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Pathfinding - optimize naval invasions (#2932)
# Pathfinding pt. 4 https://pf-pt-4.openfront.dev/ ## Description: Hello again! Pathfinding. It's fast, but inaccurate. This PR makes it more accurate and actually faster. Sadly it is _faster_ because of a blunder in previous PR (using BucketQueue where MinHeap would be better), not because of a new tech. More importantly, it is more accurate. And that's what people apparently want. ## What changed? Most of the functional changes relate to `SpatialQuery` module. This is the thingy that answers "we know the target, which tile of my territory is the best to launch an invasion". To make it compute a path from South America to the deep inland China river, it has to work on a coerced map, one with a very small resolution, so small in fact, that every 4096 map tiles gets compressed to just one pixel. I hope you see where this is going. Previously we selected a random coastal tile within this big pixel (honestly it wasn't random at all, but could very well be for the illustrative purposes). Now, we try to be a bit more deliberate. Since we already know the rough location of the probably best tile, we can exclude all other tiles from the computation. Imagine a player's territory spans both Americas on global map - that's a lot of shores. But since we already know the best tile is somewhere close to Miami, the problem space was greatly reduced, no need to consider all other shores. But pathing to the target in China from Miami is still crazy expensive. This is where second trick comes to play - instead of pathing all the way to China, we select a _waypoint_ in the rough direction of China, about 100 to 200 tiles away. This way we fairly cheaply select best tile to launch an invasion towards this abstract point. And chances are, this point is far enough, the newly computed path is very close to being optimal. When you throw a dart from far away, the difference between scoring 10 and missing is very small. This is why aiming in the general direction of the board - as opposed to the ceiling - is usually good enough. ## Okay, but what about the crazy paths when I send invasion to the opposed bank of a river?! Well, pathing from America to China is cool, but most players wouldn't notice the difference on such long paths, what about the short ones? We now try more accurate pathing first and defer to hierarchy only if it fails. This produces much better paths for short invasions. While the fix described above ensures the accuracy is improved also on medium-to-long routes. ## Playground Yes. https://github.com/user-attachments/assets/9cf9586f-c99a-416d-b856-8cf0a21c35ed ## CodeRabbit Grab a 🥕. Remember `tests/pathfinding/playground` is mostly generated code and go easy on it. It's enough for it to work and do it's job of visualizing the paths. No need for throughout review of these files. ## Please complete the following: - [x] I have added screenshots for all UI updates - [x] I process any text displayed to the user through translateText() and I've added it to the en.json file - [x] I have added relevant tests to the test directory - [x] I confirm I have thoroughly tested these changes and take full responsibility for any bugs introduced ## Please put your Discord username so you can be contacted if a bug or regression is found: moleole
This commit is contained in:
Arkadiusz Sygulski
committed by
GitHub
GitHub
parent
3cdbb5651a
commit
6bd95d4884
@@ -1,12 +1,27 @@
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import { Game, Player, TerraNullius } from "../../game/Game";
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import { TileRef } from "../../game/GameMap";
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import { DebugSpan } from "../../utilities/DebugSpan";
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import { PathFinding } from "../PathFinder";
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import { AStarWaterBounded } from "../algorithms/AStar.WaterBounded";
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type Owner = Player | TerraNullius;
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const REFINE_MAX_SEARCH_AREA = 100 * 100;
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export class SpatialQuery {
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private boundedAStar: AStarWaterBounded | null = null;
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constructor(private game: Game) {}
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private getBoundedAStar(): AStarWaterBounded {
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this.boundedAStar ??= new AStarWaterBounded(
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this.game.map(),
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REFINE_MAX_SEARCH_AREA,
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);
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return this.boundedAStar;
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}
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/**
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* Find nearest tile matching predicate using BFS traversal.
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* Uses Manhattan distance filter, ignores terrain barriers.
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@@ -64,27 +79,125 @@ export class SpatialQuery {
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* Returns null for terra nullius (no borderTiles).
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*/
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closestShoreByWater(owner: Owner, target: TileRef): TileRef | null {
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if (!owner.isPlayer()) return null;
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return DebugSpan.wrap("SpatialQuery.closestShoreByWater", () => {
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if (!owner.isPlayer()) return null;
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const gm = this.game;
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const player = owner as Player;
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const gm = this.game;
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const player = owner as Player;
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// Target must be water or shore (land adjacent to water)
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if (!gm.isWater(target) && !gm.isShore(target)) return null;
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// Target must be water or shore (land adjacent to water)
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if (!gm.isWater(target) && !gm.isShore(target)) return null;
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const targetComponent = gm.getWaterComponent(target);
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if (targetComponent === null) return null;
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const targetComponent = gm.getWaterComponent(target);
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if (targetComponent === null) return null;
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const isValidTile = (t: TileRef) => {
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if (!gm.isShore(t) || !gm.isLand(t)) return false;
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const tComponent = gm.getWaterComponent(t);
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return tComponent === targetComponent;
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const isValidTile = (t: TileRef) => {
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if (!gm.isShore(t) || !gm.isLand(t)) return false;
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const tComponent = gm.getWaterComponent(t);
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return tComponent === targetComponent;
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};
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const shores = Array.from(player.borderTiles()).filter(isValidTile);
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if (shores.length === 0) return null;
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const path = PathFinding.Water(gm).findPath(shores, target);
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if (!path || path.length === 0) return null;
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return DebugSpan.wrap("SpatialQuery.refineStartTile", () =>
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this.refineStartTile(path, shores, gm),
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);
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});
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}
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private refineStartTile(
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path: TileRef[],
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shores: TileRef[],
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gm: Game,
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): TileRef {
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const CANDIDATE_RADIUS = 20;
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const MIN_WAYPOINT_DIST = 50;
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const MAX_WAYPOINT_DIST = 200;
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const PADDING = 10;
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if (path.length <= MIN_WAYPOINT_DIST) {
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return path[0];
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}
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const bestTile = path[0];
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const map = gm.map();
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const candidates = shores.filter(
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(s) => map.manhattanDist(s, bestTile) <= CANDIDATE_RADIUS,
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);
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if (candidates.length <= 1) return bestTile;
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// Precompute candidate bounds
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let candMinX = map.x(candidates[0]);
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let candMaxX = candMinX;
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let candMinY = map.y(candidates[0]);
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let candMaxY = candMinY;
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for (let i = 1; i < candidates.length; i++) {
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const sx = map.x(candidates[i]);
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const sy = map.y(candidates[i]);
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candMinX = Math.min(candMinX, sx);
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candMaxX = Math.max(candMaxX, sx);
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candMinY = Math.min(candMinY, sy);
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candMaxY = Math.max(candMaxY, sy);
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}
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// Binary search for furthest waypoint that keeps bounds within limit
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let lo = MIN_WAYPOINT_DIST;
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let hi = Math.min(MAX_WAYPOINT_DIST, path.length - 1);
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let bestWaypointIdx = lo;
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for (let i = 0; i < 5 && lo <= hi; i++) {
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const mid = (lo + hi) >> 1;
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const wp = path[mid];
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const wpX = map.x(wp);
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const wpY = map.y(wp);
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const minX = Math.min(candMinX, wpX) - PADDING;
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const maxX = Math.max(candMaxX, wpX) + PADDING;
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const minY = Math.min(candMinY, wpY) - PADDING;
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const maxY = Math.max(candMaxY, wpY) + PADDING;
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const area = (maxX - minX + 1) * (maxY - minY + 1);
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if (area <= REFINE_MAX_SEARCH_AREA) {
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bestWaypointIdx = mid;
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lo = mid + 1;
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} else {
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hi = mid - 1;
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}
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}
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const waypoint = path[bestWaypointIdx];
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const wpX = map.x(waypoint);
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const wpY = map.y(waypoint);
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const bounds = {
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minX: Math.max(0, Math.min(candMinX, wpX) - PADDING),
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maxX: Math.min(map.width() - 1, Math.max(candMaxX, wpX) + PADDING),
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minY: Math.max(0, Math.min(candMinY, wpY) - PADDING),
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maxY: Math.min(map.height() - 1, Math.max(candMaxY, wpY) + PADDING),
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};
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const shores = Array.from(player.borderTiles()).filter(isValidTile);
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if (shores.length === 0) return null;
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const boundsArea =
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(bounds.maxX - bounds.minX + 1) * (bounds.maxY - bounds.minY + 1);
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if (boundsArea > REFINE_MAX_SEARCH_AREA) return bestTile;
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const path = PathFinding.Water(gm).findPath(shores, target);
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return path?.[0] ?? null;
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const refinedPath = this.getBoundedAStar().searchBounded(
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candidates,
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waypoint,
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bounds,
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);
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DebugSpan.set("$candidates", () => candidates);
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DebugSpan.set("$refinedPath", () => refinedPath);
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DebugSpan.set("$originalBestTile", () => bestTile);
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DebugSpan.set("$newBestTile", () => refinedPath?.[0] ?? bestTile);
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return refinedPath?.[0] ?? bestTile;
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}
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}
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