900 lines
35 KiB
JavaScript
900 lines
35 KiB
JavaScript
import { INF, MAP_H, MAP_W, SIZE, clamp, createMapFields, fbm, hash2, indexOf, inside, lerp, pickEntities, rand, smoothstep, valueNoise } from "./mapUtils.js";
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import {
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aStar,
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extractMaskBorder,
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extractRegionBorderSegments,
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generateRegionalPrefectures,
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makePrefectureMask,
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neighbors8,
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} from "./mapGeneratorHelpers.js";
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export function generateTerrainAndRivers(seed) {
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let prefectureMask;
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let prefectureBorder;
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const {
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elevation,
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moisture,
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slope,
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sea,
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river,
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floodplain,
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plain,
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agriculture,
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ridgeField,
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valleyField,
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basinField,
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coastalLowland,
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flowAccum,
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erosionField,
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depositionField,
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flowTo,
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portSuitability,
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crossingSuitability,
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passSuitability,
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} = createMapFields();
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const coastAngle = rand(seed, 11) * Math.PI * 2;
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const coastX = Math.cos(coastAngle);
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const coastY = Math.sin(coastAngle);
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const coastThreshold = 0.22 + rand(seed, 12) * 0.22;
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const coastStrength = 0.15 + rand(seed, 13) * 0.23;
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const seaLevel = 0.285;
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const mountainBlobs = Array.from({ length: 2 + Math.floor(rand(seed, 98) * 3) }, (_, i) => ({
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x: rand(seed, 100 + i) * MAP_W,
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y: rand(seed, 200 + i) * MAP_H,
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r: 10 + rand(seed, 300 + i) * 24,
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h: 0.08 + rand(seed, 400 + i) * 0.16,
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}));
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const ridgeBands = Array.from({ length: 5 + Math.floor(rand(seed, 97) * 4) }, (_, i) => ({
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x: rand(seed, 1500 + i) * MAP_W,
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y: rand(seed, 1600 + i) * MAP_H,
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angle: rand(seed, 1700 + i) * Math.PI * 2,
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width: 3 + rand(seed, 1800 + i) * 7,
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length: 42 + rand(seed, 1900 + i) * 92,
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h: 0.11 + rand(seed, 2000 + i) * 0.22,
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}));
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for (let y = 0; y < MAP_H; y++) {
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for (let x = 0; x < MAP_W; x++) {
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const nx = x / (MAP_W - 1) - 0.5;
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const ny = y / (MAP_H - 1) - 0.5;
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const i = indexOf(x, y);
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const warpX = (fbm(x * 0.62 + 180, y * 0.62 - 90, seed + 3101) - 0.5) * 13;
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const warpY = (fbm(x * 0.62 - 70, y * 0.62 + 210, seed + 3201) - 0.5) * 13;
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const wx = x + warpX;
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const wy = y + warpY;
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let mountains = 0;
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for (const blob of mountainBlobs) {
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const d = Math.hypot(wx - blob.x, wy - blob.y) / blob.r;
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mountains += Math.exp(-d * d * 2.35) * blob.h;
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}
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let ridges = 0;
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for (const ridge of ridgeBands) {
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const dx = wx - ridge.x;
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const dy = wy - ridge.y;
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const along = dx * Math.cos(ridge.angle) + dy * Math.sin(ridge.angle);
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const perp = -dx * Math.sin(ridge.angle) + dy * Math.cos(ridge.angle);
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const lengthFade = smoothstep(1 - Math.abs(along) / ridge.length);
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const serration = 0.72 + valueNoise(wx + along * 0.15, wy + perp * 0.15, seed + 2220, 8) * 0.56;
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ridges += Math.exp(-(perp * perp) / (ridge.width * ridge.width)) * lengthFade * ridge.h * serration;
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}
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const directionalCoast = nx * coastX + ny * coastY;
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const coastWave = (fbm(wx * 0.72, wy * 0.72, seed + 2222) - 0.5) * 0.12 + (valueNoise(wx, wy, seed + 2233, 18) - 0.5) * 0.08;
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const coastLower = smoothstep((directionalCoast + coastWave - coastThreshold) / 0.26);
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// Four terrain-noise bands from continental structure to fine surface roughness.
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const terrainLarge = fbm(wx * 0.36 + 40, wy * 0.36 - 60, seed + 710);
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const terrainRegional = fbm(wx * 0.95 + 80, wy * 0.95 - 20, seed + 777);
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const terrainLocal = fbm(wx * 2.05 + 17, wy * 2.05 - 31, seed + 1777);
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const terrainFine = valueNoise(wx * 2.9 + 11, wy * 2.9 - 19, seed + 2444, 4.5);
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const fineDissection = Math.abs(terrainLocal - 0.5) * 0.08 + Math.abs(terrainFine - 0.5) * 0.035;
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const basin = 0.1 * Math.sin((nx * 3.1 + ny * 1.7 + rand(seed, 15)) * Math.PI) - 0.045 * Math.cos((nx * 5.2 - ny * 3.6 + rand(seed, 16)) * Math.PI);
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const rawElevation =
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0.30 * terrainLarge +
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0.235 * terrainRegional +
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0.105 * terrainLocal +
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0.055 * terrainFine +
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mountains * 0.54 +
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ridges * 1.22 +
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basin +
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fineDissection -
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coastLower * (coastStrength + 0.19) +
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0.055;
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elevation[i] = clamp(0.5 + (rawElevation - 0.5) * 1.26);
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ridgeField[i] = clamp(ridges * 4.8 + Math.max(0, mountains - 0.10) * 0.95 + fineDissection * 2.0);
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basinField[i] = clamp(Math.max(0, -basin) * 3.0 + (1 - coastLower) * Math.max(0, 0.42 - elevation[i]) * 0.7);
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moisture[i] = clamp(0.44 * fbm(wx + 400, wy - 200, seed + 333) + 0.18 * valueNoise(wx, wy, seed + 343, 11) + 0.22 * (1 - Math.abs(ny * 1.7)) + 0.28 * coastLower - Math.max(0, elevation[i] - 0.62) * 0.22);
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}
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}
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for (let y = 0; y < MAP_H; y++) {
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for (let x = 0; x < MAP_W; x++) {
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const i = indexOf(x, y);
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const nx = x / (MAP_W - 1) - 0.5;
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const ny = y / (MAP_H - 1) - 0.5;
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const directionalCoast = nx * coastX + ny * coastY;
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const coastNoise = (fbm(x * 0.95, y * 0.95, seed + 2222) - 0.5) * 0.14 + (valueNoise(x, y, seed + 2233, 13) - 0.5) * 0.08;
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const oceanSide = directionalCoast + coastNoise > coastThreshold + 0.055;
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if (elevation[i] < seaLevel || oceanSide) sea[i] = 1;
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if (sea[i]) elevation[i] = Math.min(elevation[i], seaLevel - 0.018 + hash2(x, y, seed + 2311) * 0.012);
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}
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}
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// Align coastal elevation with the sea mask. This prevents artificial one-cell cliffs
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// when the directional coastline cuts through a high terrain cell.
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for (let y = 0; y < MAP_H; y++) {
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for (let x = 0; x < MAP_W; x++) {
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const i = indexOf(x, y);
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if (sea[i]) continue;
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let nearestSea = INF;
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for (let dy = -7; dy <= 7; dy++) {
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for (let dx = -7; dx <= 7; dx++) {
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const nx = x + dx;
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const ny = y + dy;
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if (!inside(nx, ny) || !sea[indexOf(nx, ny)]) continue;
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nearestSea = Math.min(nearestSea, Math.hypot(dx, dy));
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}
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}
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if (nearestSea <= 7) {
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const coastalCap = seaLevel + 0.018 + nearestSea * 0.028 + Math.max(0, fbm(x * 1.4, y * 1.4, seed + 2350) - 0.5) * 0.022;
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elevation[i] = Math.min(elevation[i], coastalCap);
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coastalLowland[i] = clamp(1 - nearestSea / 7);
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}
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}
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}
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for (let y = 1; y < MAP_H - 1; y++) {
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for (let x = 1; x < MAP_W - 1; x++) {
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const gx = elevation[indexOf(x + 1, y)] - elevation[indexOf(x - 1, y)];
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const gy = elevation[indexOf(x, y + 1)] - elevation[indexOf(x, y - 1)];
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slope[indexOf(x, y)] = clamp(Math.sqrt(gx * gx + gy * gy) * 10.5);
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}
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}
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const landOrder = [];
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for (let y = 1; y < MAP_H - 1; y++) {
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for (let x = 1; x < MAP_W - 1; x++) {
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const i = indexOf(x, y);
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if (sea[i]) continue;
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let low = i;
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let best = elevation[i] + 0.012 * hash2(x, y, seed + 2468);
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let localMean = 0;
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let localMax = elevation[i];
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let localMin = elevation[i];
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let nCount = 0;
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for (const [nx, ny] of neighbors8(x, y)) {
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const ni = indexOf(nx, ny);
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const ev = elevation[ni];
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localMean += ev;
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localMax = Math.max(localMax, ev);
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localMin = Math.min(localMin, ev);
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nCount++;
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const directed = ev + 0.008 * hash2(nx, ny, seed + 2469);
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if (directed < best || sea[ni]) {
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best = directed;
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low = ni;
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}
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}
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if (low !== i) flowTo[i] = low;
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localMean /= Math.max(1, nCount);
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const hollow = Math.max(0, localMean - elevation[i]);
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const relief = localMax - localMin;
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valleyField[i] = clamp(hollow * 8.4 + Math.max(0, 0.42 - elevation[i]) * 0.32 + moisture[i] * 0.08 - ridgeField[i] * 0.18);
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basinField[i] = clamp(basinField[i] + hollow * 2.4 + (relief < 0.055 && elevation[i] < 0.55 ? 0.18 : 0));
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flowAccum[i] = 0.7 + moisture[i] * 0.7 + valleyField[i] * 0.55;
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landOrder.push(i);
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}
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}
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landOrder.sort((a, b) => elevation[b] - elevation[a]);
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for (const i of landOrder) {
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const to = flowTo[i];
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if (to >= 0 && to !== i) flowAccum[to] += flowAccum[i] * 0.82;
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}
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let maxFlowAccum = 0;
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for (let i = 0; i < SIZE; i++) if (!sea[i]) maxFlowAccum = Math.max(maxFlowAccum, flowAccum[i]);
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if (maxFlowAccum > 0) {
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for (let i = 0; i < SIZE; i++) flowAccum[i] = clamp(flowAccum[i] / maxFlowAccum);
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}
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for (let i = 0; i < SIZE; i++) {
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if (!sea[i]) valleyField[i] = clamp(valleyField[i] * 0.68 + Math.pow(flowAccum[i], 0.55) * 0.48);
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}
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// First-order fluvial shaping: cut valley floors on steep/high-flow cells and
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// deposit gently in coastal lowlands and basin floors. This gives visible
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// river valleys without destroying the macro terrain structure.
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const shapedElevation = new Float32Array(elevation);
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for (let y = 1; y < MAP_H - 1; y++) {
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for (let x = 1; x < MAP_W - 1; x++) {
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const i = indexOf(x, y);
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if (sea[i]) continue;
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const flow = Math.pow(flowAccum[i], 0.46);
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const incisionNoise = 0.82 + hash2(x, y, seed + 8120) * 0.36;
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const steepValley = clamp(flow * (0.058 + slope[i] * 0.21 + ridgeField[i] * 0.046) * incisionNoise);
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const lateralCut = clamp(Math.pow(flowAccum[i], 0.66) * valleyField[i] * 0.078);
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const lowSettling = clamp(flow * (coastalLowland[i] * 0.036 + basinField[i] * 0.020 + (elevation[i] < 0.40 ? 0.012 : 0)) * (1 - slope[i] * 0.82));
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erosionField[i] = steepValley + lateralCut;
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depositionField[i] = lowSettling;
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shapedElevation[i] = clamp(elevation[i] - steepValley - lateralCut + lowSettling * 0.72, seaLevel + 0.006, 1);
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}
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}
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elevation.set(shapedElevation);
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for (let y = 1; y < MAP_H - 1; y++) {
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for (let x = 1; x < MAP_W - 1; x++) {
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const i = indexOf(x, y);
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if (sea[i]) continue;
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const gx = elevation[indexOf(x + 1, y)] - elevation[indexOf(x - 1, y)];
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const gy = elevation[indexOf(x, y + 1)] - elevation[indexOf(x, y - 1)];
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slope[i] = clamp(Math.sqrt(gx * gx + gy * gy) * 10.5);
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valleyField[i] = clamp(valleyField[i] + erosionField[i] * 2.1 + depositionField[i] * 0.8 - ridgeField[i] * 0.06);
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basinField[i] = clamp(basinField[i] + depositionField[i] * 1.6);
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}
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}
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const sourceCandidates = [];
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for (let y = 4; y < MAP_H - 4; y++) {
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for (let x = 4; x < MAP_W - 4; x++) {
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const i = indexOf(x, y);
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if (sea[i]) continue;
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const score = elevation[i] * 0.38 + moisture[i] * 0.24 + ridgeField[i] * 0.08 + flowAccum[i] * 0.56 + valleyField[i] * 0.28 + hash2(x, y, seed + 9000) * 0.06;
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if (elevation[i] > 0.40 && elevation[i] < 0.82 && moisture[i] > 0.28 && flowAccum[i] > 0.020 && ridgeField[i] < 0.88) sourceCandidates.push({ x, y, score });
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}
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}
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const sources = pickEntities(sourceCandidates, {
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max: 20 + Math.floor(rand(seed, 910) * 28),
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minDistance: 8,
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threshold: 0.53 + rand(seed, 911) * 0.11,
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seed,
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});
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function nearestWaterGoal(from) {
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let bestSea = null;
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let bestScore = INF;
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for (let y = 0; y < MAP_H; y++) {
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for (let x = 0; x < MAP_W; x++) {
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const i = indexOf(x, y);
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if (!sea[i]) continue;
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const d = Math.hypot(x - from.x, y - from.y);
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const score = d - coastalLowland[indexOf(Math.max(0, Math.min(MAP_W - 1, from.x)), Math.max(0, Math.min(MAP_H - 1, from.y)))] * 2;
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if (score < bestScore) {
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bestScore = score;
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bestSea = { x, y };
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}
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}
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}
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return bestSea;
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}
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function riverRouteCost(x, y, cx, cy) {
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const i = indexOf(x, y);
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const ci = indexOf(cx, cy);
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if (sea[i]) return 0.18;
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const uphill = Math.max(0, elevation[i] - elevation[ci]);
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const downhill = Math.max(0, elevation[ci] - elevation[i]);
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if (!sea[i] && uphill > 0.035 && flowAccum[i] < flowAccum[ci] + 0.015) return INF;
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return Math.max(
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0.18,
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1 +
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uphill * 86 +
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slope[i] * 0.38 +
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elevation[i] * 0.42 -
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downhill * 2.1 -
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valleyField[i] * 0.92 -
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flowAccum[i] * 0.72 -
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moisture[i] * 0.18 -
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coastalLowland[i] * 0.22
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);
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}
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function forceRiverToWater(path) {
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if (!path.length) return path;
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const [ex, ey] = path[path.length - 1];
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if (sea[indexOf(ex, ey)]) return path;
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const goal = nearestWaterGoal({ x: ex, y: ey });
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if (!goal) return path;
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const startElevation = elevation[indexOf(ex, ey)];
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const tail = aStar({ x: ex, y: ey }, goal, (x, y, cx, cy) => {
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const i = indexOf(x, y);
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const ci = indexOf(cx, cy);
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if (!sea[i] && elevation[i] > Math.max(startElevation + 0.045, elevation[ci] + 0.030)) return INF;
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return riverRouteCost(x, y, cx, cy);
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});
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if (tail.length <= 2) return path;
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return path.concat(tail.slice(1));
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}
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function confluenceAnglePenalty(nx, ny, dx, dy, lengthSoFar) {
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if (lengthSoFar < 7 || river[indexOf(nx, ny)] < 0.24) return 0;
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let best = 0.16;
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const inLen = Math.hypot(dx, dy) || 1;
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for (const [rx, ry] of neighbors8(nx, ny)) {
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if (river[indexOf(rx, ry)] < 0.22) continue;
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const rdx = rx - nx;
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const rdy = ry - ny;
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const cos = clamp((dx * rdx + dy * rdy) / Math.max(0.001, inLen * Math.hypot(rdx, rdy)), -1, 1);
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const angle = Math.acos(cos);
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const shallow = angle < 0.45 ? 0.28 : 0;
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best = Math.min(best, Math.abs(angle - Math.PI * 0.62) * 0.045 + shallow);
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}
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return best;
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}
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function traceRiverPath(startX, startY, bonusSeed = 0) {
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let x = startX;
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let y = startY;
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let lastDx = 0;
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let lastDy = 0;
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const path = [];
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const seen = new Set();
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let accum = 0;
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for (let step = 0; step < 600; step++) {
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const i = indexOf(x, y);
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if (seen.has(i)) break;
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seen.add(i);
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path.push([x, y]);
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river[i] += 0.44 + path.length / 160 + flowAccum[i] * 0.55;
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accum += river[i] + flowAccum[i];
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if (sea[i]) break;
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let best = null;
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let bestValue = INF;
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const currentElevation = elevation[i];
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const preferred = flowTo[i];
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for (const [nx, ny] of neighbors8(x, y)) {
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const ni = indexOf(nx, ny);
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const dx = nx - x;
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const dy = ny - y;
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const drop = currentElevation - elevation[ni];
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const uphill = Math.max(0, -drop);
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if (!sea[ni] && uphill > 0.032 && flowAccum[ni] < flowAccum[i] + 0.018) continue;
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let surrounding = 0;
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let surroundingCount = 0;
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for (const [vx, vy] of neighbors8(nx, ny)) {
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surrounding += elevation[indexOf(vx, vy)];
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surroundingCount++;
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}
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const valley = Math.max(0, surrounding / Math.max(1, surroundingCount) - elevation[ni]);
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const sameDirection = lastDx || lastDy ? (dx * lastDx + dy * lastDy) / Math.max(0.001, Math.hypot(dx, dy) * Math.hypot(lastDx, lastDy)) : 0;
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const straightPenalty = Math.max(0, sameDirection) * 0.075;
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const turnPenalty = sameDirection < -0.35 ? 0.24 : 0;
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const sideSwing = Math.abs(dx * lastDy - dy * lastDx);
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const meanderPhase = Math.sin((path.length + bonusSeed * 0.013) * 0.73) * 0.5 + 0.5;
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const meander = sideSwing * (0.032 + meanderPhase * 0.026);
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const flowBonus = ni === preferred ? 0.62 : 0;
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const junctionPenalty = confluenceAnglePenalty(nx, ny, dx, dy, path.length);
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const noise = (hash2(nx, ny, seed + bonusSeed + step * 11) - 0.5) * 0.04;
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const value =
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elevation[ni] * 1.45 +
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uphill * 88 -
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Math.max(0, drop) * 2.05 -
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valley * 1.05 -
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valleyField[ni] * 1.72 -
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flowAccum[ni] * 0.94 -
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moisture[ni] * 0.14 -
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coastalLowland[ni] * 0.28 -
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(river[ni] > 0 ? 0.22 : 0) -
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|
flowBonus +
|
|
slope[ni] * 0.04 +
|
|
straightPenalty +
|
|
turnPenalty +
|
|
junctionPenalty * 1.35 -
|
|
meander +
|
|
noise -
|
|
(sea[ni] ? 0.6 : 0);
|
|
|
|
if (value < bestValue) {
|
|
bestValue = value;
|
|
best = [nx, ny, dx, dy];
|
|
}
|
|
}
|
|
if (!best) break;
|
|
x = best[0];
|
|
y = best[1];
|
|
lastDx = best[2];
|
|
lastDy = best[3];
|
|
}
|
|
|
|
const forced = forceRiverToWater(path);
|
|
if (forced.length > path.length) {
|
|
for (const [rx, ry] of forced.slice(path.length)) {
|
|
const ri = indexOf(rx, ry);
|
|
river[ri] += 0.32 + flowAccum[ri] * 0.4;
|
|
accum += river[ri] + flowAccum[ri];
|
|
}
|
|
}
|
|
return { path: forced, accum };
|
|
}
|
|
|
|
function traceSmallStreamPath(startX, startY, bonusSeed = 0) {
|
|
let x = startX;
|
|
let y = startY;
|
|
let lastDx = 0;
|
|
let lastDy = 0;
|
|
const path = [];
|
|
const seen = new Set();
|
|
for (let step = 0; step < 160; step++) {
|
|
const i = indexOf(x, y);
|
|
if (seen.has(i)) break;
|
|
seen.add(i);
|
|
path.push([x, y]);
|
|
river[i] += 0.12 + flowAccum[i] * 0.18;
|
|
if ((river[i] > 0.48 && path.length > 5) || sea[i]) break;
|
|
let best = null;
|
|
let bestValue = INF;
|
|
for (const [nx, ny] of neighbors8(x, y)) {
|
|
const ni = indexOf(nx, ny);
|
|
const dx = nx - x;
|
|
const dy = ny - y;
|
|
const drop = elevation[i] - elevation[ni];
|
|
const sameDirection = lastDx || lastDy ? (dx * lastDx + dy * lastDy) / Math.max(0.001, Math.hypot(dx, dy) * Math.hypot(lastDx, lastDy)) : 0;
|
|
const value = elevation[ni] * 1.2 + Math.max(0, -drop) * 26 - Math.max(0, drop) * 1.4 - valleyField[ni] * 1.15 - flowAccum[ni] * 0.55 - moisture[ni] * 0.12 + Math.max(0, sameDirection) * 0.04 - Math.abs(dx * lastDy - dy * lastDx) * 0.018 + (hash2(nx, ny, seed + bonusSeed + step * 13) - 0.5) * 0.05;
|
|
if (value < bestValue) { bestValue = value; best = [nx, ny, dx, dy]; }
|
|
}
|
|
if (!best) break;
|
|
x = best[0];
|
|
y = best[1];
|
|
lastDx = best[2];
|
|
lastDy = best[3];
|
|
}
|
|
return path;
|
|
}
|
|
|
|
const riverPaths = [];
|
|
const riverScores = [];
|
|
for (const source of sources) {
|
|
const { path, accum } = traceRiverPath(source.x, source.y, 0);
|
|
if (path.length > 6) {
|
|
riverPaths.push(path);
|
|
riverScores.push(path.length + accum * 0.18);
|
|
}
|
|
}
|
|
|
|
const preliminaryMainRiverCells = new Set(riverPaths.slice().sort((a, b) => b.length - a.length).slice(0, 5).flatMap((path) => path.map(([x, y]) => `${x},${y}`)));
|
|
const tributarySources = pickEntities(sourceCandidates
|
|
.filter((p) => !preliminaryMainRiverCells.has(`${p.x},${p.y}`))
|
|
.map((p) => ({ ...p, score: p.score + flowAccum[indexOf(p.x, p.y)] * 0.75 + valleyField[indexOf(p.x, p.y)] * 0.24 })), {
|
|
max: 14 + Math.floor(rand(seed, 915) * 20),
|
|
minDistance: 6,
|
|
threshold: 0.45,
|
|
seed: seed + 916,
|
|
jitter: 0.02,
|
|
});
|
|
for (const source of tributarySources) {
|
|
const { path, accum } = traceRiverPath(source.x, source.y, 4000 + source.x * 7 + source.y * 11);
|
|
if (path.length > 8) {
|
|
riverPaths.push(path);
|
|
riverScores.push(path.length * 0.7 + accum * 0.12);
|
|
}
|
|
}
|
|
|
|
const streamPaths = [];
|
|
const streamSources = pickEntities(sourceCandidates
|
|
.map((p) => ({ ...p, score: valleyField[indexOf(p.x, p.y)] * 0.46 + flowAccum[indexOf(p.x, p.y)] * 0.36 + moisture[indexOf(p.x, p.y)] * 0.18 + hash2(p.x, p.y, seed + 918) * 0.05 }))
|
|
.filter((p) => p.score > 0.18), {
|
|
max: 22 + Math.floor(rand(seed, 919) * 20),
|
|
minDistance: 4,
|
|
threshold: 0.18,
|
|
seed: seed + 919,
|
|
jitter: 0.015,
|
|
});
|
|
for (const source of streamSources) {
|
|
const path = traceSmallStreamPath(source.x, source.y, 7000 + source.x * 5 + source.y * 17);
|
|
if (path.length > 4) streamPaths.push(path);
|
|
}
|
|
|
|
if (riverPaths.length === 0 && sourceCandidates.length > 0) {
|
|
const fallback = sourceCandidates.slice().sort((a, b) => b.score - a.score)[0];
|
|
let bestSea = null;
|
|
let bestSeaDist = INF;
|
|
for (let y = 0; y < MAP_H; y++) {
|
|
for (let x = 0; x < MAP_W; x++) {
|
|
if (!sea[indexOf(x, y)]) continue;
|
|
const d = Math.hypot(x - fallback.x, y - fallback.y);
|
|
if (d < bestSeaDist) {
|
|
bestSeaDist = d;
|
|
bestSea = { x, y };
|
|
}
|
|
}
|
|
}
|
|
if (bestSea) {
|
|
const fallbackPath = aStar(fallback, bestSea, (x, y, cx, cy) => {
|
|
const i = indexOf(x, y);
|
|
const ci = indexOf(cx, cy);
|
|
if (sea[i]) return 0.25;
|
|
const uphill = Math.max(0, elevation[i] - elevation[ci]) * 24;
|
|
const downhill = Math.max(0, elevation[ci] - elevation[i]) * 1.8;
|
|
return Math.max(0.24, 1 + uphill + slope[i] * 0.7 + elevation[i] * 0.8 - downhill - Math.min(0.55, river[i] * 0.1));
|
|
});
|
|
if (fallbackPath.length > 6) {
|
|
let accum = 0;
|
|
for (const [x, y] of fallbackPath) {
|
|
const i = indexOf(x, y);
|
|
river[i] += 0.42;
|
|
accum += river[i];
|
|
}
|
|
riverPaths.push(fallbackPath);
|
|
riverScores.push(fallbackPath.length + accum * 0.18);
|
|
}
|
|
}
|
|
}
|
|
|
|
function sanitizeDownhillRiverPath(path, tolerance = 0.040) {
|
|
if (!path || path.length < 2) return path || [];
|
|
const out = [path[0]];
|
|
for (let k = 1; k < path.length; k++) {
|
|
const [px, py] = out[out.length - 1];
|
|
const [x, y] = path[k];
|
|
const pi = indexOf(px, py);
|
|
const i = indexOf(x, y);
|
|
if (!sea[i] && elevation[i] > elevation[pi] + tolerance) break;
|
|
out.push(path[k]);
|
|
if (sea[i]) break;
|
|
}
|
|
return out.length >= 2 ? out : [];
|
|
}
|
|
function trimMountainHeadwaters(path) {
|
|
if (!path || path.length < 4) return path || [];
|
|
let start = 0;
|
|
while (start < path.length - 3) {
|
|
const [x, y] = path[start];
|
|
const i = indexOf(x, y);
|
|
if (sea[i]) break;
|
|
if (elevation[i] <= 0.72 && (valleyField[i] >= 0.18 || flowAccum[i] >= 0.05)) break;
|
|
start++;
|
|
}
|
|
return path.slice(start);
|
|
}
|
|
for (let r = 0; r < riverPaths.length; r++) riverPaths[r] = sanitizeDownhillRiverPath(trimMountainHeadwaters(riverPaths[r]), 0.032);
|
|
for (let r = riverPaths.length - 1; r >= 0; r--) if (riverPaths[r].length < 2) riverPaths.splice(r, 1);
|
|
for (let r = 0; r < streamPaths.length; r++) streamPaths[r] = sanitizeDownhillRiverPath(trimMountainHeadwaters(streamPaths[r]), 0.026);
|
|
for (let r = streamPaths.length - 1; r >= 0; r--) if (streamPaths[r].length < 2) streamPaths.splice(r, 1);
|
|
river.fill(0);
|
|
for (const path of riverPaths) {
|
|
for (let k = 0; k < path.length; k++) {
|
|
const [x, y] = path[k];
|
|
const i = indexOf(x, y);
|
|
river[i] += 0.42 + k / 170 + flowAccum[i] * 0.55;
|
|
}
|
|
}
|
|
for (const path of streamPaths) {
|
|
for (let k = 0; k < path.length; k++) {
|
|
const [x, y] = path[k];
|
|
const i = indexOf(x, y);
|
|
river[i] += 0.11 + flowAccum[i] * 0.18;
|
|
}
|
|
}
|
|
|
|
const expandedRiver = new Float32Array(river);
|
|
for (let y = 1; y < MAP_H - 1; y++) {
|
|
for (let x = 1; x < MAP_W - 1; x++) {
|
|
const i = indexOf(x, y);
|
|
if (river[i] <= 0) continue;
|
|
for (const [nx, ny] of neighbors8(x, y)) {
|
|
expandedRiver[indexOf(nx, ny)] = Math.max(expandedRiver[indexOf(nx, ny)], river[i] * 0.35);
|
|
}
|
|
}
|
|
}
|
|
river.set(expandedRiver);
|
|
|
|
// Second fluvial pass uses the actual traced river network. Main channels cut
|
|
// visible V-shaped valleys; lower reaches accumulate alluvial deposits.
|
|
const fluvialElevation = new Float32Array(elevation);
|
|
for (let y = 1; y < MAP_H - 1; y++) {
|
|
for (let x = 1; x < MAP_W - 1; x++) {
|
|
const i = indexOf(x, y);
|
|
if (sea[i] || river[i] <= 0.02) continue;
|
|
const r = clamp(river[i] / 3.4);
|
|
const channelCut = clamp(Math.pow(r, 0.55) * (0.060 + slope[i] * 0.145 + ridgeField[i] * 0.038));
|
|
const valleyWiden = clamp(Math.pow(r, 0.72) * (0.020 + Math.max(0, elevation[i] - seaLevel) * 0.058 + valleyField[i] * 0.040));
|
|
const alluvium = clamp(Math.pow(r, 0.72) * (coastalLowland[i] * 0.030 + basinField[i] * 0.020 + (slope[i] < 0.10 ? 0.010 : 0)));
|
|
erosionField[i] = clamp(erosionField[i] + channelCut + valleyWiden);
|
|
depositionField[i] = clamp(depositionField[i] + alluvium);
|
|
fluvialElevation[i] = clamp(elevation[i] - channelCut - valleyWiden + alluvium, seaLevel + 0.005, 1);
|
|
valleyField[i] = clamp(valleyField[i] + r * 0.62 + channelCut * 6.4);
|
|
basinField[i] = clamp(basinField[i] + alluvium * 3.2);
|
|
}
|
|
}
|
|
// Lateral valley carving around the traced river network deepens valleys and
|
|
// makes ridge/valley contrast legible at the map scale.
|
|
for (const path of riverPaths) {
|
|
for (const [rx, ry] of path) {
|
|
const ri = indexOf(rx, ry);
|
|
const r = clamp(river[ri] / 3.0);
|
|
const radius = r > 0.48 ? 2 : 1;
|
|
for (let dy = -radius; dy <= radius; dy++) {
|
|
for (let dx = -radius; dx <= radius; dx++) {
|
|
const nx = rx + dx;
|
|
const ny = ry + dy;
|
|
if (!inside(nx, ny)) continue;
|
|
const ni = indexOf(nx, ny);
|
|
if (sea[ni]) continue;
|
|
const d = Math.hypot(dx, dy);
|
|
if (d > radius || d === 0) continue;
|
|
const weight = (radius + 0.35 - d) / (radius + 0.35);
|
|
const carve = Math.max(0, weight) * (0.008 + r * 0.026) * Math.max(0.45, slope[ni] + 0.22);
|
|
fluvialElevation[ni] = clamp(fluvialElevation[ni] - carve, seaLevel + 0.005, 1);
|
|
erosionField[ni] = clamp(erosionField[ni] + carve * 3.0);
|
|
valleyField[ni] = clamp(valleyField[ni] + carve * 12.0);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Restore rugged summit relief after strong river incision. This prevents highlands
|
|
// from becoming unnaturally flat or visually concave while keeping valleys cut.
|
|
for (let y = 1; y < MAP_H - 1; y++) {
|
|
for (let x = 1; x < MAP_W - 1; x++) {
|
|
const i = indexOf(x, y);
|
|
if (sea[i]) continue;
|
|
const high = clamp((fluvialElevation[i] - 0.62) / 0.26);
|
|
const summit = high * clamp(ridgeField[i] * 1.4 - flowAccum[i] * 0.8);
|
|
const rugged = (valueNoise(x * 2.1 + 19, y * 2.1 - 23, seed + 9661, 3.2) - 0.5) * 0.035;
|
|
const uplift = summit * (0.018 + Math.max(0, rugged));
|
|
if (uplift > 0) {
|
|
fluvialElevation[i] = clamp(fluvialElevation[i] + uplift, seaLevel + 0.005, 1);
|
|
erosionField[i] = Math.max(0, erosionField[i] - uplift * 0.6);
|
|
}
|
|
}
|
|
}
|
|
|
|
elevation.set(fluvialElevation);
|
|
|
|
// Broad alluvial/coastal/basin plains. The plain score alone is not enough;
|
|
// the elevation surface must also be locally calm, otherwise every lowland
|
|
// still reads as rugged terrain. Smooth only low, wet depositional cells and
|
|
// leave ridges/headwaters untouched.
|
|
for (let pass = 0; pass < 4; pass++) {
|
|
const nextElevation = new Float32Array(elevation);
|
|
for (let y = 2; y < MAP_H - 2; y++) {
|
|
for (let x = 2; x < MAP_W - 2; x++) {
|
|
const i = indexOf(x, y);
|
|
if (sea[i]) continue;
|
|
const lowland = clamp(
|
|
coastalLowland[i] * 0.72 +
|
|
basinField[i] * 0.54 +
|
|
valleyField[i] * 0.34 +
|
|
Math.pow(flowAccum[i], 0.58) * 0.24 -
|
|
ridgeField[i] * 0.62 -
|
|
Math.max(0, elevation[i] - 0.54) * 1.65 -
|
|
slope[i] * 0.74
|
|
);
|
|
if (lowland <= 0.12) continue;
|
|
let sum = 0;
|
|
let weight = 0;
|
|
for (let dy = -2; dy <= 2; dy++) {
|
|
for (let dx = -2; dx <= 2; dx++) {
|
|
const nx = x + dx;
|
|
const ny = y + dy;
|
|
const ni = indexOf(nx, ny);
|
|
if (sea[ni]) continue;
|
|
const d = Math.hypot(dx, dy);
|
|
if (d > 2.25) continue;
|
|
const compatible = clamp(1 - Math.abs(elevation[ni] - elevation[i]) / 0.11);
|
|
const w = compatible / (1 + d);
|
|
sum += elevation[ni] * w;
|
|
weight += w;
|
|
}
|
|
}
|
|
if (weight <= 0) continue;
|
|
const localMean = sum / weight;
|
|
const terrace = Math.round(localMean * 42) / 42;
|
|
const target = lerp(localMean, terrace, 0.28);
|
|
nextElevation[i] = clamp(lerp(elevation[i], target, lowland * 0.42), seaLevel + 0.006, 1);
|
|
if (lowland > 0.55) {
|
|
depositionField[i] = clamp(depositionField[i] + lowland * 0.018);
|
|
erosionField[i] = Math.max(0, erosionField[i] - lowland * 0.012);
|
|
}
|
|
}
|
|
}
|
|
elevation.set(nextElevation);
|
|
}
|
|
|
|
for (let y = 1; y < MAP_H - 1; y++) {
|
|
for (let x = 1; x < MAP_W - 1; x++) {
|
|
const i = indexOf(x, y);
|
|
if (sea[i]) continue;
|
|
const gx = elevation[indexOf(x + 1, y)] - elevation[indexOf(x - 1, y)];
|
|
const gy = elevation[indexOf(x, y + 1)] - elevation[indexOf(x, y - 1)];
|
|
slope[i] = clamp(Math.sqrt(gx * gx + gy * gy) * 11.2);
|
|
}
|
|
}
|
|
|
|
// Re-trim visible river paths after fluvial reshaping changes local elevation.
|
|
for (let r = 0; r < riverPaths.length; r++) riverPaths[r] = sanitizeDownhillRiverPath(trimMountainHeadwaters(riverPaths[r]), 0.028);
|
|
for (let r = riverPaths.length - 1; r >= 0; r--) if (riverPaths[r].length < 2) riverPaths.splice(r, 1);
|
|
for (let r = 0; r < streamPaths.length; r++) streamPaths[r] = sanitizeDownhillRiverPath(trimMountainHeadwaters(streamPaths[r]), 0.022);
|
|
for (let r = streamPaths.length - 1; r >= 0; r--) if (streamPaths[r].length < 2) streamPaths.splice(r, 1);
|
|
|
|
const mainRivers = riverPaths
|
|
.map((p, i) => ({ path: p, score: riverScores[i] }))
|
|
.sort((a, b) => b.score - a.score)
|
|
.slice(0, Math.min(6, riverPaths.length))
|
|
.map((x) => x.path);
|
|
|
|
if (mainRivers.length === 0 && riverPaths.length > 0) mainRivers.push(riverPaths[0]);
|
|
if (mainRivers.length === 0) {
|
|
let start = null;
|
|
let startScore = -INF;
|
|
for (let y = 4; y < MAP_H - 4; y++) {
|
|
for (let x = 4; x < MAP_W - 4; x++) {
|
|
const i = indexOf(x, y);
|
|
if (sea[i]) continue;
|
|
const score = elevation[i] * 0.55 + moisture[i] * 0.35 - slope[i] * 0.15;
|
|
if (score > startScore) {
|
|
startScore = score;
|
|
start = { x, y };
|
|
}
|
|
}
|
|
}
|
|
if (start) {
|
|
let goal = null;
|
|
let goalDist = INF;
|
|
for (let y = 0; y < MAP_H; y++) {
|
|
for (let x = 0; x < MAP_W; x++) {
|
|
if (!sea[indexOf(x, y)]) continue;
|
|
const d = Math.hypot(x - start.x, y - start.y);
|
|
if (d < goalDist) {
|
|
goalDist = d;
|
|
goal = { x, y };
|
|
}
|
|
}
|
|
}
|
|
if (goal) {
|
|
const fallbackPath = aStar(start, goal, (x, y, cx, cy) => {
|
|
const i = indexOf(x, y);
|
|
const ci = indexOf(cx, cy);
|
|
if (sea[i]) return 0.2;
|
|
const uphillBias = Math.max(0, elevation[i] - elevation[ci]) * 22;
|
|
const downhillBias = Math.max(0, elevation[ci] - elevation[i]) * 1.7;
|
|
return Math.max(0.25, 1 + uphillBias + slope[i] * 0.65 + elevation[i] * 0.8 - downhillBias);
|
|
});
|
|
if (fallbackPath.length > 4) {
|
|
riverPaths.push(fallbackPath);
|
|
mainRivers.push(fallbackPath);
|
|
for (const [x, y] of fallbackPath) river[indexOf(x, y)] += 0.4;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
const mainRiverCells = new Set(mainRivers.flatMap((path) => path.map(([x, y]) => `${x},${y}`)));
|
|
const tributaryRivers = riverPaths.filter((path) => path.some(([x, y]) => !mainRiverCells.has(`${x},${y}`)) && !mainRivers.includes(path));
|
|
const smallStreams = streamPaths.filter((path) => path.length >= 5);
|
|
|
|
prefectureMask = makePrefectureMask(seed, sea, elevation, slope, river);
|
|
prefectureBorder = extractMaskBorder(prefectureMask, sea);
|
|
const regionalPrefectures = generateRegionalPrefectures(seed, sea, elevation, slope, river, ridgeField, flowAccum, prefectureMask);
|
|
const prefectureRegionId = regionalPrefectures.regionId;
|
|
const regionalDebug = regionalPrefectures.debug;
|
|
const regionalPrefectureBorders = extractRegionBorderSegments(prefectureRegionId, sea);
|
|
|
|
for (let y = 1; y < MAP_H - 1; y++) {
|
|
for (let x = 1; x < MAP_W - 1; x++) {
|
|
const i = indexOf(x, y);
|
|
if (sea[i]) continue;
|
|
const low = 1 - clamp((elevation[i] - 0.28) / 0.4);
|
|
const flat = 1 - slope[i];
|
|
const valleyPlain = valleyField[i] * 0.44 + basinField[i] * 0.36 + coastalLowland[i] * 0.55;
|
|
plain[i] = clamp(low * 0.44 + flat * 0.58 + valleyPlain - ridgeField[i] * 0.28 - (elevation[i] > 0.62 ? 0.48 : 0));
|
|
|
|
let nearRiver = 0;
|
|
for (let dy = -4; dy <= 4; dy++) {
|
|
for (let dx = -4; dx <= 4; dx++) {
|
|
const nx = x + dx;
|
|
const ny = y + dy;
|
|
if (!inside(nx, ny)) continue;
|
|
nearRiver = Math.max(nearRiver, river[indexOf(nx, ny)] / (1 + Math.hypot(dx, dy)));
|
|
}
|
|
}
|
|
|
|
const fan = clamp(valleyField[i] * (1 - coastalLowland[i]) * (elevation[i] > 0.34 && elevation[i] < 0.58 ? 0.9 : 0.35) * (1 - slope[i] * 0.55));
|
|
floodplain[i] = clamp(nearRiver * plain[i] * 0.92 + coastalLowland[i] * nearRiver * 0.22);
|
|
agriculture[i] = clamp(plain[i] * 0.58 + fan * 0.26 + basinField[i] * 0.2 + moisture[i] * 0.14 + clamp(nearRiver) * 0.32 - slope[i] * 0.34 - ridgeField[i] * 0.18 - floodplain[i] * 0.06);
|
|
}
|
|
}
|
|
|
|
for (let y = 2; y < MAP_H - 2; y++) {
|
|
for (let x = 2; x < MAP_W - 2; x++) {
|
|
const i = indexOf(x, y);
|
|
if (sea[i]) continue;
|
|
let seaNear = 0;
|
|
let riverNear = 0;
|
|
let sheltered = 0;
|
|
|
|
for (let dy = -5; dy <= 5; dy++) {
|
|
for (let dx = -5; dx <= 5; dx++) {
|
|
const nx = x + dx;
|
|
const ny = y + dy;
|
|
if (!inside(nx, ny)) continue;
|
|
const d = Math.hypot(dx, dy);
|
|
if (sea[indexOf(nx, ny)]) seaNear += 1 / (1 + d);
|
|
riverNear = Math.max(riverNear, river[indexOf(nx, ny)] / (1 + d));
|
|
}
|
|
}
|
|
|
|
for (let dy = -2; dy <= 2; dy++) {
|
|
for (let dx = -2; dx <= 2; dx++) {
|
|
const nx = x + dx;
|
|
const ny = y + dy;
|
|
if (inside(nx, ny) && !sea[indexOf(nx, ny)]) sheltered += 1;
|
|
}
|
|
}
|
|
|
|
const isDelta = riverNear > 0.22 && coastalLowland[i] > 0.18;
|
|
const bayShelter = sheltered * 0.012 + seaNear * 0.055 + coastalLowland[i] * 0.16;
|
|
portSuitability[i] = clamp(bayShelter + riverNear * 0.24 + (isDelta ? 0.22 : 0) + plain[i] * 0.08 - slope[i] * 0.48 - ridgeField[i] * 0.16);
|
|
}
|
|
}
|
|
|
|
for (let y = 3; y < MAP_H - 3; y++) {
|
|
for (let x = 3; x < MAP_W - 3; x++) {
|
|
const i = indexOf(x, y);
|
|
if (sea[i]) continue;
|
|
const r = river[i];
|
|
if (r < 0.2 || r > 1.85) continue;
|
|
let bankPlain = 0;
|
|
for (const [nx, ny] of neighbors8(x, y)) bankPlain += plain[indexOf(nx, ny)];
|
|
crossingSuitability[i] = clamp(r * 0.34 + (bankPlain / 8) * 0.54 + valleyField[i] * 0.18 - slope[i] * 0.55 - floodplain[i] * 0.06);
|
|
}
|
|
}
|
|
|
|
for (let y = 4; y < MAP_H - 4; y++) {
|
|
for (let x = 4; x < MAP_W - 4; x++) {
|
|
const i = indexOf(x, y);
|
|
if (sea[i]) continue;
|
|
const e = elevation[i];
|
|
if (e < 0.43 || e > 0.82) continue;
|
|
const ewHigh = (elevation[indexOf(x - 3, y)] + elevation[indexOf(x + 3, y)]) / 2;
|
|
const nsHigh = (elevation[indexOf(x, y - 3)] + elevation[indexOf(x, y + 3)]) / 2;
|
|
const diagLow = Math.min(
|
|
elevation[indexOf(x - 3, y - 3)],
|
|
elevation[indexOf(x + 3, y + 3)],
|
|
elevation[indexOf(x - 3, y + 3)],
|
|
elevation[indexOf(x + 3, y - 3)]
|
|
);
|
|
passSuitability[i] = clamp((Math.max(ewHigh, nsHigh) - e) * 2.2 + (e - diagLow) * 0.55 + valleyField[i] * 0.28 - ridgeField[i] * 0.18 - slope[i] * 0.2);
|
|
}
|
|
}
|
|
|
|
|
|
return {
|
|
elevation,
|
|
moisture,
|
|
slope,
|
|
sea,
|
|
river,
|
|
floodplain,
|
|
plain,
|
|
agriculture,
|
|
ridgeField,
|
|
valleyField,
|
|
basinField,
|
|
coastalLowland,
|
|
flowAccum,
|
|
erosionField,
|
|
depositionField,
|
|
portSuitability,
|
|
crossingSuitability,
|
|
passSuitability,
|
|
prefectureMask,
|
|
prefectureBorder,
|
|
prefectureRegionId,
|
|
regionalDebug,
|
|
regionalPrefectureBorders,
|
|
riverPaths,
|
|
mainRivers,
|
|
tributaryRivers,
|
|
smallStreams,
|
|
};
|
|
}
|