mirror of
https://github.com/Azgaar/Fantasy-Map-Generator.git
synced 2025-12-17 17:51:24 +01:00
92 lines
3.1 KiB
TypeScript
92 lines
3.1 KiB
TypeScript
import * as d3 from "d3";
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import {ERROR} from "../config/logging";
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import {minmax, rn} from "./numberUtils";
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// random number in range
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export function rand(min: number, max?: number) {
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if (max === undefined) {
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max = min;
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min = 0;
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}
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return Math.floor(Math.random() * (max - min + 1)) + min;
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}
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// probability shorthand
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export function P(probability: number) {
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if (probability >= 1) return true;
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if (probability <= 0) return false;
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return Math.random() < probability;
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}
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export function each(n: number) {
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return (i: number) => i % n === 0;
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}
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// random number using normal distribution
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export function gauss(expected = 100, deviation = 30, min = 0, max = 300, round = 0) {
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const randomValue = d3.randomNormal(expected, deviation);
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const clamped = minmax(randomValue(), min, max);
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return rn(clamped, round);
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}
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// probability shorthand for floats
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export function Pint(float: number) {
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return ~~float + +P(float % 1);
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}
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// return random value from the array
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export function ra<T>(array: T[]) {
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return array[Math.floor(Math.random() * array.length)];
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}
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// return random value from weighted array
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export function rw(object: {[key: string]: number}) {
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const weightedArray = Object.entries(object)
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.map(([choise, weight]) => new Array(weight).fill(choise))
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.flat();
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return ra(weightedArray);
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}
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// return a random integer from min to max biased towards one end based on exponent distribution
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// the bigger exponent the higher bias towards min
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// biased(0, 10, 10): {0: 74%, 1: 9%, 2: 4%, 3: 3%, 4: 2%, 5: 2%, 6: 2%, 7: 1%, 8: 1%, 9: 1%, 10: 0%}
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// biased(0, 10, 5): {0: 55%, 1: 14%, 2: 7%, 3: 5%, 4: 4%, 5: 4%, 6: 3%, 7%: 3%, 8: 2%, 9: 2%, 10: 1%}
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// biased(0, 10, 4): {0: 46%, 1: 15%, 2: 8%, 3: 6%, 4: 5%, 5: 4%, 6: 4%, 7%: 3, 8: 3%, 9: 3%, 10: 1%}
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// biased(0, 10, 3): {0: 36%, 1: 16%, 2: 10%, 3: 8%, 4: 6%, 5: 5%, 6: 5%, 7%: 4, 8: 4%, 9: 4%, 10: 2%}
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// biased(0, 10, 2): {0: 22%, 1: 17%, 2: 11%, 3: 9%, 4: 8%, 5: 7%, 6: 6%, 7%: 6, 8: 6%, 9: 5%, 10: 2%}
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// biased{0, 10, 1): {0: 5%, 1: 10%, 2: 10%, 3: 10%, 4: 10%, 5: 10%, 6: 10%, 7%: 10, 8%: 10, 9: 10%, 10: 5%}
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export function biased(min: number, max: number, exponent: number) {
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if (exponent <= 1) throw new Error("Exponent must be greater than 1");
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return Math.round(min + (max - min) * Math.pow(Math.random(), exponent));
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}
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// get number from string in format "1-3" or "2" or "0.5"
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export function getNumberInRange(rangeString: string) {
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if (typeof rangeString !== "string") {
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ERROR && console.error("The value should be a string", rangeString);
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return 0;
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}
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const rangeNumber = Number(rangeString);
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if (!isNaN(rangeNumber)) return Pint(rangeNumber);
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const negative = rangeString.startsWith("-");
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const sign = negative ? -1 : 1;
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if (negative) rangeString = rangeString.substring(1);
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const [min, max] = rangeString.split("-");
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const count = rand(sign * +min, +max);
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if (isNaN(count) || count < 0) {
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ERROR && console.error("Cannot parse number. Check the format", rangeString);
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return 0;
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}
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return count;
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}
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export function generateSeed() {
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return String(Math.floor(Math.random() * 1e9));
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}
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