rpg-mcp

import seedrandom from 'seedrandom'; import { BiomeType } from '../../schema/biome.js'; export interface Region { id: number; name: string; // Placeholder for now capital: { x: number; y: number }; area: number; biome: BiomeType; // Dominant biome } export interface RegionMap { regions: Region[]; regionMap: Int32Array; // Maps index to region ID } export interface RegionGenerationOptions { seed: string; width: number; height: number; elevation: Uint8Array; biomes: BiomeType[][]; numRegions?: number; seaLevel?: number; } // Helper to convert 2D coords to 1D index const toIndex = (x: number, y: number, width: number) => y * width + x; const fromIndex = (index: number, width: number) => ({ x: index % width, y: Math.floor(index / width) }); export function generateRegions(options: RegionGenerationOptions): RegionMap { const { seed, width, height, elevation, biomes, numRegions = 10, seaLevel = 20 } = options; const size = width * height; const rng = seedrandom(seed); const regionMap = new Int32Array(size).fill(-1); const regions: Region[] = []; // 1. Pick Seeds (Capitals) // Only pick land tiles const landIndices: number[] = []; for (let i = 0; i < size; i++) { if (elevation[i] >= seaLevel) { landIndices.push(i); } } // Shuffle land indices to pick random seeds // Fisher-Yates shuffle (partial) for (let i = landIndices.length - 1; i > 0; i--) { const j = Math.floor(rng() * (i + 1)); [landIndices[i], landIndices[j]] = [landIndices[j], landIndices[i]]; } // Select top N as seeds // Ensure seeds are somewhat spaced out? For now, just random is fine for MVP. // A better approach is Poisson Disk, but let's stick to simple random for now. // To avoid clumping, we can check distance to existing seeds. const seeds: number[] = []; const minDistance = Math.sqrt(size) / numRegions; // Heuristic for (const idx of landIndices) { if (seeds.length >= numRegions) break; const { x, y } = fromIndex(idx, width); let tooClose = false; for (const seedIdx of seeds) { const s = fromIndex(seedIdx, width); const dist = Math.sqrt((x - s.x) ** 2 + (y - s.y) ** 2); if (dist < minDistance) { tooClose = true; break; } } if (!tooClose) { seeds.push(idx); } } // If we couldn't find enough spaced seeds, just fill with random ones if (seeds.length < numRegions) { for (const idx of landIndices) { if (seeds.length >= numRegions) break; if (!seeds.includes(idx)) { seeds.push(idx); } } } // Initialize regions const queues: number[][] = []; // One queue per region seeds.forEach((seedIdx, id) => { const { x, y } = fromIndex(seedIdx, width); regions.push({ id, name: `Region ${id + 1}`, capital: { x, y }, area: 0, biome: biomes[y][x] }); regionMap[seedIdx] = id; queues.push([seedIdx]); }); // 2. Multi-Source BFS (Flood Fill) // We process one step for each region in round-robin to ensure even growth let active = true; while (active) { active = false; for (let id = 0; id < regions.length; id++) { const queue = queues[id]; if (queue.length === 0) continue; // Process a batch of pixels (e.g., the current "frontier") // For true round-robin, we should process only the current depth, but popping one is simpler // and creates roughly circular regions if we randomize order or do it layer by layer. // Let's do a "layer" approach: process all currently in queue, add neighbors to next_queue const nextQueue: number[] = []; // Process entire current frontier to grow uniformly while (queue.length > 0) { const currIdx = queue.shift()!; const { x, y } = fromIndex(currIdx, width); const neighbors = [ { nx: x, ny: y - 1 }, { nx: x + 1, ny: y }, { nx: x, ny: y + 1 }, { nx: x - 1, ny: y } ]; for (const { nx, ny } of neighbors) { if (nx >= 0 && nx < width && ny >= 0 && ny < height) { const nIdx = toIndex(nx, ny, width); // If unassigned and land if (regionMap[nIdx] === -1 && elevation[nIdx] >= seaLevel) { regionMap[nIdx] = id; nextQueue.push(nIdx); regions[id].area++; active = true; } } } } queues[id] = nextQueue; } } // 3. Post-processing: Fill gaps? // The BFS should fill all reachable land. Unreachable islands might be left -1. // We can optionally assign them to the nearest region or leave them wild. // For now, let's leave them as -1 (Wildlands). return { regions, regionMap }; }