Pathfinding prerelease

lang/en.json

@@ -34,6 +34,10 @@
 				"name": "Show PC speed to everyone",
 				"hint": "If enabled the coloring based on actor speed for player characters will shown to everyone, even if they don't have observer permission for the character sheet."
 			},
+			"autoPathfinding": {
+				"name": "Pathfinding by default",
+				"hint": "If enabled, dragging a token will automatically use a pathfinding ruler"
+			},
 			"enableMovementHistory": {
 				"name": "Enable movement history during combat",
 				"hint": "If enabled, Drag Ruler will remember the path a token took during it's turn in combat and will display it when you pick the token back up."

module.json

@@ -2,7 +2,7 @@
 	"name": "drag-ruler",
 	"title": "Drag Ruler",
 	"description": "When dragging a token displays a ruler showing how far you've moved that token.",
-	"version": "1.7.7",
+	"version": "1.7.7-prerelease1",
 	"minimumCoreVersion" : "0.8.5",
 	"compatibleCoreVersion" : "0.8.8",
 	"authors": [
@@ -59,7 +59,7 @@
 	],
 	"socket": true,
 	"url": "https://github.com/manuelVo/foundryvtt-drag-ruler",
-	"download": "https://github.com/manuelVo/foundryvtt-drag-ruler/archive/v1.7.7.zip",
+	"download": "https://codeload.github.com/manuelVo/foundryvtt-drag-ruler/zip/refs/heads/prerelease",
 	"manifest": "https://raw.githubusercontent.com/manuelVo/foundryvtt-drag-ruler/master/module.json",
 	"readme": "https://github.com/manuelVo/foundryvtt-drag-ruler/blob/master/README.md",
 	"changelog": "https://github.com/manuelVo/foundryvtt-drag-ruler/blob/master/CHANGELOG.md",

src/foundry_fixes.js

@@ -16,3 +16,21 @@ export function getGridPositionFromPixels(xPixel, yPixel) {
 		return [y, x]
 	return [x, y]
 }
+
+export function getGridPositionFromPixelsObj(o) {
+	const r = {};
+	[r.x, r.y] = getGridPositionFromPixels(o.x, o.y);
+	return r;
+}
+
+export function getPixelsFromGridPositionObj(o) {
+	const r = {};
+	[r.x, r.y] = getPixelsFromGridPosition(o.x, o.y);
+	return r;
+}
+
+export function getCenterFromGridPositionObj(o) {
+	const r = getPixelsFromGridPositionObj(o);
+	[r.x, r.y] = canvas.grid.getCenter(r.x, r.y);
+	return r;
+}

src/foundry_imports.js

@@ -1,8 +1,10 @@
 import {highlightMeasurementTerrainRuler, measureDistances} from "./compatibility.js";
-import {getGridPositionFromPixels} from "./foundry_fixes.js";
+import {getCenterFromGridPositionObj, getGridPositionFromPixels, getGridPositionFromPixelsObj} from "./foundry_fixes.js";
 import {Line} from "./geometry.js";
 import {getColorForDistance} from "./main.js"
 import {trackRays} from "./movement_tracking.js"
+import {find_path} from "./pathfinding.js";
+import {settingsKey} from "./settings.js";
 import {recalculate} from "./socket.js";
 import {applyTokenSizeOffset, getSnapPointForEntity, getSnapPointForToken, getTokenShape, highlightTokenShape, zip} from "./util.js";
 
@@ -77,6 +79,7 @@ async function animateEntities(entities, draggedEntity, draggedRays, wasPaused)
 	this.cancelMovement = false;
 
 	for (let i = startWaypoint;i < entityAnimationData[0].rays.length; i++) {
+
 		if (!wasPaused && game.paused) break;
 		const entityPaths = entityAnimationData.map(({entity, rays, dx, dy}) => {
 			const ray = rays[i];
@@ -101,6 +104,7 @@ async function animateEntities(entities, draggedEntity, draggedRays, wasPaused)
 		trackRays(entities, entityAnimationData.map(({rays}) => rays)).then(() => recalculate(entities));
 }
 
+
 function calculateEntityOffset(entityA, entityB) {
 	return {x: entityA.data.x - entityB.data.x, y: entityA.data.y - entityB.data.y};
 }
@@ -116,6 +120,7 @@ export function onMouseMove(event) {
 	if (this._state === Ruler.STATES.MOVING) return;
 
 	// Extract event data
+
 	const destination = {x: event.data.destination.x + this.rulerOffset.x, y: event.data.destination.y + this.rulerOffset.y}
 
 	// Hide any existing Token HUD
@@ -131,7 +136,7 @@ function scheduleMeasurement(destination, event) {
 	const mt = event._measureTime || 0;
 	const originalEvent = event.data.originalEvent;
 	if (Date.now() - mt > measurementInterval) {
-		this.measure(destination, {snap: !originalEvent.shiftKey});
+		this.measure(destination, {snap: !originalEvent.shiftKey, pathfinding: game.settings.get(settingsKey, "autoPathfinding") != game.keyboard.isDown("y")});
 		event._measureTime = Date.now();
 		this._state = Ruler.STATES.MEASURING;
 		window.clearTimeout(this.deferredMeasurementTimeout);
@@ -148,7 +153,7 @@ function scheduleMeasurement(destination, event) {
 }
 
 // This is a modified version of Ruler.measure form foundry 0.7.9
-export function measure(destination, {gridSpaces=true, snap=false} = {}) {
+export function measure(destination, {gridSpaces=true, snap=false, pathfinding=false} = {}) {
 	const isToken = this.draggedEntity instanceof Token;
 	if (isToken && !this.draggedEntity.isVisible)
 		return []
@@ -157,6 +162,22 @@ export function measure(destination, {gridSpaces=true, snap=false} = {}) {
 		destination = getSnapPointForEntity(destination.x, destination.y, this.draggedEntity);
 	}
 
+	// Remove waypoints generated by pathfinding
+	this.waypoints = this.waypoints.filter(waypoint => !waypoint.isPathfinding);
+
+	if (isToken && pathfinding) {
+		let path = find_path(getGridPositionFromPixelsObj(this.waypoints[this.waypoints.length - 1]), getGridPositionFromPixelsObj(destination));
+		if (path) {
+			path = path.map(point => getCenterFromGridPositionObj(point));
+			path.forEach(point => point.isPathfinding = true);
+			this.waypoints = this.waypoints.concat(path);
+		}
+		else {
+			// Don't show a path if the pathfinding yields no result to show the user that the destination is unreachable
+			destination = this.waypoints[this.waypoints.length - 1];
+		}
+	}
+
 	const terrainRulerAvailable = isToken && game.modules.get("terrain-ruler")?.active && (!game.modules.get("TerrainLayer")?.active || canvas.grid.type !== CONST.GRID_TYPES.GRIDLESS);
 
 	const waypoints = this.waypoints.concat([destination]);

src/main.js

@@ -9,6 +9,7 @@ import {getMovementHistory, resetMovementHistory} from "./movement_tracking.js";
 import {registerSettings, settingsKey} from "./settings.js"
 import {recalculate} from "./socket.js";
 import {SpeedProvider} from "./speed_provider.js"
+import { wipe_cache } from "./pathfinding.js";
 
 Hooks.once("init", () => {
 	registerSettings()
@@ -137,6 +138,7 @@ function onEntityLeftDragStart(event) {
 	else
 		entityCenter = this.center;
 	ruler.clear();
+	wipe_cache();
 	ruler._state = Ruler.STATES.STARTING;
 	ruler.rulerOffset = {x: entityCenter.x - event.data.origin.x, y: entityCenter.y - event.data.origin.y};
 	if (isToken && game.settings.get(settingsKey, "enableMovementHistory"))

src/pathfinding.js

@@ -0,0 +1,98 @@
+import {getCenterFromGridPositionObj} from "./foundry_fixes.js";
+
+// TODO Wipe cache if walls layer is being modified
+let cached_nodes = undefined;
+
+function get_node(pos, initialize=true) {
+	if (!cached_nodes)
+		// TODO Check if ceil is the right thing to do here
+		cached_nodes = new Array(Math.ceil(canvas.dimensions.sceneHeight / canvas.dimensions.size));
+	if (!cached_nodes[pos.y])
+		cached_nodes[pos.y] = new Array(Math.ceil(canvas.dimensions.sceneWidth / canvas.dimensions.size));
+	if (!cached_nodes[pos.y][pos.x]) {
+		cached_nodes[pos.y][pos.x] = {x: pos.x, y: pos.y};
+	}
+
+	const node = cached_nodes[pos.y][pos.x];
+	if (initialize && !node.edges) {
+		node.edges = [];
+		for (const neighborPos of neighbors(pos)) {
+			// TODO Work with pixels instead of grid locations
+			if (!canvas.walls.checkCollision(new Ray(getCenterFromGridPositionObj(pos), getCenterFromGridPositionObj(neighborPos)))) {
+				const neighbor = get_node(neighborPos, false);
+				node.edges.push({target: neighbor, cost: 1});
+			}
+		}
+	}
+	return node;
+}
+
+function* neighbors(pos) {
+	for (let y = -1;y < 2;y++) {
+		for (let x = -1;x < 2;x++) {
+			if (x != 0 || y != 0)
+				yield {x: pos.x + x, y: pos.y + y};
+		}
+	}
+}
+
+function calculate_path(from, to) {
+	const nextNodes = [{node: get_node(to), cost: 0, estimated: estimate_cost(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 = get_node(edge.target);
+			if (previousNodes.has(neighborNode))
+				continue;
+			// TODO We currently assume a cost of one for all transitions. Change this for 5/10/5 or difficult terrain support
+			// We charge an extra 0.0001 for diagonals
+			const isDiagonal = currentNode.node.x !== neighborNode.x && currentNode.node.y !== neighborNode.y;
+			const edgeCost = isDiagonal ? 1.0001 : 1;
+			const neighbor = {node: neighborNode, cost: currentNode.cost + edgeCost, estimated: currentNode.cost + edgeCost + estimate_cost(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 estimate_cost(pos, target) {
+	return Math.max(Math.abs(pos.x - target.x), Math.abs(pos.y - target.y));
+}
+
+export function find_path(from, to) {
+	const lastNode = calculate_path(from, to);
+	if (!lastNode)
+		return null;
+	const path = [];
+	let currentNode = lastNode;
+	while (currentNode) {
+		// TODO Check if the distance doesn't change
+		if (path.length >= 2 && !canvas.walls.checkCollision(new Ray(getCenterFromGridPositionObj(currentNode.node), getCenterFromGridPositionObj(path[path.length - 2]))))
+			// 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 wipe_cache() {
+	cached_nodes = undefined;
+}

src/ruler.js

@@ -35,8 +35,13 @@ export class DragRulerRuler extends Ruler {
 		const json = super.toJSON();
 		if (this.draggedEntity) {
 			const isToken = this.draggedEntity instanceof Token;
-			json["draggedEntityIsToken"] = isToken;
-			json["draggedEntity"] = this.draggedEntity.id;
+			json.draggedEntityIsToken = isToken;
+			json.draggedEntity = this.draggedEntity.id;
+			json.waypoints = json.waypoints.map(old => {
+				let w = duplicate(old);
+				w.isPathfinding = undefined;
+				return w;
+			});
 		}
 		return json;
 	}

src/settings.js

@@ -47,6 +47,15 @@ export function registerSettings() {
 		default: true,
 	});
 
+	game.settings.register(settingsKey, "autoPathfinding", {
+		name: "drag-ruler.settings.autoPathfinding.name",
+		hint: "drag-ruler.settings.autoPathfinding.hint",
+		scpoe: "client",
+		config: true,
+		type: Boolean,
+		defualt: true,
+	});
+
 	game.settings.register(settingsKey, "lastTerrainRulerHintTime", {
 		config: false,
 		type: Number,