A* Pathfinding Project  4.1.5
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PointGraph Class Reference

Basic point graph. More...

Detailed Description

Basic point graph.

The point graph is the most basic graph structure, it consists of a number of interconnected points in space called nodes or waypoints.
The point graph takes a Transform object as "root", this Transform will be searched for child objects, every child object will be treated as a node. If recursive is enabled, it will also search the child objects of the children recursively. It will then check if any connections between the nodes can be made, first it will check if the distance between the nodes isn't too large (maxDistance) and then it will check if the axis aligned distance isn't too high. The axis aligned distance, named limits, is useful because usually an AI cannot climb very high, but linking nodes far away from each other, but on the same Y level should still be possible. limits and maxDistance are treated as being set to infinity if they are set to 0 (zero).
Lastly it will check if there are any obstructions between the nodes using raycasting which can optionally be thick.
One thing to think about when using raycasting is to either place the nodes a small distance above the ground in your scene or to make sure that the ground is not in the raycast mask to avoid the raycast from hitting the ground.

Alternatively, a tag can be used to search for nodes.

See Also
http://docs.unity3d.com/Manual/Tags.html

For larger graphs, it can take quite some time to scan the graph with the default settings. If you have the pro version you can enable 'optimizeForSparseGraph' which will in most cases reduce the calculation times drastically.

Note
Does not support linecast because of obvious reasons.

Public Member Functions

PointNode AddNode (Int3 position)
 Add a node to the graph at the specified position.
 
AddNode< T > (T node, Int3 position)
 Add a node with the specified type to the graph at the specified position.
 
override int CountNodes ()
 Number of nodes in the graph.
 
override NNInfoInternal GetNearest (Vector3 position, NNConstraint constraint, GraphNode hint)
 Returns the nearest node to a position using the specified NNConstraint.
 
override NNInfoInternal GetNearestForce (Vector3 position, NNConstraint constraint)
 Returns the nearest node to a position using the specified constraint .
 
override void GetNodes (System.Action< GraphNode > action)
 Calls a delegate with all nodes in the graph.
 
virtual bool IsValidConnection (GraphNode a, GraphNode b, out float dist)
 Returns if the connection between a and b is valid.
 
void RebuildNodeLookup ()
 Rebuilds the lookup structure for nodes.
 
override void RelocateNodes (Matrix4x4 deltaMatrix)
 Moves the nodes in this graph.
 
- Public Member Functions inherited from NavGraph
NNInfoInternal GetNearest (Vector3 position)
 Returns the nearest node to a position using the default NNConstraint.
 
NNInfoInternal GetNearest (Vector3 position, NNConstraint constraint)
 Returns the nearest node to a position using the specified NNConstraint.
 
void GetNodes (System.Func< GraphNode, bool > action)
 Calls a delegate with all nodes in the graph until the delegate returns false.
 
virtual void OnDrawGizmos (RetainedGizmos gizmos, bool drawNodes)
 Draw gizmos for the graph.
 
void RelocateNodes (Matrix4x4 oldMatrix, Matrix4x4 newMatrix)
 Moves nodes in this graph.
 
void Scan ()
 Scan the graph.
 
void ScanGraph ()
 Scan the graph.
 
void SetMatrix (Matrix4x4 m)
 Use to set both matrix and inverseMatrix at the same time.
 
- Public Member Functions inherited from IGraphInternals
void DeserializeExtraInfo (GraphSerializationContext ctx)
 
void DeserializeSettingsCompatibility (GraphSerializationContext ctx)
 
void DestroyAllNodes ()
 
void OnDestroy ()
 
void PostDeserialization (GraphSerializationContext ctx)
 
IEnumerable< ProgressScanInternal ()
 
void SerializeExtraInfo (GraphSerializationContext ctx)
 
- Public Member Functions inherited from IUpdatableGraph
GraphUpdateThreading CanUpdateAsync (GraphUpdateObject o)
 
void UpdateArea (GraphUpdateObject o)
 Updates an area using the specified #GraphUpdateObject.
 
void UpdateAreaInit (GraphUpdateObject o)
 May be called on the Unity thread before starting the update.
 
void UpdateAreaPost (GraphUpdateObject o)
 May be called on the Unity thread after executing the update.
 

Public Attributes

Vector3 limits
 Max distance along the axis for a connection to be valid.
 
LayerMask mask
 Layer mask to use for raycast.
 
float maxDistance
 Max distance for a connection to be valid.
 
PointNode[] nodes
 All nodes in this graph.
 
bool optimizeForSparseGraph
 Optimizes the graph for sparse graphs.
 
bool raycast = true
 Use raycasts to check connections.
 
bool recursive = true
 Recursively search for child nodes to the root.
 
Transform root
 Childs of this transform are treated as nodes.
 
string searchTag
 If no root is set, all nodes with the tag is used as nodes.
 
bool thickRaycast
 Use thick raycast.
 
float thickRaycastRadius = 1
 Thick raycast radius.
 
bool use2DPhysics
 Use the 2D Physics API.
 
- Public Attributes inherited from NavGraph
AstarPath active
 Reference to the AstarPath object in the scene.
 
bool drawGizmos = true
 Enable to draw gizmos in the Unity scene view.
 
uint graphIndex
 Index of the graph, used for identification purposes.
 
Guid guid
 Used as an ID of the graph, considered to be unique.
 
bool infoScreenOpen
 Used in the editor to check if the info screen is open.
 
uint initialPenalty
 Default penalty to apply to all nodes.
 
Matrix4x4 inverseMatrix = Matrix4x4.identity
 Inverse of matrix.
 
Matrix4x4 matrix = Matrix4x4.identity
 A matrix for translating/rotating/scaling the graph.
 
string name
 Name of the graph.
 
bool open
 Is the graph open in the editor.
 

Protected Member Functions

void AddChildren (ref int c, Transform tr)
 Recursively adds childrens of a transform as nodes.
 
virtual PointNode[] CreateNodes (int count)
 
override void DeserializeExtraInfo (GraphSerializationContext ctx)
 Deserializes graph type specific node data.
 
override void DeserializeSettingsCompatibility (GraphSerializationContext ctx)
 An old format for serializing settings.
 
override void PostDeserialization (GraphSerializationContext ctx)
 Called after all deserialization has been done for all graphs.
 
override IEnumerable< ProgressScanInternal ()
 Internal method to scan the graph.
 
override void SerializeExtraInfo (GraphSerializationContext ctx)
 Serializes graph type specific node data.
 
- Protected Member Functions inherited from NavGraph
virtual void DestroyAllNodes ()
 Destroys all nodes in the graph.
 
void DrawUnwalkableNodes (float size)
 
virtual void OnDestroy ()
 Function for cleaning up references.
 

Static Protected Member Functions

static int CountChildren (Transform tr)
 Recursively counds children of a transform.
 

Properties

int nodeCount [get, set]
 Number of nodes in this graph.
 
- Properties inherited from NavGraph
bool exists [get]
 True if the graph exists, false if it has been destroyed.
 

Private Member Functions

void AddToLookup (PointNode node)
 
GraphUpdateThreading
IUpdatableGraph. 
CanUpdateAsync (GraphUpdateObject o)
 
IEnumerable< ProgressConnectNodes ()
 Calculates connections for all nodes in the graph.
 
void IUpdatableGraph. UpdateArea (GraphUpdateObject guo)
 Updates an area in the list graph.
 
void IUpdatableGraph. UpdateAreaInit (GraphUpdateObject o)
 
void IUpdatableGraph. UpdateAreaPost (GraphUpdateObject o)
 

Private Attributes

PointKDTree lookupTree = new PointKDTree()
 

Member Function Documentation

void AddChildren ( ref int  c,
Transform  tr 
)
protected

Recursively adds childrens of a transform as nodes.

PointNode AddNode ( Int3  position)

Add a node to the graph at the specified position.

Note
Vector3 can be casted to Int3 using (Int3)myVector.
This needs to be called when it is safe to update nodes, which is
AstarPath.active.AddWorkItem(new AstarWorkItem(ctx => {
var graph = AstarPath.active.data.pointGraph;
// Add 2 nodes and connect them
var node1 = graph.AddNode((Int3)transform.position);
var node2 = graph.AddNode((Int3)(transform.position + Vector3.right));
var cost = (uint)(node2.position - node1.position).costMagnitude;
node1.AddConnection(node2, cost);
node2.AddConnection(node1, cost);
// Required because we have changed connectivity of the graph
ctx.QueueFloodFill();
}));
T AddNode< T > ( node,
Int3  position 
)

Add a node with the specified type to the graph at the specified position.

Parameters
nodeThis must be a node created using T(AstarPath.active) right before the call to this method. The node parameter is only there because there is no new(AstarPath) constraint on generic type parameters.
positionThe node will be set to this position.
Note
Vector3 can be casted to Int3 using (Int3)myVector.
This needs to be called when it is safe to update nodes, which is
See Also
AstarPath.AddWorkItem
Type Constraints
T :PointNode 
void AddToLookup ( PointNode  node)
private
GraphUpdateThreading IUpdatableGraph. CanUpdateAsync ( GraphUpdateObject  o)
private
IEnumerable<Progress> ConnectNodes ( )
private

Calculates connections for all nodes in the graph.

This is an IEnumerable, you can iterate through it using e.g foreach to get progress information.

static int CountChildren ( Transform  tr)
staticprotected

Recursively counds children of a transform.

override int CountNodes ( )
virtual

Number of nodes in the graph.

Note that this is, unless the graph type has overriden it, an O(n) operation.

This is an O(1) operation for grid graphs and point graphs. For layered grid graphs it is an O(n) operation.

Reimplemented from NavGraph.

virtual PointNode [] CreateNodes ( int  count)
protectedvirtual
override void DeserializeExtraInfo ( GraphSerializationContext  ctx)
protectedvirtual

Deserializes graph type specific node data.

See Also
SerializeExtraInfo

Reimplemented from NavGraph.

override void DeserializeSettingsCompatibility ( GraphSerializationContext  ctx)
protectedvirtual

An old format for serializing settings.

Deprecated:
This is deprecated now, but the deserialization code is kept to avoid loosing data when upgrading from older versions.

Reimplemented from NavGraph.

override NNInfoInternal GetNearest ( Vector3  position,
NNConstraint  constraint,
GraphNode  hint 
)
virtual

Returns the nearest node to a position using the specified NNConstraint.

Parameters
positionThe position to try to find a close node to
hintCan be passed to enable some graph generators to find the nearest node faster.
constraintCan for example tell the function to try to return a walkable node. If you do not get a good node back, consider calling GetNearestForce.

Reimplemented from NavGraph.

override NNInfoInternal GetNearestForce ( Vector3  position,
NNConstraint  constraint 
)
virtual

Returns the nearest node to a position using the specified constraint .

Returns
an NNInfo. This method will only return an empty NNInfo if there are no nodes which comply with the specified constraint.

Reimplemented from NavGraph.

override void GetNodes ( System.Action< GraphNode action)
virtual

Calls a delegate with all nodes in the graph.

This is the primary way of iterating through all nodes in a graph.

Do not change the graph structure inside the delegate.

var gg = AstarPath.active.data.gridGraph;
gg.GetNodes(node => {
// Here is a node
Debug.Log("I found a node at position " + (Vector3)node.position);
});

If you want to store all nodes in a list you can do this

var gg = AstarPath.active.data.gridGraph;
List<GraphNode> nodes = new List<GraphNode>();
gg.GetNodes((System.Action<GraphNode>)nodes.Add);

Implements NavGraph.

virtual bool IsValidConnection ( GraphNode  a,
GraphNode  b,
out float  dist 
)
virtual

Returns if the connection between a and b is valid.

Checks for obstructions using raycasts (if enabled) and checks for height differences.
As a bonus, it outputs the distance between the nodes too if the connection is valid.

Note
This is not the same as checking if node a is connected to node b. That should be done using a.ContainsConnection(b)
override void PostDeserialization ( GraphSerializationContext  ctx)
protectedvirtual

Called after all deserialization has been done for all graphs.

Can be used to set up more graph data which is not serialized

Reimplemented from NavGraph.

void RebuildNodeLookup ( )

Rebuilds the lookup structure for nodes.

This is used when optimizeForSparseGraph is enabled.

You should call this method every time you move a node in the graph manually and you are using optimizeForSparseGraph, otherwise pathfinding might not work correctly.

You may also call this after you have added many nodes using the AddNode method. When adding nodes using the AddNode method they will be added to the lookup structure. The lookup structure will rebalance itself when it gets too unbalanced however if you are sure you won't be adding any more nodes in the short term, you can make sure it is perfectly balanced and thus squeeze out the last bit of performance by calling this method. This can improve the performance of the GetNearest method slightly. The improvements are on the order of 10-20%.

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
override void RelocateNodes ( Matrix4x4  deltaMatrix)
virtual

Moves the nodes in this graph.

Multiplies all node positions by deltaMatrix.

For example if you want to move all your nodes in e.g a point graph 10 units along the X axis from the initial position

var graph = AstarPath.data.pointGraph;
var m = Matrix4x4.TRS (new Vector3(10,0,0), Quaternion.identity, Vector3.one);
graph.RelocateNodes (m);
Note
For grid graphs, navmesh graphs and recast graphs it is recommended to use their custom overloads of the RelocateNodes method which take parameters for e.g center and nodeSize (and additional parameters) instead since they are both easier to use and are less likely to mess up pathfinding.
Warning
This method is lossy for PointGraphs, so calling it many times may cause node positions to lose precision. For example if you set the scale to 0 in one call then all nodes will be scaled/moved to the same point and you will not be able to recover their original positions. The same thing happens for other - less extreme - values as well, but to a lesser degree.

Reimplemented from NavGraph.

override IEnumerable<Progress> ScanInternal ( )
protectedvirtual

Internal method to scan the graph.

Called from AstarPath.ScanAsync. Override this function to implement custom scanning logic. Progress objects can be yielded to show progress info in the editor and to split up processing over several frames when using async scanning.

Implements NavGraph.

override void SerializeExtraInfo ( GraphSerializationContext  ctx)
protectedvirtual

Serializes graph type specific node data.

This function can be overriden to serialize extra node information (or graph information for that matter) which cannot be serialized using the standard serialization. Serialize the data in any way you want and return a byte array. When loading, the exact same byte array will be passed to the DeserializeExtraInfo function.
These functions will only be called if node serialization is enabled.

Reimplemented from NavGraph.

void IUpdatableGraph. UpdateArea ( GraphUpdateObject  guo)
private

Updates an area in the list graph.

Recalculates possibly affected connections, i.e all connectionlines passing trough the bounds of the guo will be recalculated

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
void IUpdatableGraph. UpdateAreaInit ( GraphUpdateObject  o)
private
void IUpdatableGraph. UpdateAreaPost ( GraphUpdateObject  o)
private

Member Data Documentation

Vector3 limits

Max distance along the axis for a connection to be valid.

0 = infinity

PointKDTree lookupTree = new PointKDTree()
private
LayerMask mask

Layer mask to use for raycast.

float maxDistance

Max distance for a connection to be valid.

The value 0 (zero) will be read as infinity and thus all nodes not restricted by other constraints will be added as connections.

A negative value will disable any neighbours to be added. It will completely stop the connection processing to be done, so it can save you processing power if you don't these connections.

PointNode [] nodes

All nodes in this graph.

Note that only the first nodeCount will be non-null.

You can also use the GetNodes method to get all nodes.

bool optimizeForSparseGraph

Optimizes the graph for sparse graphs.

This can reduce calculation times for both scanning and for normal path requests by huge amounts. It reduces the number of node-node checks that need to be done during scan, and can also optimize getting the nearest node from the graph (such as when querying for a path).

Try enabling and disabling this option, check the scan times logged when you scan the graph to see if your graph is suited for this optimization or if it makes it slower.

The gain of using this optimization increases with larger graphs, the default scan algorithm is brute force and requires O(n^2) checks, this optimization along with a graph suited for it, requires only O(n) checks during scan (assuming the connection distance limits are reasonable).

Warning
When you have this enabled, you will not be able to move nodes around using scripting unless you recalculate the lookup structure at the same time.
See Also
RebuildNodeLookup

If you enable this during runtime, you will need to call RebuildNodeLookup to make sure any existing nodes are added to the lookup structure. If the graph doesn't have any nodes yet or if you are going to scan the graph afterwards then you do not need to do this.

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
bool raycast = true

Use raycasts to check connections.

bool recursive = true

Recursively search for child nodes to the root.

Transform root

Childs of this transform are treated as nodes.

string searchTag

If no root is set, all nodes with the tag is used as nodes.

bool thickRaycast

Use thick raycast.

float thickRaycastRadius = 1

Thick raycast radius.

bool use2DPhysics

Use the 2D Physics API.

Property Documentation

int nodeCount
getset

Number of nodes in this graph.


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