Rename src/ to js/

js/pathfinding.js

@@ -0,0 +1,153 @@
+import {getGridPositionFromPixelsObj, getPixelsFromGridPositionObj} from "./foundry_fixes.js";
+import {togglePathfinding} from "./keybindings.js";
+import {debugGraphics} from "./main.js";
+import {settingsKey} from "./settings.js";
+import {getSnapPointForTokenObj, iterPairs} from "./util.js";
+
+let cachedNodes = undefined;
+let use5105 = false;
+
+export function isPathfindingEnabled() {
+	if (canvas.grid.type === CONST.GRID_TYPES.GRIDLESS)
+		return false;
+	if (!game.settings.get(settingsKey, "allowPathfinding"))
+		return false;
+	return game.settings.get(settingsKey, "autoPathfinding") != togglePathfinding;
+}
+
+export function findPath(from, to, token, previousWaypoints) {
+	const lastNode = calculatePath(from, to, token, previousWaypoints);
+	if (!lastNode)
+		return null;
+	paintPathfindingDebug(lastNode, token);
+	const path = [];
+	let currentNode = lastNode;
+	while (currentNode) {
+		// TODO Check if the distance doesn't change
+		if (path.length >= 2 && !stepCollidesWithWall(currentNode.node, path[path.length - 2], token))
+			// Replace last waypoint if the current waypoint leads to a valid path
+			path[path.length - 1] = {x: currentNode.node.x, y: currentNode.node.y};
+		else
+			path.push({x: currentNode.node.x, y: currentNode.node.y});
+		currentNode = currentNode.previous;
+	}
+	return path;
+}
+
+export function wipePathfindingCache() {
+	cachedNodes = undefined;
+}
+
+function getNode(pos, token, initialize=true) {
+	pos = {layer: 0, ...pos}; // Copy pos and set pos.layer to the default value if it's unset
+	if (!cachedNodes)
+		cachedNodes = new Array(2);
+	if (!cachedNodes[pos.layer])
+		cachedNodes[pos.layer] = new Array(Math.ceil(canvas.dimensions.height / canvas.grid.h));
+	if (!cachedNodes[pos.layer][pos.y])
+	cachedNodes[pos.layer][pos.y] = new Array(Math.ceil(canvas.dimensions.width / canvas.grid.w));
+	if (!cachedNodes[pos.layer][pos.y][pos.x]) {
+		cachedNodes[pos.layer][pos.y][pos.x] = pos;
+	}
+
+	const node = cachedNodes[pos.layer][pos.y][pos.x];
+	if (initialize && !node.edges) {
+		node.edges = [];
+		for (const neighborPos of canvas.grid.grid.getNeighbors(pos.y, pos.x).map(([y, x]) => {return {x, y};})) {
+			if (neighborPos.x < 0 || neighborPos.y < 0)
+				continue;
+			// TODO Work with pixels instead of grid locations
+			if (!stepCollidesWithWall(pos, neighborPos, token)) {
+				const isDiagonal = node.x !== neighborPos.x && node.y !== neighborPos.y && canvas.grid.type === CONST.GRID_TYPES.SQUARE;
+				let targetLayer = pos.layer;
+				if (use5105 && isDiagonal)
+					targetLayer = 1 - targetLayer;
+				const neighbor = getNode({...neighborPos, layer: targetLayer}, token, false);
+
+				// TODO We currently assume a cost of one or two for all transitions. Change this for difficult terrain support
+				let edgeCost = 1;
+				if (isDiagonal) {
+					// We charge 0.0001 more for edges to avoid unnecessary diagonal steps
+					edgeCost = pos.layer === 1 && targetLayer === 0 ? 2 : 1.0001;
+				}
+				node.edges.push({target: neighbor, cost: edgeCost});
+			}
+		}
+	}
+	return node;
+}
+
+function calculatePath(from, to, token, previousWaypoints) {
+	if (game.system.id === "pf2e")
+		use5105 = true;
+	if (canvas.grid.diagonalRule === "5105")
+		use5105 = true;
+	let startLayer = 0;
+	if (use5105 && canvas.grid.type === CONST.GRID_TYPES.SQUARE) {
+		previousWaypoints = previousWaypoints.map(w => getGridPositionFromPixelsObj(w));
+		startLayer = calcNoDiagonals(previousWaypoints) % 2;
+	}
+	const nextNodes = [{node: getNode({...to, layer: startLayer}, token), cost: 0, estimated: estimateCost(to, from), previous: null}];
+	const previousNodes = new Set();
+	while (nextNodes.length > 0) {
+		// Sort by estimated cost, high to low
+		// TODO Re-sorting every iteration is expensive. Think of something better
+		nextNodes.sort((a, b) => b.estimated - a.estimated);
+		// Get node with cheapest estimate
+		const currentNode = nextNodes.pop();
+		if (currentNode.node.x === from.x && currentNode.node.y === from.y)
+			return currentNode;
+		previousNodes.add(currentNode.node);
+		for (const edge of currentNode.node.edges) {
+			const neighborNode = getNode(edge.target, token);
+			if (previousNodes.has(neighborNode))
+				continue;
+			const neighbor = {node: neighborNode, cost: currentNode.cost + edge.cost, estimated: currentNode.cost + edge.cost + estimateCost(neighborNode, from), previous: currentNode};
+			const neighborIndex = nextNodes.findIndex(node => node.node === neighbor.node);
+			if (neighborIndex >= 0) {
+				// If the neighbor is cheaper to reach via the current route than through previously discovered routes, replace it
+				if (nextNodes[neighborIndex].cost > neighbor.cost) {
+					nextNodes[neighborIndex] = neighbor;
+				}
+			}
+			else {
+				nextNodes.push(neighbor);
+			}
+		}
+	}
+}
+
+function calcNoDiagonals(waypoints) {
+	let diagonals = 0;
+	for (const [p1, p2] of iterPairs(waypoints)) {
+		diagonals += Math.min(Math.abs(p1.x - p2.x), Math.abs(p1.y - p2.y));
+	}
+	return diagonals;
+}
+
+function estimateCost(pos, target) {
+	return Math.max(Math.abs(pos.x - target.x), Math.abs(pos.y - target.y));
+}
+
+function stepCollidesWithWall(from, to, token) {
+	const stepStart = getSnapPointForTokenObj(getPixelsFromGridPositionObj(from), token);
+	const stepEnd = getSnapPointForTokenObj(getPixelsFromGridPositionObj(to), token);
+	return canvas.walls.checkCollision(new Ray(stepStart, stepEnd));
+}
+
+function paintPathfindingDebug(lastNode, token) {
+	if (!CONFIG.debug.dragRuler)
+		return;
+
+	debugGraphics.removeChildren();
+	let currentNode = lastNode;
+	while (currentNode) {
+		let text = new PIXI.Text(currentNode.cost.toFixed(0));
+		let pixels = getSnapPointForTokenObj(getPixelsFromGridPositionObj(currentNode.node), token);
+		text.anchor.set(0.5, 1.0);
+		text.x = pixels.x;
+		text.y = pixels.y;
+		debugGraphics.addChild(text);
+		currentNode = currentNode.previous;
+	}
+}