Files
Mindustry/core/src/mindustry/ai/Astar.java
2021-09-28 17:20:20 -04:00

105 lines
3.4 KiB
Java

package mindustry.ai;
import arc.func.*;
import arc.math.geom.*;
import arc.struct.*;
import arc.util.*;
import mindustry.world.*;
import java.util.*;
import static mindustry.Vars.*;
public class Astar{
public static final DistanceHeuristic manhattan = (x1, y1, x2, y2) -> Math.abs(x1 - x2) + Math.abs(y1 - y2);
private static final Seq<Tile> out = new Seq<>();
private static final PQueue<Tile> queue = new PQueue<>(200 * 200 / 4, (a, b) -> 0);
private static float[] costs;
private static byte[][] rotations;
public static Seq<Tile> pathfind(Tile from, Tile to, TileHueristic th, Boolf<Tile> passable){
return pathfind(from.x, from.y, to.x, to.y, th, manhattan, passable);
}
public static Seq<Tile> pathfind(int startX, int startY, int endX, int endY, TileHueristic th, Boolf<Tile> passable){
return pathfind(startX, startY, endX, endY, th, manhattan, passable);
}
public static Seq<Tile> pathfind(int startX, int startY, int endX, int endY, TileHueristic th, DistanceHeuristic dh, Boolf<Tile> passable){
Tiles tiles = world.tiles;
Tile start = tiles.getn(startX, startY);
Tile end = tiles.getn(endX, endY);
GridBits closed = new GridBits(tiles.width, tiles.height);
if(costs == null || costs.length != tiles.width * tiles.height){
costs = new float[tiles.width * tiles.height];
}
Arrays.fill(costs, 0);
queue.clear();
queue.comparator = Structs.comparingFloat(a -> costs[a.array()] + dh.cost(a.x, a.y, end.x, end.y));
queue.add(start);
if(rotations == null || rotations.length != world.width() || rotations[0].length != world.height()){
rotations = new byte[world.width()][world.height()];
}
boolean found = false;
while(!queue.empty()){
Tile next = queue.poll();
float baseCost = costs[next.array()];
if(next == end){
found = true;
break;
}
closed.set(next.x, next.y);
for(Point2 point : Geometry.d4){
int newx = next.x + point.x, newy = next.y + point.y;
if(Structs.inBounds(newx, newy, tiles.width, tiles.height)){
Tile child = tiles.getn(newx, newy);
if(passable.get(child)){
float newCost = th.cost(next, child) + baseCost;
if(!closed.get(child.x, child.y)){
closed.set(child.x, child.y);
rotations[child.x][child.y] = child.relativeTo(next.x, next.y);
costs[child.array()] = newCost;
queue.add(child);
}
}
}
}
}
out.clear();
if(!found) return out;
Tile current = end;
while(current != start){
out.add(current);
byte rot = rotations[current.x][current.y];
current = tiles.getn(current.x + Geometry.d4x[rot], current.y + Geometry.d4y[rot]);
}
out.reverse();
return out;
}
public interface DistanceHeuristic{
float cost(int x1, int y1, int x2, int y2);
}
public interface TileHueristic{
float cost(Tile tile);
default float cost(Tile from, Tile tile){
return cost(tile);
}
}
}