Package de.bsommerfeld.pathetic.engine.pathfinder

Class AStarPathfinder

java.lang.Object

de.bsommerfeld.pathetic.engine.pathfinder.AbstractPathfinder<de.bsommerfeld.pathetic.engine.pathfinder.AStarSearchState>

de.bsommerfeld.pathetic.engine.pathfinder.AStarPathfinder

All Implemented Interfaces:

Pathfinder

public final class AStarPathfinder
extends AbstractPathfinder<de.bsommerfeld.pathetic.engine.pathfinder.AStarSearchState>

An A* pathfinding algorithm that uses a heuristic to guide the search toward the target. It balances the actual cost from the start (G-cost) with the estimated cost to the target (H-cost).

This implementation uses:

• A quaternary primitive min-heap for the open set (priority queue), keyed by dense node ids so decrease-key position tracking is a plain array access.
• A single per-search hash map from packed position keys to dense ids; open-set nodes, the closed set, and recorded G-costs are all id-indexed arrays (AStarSearchState).

Thread-safety: each pathfinding operation gets its own AStarSearchState, created as a stack local in the base loop and passed explicitly into the template methods. Concurrent requests on a single pathfinder are therefore isolated by the call stack; no per-search state is stored on the pathfinder itself.

Exploration radius: node keys are packed relative to the search start (see RegionKey), so absolute world coordinates are unconstrained. A single search can expand positions up to roughly two million blocks (X/Z) and half a million blocks (Y) away from its start; positions beyond that radius are treated as non-navigable.

Field Summary

Fields inherited from class de.bsommerfeld.pathetic.engine.pathfinder.AbstractPathfinder

costProcessors, EMPTY_PATH_POSITIONS, executorService, hasCustomProcessors, navigationPointProvider, neighborStrategy, pathfinderConfiguration, validationProcessors

Constructor Summary

Constructors

Constructor	Description
AStarPathfinder(PathfinderConfiguration configuration)

Method Summary

Modifier and Type	Method	Description
protected de.bsommerfeld.pathetic.engine.pathfinder.AStarSearchState	createSearchState(PathPosition start, int expectedNodes)	Creates the per-search state holding this algorithm's open and closed sets.
protected void	processSuccessors(PathPosition start, PathPosition target, Node currentNode, de.bsommerfeld.pathetic.engine.pathfinder.AStarSearchState state, SearchContext searchContext)	Processes the successors of the current node, checking if they're in the open or closed set, calculating costs, validating traversability, and updating the open set as needed.

Methods inherited from class de.bsommerfeld.pathetic.engine.pathfinder.AbstractPathfinder

createStartNode, findPath, reconstructPath, registerPathfindingHook

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface de.bsommerfeld.pathetic.api.pathing.Pathfinder

findPath

Constructor Details

AStarPathfinder

public AStarPathfinder(PathfinderConfiguration configuration)

Method Details

createSearchState

protected de.bsommerfeld.pathetic.engine.pathfinder.AStarSearchState createSearchState(PathPosition start,
 int expectedNodes)

Description copied from class: AbstractPathfinder

Creates the per-search state holding this algorithm's open and closed sets. Called once at the start of every request; the returned instance lives as a stack local and is passed back into AbstractPathfinder.processSuccessors(de.bsommerfeld.pathetic.api.wrapper.PathPosition, de.bsommerfeld.pathetic.api.wrapper.PathPosition, de.bsommerfeld.pathetic.engine.Node, S, de.bsommerfeld.pathetic.api.pathing.processing.context.SearchContext), so it never needs to be stored on the pathfinder.

Specified by:

createSearchState in class AbstractPathfinder<de.bsommerfeld.pathetic.engine.pathfinder.AStarSearchState>

Parameters:

start - The effective (floored) start position of the request; implementations that key their per-search state relative to the search origin derive that origin from it.

expectedNodes - Estimated number of nodes the search will touch; implementations should size their per-search structures from it so small requests pay small setup costs.

Returns:

a fresh, empty search state for this request.

processSuccessors

protected void processSuccessors(PathPosition start,
 PathPosition target,
 Node currentNode,
 de.bsommerfeld.pathetic.engine.pathfinder.AStarSearchState state,
 SearchContext searchContext)

Processes the successors of the current node, checking if they're in the open or closed set, calculating costs, validating traversability, and updating the open set as needed.

Specified by:

processSuccessors in class AbstractPathfinder<de.bsommerfeld.pathetic.engine.pathfinder.AStarSearchState>

Parameters:

start - The starting position of the pathfinding request.

target - The target position of the pathfinding request.

currentNode - The node being expanded.

state - The per-search state holding the open and closed sets.

searchContext - The context for the current search.