@mousepox/math/dist/astar.js

Math-related objects and utilities

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.astar = void 0;
const core_1 = require("./core");
function makeNode(x, y, parent) {
    return { f: 0, g: 0, parent, x, y };
}
function addNode(nodes, node) {
    const len = nodes.length;
    for (let i = 0; i < len; i++) {
        if (nodes[i].f > node.f) {
            nodes.splice(i, 0, node);
            return;
        }
    }
    nodes.push(node);
}
function createPathFromNode(node) {
    let n = node;
    const path = [];
    while (n !== undefined) {
        path.push({ x: n.x, y: n.y });
        n = n.parent;
    }
    path.reverse();
    return path;
}
function astar(grid, x1, y1, x2, y2) {
    const start = makeNode(x1, y1);
    const goal = makeNode(x2, y2);
    const open = [start];
    const closed = [];
    while (open.length > 0) {
        const node = open.shift();
        if (node === undefined) {
            break;
        }
        if (node.x === goal.x && node.y === goal.y) {
            return createPathFromNode(node);
        }
        else {
            grid.forEachAdjacent(node.x, node.y, (value, x, y) => {
                if (value !== 0) {
                    return;
                }
                const index = grid.xyToIndex(x, y);
                if (closed.indexOf(index) === -1) {
                    const n = makeNode(x, y, node);
                    n.g = node.g + (0, core_1.distance)(n.x, n.y, node.x, node.y);
                    n.f = n.g + (0, core_1.distance)(n.x, n.y, goal.x, goal.y);
                    addNode(open, n);
                    closed.push(index);
                }
            });
        }
    }
    return;
}
exports.astar = astar;