Browser cat

A small cat that follows your cursor

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         Browser cat
// @namespace    http://tampermonkey.net/
// @version      1.0
// @license      MIT
// @description  A small  cat that follows your cursor
// @author       Boofdev
// @match        *://*/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=githubusercontent.com
// @grant        none
// ==/UserScript==

(function oneko() {
    const nekoEl = document.createElement("div");
    let nekoPosX = 32;
    let nekoPosY = 32;
    let mousePosX = 0;
    let mousePosY = 0;
    let frameCount = 0;
    let idleTime = 0;
    let idleAnimation = null;
    let idleAnimationFrame = 0;
    const nekoSpeed = 10;
    const spriteSets = {
        idle: [[-3, -3]],
        alert: [[-7, -3]],
        scratch: [
            [-5, 0],
            [-6, 0],
            [-7, 0],
        ],
        tired: [[-3, -2]],
        sleeping: [
            [-2, 0],
            [-2, -1],
        ],
        N: [
            [-1, -2],
            [-1, -3],
        ],
        NE: [
            [0, -2],
            [0, -3],
        ],
        E: [
            [-3, 0],
            [-3, -1],
        ],
        SE: [
            [-5, -1],
            [-5, -2],
        ],
        S: [
            [-6, -3],
            [-7, -2],
        ],
        SW: [
            [-5, -3],
            [-6, -1],
        ],
        W: [
            [-4, -2],
            [-4, -3],
        ],
        NW: [
            [-1, 0],
            [-1, -1],
        ],
    };
    function create() {
        nekoEl.id = "oneko";
        nekoEl.style.width = "32px";
        nekoEl.style.height = "32px";
        nekoEl.style.position = "fixed";
        nekoEl.style.pointerEvents = "none";
        nekoEl.style.backgroundImage = "url('https://raw.githubusercontent.com/adryd325/oneko.js/14bab15a755d0e35cd4ae19c931d96d306f99f42/oneko.gif')";
        nekoEl.style.imageRendering = "pixelated";
        nekoEl.style.left = "16px";
        nekoEl.style.top = "16px";

        document.body.appendChild(nekoEl);

        document.onmousemove = (event) => {
            mousePosX = event.clientX;
            mousePosY = event.clientY;
        };

        window.onekoInterval = setInterval(frame, 100);
    }

    function setSprite(name, frame) {
        const sprite = spriteSets[name][frame % spriteSets[name].length];
        nekoEl.style.backgroundPosition = `${sprite[0] * 32}px ${
            sprite[1] * 32
        }px`;
    }

    function resetIdleAnimation() {
        idleAnimation = null;
        idleAnimationFrame = 0;
    }

    function idle() {
        idleTime += 1;

        // every ~ 20 seconds
        if (
            idleTime > 10 &&
            Math.floor(Math.random() * 200) == 0 &&
            idleAnimation == null
        ) {
            idleAnimation = ["sleeping", "scratch"][
                Math.floor(Math.random() * 2)
            ];
        }

        switch (idleAnimation) {
            case "sleeping":
                if (idleAnimationFrame < 8) {
                    setSprite("tired", 0);
                    break;
                }
                setSprite("sleeping", Math.floor(idleAnimationFrame / 4));
                if (idleAnimationFrame > 192) {
                    resetIdleAnimation();
                }
                break;
            case "scratch":
                setSprite("scratch", idleAnimationFrame);
                if (idleAnimationFrame > 9) {
                    resetIdleAnimation();
                }
                break;
            default:
                setSprite("idle", 0);
                return;
        }
        idleAnimationFrame += 1;
    }

    function frame() {
        frameCount += 1;
        const diffX = nekoPosX - mousePosX;
        const diffY = nekoPosY - mousePosY;
        const distance = Math.sqrt(diffX ** 2 + diffY ** 2);

        if (distance < nekoSpeed || distance < 48) {
            idle();
            return;
        }

        idleAnimation = null;
        idleAnimationFrame = 0;

        if (idleTime > 1) {
            setSprite("alert", 0);
            // count down after being alerted before moving
            idleTime = Math.min(idleTime, 7);
            idleTime -= 1;
            return;
        }

        direction = diffY / distance > 0.5 ? "N" : "";
        direction += diffY / distance < -0.5 ? "S" : "";
        direction += diffX / distance > 0.5 ? "W" : "";
        direction += diffX / distance < -0.5 ? "E" : "";
        setSprite(direction, frameCount);

        nekoPosX -= (diffX / distance) * nekoSpeed;
        nekoPosY -= (diffY / distance) * nekoSpeed;

        nekoEl.style.left = `${nekoPosX - 16}px`;
        nekoEl.style.top = `${nekoPosY - 16}px`;
    }

    create();
})();