feat: add prim maze generator

PROJECT_DESCRIPTION.md

@@ -36,7 +36,7 @@ npm run build
 | Need | Algorithm(s) | Module | Example |
 | ---- | ------------ | ------ | ------- |
 | Grid pathfinding | `astar`, `dijkstra`, `jumpPointSearch`, `computeFlowField`, `buildNavMesh`, `findNavMeshPath`, `manhattanDistance`, `gridFromString` | `pathfinding/astar.ts`, `pathfinding/dijkstra.ts`, `pathfinding/jumpPointSearch.ts`, `pathfinding/flowField.ts`, `pathfinding/navMesh.ts` | `examples/astar.ts`, `examples/flowField.ts`, `examples/navMesh.ts` |
-| Procedural textures & terrain | `perlin`, `perlin3D`, `simplex2D`, `simplex3D`, `worley`, `worleySample`, `waveFunctionCollapse`, `cellularAutomataCave`, `poissonDiskSampling`, `computeVoronoiDiagram`, `diamondSquare`, `generateLSystem`, `generateBspDungeon`, `generateRecursiveMaze` | `procedural/*.ts` | `examples/simplex.ts`, `examples/worley.ts`, `examples/waveFunctionCollapse.ts`, `examples/cellularAutomata.ts`, `examples/poissonDisk.ts`, `examples/voronoi.ts`, `examples/diamondSquare.ts`, `examples/lSystem.ts`, `examples/dungeonBsp.ts`, `examples/mazeRecursive.ts` |
+| Procedural textures & terrain | `perlin`, `perlin3D`, `simplex2D`, `simplex3D`, `worley`, `worleySample`, `waveFunctionCollapse`, `cellularAutomataCave`, `poissonDiskSampling`, `computeVoronoiDiagram`, `diamondSquare`, `generateLSystem`, `generateBspDungeon`, `generateRecursiveMaze`, `generatePrimMaze` | `procedural/*.ts` | `examples/simplex.ts`, `examples/worley.ts`, `examples/waveFunctionCollapse.ts`, `examples/cellularAutomata.ts`, `examples/poissonDisk.ts`, `examples/voronoi.ts`, `examples/diamondSquare.ts`, `examples/lSystem.ts`, `examples/dungeonBsp.ts`, `examples/mazeRecursive.ts`, `examples/mazePrim.ts` |
 | Spatial queries & collision | `Quadtree`, `aabbCollision`, `aabbIntersection`, `satCollision`, `circleRayIntersection`, `sweptAABB` | `spatial/*.ts` | `examples/sat.ts` |
 | Web performance & UI throttling | `debounce`, `throttle`, `LRUCache`, `memoize`, `deduplicateRequest`, `clearRequestDedup`, `calculateVirtualRange` | `util/*.ts` | `examples/requestDedup.ts`, `examples/virtualScroll.ts` |
 | Text & search | `fuzzySearch`, `fuzzyScore`, `Trie`, `binarySearch`, `levenshteinDistance` | `search/*.ts` | `examples/search.ts` |

README.md

@@ -25,7 +25,7 @@ CDN usage:
 | Goal | Algorithms | Import From | Example |
 | ---- | ---------- | ----------- | ------- |
 | Pathfinding & navigation | `astar`, `dijkstra`, `jumpPointSearch`, `computeFlowField`, `buildNavMesh`, `findNavMeshPath`, `manhattanDistance`, `gridFromString` | `pathfinding/astar.ts`, `pathfinding/dijkstra.ts`, `pathfinding/jumpPointSearch.ts`, `pathfinding/flowField.ts`, `pathfinding/navMesh.ts` | `examples/astar.ts`, `examples/flowField.ts`, `examples/navMesh.ts` |
-| Procedural generation | `perlin`, `perlin3D`, `simplex2D`, `simplex3D`, `worley`, `worleySample`, `waveFunctionCollapse`, `cellularAutomataCave`, `poissonDiskSampling`, `computeVoronoiDiagram`, `diamondSquare`, `generateLSystem`, `generateBspDungeon`, `generateRecursiveMaze` | `procedural/*.ts` | `examples/simplex.ts`, `examples/worley.ts`, `examples/waveFunctionCollapse.ts`, `examples/cellularAutomata.ts`, `examples/poissonDisk.ts`, `examples/voronoi.ts`, `examples/diamondSquare.ts`, `examples/lSystem.ts`, `examples/dungeonBsp.ts`, `examples/mazeRecursive.ts` |
+| Procedural generation | `perlin`, `perlin3D`, `simplex2D`, `simplex3D`, `worley`, `worleySample`, `waveFunctionCollapse`, `cellularAutomataCave`, `poissonDiskSampling`, `computeVoronoiDiagram`, `diamondSquare`, `generateLSystem`, `generateBspDungeon`, `generateRecursiveMaze`, `generatePrimMaze` | `procedural/*.ts` | `examples/simplex.ts`, `examples/worley.ts`, `examples/waveFunctionCollapse.ts`, `examples/cellularAutomata.ts`, `examples/poissonDisk.ts`, `examples/voronoi.ts`, `examples/diamondSquare.ts`, `examples/lSystem.ts`, `examples/dungeonBsp.ts`, `examples/mazeRecursive.ts`, `examples/mazePrim.ts` |
 | Spatial queries & collision | `Quadtree`, `aabbCollision`, `aabbIntersection`, `satCollision`, `circleRayIntersection`, `sweptAABB` | `spatial/*.ts` | `examples/sat.ts` |
 | AI behaviours & crowds | `seek`, `flee`, `arrive`, `pursue`, `wander`, `updateBoids`, `BehaviorTree`, `rvoStep` | `ai/steering.ts`, `ai/boids.ts`, `ai/behaviorTree.ts`, `ai/rvo.ts` | `examples/steering.ts`, `examples/boids.ts`, `examples/rvo.ts` |
 | Web performance & UI | `debounce`, `throttle`, `LRUCache`, `memoize`, `deduplicateRequest`, `clearRequestDedup`, `calculateVirtualRange` | `util/*.ts` | `examples/requestDedup.ts`, `examples/virtualScroll.ts` |
@@ -52,7 +52,7 @@ npm run size        # Enforce bundle size budget
 - Milestone 0.2 next targets crowd-flow integrations (RVO + flow fields) and behaviour-tree decorators for richer AI control.
 - Milestone 0.4 plans a procedural + gameplay systems toolkit (Wave Function Collapse, dungeon suite, L-systems, game loop, camera, particles, inventory, combat, save/load, and more).
 
-Examples live under `examples/` and can be executed with `tsx`/`ts-node` or compiled for the browser. See `examples/astar.ts`, `examples/flowField.ts`, `examples/navMesh.ts`, `examples/cellularAutomata.ts`, `examples/poissonDisk.ts`, `examples/voronoi.ts`, `examples/diamondSquare.ts`, `examples/lSystem.ts`, `examples/dungeonBsp.ts`, `examples/mazeRecursive.ts`, `examples/steering.ts`, `examples/boids.ts`, `examples/requestDedup.ts`, `examples/search.ts`, `examples/graph.ts`, `examples/geometry.ts`, `examples/visual.ts`, `examples/sat.ts`, `examples/simplex.ts`, and `examples/worley.ts` for quick starts. The `examples` registry exported from `src/index.ts` provides a typed index you can traverse programmatically.
+Examples live under `examples/` and can be executed with `tsx`/`ts-node` or compiled for the browser. See `examples/astar.ts`, `examples/flowField.ts`, `examples/navMesh.ts`, `examples/cellularAutomata.ts`, `examples/poissonDisk.ts`, `examples/voronoi.ts`, `examples/diamondSquare.ts`, `examples/lSystem.ts`, `examples/dungeonBsp.ts`, `examples/mazeRecursive.ts`, `examples/mazePrim.ts`, `examples/steering.ts`, `examples/boids.ts`, `examples/requestDedup.ts`, `examples/search.ts`, `examples/graph.ts`, `examples/geometry.ts`, `examples/visual.ts`, `examples/sat.ts`, `examples/simplex.ts`, and `examples/worley.ts` for quick starts. The `examples` registry exported from `src/index.ts` provides a typed index you can traverse programmatically.
 
 ## Contributing
 1. Fork the repository.

ROADMAP.md

@@ -42,7 +42,7 @@
   - [x] Diamond-square terrain height map generator
   - [x] L-system generator for foliage and organic structures
   - [x] Dungeon generation suite (BSP subdivision, rooms & corridors variants)
-  - [ ] Maze algorithms pack (Recursive backtracking, Prim's, Kruskal's, Wilson's, Aldous–Broder, Recursive Division)
+  - [ ] Maze algorithms pack (Recursive backtracking ✅, Prim's ✅, Kruskal's, Wilson's, Aldous–Broder, Recursive Division)
 - Gameplay systems & utilities:
   - [ ] Fixed-timestep game loop utility with interpolation helpers
   - [ ] Delta-time manager for frame-independent timing

docs/index.d.ts

@@ -53,6 +53,7 @@ export const examples: {
     readonly generateLSystem: 'examples/lSystem.ts';
     readonly generateBspDungeon: 'examples/dungeonBsp.ts';
     readonly generateRecursiveMaze: 'examples/mazeRecursive.ts';
+    readonly generatePrimMaze: 'examples/mazePrim.ts';
   };
   readonly spatial: {
     readonly Quadtree: 'examples/sat.ts';
@@ -610,6 +611,14 @@ export interface MazeResult {
  */
 export function generateRecursiveMaze(options: MazeOptions): MazeResult;
 
+/**
+ * Generates a maze using Prim's algorithm.
+ * Use for: compact mazes with branching corridors, alternative structures.
+ * Performance: O(width × height).
+ * Import: procedural/maze.ts
+ */
+export function generatePrimMaze(options: MazeOptions): MazeResult;
+
 /**
  * Simplex noise generator for smooth gradients without directional artifacts.
  * Use for: large terrain synthesis, animated textures, volumetric noise.

examples/mazePrim.ts

@@ -0,0 +1,11 @@
+import { generatePrimMaze } from '../src/index.js';
+
+const { grid, start, end } = generatePrimMaze({
+  width: 21,
+  height: 21,
+  seed: 512,
+});
+
+console.log('Start:', start);
+console.log('End:', end);
+console.log('Middle row preview:', grid[10]?.join(''));

src/index.ts

@@ -49,6 +49,7 @@ export const examples = {
     generateLSystem: 'examples/lSystem.ts',
     generateBspDungeon: 'examples/dungeonBsp.ts',
     generateRecursiveMaze: 'examples/mazeRecursive.ts',
+    generatePrimMaze: 'examples/mazePrim.ts',
   },
   spatial: {
     Quadtree: 'examples/sat.ts',
@@ -282,6 +283,13 @@ export { generateBspDungeon } from './procedural/dungeonBsp.js';
  */
 export { generateRecursiveMaze } from './procedural/maze.js';
 
+/**
+ * Prim's maze generator for alternative maze structures.
+ *
+ * Example file: examples/mazePrim.ts
+ */
+export { generatePrimMaze } from './procedural/maze.js';
+
 // ============================================================================
 // 🎯 SPATIAL & COLLISION
 // ============================================================================

src/procedural/maze.ts

@@ -63,6 +63,53 @@ export function generateRecursiveMaze({
   return { grid, start, end };
 }
 
+/**
+ * Generates a maze using randomized Prim's algorithm.
+ * Useful for: maze layouts with different structural characteristics than DFS.
+ */
+export function generatePrimMaze({
+  width,
+  height,
+  seed = Date.now(),
+}: MazeOptions): MazeResult {
+  validateDimensions(width, height);
+
+  const grid = Array.from({ length: height }, () => Array<number>(width).fill(WALL));
+  const random = createLinearCongruentialGenerator(seed);
+
+  const start: Cell = { x: 1, y: 1 };
+  carveCell(grid, start);
+
+  const frontier: Cell[] = [];
+  addFrontierCells(start, grid, frontier);
+
+  while (frontier.length > 0) {
+    const index = Math.floor(random() * frontier.length);
+    const [cell] = frontier.splice(index, 1);
+    if (!cell) {
+      continue;
+    }
+
+    const neighbours = shuffledNeighbours(cell, grid, random).filter((candidate) => !isWall(candidate, grid));
+    if (neighbours.length === 0) {
+      continue;
+    }
+
+    const neighbour = neighbours[Math.floor(random() * neighbours.length)];
+    if (!neighbour) {
+      continue;
+    }
+    carveCorridorBetween(grid, cell, neighbour);
+    carveCell(grid, cell);
+    addFrontierCells(cell, grid, frontier);
+  }
+
+  const end = findFarthestCell(start, grid);
+  carveCell(grid, end);
+
+  return { grid, start, end };
+}
+
 function validateDimensions(width: number, height: number): void {
   if (!Number.isInteger(width) || !Number.isInteger(height)) {
     throw new Error('width and height must be integers.');
@@ -88,10 +135,11 @@ function shuffledNeighbours(cell: Cell, grid: number[][], random: () => number):
   }
 
   const neighbours: Cell[] = [];
+  const width = grid[0]?.length ?? 0;
   for (const [dx, dy] of offsets) {
     const nx = cell.x + dx;
     const ny = cell.y + dy;
-    if (ny > 0 && ny < grid.length && nx > 0 && nx < grid[0]!.length) {
+    if (ny > 0 && ny < grid.length && nx > 0 && nx < width) {
       neighbours.push({ x: nx, y: ny });
     }
   }
@@ -108,11 +156,43 @@ function carveCell(grid: number[][], cell: Cell): void {
   }
 }
 
+function carveCorridorBetween(grid: number[][], from: Cell, to: Cell): void {
+  const mid = {
+    x: from.x + (to.x - from.x) / 2,
+    y: from.y + (to.y - from.y) / 2,
+  };
+  carveCell(grid, mid);
+  carveCell(grid, to);
+}
+
+function addFrontierCells(cell: Cell, grid: number[][], frontier: Cell[]): void {
+  const height = grid.length;
+  const width = grid[0]?.length ?? 0;
+  const offsets: Array<[number, number]> = [
+    [0, -2],
+    [2, 0],
+    [0, 2],
+    [-2, 0],
+  ];
+
+  for (const [dx, dy] of offsets) {
+    const nx = cell.x + dx;
+    const ny = cell.y + dy;
+    if (ny > 0 && ny < height && nx > 0 && nx < width && grid[ny][nx] === WALL) {
+      const alreadyFrontier = frontier.some((frontierCell) => frontierCell.x === nx && frontierCell.y === ny);
+      if (!alreadyFrontier) {
+        frontier.push({ x: nx, y: ny });
+      }
+    }
+  }
+}
+
 function findFarthestCell(start: Cell, grid: number[][]): Cell {
   let farthest = start;
   let maxDistance = -1;
+  const width = grid[0]?.length ?? 0;
   for (let y = 1; y < grid.length; y += 2) {
-    for (let x = 1; x < grid[0]!.length; x += 2) {
+    for (let x = 1; x < width; x += 2) {
       if (grid[y][x] === PATH) {
         const distance = Math.abs(start.x - x) + Math.abs(start.y - y);
         if (distance > maxDistance) {

tests/index.test.ts

@@ -14,6 +14,8 @@ describe('package entry point', () => {
     expect(examples.procedural.diamondSquare).toBe('examples/diamondSquare.ts');
     expect(examples.procedural.generateLSystem).toBe('examples/lSystem.ts');
     expect(examples.procedural.generateBspDungeon).toBe('examples/dungeonBsp.ts');
+    expect(examples.procedural.generateRecursiveMaze).toBe('examples/mazeRecursive.ts');
+    expect(examples.procedural.generatePrimMaze).toBe('examples/mazePrim.ts');
     expect(examples.search.Trie).toBe('examples/search.ts');
     expect(examples.pathfinding.buildNavMesh).toBe('examples/navMesh.ts');
   });
@@ -58,6 +60,8 @@ describe('package entry point', () => {
       | 'diamondSquare'
       | 'generateLSystem'
       | 'generateBspDungeon'
+      | 'generateRecursiveMaze'
+      | 'generatePrimMaze'
     >();
   });
 });

tests/mazePrim.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, it } from 'vitest';
+
+import { generatePrimMaze } from '../src/index.js';
+
+describe('generatePrimMaze', () => {
+  it('is deterministic for identical seeds', () => {
+    const options = { width: 21, height: 21, seed: 333 } as const;
+    const a = generatePrimMaze(options);
+    const b = generatePrimMaze(options);
+
+    expect(a.grid).toEqual(b.grid);
+    expect(a.start).toEqual(b.start);
+    expect(a.end).toEqual(b.end);
+  });
+
+  it('carves corridors bounded by walls', () => {
+    const { grid } = generatePrimMaze({ width: 15, height: 15, seed: 99 });
+    expect(grid.length).toBe(15);
+    expect(grid.every((row) => row.length === 15)).toBe(true);
+
+    const borderTop = grid[0].every((cell) => cell === 1);
+    const borderBottom = grid[grid.length - 1].every((cell) => cell === 1);
+    const borderSides = grid.every((row) => row[0] === 1 && row[row.length - 1] === 1);
+    expect(borderTop && borderBottom && borderSides).toBe(true);
+
+    const walkableTiles = grid.flat().filter((cell) => cell === 0).length;
+    expect(walkableTiles).toBeGreaterThan(0);
+  });
+});