Fantasy-Map-Generator/modules/features.js
2024-09-22 13:04:22 +02:00

271 lines
9.8 KiB
JavaScript

"use strict";
window.Features = (function () {
const DEEPER_LAND = 3;
const LANDLOCKED = 2;
const LAND_COAST = 1;
const UNMARKED = 0;
const WATER_COAST = -1;
const DEEP_WATER = -2;
// calculate distance to coast for every cell
function markup({distanceField, neighbors, start, increment, limit = INT8_MAX}) {
for (let distance = start, marked = Infinity; marked > 0 && distance !== limit; distance += increment) {
marked = 0;
const prevDistance = distance - increment;
for (let cellId = 0; cellId < neighbors.length; cellId++) {
if (distanceField[cellId] !== prevDistance) continue;
for (const neighborId of neighbors[cellId]) {
if (distanceField[neighborId] !== UNMARKED) continue;
distanceField[neighborId] = distance;
marked++;
}
}
}
}
// mark Grid features (ocean, lakes, islands) and calculate distance field
function markupGrid() {
TIME && console.time("markupGrid");
Math.random = aleaPRNG(seed); // get the same result on heightmap edit in Erase mode
const {h: heights, c: neighbors, b: borderCells, i} = grid.cells;
const cellsNumber = i.length;
const distanceField = new Int8Array(cellsNumber); // gird.cells.t
const featureIds = new Uint16Array(cellsNumber); // gird.cells.f
const features = [0];
const queue = [0];
for (let featureId = 1; queue[0] !== -1; featureId++) {
const firstCell = queue[0];
featureIds[firstCell] = featureId;
const land = heights[firstCell] >= 20;
let border = false; // set true if feature touches map edge
while (queue.length) {
const cellId = queue.pop();
if (!border && borderCells[cellId]) border = true;
for (const neighborId of neighbors[cellId]) {
const isNeibLand = heights[neighborId] >= 20;
if (land === isNeibLand && featureIds[neighborId] === UNMARKED) {
featureIds[neighborId] = featureId;
queue.push(neighborId);
} else if (land && !isNeibLand) {
distanceField[cellId] = LAND_COAST;
distanceField[neighborId] = WATER_COAST;
}
}
}
const type = land ? "island" : border ? "ocean" : "lake";
features.push({i: featureId, land, border, type});
queue[0] = featureIds.findIndex(f => f === UNMARKED); // find unmarked cell
}
// markup deep ocean cells
markup({distanceField, neighbors, start: DEEP_WATER, increment: -1, limit: -10});
grid.cells.t = distanceField;
grid.cells.f = featureIds;
grid.features = features;
TIME && console.timeEnd("markupGrid");
}
// mark Pack features (ocean, lakes, islands), calculate distance field and add properties
function markupPack() {
TIME && console.time("markupPack");
const {cells, vertices} = pack;
const {c: neighbors, b: borderCells, i} = cells;
const packCellsNumber = i.length;
if (!packCellsNumber) return; // no cells -> there is nothing to do
const distanceField = new Int8Array(packCellsNumber); // pack.cells.t
const featureIds = new Uint16Array(packCellsNumber); // pack.cells.f
const haven = createTypedArray({maxValue: packCellsNumber, length: packCellsNumber}); // haven: opposite water cell
const harbor = new Uint8Array(packCellsNumber); // harbor: number of adjacent water cells
const features = [0];
const queue = [0];
for (let featureId = 1; queue[0] !== -1; featureId++) {
const firstCell = queue[0];
featureIds[firstCell] = featureId;
const land = isLand(firstCell);
let border = Boolean(borderCells[firstCell]); // true if feature touches map border
let totalCells = 1; // count cells in a feature
while (queue.length) {
const cellId = queue.pop();
if (borderCells[cellId]) border = true;
if (!border && borderCells[cellId]) border = true;
for (const neighborId of neighbors[cellId]) {
const isNeibLand = isLand(neighborId);
if (land && !isNeibLand) {
distanceField[cellId] = LAND_COAST;
distanceField[neighborId] = WATER_COAST;
if (!haven[cellId]) defineHaven(cellId);
} else if (land && isNeibLand) {
if (distanceField[neighborId] === UNMARKED && distanceField[cellId] === LAND_COAST)
distanceField[neighborId] = LANDLOCKED;
else if (distanceField[cellId] === UNMARKED && distanceField[neighborId] === LAND_COAST)
distanceField[cellId] = LANDLOCKED;
}
if (!featureIds[neighborId] && land === isNeibLand) {
queue.push(neighborId);
featureIds[neighborId] = featureId;
totalCells++;
}
}
}
features.push(addFeature({firstCell, land, border, featureId, totalCells}));
queue[0] = featureIds.findIndex(f => f === UNMARKED); // find unmarked cell
}
markup({distanceField, neighbors, start: DEEPER_LAND, increment: 1}); // markup pack land
markup({distanceField, neighbors, start: DEEP_WATER, increment: -1, limit: -10}); // markup pack water
pack.cells.t = distanceField;
pack.cells.f = featureIds;
pack.cells.haven = haven;
pack.cells.harbor = harbor;
pack.features = features;
TIME && console.timeEnd("markupPack");
function defineHaven(cellId) {
const waterCells = neighbors[cellId].filter(isWater);
const distances = waterCells.map(neibCellId => dist2(cells.p[cellId], cells.p[neibCellId]));
const closest = distances.indexOf(Math.min.apply(Math, distances));
haven[cellId] = waterCells[closest];
harbor[cellId] = waterCells.length;
}
function addFeature({firstCell, land, border, featureId, totalCells}) {
const type = land ? "island" : border ? "ocean" : "lake";
const [startCell, featureVertices] = getCellsData(type, firstCell);
const points = clipPoly(featureVertices.map(vertex => vertices.p[vertex]));
const area = d3.polygonArea(points); // feature perimiter area
const absArea = Math.abs(rn(area));
const feature = {
i: featureId,
type,
land,
border,
cells: totalCells,
firstCell: startCell,
vertices: featureVertices,
area: absArea
};
if (type === "lake") {
if (area > 0) feature.vertices = feature.vertices.reverse();
feature.shoreline = unique(feature.vertices.map(vertex => vertices.c[vertex].filter(isLand)).flat());
feature.height = Lakes.getHeight(feature);
}
return feature;
function getCellsData(featureType, firstCell) {
if (featureType === "ocean") return [firstCell, []];
const getType = cellId => featureIds[cellId];
const type = getType(firstCell);
const ofSameType = cellId => getType(cellId) === type;
const ofDifferentType = cellId => getType(cellId) !== type;
const startCell = findOnBorderCell(firstCell);
const featureVertices = getFeatureVertices(startCell);
return [startCell, featureVertices];
function findOnBorderCell(firstCell) {
const isOnBorder = cellId => borderCells[cellId] || neighbors[cellId].some(ofDifferentType);
if (isOnBorder(firstCell)) return firstCell;
const startCell = cells.i.filter(ofSameType).find(isOnBorder);
if (startCell === undefined)
throw new Error(`Markup: firstCell ${firstCell} is not on the feature or map border`);
return startCell;
}
function getFeatureVertices(startCell) {
const startingVertex = cells.v[startCell].find(v => vertices.c[v].some(ofDifferentType));
if (startingVertex === undefined)
throw new Error(`Markup: startingVertex for cell ${startCell} is not found`);
return connectVertices({vertices, startingVertex, ofSameType, closeRing: false});
}
}
}
}
// add properties to pack features
function specify() {
const gridCellsNumber = grid.cells.i.length;
const OCEAN_MIN_SIZE = gridCellsNumber / 25;
const SEA_MIN_SIZE = gridCellsNumber / 1000;
const CONTINENT_MIN_SIZE = gridCellsNumber / 10;
const ISLAND_MIN_SIZE = gridCellsNumber / 1000;
for (const feature of pack.features) {
if (!feature || feature.type === "ocean") continue;
feature.group = defineGroup(feature);
if (feature.type === "lake") {
feature.height = Lakes.getHeight(feature);
feature.name = Lakes.getName(feature);
}
}
function defineGroup(feature) {
if (feature.type === "island") return defineIslandGroup(feature);
if (feature.type === "ocean") return defineOceanGroup();
if (feature.type === "lake") return defineLakeGroup(feature);
throw new Error(`Markup: unknown feature type ${feature.type}`);
}
function defineOceanGroup(feature) {
if (feature.cells > OCEAN_MIN_SIZE) return "ocean";
if (feature.cells > SEA_MIN_SIZE) return "sea";
return "gulf";
}
function defineIslandGroup(feature) {
const prevFeature = pack.features[pack.cells.f[feature.firstCell - 1]];
if (prevFeature && prevFeature.type === "lake") return "lake_island";
if (feature.cells > CONTINENT_MIN_SIZE) return "continent";
if (feature.cells > ISLAND_MIN_SIZE) return "island";
return "isle";
}
function defineLakeGroup(feature) {
if (feature.temp < -3) return "frozen";
if (feature.height > 60 && feature.cells < 10 && feature.firstCell % 10 === 0) return "lava";
if (!feature.inlets && !feature.outlet) {
if (feature.evaporation > feature.flux * 4) return "dry";
if (feature.cells < 3 && feature.firstCell % 10 === 0) return "sinkhole";
}
if (!feature.outlet && feature.evaporation > feature.flux) return "salt";
return "freshwater";
}
}
return {markupGrid, markupPack, specify};
})();