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Amit Patel redblobgames

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redblobgames / utils.js
Created March 21, 2025 15:22
My one line utility functions that I copy into various projects
function clamp(x, lo, hi) { return x < lo ? lo : x > hi ? hi : x; }
function lerp(a, b, t) { return a * (1-t) + b * t; }
function unlerp(a, b, t) { return (t - a) / (b - a); }
function rescale(v, from_lo, from_hi, to_lo, to_hi) { return lerp(to_lo, to_hi, unlerp(from_lo, from_hi, v)); }
function mod(a, b) { return (a % b + b) % b; }
function radiansToDegrees(radians) { return 180 / Math.PI * radians; }
function linearstep(a, b, t) { return clamp(unlerp(a, b, t), 0, 1); }
function smoothstep(a, b, t) { let x = linearstep(a, b, t); return 3 * x**2 - 2 * x**3; }
function randRange(lo, hi) { return Math.floor(Math.random() * (hi-lo)) + lo; }
function randInt(lo, hi) { return randRange(lo, hi+1); }
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redblobgames / client.js
Created March 1, 2025 17:56
Hello World of websockets, javascript client, python server
/**
* This is based on the example code from
* https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API/Writing_WebSocket_client_applications
*/
const exampleSocket = new WebSocket("ws://localhost:9999");
function send(msg) {
document.querySelector("#send").textContent += msg + "\n";
exampleSocket.send(msg);
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redblobgames / README.md
Created April 29, 2023 23:19
Three-Rhombus storage of a hex map

Reddit user /u/GavrielBA is using three rhombuses to store a hexagon-shaped map

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redblobgames / Test.cs
Last active October 21, 2022 23:58
C# distance test, are Abs, Pow, or Sqrt slow? Yes - Pow(v,2) is much slower than v*v
using System;
using System.Numerics;
static bool InDistance1(Vector2 pos1, Vector2 pos2, float maxDistance) {
var distance = Math.Sqrt(Math.Pow(Math.Abs(pos2.X - pos1.X), 2) + Math.Pow(Math.Abs(pos2.Y - pos1.Y), 2));
return distance <= maxDistance;
}
static bool InDistance2(Vector2 pos1, Vector2 pos2, float maxDistance) {
var distanceSquared = (pos2.X - pos1.X) * (pos2.X - pos1.X) + (pos2.Y - pos1.Y) * (pos2.Y - pos1.Y);
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redblobgames / .block
Last active September 30, 2022 16:42 — forked from HarryStevens/.block
Voronoi Jiggle
license: gpl-3.0
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redblobgames / treedemo.as
Created June 2, 2022 04:37
Tree generator I wrote in 2011 - but it's for Flash
// Draw simple trees
// Author: amitp@cs.stanford.edu
// License: MIT
// TODO: read http://procworld.blogspot.com/2011/04/tree-bits.html
// TODO: read http://procworld.blogspot.com/2011/05/mango-sequoia-baobab.html
package {
import flash.display.*;
import flash.geom.Point;
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redblobgames / sfc32.ts
Created May 10, 2022 16:21
sfc32 random number generator, typescript
// SFC32 random number generator, public domain code adapted
// from https://github.com/bryc/code/blob/master/jshash/PRNGs.md
function PRNG(seed: number): {
nextInt(): number;
nextFloat(): number;
getState(): number[];
setState(state: number[]): void
} {
let a = 0, b = seed, c = 0, d = 1;
function sfc32() {
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redblobgames / for.js
Created March 22, 2022 02:16
for loop comparison - probably poor benchmarking on my part
(function() {
let array = [];
for (let i = 0; i < 10000000; ++i) {
array.push({
a: i,
b: i / 2,
r: 0,
});
}
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redblobgames / hyphens.html
Last active November 27, 2021 17:40
Hyphen rendering messed up on my machine
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<style>
p {
max-width: 30em;
hyphens: auto; -webkit-hyphens: auto;
font-family: Arial;
}
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redblobgames / my-notes.el
Last active January 31, 2022 23:09
My note taking setup in emacs
;;; my-notes.el ---
;;; Commentary:
;; My notes, inspired by org-roam, but built on other packages I already use.
;;
;; 1. Capture into a queue (org-capture)
;; 2. Review queue (org-agenda)
;; 3. Find note (find-file in folder).
;; 4. Make new note. Fill with title, date.