More... | |
Public Attributes inherited from Path | |
OnPathDelegate | callback |
Callback to call when the path is complete. More... | |
int | enabledTags = -1 |
Which graph tags are traversable. More... | |
Heuristic | heuristic |
Determines which heuristic to use. More... | |
float | heuristicScale = 1F |
Scale of the heuristic values. More... | |
OnPathDelegate | immediateCallback |
Immediate callback to call when the path is complete. More... | |
NNConstraint | nnConstraint = PathNNConstraint.Default |
Constraint for how to search for nodes. More... | |
List< GraphNode > | path |
Holds the path as a Node array. More... | |
ITraversalProvider | traversalProvider |
Provides additional traversal information to a path request. More... | |
List< Vector3 > | vectorPath |
Holds the (possibly post processed) path as a Vector3 list. More... | |
Protected Member Functions | |
override void | CalculateStep (long targetTick) |
Calculates the path until completed or until the time has passed targetTick. More... | |
override void | Cleanup () |
Always called after the path has been calculated. More... | |
void | FoundTarget (PathNode nodeR, int i) |
override void | Initialize () |
Initializes the path. More... | |
override void | OnEnterPool () |
Called when the path enters the pool. More... | |
override void | Prepare () |
Prepares the path. More... | |
void | RebuildOpenList () |
override void | Reset () |
Reset all values to their default values. More... | |
override void | ReturnPath () |
Calls callback to return the calculated path. More... | |
void | Setup (Vector3 start, Vector3[] targets, OnPathDelegate[] callbackDelegates, OnPathDelegate callback) |
override void | Trace (PathNode node) |
Traces the calculated path from the end node to the start. More... | |
Protected Member Functions inherited from ABPath | |
virtual void | CompletePathIfStartIsValidTarget () |
Checks if the start node is the target and complete the path if that is the case. More... | |
virtual bool | EndPointGridGraphSpecialCase (GraphNode closestWalkableEndNode) |
Applies a special case for grid nodes. More... | |
void | UpdateStartEnd (Vector3 start, Vector3 end) |
Sets the start and end points. More... | |
void | Setup (Vector3 start, Vector3 end, OnPathDelegate callbackDelegate) |
Protected Member Functions inherited from Path | |
void | DebugStringPrefix (PathLog logMode, System.Text.StringBuilder text) |
Writes text shared for all overrides of DebugString to the string builder. More... | |
void | DebugStringSuffix (PathLog logMode, System.Text.StringBuilder text) |
Writes text shared for all overrides of DebugString to the string builder. More... | |
void | PrepareBase (PathHandler pathHandler) |
Prepares low level path variables for calculation. More... | |
Protected Attributes | |
int | targetNodeCount |
Number of target nodes left to find. More... | |
Protected Attributes inherited from ABPath | |
int [] | endNodeCosts |
Saved original costs for the end node. More... | |
PathNode | partialBestTarget |
Current best target for the partial path. More... | |
Protected Attributes inherited from Path | |
PathCompleteState | completeState |
Backing field for CompleteState. More... | |
PathNode | currentR |
The node currently being processed. More... | |
bool | hasBeenReset |
True if the Reset function has been called. More... | |
Int3 | hTarget |
Target to use for H score calculations. More... | |
GraphNode | hTargetNode |
Target to use for H score calculation. More... | |
int [] | internalTagPenalties |
The tag penalties that are actually used. More... | |
int [] | manualTagPenalties |
Tag penalties set by other scripts. More... | |
PathHandler | pathHandler |
Data for the thread calculating this path. More... | |
Package Functions | |
override string | DebugString (PathLog logMode) |
Returns a debug string for this path. More... | |
Package Functions inherited from ABPath | |
override uint | GetConnectionSpecialCost (GraphNode a, GraphNode b, uint currentCost) |
May be called by graph nodes to get a special cost for some connections. More... | |
Package Functions inherited from Path | |
uint | CalculateHScore (GraphNode node) |
Estimated cost from the specified node to the target. More... | |
bool | CanTraverse (GraphNode node) |
Returns if the node can be traversed. More... | |
void | FailWithError (string msg) |
Causes the path to fail and sets errorLog to msg. More... | |
Int3 | GetHTarget () |
uint | GetTagPenalty (int tag) |
Returns penalty for the given tag. More... | |
uint | GetTraversalCost (GraphNode node) |
void | Log (string msg) |
Appends a message to the errorLog. More... | |
void | LogError (string msg) |
Logs an error. More... | |
void | ReleaseSilent (System.Object o) |
Releases the path silently (pooling). More... | |
Properties | |
bool | inverted [get, protected set] |
False if the path goes from one point to multiple targets. More... | |
Properties inherited from ABPath | |
virtual bool | hasEndPoint [get] |
Determines if a search for an end node should be done. More... | |
Properties inherited from Path | |
PathCompleteState | CompleteState [get, protected set] |
Current state of the path. More... | |
bool | error [get] |
If the path failed, this is true. More... | |
string | errorLog [get, private set] |
Additional info on why a path failed. More... | |
virtual bool | FloodingPath [get] |
True for paths that want to search all nodes and not jump over nodes as optimizations. More... | |
PathHandler IPathInternals. | PathHandler [get] |
ushort | pathID [get, private set] |
ID of this path. More... | |
PathState | PipelineState [get, private set] |
Returns the state of the path in the pathfinding pipeline. More... | |
bool IPathInternals. | Pooled [get, set] |
True if the path is currently pooled. More... | |
bool | recycled [get] |
True if the path is currently recycled (i.e in the path pool). More... | |
int [] | tagPenalties [get, set] |
Penalties for each tag. More... | |
Properties inherited from IPathInternals | |
PathHandler | PathHandler [get] |
bool | Pooled [get, set] |
Private Member Functions | |
void | ChooseShortestPath () |
Set chosenTarget to the index of the shortest path. More... | |
void | RecalculateHTarget (bool firstTime) |
void | ResetFlags () |
Reset flag1 on all nodes after the pathfinding has completed (no matter if an error occurs or if the path is canceled) More... | |
void | SetPathParametersForReturn (int target) |
Private Attributes | |
int | sequentialTarget |
Current target for Sequential heuristicMode. More... | |
Additional Inherited Members | |
Package Attributes inherited from Path | |
float | duration |
How long it took to calculate this path in milliseconds. More... | |
Path | next |
Internal linked list implementation. More... | |
int | searchedNodes |
Number of nodes this path has searched. More... | |
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MultiTargetPath | ( | ) |
Default constructor.
Do not use this. Instead use the static Construct method which can handle path pooling.
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protectedvirtual |
Calculates the path until completed or until the time has passed targetTick.
Usually a check is only done every 500 nodes if the time has passed targetTick. Time/Ticks are got from System.DateTime.UtcNow.Ticks.
Basic outline of what the function does for the standard path (Pathfinding.ABPath).
Reimplemented from ABPath.
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Set chosenTarget to the index of the shortest path.
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protectedvirtual |
Always called after the path has been calculated.
Guaranteed to be called before other paths have been calculated on the same thread. Use for cleaning up things like node tagging and similar.
Reimplemented from ABPath.
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packagevirtual |
Returns a debug string for this path.
Reimplemented from ABPath.
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Initializes the path.
Sets up the open list and adds the first node to it
Reimplemented from ABPath.
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Called when the path enters the pool.
This method should release e.g pooled lists and other pooled resources The base version of this method releases vectorPath and path lists. Reset() will be called after this function, not before.
Reimplemented from Path.
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protectedvirtual |
Prepares the path.
Searches for start and end nodes and does some simple checking if a path is at all possible
Reimplemented from ABPath.
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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 ABPath.
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Reset flag1 on all nodes after the pathfinding has completed (no matter if an error occurs or if the path is canceled)
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Traces the calculated path from the end node to the start.
This will build an array (path) of the nodes this path will pass through and also set the vectorPath array to the path arrays positions. Assumes the vectorPath and path are empty and not null (which will be the case for a correctly initialized path).
Reimplemented from Path.
OnPathDelegate [] callbacks |
Callbacks to call for each individual path.
int chosenTarget = -1 |
The closest target index (if any target was found)
HeuristicMode heuristicMode = HeuristicMode.Sequential |
How to calculate the heuristic.
The heuristic target point can be calculated in different ways, by taking the Average position of all targets, or taking the mid point of them (i.e center of the AABB encapsulating all targets).
The one which works best seems to be Sequential, it sets hTarget to the target furthest away, and when that target is found, it moves on to the next one.
Some modes have the option to be 'moving' (e.g 'MovingAverage'), that means that it is updated every time a target is found.
The H score is calculated according to AstarPath.heuristic
List<GraphNode> [] nodePaths |
Stores all paths to the targets.
Elements are null if no path was found
Vector3 [] originalTargetPoints |
Target points specified when creating the path.
These are not snapped to the nearest nodes
bool pathsForAll = true |
If true, a path to all targets will be returned, otherwise just the one to the closest one.
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Current target for Sequential heuristicMode.
Refers to an item in the targetPoints array
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protected |
Number of target nodes left to find.
GraphNode [] targetNodes |
Nearest nodes to the targetPoints.
Vector3 [] targetPoints |
Target points specified when creating the path.
These are snapped to the nearest nodes
bool [] targetsFound |
Indicates if the target has been found.
Also true if the target cannot be reached (is in another area)
List<Vector3> [] vectorPaths |
Stores all vector paths to the targets.
Elements are null if no path was found
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getprotected set |
False if the path goes from one point to multiple targets.
True if it goes from multiple start points to one target point