mirror of
https://github.com/Azgaar/Fantasy-Map-Generator.git
synced 2026-02-04 17:41:23 +01:00
562 lines
No EOL
19 KiB
TypeScript
562 lines
No EOL
19 KiB
TypeScript
import Alea from "alea";
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import { curveBasis,
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line,
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mean, min, sum, curveCatmullRom, Selection } from "d3";
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import { each,
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rn,round,
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rw} from "../utils";
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import { PackedGraphFeature } from "./features";
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import { PackedGraph } from "./PackedGraph";
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declare global {
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interface Window {
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Rivers: any;
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}
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var WARN: boolean;
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var graphHeight: number;
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var graphWidth: number;
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var pack: any;
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var rivers: Selection<SVGElement, unknown, null, undefined>;
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var pointsInput: HTMLInputElement;
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var grid: any;
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var seed: string;
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var TIME: boolean;
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var Names: any;
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var Lakes: any;
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}
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export interface River {
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i: number; // river id
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source: number; // source cell index
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mouth: number; // mouth cell index
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parent: number; // parent river id
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basin: number; // basin river id
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length: number; // river length
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discharge: number; // river discharge in m3/s
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width: number; // mouth width in km
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widthFactor: number; // width scaling factor
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sourceWidth: number; // source width in km
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name: string; // river name
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type: string; // river type
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cells: number[]; // cells forming the river path
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}
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class RiverModule {
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private FLUX_FACTOR = 500;
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private MAX_FLUX_WIDTH = 1;
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private LENGTH_FACTOR = 200;
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private LENGTH_STEP_WIDTH = 1 / this.LENGTH_FACTOR;
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private LENGTH_PROGRESSION = [1, 1, 2, 3, 5, 8, 13, 21, 34].map(n => n / this.LENGTH_FACTOR);
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private lineGen = line().curve(curveBasis)
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riverTypes = {
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main: {
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big: {River: 1},
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small: {Creek: 9, River: 3, Brook: 3, Stream: 1}
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},
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fork: {
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big: {Fork: 1},
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small: {Branch: 1}
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}
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};
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smallLength: number | null = null;
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get graphHeight() {
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return graphHeight;
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}
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get graphWidth() {
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return graphWidth;
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}
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get pack(): PackedGraph {
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return pack;
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}
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generate(allowErosion = true) {
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TIME && console.time("generateRivers");
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Math.random = Alea(seed);
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const {cells, features} = this.pack;
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const riversData: {[riverId: number]: number[]} = {};
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const riverParents: {[key: number]: number} = {};
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const addCellToRiver = (cellId: number, riverId: number) => {
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if (!riversData[riverId]) riversData[riverId] = [cellId];
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else riversData[riverId].push(cellId);
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};
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const drainWater = () => {
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const MIN_FLUX_TO_FORM_RIVER = 30;
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const cellsNumberModifier = (parseInt(pointsInput.dataset.cells || "10000") / 10000) ** 0.25;
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const prec = grid.cells.prec;
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const land = cells.i.filter((i: number) => h[i] >= 20).sort((a: number, b: number) => h[b] - h[a]);
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const lakeOutCells = Lakes.defineClimateData(h);
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land.forEach(function (i: number) {
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cells.fl[i] += prec[cells.g[i]] / cellsNumberModifier; // add flux from precipitation
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// create lake outlet if lake is not in deep depression and flux > evaporation
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const lakes = lakeOutCells[i]
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? features.filter((feature: any) => i === feature.outCell && feature.flux > feature.evaporation)
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: [];
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for (const lake of lakes) {
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const lakeCell: number = cells.c[i].find((c: number) => h[c] < 20 && cells.f[c] === lake.i) || i;
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cells.fl[lakeCell] += Math.max(lake.flux - lake.evaporation, 0); // not evaporated lake water drains to outlet
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// allow chain lakes to retain identity
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if (cells.r[lakeCell] !== lake.river) {
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const sameRiver = cells.c[lakeCell].some((c: number) => cells.r[c] === lake.river);
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if (sameRiver) {
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cells.r[lakeCell] = lake.river;
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addCellToRiver(lakeCell, lake.river);
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} else {
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cells.r[lakeCell] = riverNext;
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addCellToRiver(lakeCell, riverNext);
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riverNext++;
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}
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}
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lake.outlet = cells.r[lakeCell];
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flowDown(i, cells.fl[lakeCell], lake.outlet);
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}
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// assign all tributary rivers to outlet basin
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const outlet = lakes[0]?.outlet;
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for (const lake of lakes) {
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if (!Array.isArray(lake.inlets)) continue;
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for (const inlet of lake.inlets) {
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riverParents[inlet] = outlet;
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}
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}
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// near-border cell: pour water out of the screen
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if (cells.b[i] && cells.r[i]) return addCellToRiver(-1, cells.r[i]);
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// downhill cell (make sure it's not in the source lake)
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let min = null;
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if (lakeOutCells[i]) {
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const filtered = cells.c[i].filter((c: number) => !lakes.map((lake: any) => lake.i).includes(cells.f[c]));
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min = filtered.sort((a: number, b: number) => h[a] - h[b])[0];
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} else if (cells.haven[i]) {
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min = cells.haven[i];
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} else {
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min = cells.c[i].sort((a: number, b: number) => h[a] - h[b])[0];
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}
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// cells is depressed
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if (h[i] <= h[min]) return;
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// debug
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// .append("line")
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// .attr("x1", pack.cells.p[i][0])
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// .attr("y1", pack.cells.p[i][1])
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// .attr("x2", pack.cells.p[min][0])
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// .attr("y2", pack.cells.p[min][1])
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// .attr("stroke", "#333")
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// .attr("stroke-width", 0.2);
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if (cells.fl[i] < MIN_FLUX_TO_FORM_RIVER) {
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// flux is too small to operate as a river
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if (h[min] >= 20) cells.fl[min] += cells.fl[i];
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return;
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}
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// proclaim a new river
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if (!cells.r[i]) {
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cells.r[i] = riverNext;
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addCellToRiver(i, riverNext);
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riverNext++;
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}
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flowDown(min, cells.fl[i], cells.r[i]);
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});
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}
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const flowDown = (toCell: number, fromFlux: number, river: number) => {
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const toFlux = cells.fl[toCell] - cells.conf[toCell];
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const toRiver = cells.r[toCell];
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if (toRiver) {
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// downhill cell already has river assigned
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if (fromFlux > toFlux) {
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cells.conf[toCell] += cells.fl[toCell]; // mark confluence
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if (h[toCell] >= 20) riverParents[toRiver] = river; // min river is a tributary of current river
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cells.r[toCell] = river; // re-assign river if downhill part has less flux
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} else {
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cells.conf[toCell] += fromFlux; // mark confluence
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if (h[toCell] >= 20) riverParents[river] = toRiver; // current river is a tributary of min river
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}
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} else cells.r[toCell] = river; // assign the river to the downhill cell
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if (h[toCell] < 20) {
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// pour water to the water body
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const waterBody = features[cells.f[toCell]];
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if (waterBody.type === "lake") {
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if (!waterBody.river || fromFlux > waterBody.enteringFlux) {
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waterBody.river = river;
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waterBody.enteringFlux = fromFlux;
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}
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waterBody.flux = waterBody.flux + fromFlux;
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if (!waterBody.inlets) waterBody.inlets = [river];
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else waterBody.inlets.push(river);
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}
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} else {
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// propagate flux and add next river segment
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cells.fl[toCell] += fromFlux;
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}
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addCellToRiver(toCell, river);
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}
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const defineRivers = () => {
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// re-initialize rivers and confluence arrays
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cells.r = new Uint16Array(cells.i.length);
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cells.conf = new Uint16Array(cells.i.length);
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this.pack.rivers = [];
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const defaultWidthFactor = rn(1 / (parseInt(pointsInput.dataset.cells || "10000") / 10000) ** 0.25, 2);
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const mainStemWidthFactor = defaultWidthFactor * 1.2;
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for (const key in riversData) {
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const riverCells = riversData[key];
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if (riverCells.length < 3) continue; // exclude tiny rivers
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const riverId = +key;
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for (const cell of riverCells) {
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if (cell < 0 || cells.h[cell] < 20) continue;
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// mark real confluences and assign river to cells
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if (cells.r[cell]) cells.conf[cell] = 1;
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else cells.r[cell] = riverId;
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}
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const source = riverCells[0];
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const mouth = riverCells[riverCells.length - 2];
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const parent = riverParents[key] || 0;
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const widthFactor = !parent || parent === riverId ? mainStemWidthFactor : defaultWidthFactor;
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const meanderedPoints = this.addMeandering(riverCells);
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const discharge = cells.fl[mouth]; // m3 in second
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const length = this.getApproximateLength(meanderedPoints);
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const sourceWidth = this.getSourceWidth(cells.fl[source]);
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const width = this.getWidth(
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this.getOffset({
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flux: discharge,
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pointIndex: meanderedPoints.length,
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widthFactor,
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startingWidth: sourceWidth
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})
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);
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this.pack.rivers.push({
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i: riverId,
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source,
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mouth,
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discharge,
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length,
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width,
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widthFactor,
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sourceWidth,
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parent,
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cells: riverCells
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} as River);
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}
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}
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const downcutRivers = () => {
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const MAX_DOWNCUT = 5;
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for (const i of this.pack.cells.i) {
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if (cells.h[i] < 35) continue; // don't donwcut lowlands
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if (!cells.fl[i]) continue;
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const higherCells = cells.c[i].filter((c: number) => cells.h[c] > cells.h[i]);
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const higherFlux = higherCells.reduce((acc: number, c: number) => acc + cells.fl[c], 0) / higherCells.length;
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if (!higherFlux) continue;
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const downcut = Math.floor(cells.fl[i] / higherFlux);
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if (downcut) cells.h[i] -= Math.min(downcut, MAX_DOWNCUT);
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}
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}
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const calculateConfluenceFlux = () => {
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for (const i of cells.i) {
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if (!cells.conf[i]) continue;
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const sortedInflux = cells.c[i]
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.filter((c: number) => cells.r[c] && h[c] > h[i])
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.map((c: number) => cells.fl[c])
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.sort((a: number, b: number) => b - a);
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cells.conf[i] = sortedInflux.reduce((acc: number, flux: number, index: number) => (index ? acc + flux : acc), 0);
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}
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}
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cells.fl = new Uint16Array(cells.i.length); // water flux array
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cells.r = new Uint16Array(cells.i.length); // rivers array
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cells.conf = new Uint8Array(cells.i.length); // confluences array
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let riverNext = 1; // first river id is 1
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const h = this.alterHeights();
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Lakes.detectCloseLakes(h);
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this.resolveDepressions(h);
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drainWater();
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defineRivers();
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calculateConfluenceFlux();
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Lakes.cleanupLakeData();
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if (allowErosion) {
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cells.h = Uint8Array.from(h); // apply gradient
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downcutRivers(); // downcut river beds
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}
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TIME && console.timeEnd("generateRivers");
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};
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alterHeights() {
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const {h, c, t} = this.pack.cells as {h: Uint8Array, c: number[][], t: Uint8Array};
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return Array.from(h).map((h, i) => {
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if (h < 20 || t[i] < 1) return h;
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return h + t[i] / 100 + (mean(c[i].map(c => t[c])) || 0) / 10000;
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});
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};
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// depression filling algorithm (for a correct water flux modeling)
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resolveDepressions(h: number[]) {
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const {cells, features} = this.pack;
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const maxIterations = +(document.getElementById("resolveDepressionsStepsOutput") as HTMLInputElement)?.value;
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const checkLakeMaxIteration = maxIterations * 0.85;
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const elevateLakeMaxIteration = maxIterations * 0.75;
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const height = (i: number) => features[cells.f[i]].height || h[i]; // height of lake or specific cell
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const lakes = features.filter((feature: PackedGraphFeature) => feature.type === "lake");
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const land = cells.i.filter((i: number) => h[i] >= 20 && !cells.b[i]); // exclude near-border cells
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land.sort((a: number, b: number) => h[a] - h[b]); // lowest cells go first
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const progress = [];
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let depressions = Infinity;
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let prevDepressions = null;
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for (let iteration = 0; depressions && iteration < maxIterations; iteration++) {
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if (progress.length > 5 && sum(progress) > 0) {
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// bad progress, abort and set heights back
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h = this.alterHeights();
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depressions = progress[0];
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break;
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}
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depressions = 0;
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if (iteration < checkLakeMaxIteration) {
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for (const l of lakes) {
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if (l.closed) continue;
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const minHeight: number = min<number>(l.shoreline.map((s: number) => h[s])) || 100;
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if (minHeight >= 100 || l.height > minHeight) continue;
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if (iteration > elevateLakeMaxIteration) {
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l.shoreline.forEach((i: number) => (h[i] = cells.h[i]));
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l.height = (min<number>(l.shoreline.map((s: number) => h[s])) || 100) - 1;
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l.closed = true;
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continue;
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}
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depressions++;
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l.height = minHeight + 0.2;
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}
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}
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for (const i of land) {
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const minHeight = min<number>(cells.c[i].map((c: number) => height(c))) || 100;
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if (minHeight >= 100 || h[i] > minHeight) continue;
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depressions++;
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h[i] = minHeight + 0.1;
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}
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prevDepressions !== null && progress.push(depressions - prevDepressions);
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prevDepressions = depressions;
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}
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depressions && WARN && console.warn(`Unresolved depressions: ${depressions}. Edit heightmap to fix`);
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};
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addMeandering(riverCells: number[], riverPoints = null, meandering = 0.5): [number, number, number][] {
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const {fl, h} = this.pack.cells;
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const meandered = [];
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const lastStep = riverCells.length - 1;
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const points = this.getRiverPoints(riverCells, riverPoints);
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let step = h[riverCells[0]] < 20 ? 1 : 10;
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for (let i = 0; i <= lastStep; i++, step++) {
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const cell = riverCells[i];
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const isLastCell = i === lastStep;
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const [x1, y1] = points[i];
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meandered.push([x1, y1, fl[cell]]);
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if (isLastCell) break;
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const nextCell = riverCells[i + 1];
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const [x2, y2] = points[i + 1];
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if (nextCell === -1) {
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meandered.push([x2, y2, fl[cell]]);
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break;
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}
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const dist2 = (x2 - x1) ** 2 + (y2 - y1) ** 2; // square distance between cells
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if (dist2 <= 25 && riverCells.length >= 6) continue;
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const meander = meandering + 1 / step + Math.max(meandering - step / 100, 0);
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const angle = Math.atan2(y2 - y1, x2 - x1);
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const sinMeander = Math.sin(angle) * meander;
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const cosMeander = Math.cos(angle) * meander;
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if (step < 20 && (dist2 > 64 || (dist2 > 36 && riverCells.length < 5))) {
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// if dist2 is big or river is small add extra points at 1/3 and 2/3 of segment
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const p1x = (x1 * 2 + x2) / 3 + -sinMeander;
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const p1y = (y1 * 2 + y2) / 3 + cosMeander;
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const p2x = (x1 + x2 * 2) / 3 + sinMeander / 2;
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const p2y = (y1 + y2 * 2) / 3 - cosMeander / 2;
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meandered.push([p1x, p1y, 0], [p2x, p2y, 0]);
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} else if (dist2 > 25 || riverCells.length < 6) {
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// if dist is medium or river is small add 1 extra middlepoint
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const p1x = (x1 + x2) / 2 + -sinMeander;
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const p1y = (y1 + y2) / 2 + cosMeander;
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meandered.push([p1x, p1y, 0]);
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}
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}
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return meandered as [number, number, number][];
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};
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getRiverPoints(riverCells: number[], riverPoints: [number, number][] | null) {
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if (riverPoints) return riverPoints;
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const {p} = this.pack.cells;
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return riverCells.map((cell, i) => {
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if (cell === -1) return this.getBorderPoint(riverCells[i - 1]);
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return p[cell];
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});
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};
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getBorderPoint(i: number) {
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const [x, y] = this.pack.cells.p[i];
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const min = Math.min(y, this.graphHeight - y, x, this.graphWidth - x);
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if (min === y) return [x, 0];
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else if (min === this.graphHeight - y) return [x, this.graphHeight];
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else if (min === x) return [0, y];
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return [this.graphWidth, y];
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};
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getOffset({flux, pointIndex, widthFactor, startingWidth}: {flux: number, pointIndex: number, widthFactor: number, startingWidth: number}) {
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if (pointIndex === 0) return startingWidth;
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const fluxWidth = Math.min(flux ** 0.7 / this.FLUX_FACTOR, this.MAX_FLUX_WIDTH);
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const lengthWidth = pointIndex * this.LENGTH_STEP_WIDTH + (this.LENGTH_PROGRESSION[pointIndex] || this.LENGTH_PROGRESSION.at(-1) || 0);
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return widthFactor * (lengthWidth + fluxWidth) + startingWidth;
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};
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getSourceWidth(flux: number) {
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return rn(Math.min(flux ** 0.9 / this.FLUX_FACTOR, this.MAX_FLUX_WIDTH), 2);
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}
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// build polygon from a list of points and calculated offset (width)
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getRiverPath(points: [number, number, number][], widthFactor: number, startingWidth: number) {
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this.lineGen.curve(curveCatmullRom.alpha(0.1));
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const riverPointsLeft: [number, number][] = [];
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const riverPointsRight: [number, number][] = [];
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let flux = 0;
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for (let pointIndex = 0; pointIndex < points.length; pointIndex++) {
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const [x0, y0] = points[pointIndex - 1] || points[pointIndex];
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const [x1, y1, pointFlux] = points[pointIndex];
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const [x2, y2] = points[pointIndex + 1] || points[pointIndex];
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if (pointFlux > flux) flux = pointFlux;
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const offset = this.getOffset({flux, pointIndex, widthFactor, startingWidth});
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const angle = Math.atan2(y0 - y2, x0 - x2);
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const sinOffset = Math.sin(angle) * offset;
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const cosOffset = Math.cos(angle) * offset;
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riverPointsLeft.push([x1 - sinOffset, y1 + cosOffset]);
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riverPointsRight.push([x1 + sinOffset, y1 - cosOffset]);
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}
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|
|
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const right = this.lineGen(riverPointsRight.reverse());
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let left = this.lineGen(riverPointsLeft) || "";
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left = left.substring(left.indexOf("C"));
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|
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return round(right + left, 1);
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};
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|
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specify() {
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const rivers = this.pack.rivers;
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if (!rivers.length) return;
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|
|
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for (const river of rivers) {
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river.basin = this.getBasin(river.i);
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river.name = this.getName(river.mouth);
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river.type = this.getType(river);
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}
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};
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|
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getName(cell: number) {
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return Names.getCulture(this.pack.cells.culture[cell]);
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};
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|
|
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getType({i, length, parent}: River) {
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if (this.smallLength === null) {
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const threshold = Math.ceil(this.pack.rivers.length * 0.15);
|
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this.smallLength = this.pack.rivers.map(r => r.length || 0).sort((a: number, b: number) => a - b)[threshold];
|
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}
|
|
|
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const isSmall: boolean = length < (this.smallLength as number);
|
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const isFork = each(3)(i) && parent && parent !== i;
|
|
return rw(this.riverTypes[isFork ? "fork" : "main"][isSmall ? "small" : "big"]);
|
|
};
|
|
|
|
getApproximateLength(points: [number, number, number][]) {
|
|
const length = points.reduce((s, v, i, p) => s + (i ? Math.hypot(v[0] - p[i - 1][0], v[1] - p[i - 1][1]) : 0), 0);
|
|
return rn(length, 2);
|
|
};
|
|
|
|
// Real mouth width examples: Amazon 6000m, Volga 6000m, Dniepr 3000m, Mississippi 1300m, Themes 900m,
|
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// Danube 800m, Daugava 600m, Neva 500m, Nile 450m, Don 400m, Wisla 300m, Pripyat 150m, Bug 140m, Muchavets 40m
|
|
getWidth(offset: number) {
|
|
return rn((offset / 1.5) ** 1.8, 2); // mouth width in km
|
|
};
|
|
|
|
// remove river and all its tributaries
|
|
remove(id: number) {
|
|
const cells = this.pack.cells;
|
|
const riversToRemove = this.pack.rivers.filter(r => r.i === id || r.parent === id || r.basin === id).map(r => r.i);
|
|
riversToRemove.forEach(r => rivers.select("#river" + r).remove());
|
|
cells.r.forEach((r, i) => {
|
|
if (!r || !riversToRemove.includes(r)) return;
|
|
cells.r[i] = 0;
|
|
cells.fl[i] = grid.cells.prec[cells.g[i]];
|
|
cells.conf[i] = 0;
|
|
});
|
|
this.pack.rivers = this.pack.rivers.filter(r => !riversToRemove.includes(r.i));
|
|
};
|
|
|
|
getBasin(r: number): number {
|
|
const parent = this.pack.rivers.find(river => river.i === r)?.parent;
|
|
if (!parent || r === parent) return r;
|
|
return this.getBasin(parent);
|
|
};
|
|
|
|
getNextId(rivers: {i: number}[]) {
|
|
return rivers.length ? Math.max(...rivers.map(r => r.i)) + 1 : 1;
|
|
};
|
|
}
|
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window.Rivers = new RiverModule() |