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Implement FollowEntityAI strategy | Discard other passage abilities than BLOCK and ALLOW

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Bartłomiej Przemysław Pluta
2021-03-08 19:38:10 +01:00
parent 8b09f16827
commit bbae364908
6 changed files with 69 additions and 43 deletions
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23
api/src/main/java/com/bartlomiejpluta/base/api/game/ai/FollowEntityAI.java
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@@ -8,27 +8,42 @@ import com.bartlomiejpluta.base.api.util.pathfinding.PathFinder;
import org.joml.Vector2i;
public class FollowEntityAI implements AI {
private static final float recalculateInterval = 0.5f;
private final NPC npc;
private final Entity target;
private final PathFinder pathFinder = new AstarPathFinder();
private final PathFinder pathFinder = new AstarPathFinder(100);
public FollowEntityAI(NPC npc, Entity target) {
private final int range;
private float accumulator = 0.0f;
public FollowEntityAI(NPC npc, Entity target, int range) {
this.npc = npc;
this.range = range;
this.target = target;
}
@Override
public void nextActivity(ObjectLayer layer, float dt) {
if (!npc.isMoving() && npc.manhattanDistance(target) > 1) {
var path = pathFinder.findPath(layer, npc.getCoordinates(), target.getCoordinates(), 30);
var distance = npc.manhattanDistance(target);
if (!npc.isMoving() && distance > 1 && distance < range && accumulator >= recalculateInterval) {
var path = pathFinder.findPath(layer, npc.getCoordinates(), target.getCoordinates());
if (!path.isEmpty()) {
accumulator = recalculateInterval;
var node = new Vector2i(path.getLast()).sub(npc.getCoordinates());
var direction = Direction.ofVector(node);
var movement = npc.prepareMovement(direction);
layer.pushMovement(movement);
} else {
accumulator = 0.0f;
}
}
accumulator += dt;
}
}

2
api/src/main/java/com/bartlomiejpluta/base/api/game/ai/FollowPathAI.java
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@@ -82,7 +82,7 @@ public class FollowPathAI implements AI {
public boolean perform(NPC npc, ObjectLayer layer, float dt) {
Movement movement = npc.prepareMovement(direction);
if (ignore || layer.isMovementPossible(movement)) {
if (ignore || layer.isTileReachable(movement.getTo())) {
layer.pushMovement(movement);
return true;
}

3
api/src/main/java/com/bartlomiejpluta/base/api/game/map/layer/object/ObjectLayer.java
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@@ -4,6 +4,7 @@ import com.bartlomiejpluta.base.api.game.entity.Entity;
import com.bartlomiejpluta.base.api.game.entity.Movement;
import com.bartlomiejpluta.base.api.game.map.layer.base.Layer;
import com.bartlomiejpluta.base.api.game.rule.Rule;
import org.joml.Vector2i;
import java.util.List;
@@ -26,7 +27,7 @@ public interface ObjectLayer extends Layer {
PassageAbility[][] getPassageMap();
boolean isMovementPossible(Movement movement);
boolean isTileReachable(Vector2i tileCoordinates);
void pushMovement(Movement movement);
}

42
api/src/main/java/com/bartlomiejpluta/base/api/util/pathfinding/AstarPathFinder.java
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@@ -4,6 +4,7 @@ import com.bartlomiejpluta.base.api.game.map.layer.object.ObjectLayer;
import com.bartlomiejpluta.base.api.game.map.layer.object.PassageAbility;
import org.joml.Vector2i;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Objects;
import java.util.PriorityQueue;
@@ -30,8 +31,14 @@ public class AstarPathFinder implements PathFinder {
new Vector2i(0, 1)
};
private final int maxNodes;
public AstarPathFinder(int maxNodes) {
this.maxNodes = maxNodes;
}
@Override
public LinkedList<Vector2i> findPath(ObjectLayer layer, Vector2i start, Vector2i end, int range) {
public LinkedList<Vector2i> findPath(ObjectLayer layer, Vector2i start, Vector2i end) {
var columns = layer.getMap().getColumns();
var rows = layer.getMap().getRows();
@@ -47,12 +54,20 @@ public class AstarPathFinder implements PathFinder {
// We are starting with one open node (the start one) end empty closed lists
var open = new PriorityQueue<Node>();
var closed = new LinkedList<Node>();
var closed = new HashSet<Node>();
open.add(startNode);
// As long as there are at least one open node
while (!open.isEmpty()) {
// A safety valve which ideally should be used only and only
// if the target is not reachable (the path does not exist at all).
// It determines the maximum algorithm depth
// It's not the part of model A* algorithm.
if (closed.size() > maxNodes) {
return new LinkedList<>();
}
// We are retrieving the node with the **smallest** f score
// (That's the way the Astar.compare() comparator works)
// And the same time we are removing the node from open list
@@ -81,9 +96,9 @@ public class AstarPathFinder implements PathFinder {
// We are limiting the algorithm to given range
// If current neighbour distance to start node exceeds given range parameter
// we are getting rid of this neighbour
if (manhattanDistance(startNode.position, position) > range) {
continue;
}
//if (manhattanDistance(startNode.position, position) > range) {
// continue;
//}
// Define new neighbour
var neighbour = new Node(position);
@@ -97,7 +112,18 @@ public class AstarPathFinder implements PathFinder {
}
// Get rid of nodes that are not reachable (blocked or something is staying on there)
var reachable = layer.getPassageMap()[position.y][position.x] == PassageAbility.ALLOW;
//
// ASSUME, that the end tile **always is** reachable, even if actually it is not.
// That means, if you want to have empty list if target actually is not reachable,
// you need to implement that condition by yourself.
// The reason for that is the fact, that when ObjectLayer is checking if
// the current tile is reachable via isTileReachable() method.
// If the target position is actually an entity which is blocking (does not allow other entities pass
// through it), the method rejects the end tile as reachable (because de facto it is not reachable since
// it is blocking) and eventually the path is assumed as not existing.
// It may not be consistent with a A* model implementation, however it is required to adapt
// the algorithm for the BASE project purpose.
var reachable = layer.isTileReachable(position) || position.equals(end);
if (!reachable) {
continue;
}
@@ -158,12 +184,12 @@ public class AstarPathFinder implements PathFinder {
for (Vector2i node : nodes) {
if (node.equals(column, row)) {
System.out.print("#");
System.out.print(" # ");
continue tiles;
}
}
System.out.print(layer.getPassageMap()[row][column] == PassageAbility.ALLOW ? " " : ".");
System.out.print(layer.getPassageMap()[row][column] == PassageAbility.ALLOW ? " " : " . ");
}
System.out.println("|");

2
api/src/main/java/com/bartlomiejpluta/base/api/util/pathfinding/PathFinder.java
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@@ -6,5 +6,5 @@ import org.joml.Vector2i;
import java.util.LinkedList;
public interface PathFinder {
LinkedList<Vector2i> findPath(ObjectLayer layer, Vector2i start, Vector2i end, int range);
LinkedList<Vector2i> findPath(ObjectLayer layer, Vector2i start, Vector2i end);
}

38
engine/src/main/java/com/bartlomiejpluta/base/engine/world/map/layer/object/DefaultObjectLayer.java
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@@ -2,7 +2,6 @@ package com.bartlomiejpluta.base.engine.world.map.layer.object;
import com.bartlomiejpluta.base.api.game.ai.NPC;
import com.bartlomiejpluta.base.api.game.camera.Camera;
import com.bartlomiejpluta.base.api.game.entity.Direction;
import com.bartlomiejpluta.base.api.game.entity.Entity;
import com.bartlomiejpluta.base.api.game.entity.Movement;
import com.bartlomiejpluta.base.api.game.map.layer.object.ObjectLayer;
@@ -14,6 +13,7 @@ import com.bartlomiejpluta.base.api.internal.render.ShaderManager;
import lombok.Getter;
import lombok.NonNull;
import org.joml.Vector2f;
import org.joml.Vector2i;
import java.util.ArrayList;
import java.util.LinkedList;
@@ -86,51 +86,35 @@ public class DefaultObjectLayer implements ObjectLayer {
}
@Override
public boolean isMovementPossible(Movement movement) {
var target = movement.getTo();
public boolean isTileReachable(Vector2i tileCoordinates) {
// Is trying to go beyond the map
if (target.x < 0 || target.y < 0 || target.x >= columns || target.y >= rows) {
if (tileCoordinates.x < 0 || tileCoordinates.y < 0 || tileCoordinates.x >= columns || tileCoordinates.y >= rows) {
return false;
}
var source = movement.getFrom();
var direction = movement.getDirection();
if (passageMap[tileCoordinates.y][tileCoordinates.x] != PassageAbility.ALLOW) {
return false;
}
var isTargetReachable = switch (passageMap[target.y][target.x]) {
case UP_ONLY -> direction != Direction.DOWN;
case DOWN_ONLY -> direction != Direction.UP;
case LEFT_ONLY -> direction != Direction.RIGHT;
case RIGHT_ONLY -> direction != Direction.LEFT;
case BLOCK -> false;
case ALLOW -> true;
};
var canMoveFromCurrentTile = switch (passageMap[source.y][source.x]) {
case UP_ONLY -> direction == Direction.UP;
case DOWN_ONLY -> direction == Direction.DOWN;
case LEFT_ONLY -> direction == Direction.LEFT;
case RIGHT_ONLY -> direction == Direction.RIGHT;
default -> true;
};
for (var entity : entities) {
if (entity.isBlocking()) {
// The tile is occupied by other entity
if (entity.getCoordinates().equals(target)) {
if (entity.getCoordinates().equals(tileCoordinates)) {
return false;
}
// The tile is empty, however another entity is moving on it
var otherMovement = entity.getMovement();
if (otherMovement != null && otherMovement.getTo().equals(target)) {
if (otherMovement != null && otherMovement.getTo().equals(tileCoordinates)) {
return false;
}
}
}
return isTargetReachable && canMoveFromCurrentTile;
return true;
}
@Override
@@ -143,7 +127,7 @@ public class DefaultObjectLayer implements ObjectLayer {
for (var iterator = movements.iterator(); iterator.hasNext(); ) {
var movement = iterator.next();
if (isMovementPossible(movement)) {
if (isTileReachable(movement.getTo())) {
movement.perform();
}