react frontend app (display screen, join)

tank-frontend/src/ClientScreen.css

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+
+#screen {
+    aspect-ratio: calc(352 / 160);
+    flex-grow: 1;
+    object-fit: contain;
+    max-width: 100%;
+}

tank-frontend/src/ClientScreen.tsx

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+import useWebSocket, {ReadyState} from 'react-use-websocket';
+import {useEffect, useRef} from 'react';
+import './ClientScreen.css';
+
+const pixelsPerRow = 352;
+const pixelsPerCol = 160;
+
+function getIndexes(bitIndex: number) {
+    return {
+        byteIndex: 10 + Math.floor(bitIndex / 8),
+        bitInByteIndex: 7 - bitIndex % 8
+    };
+}
+
+function drawPixelsToCanvas(pixels: Uint8Array, canvas: HTMLCanvasElement) {
+    const drawContext = canvas.getContext('2d');
+    if (!drawContext)
+        throw new Error('could not get draw context');
+
+    const imageData = drawContext.getImageData(0, 0, canvas.width, canvas.height, {colorSpace: 'srgb'});
+    const data = imageData.data;
+
+    console.log('draw', {width: canvas.width, height: canvas.height, dataLength: data.byteLength});
+
+    for (let y = 0; y < canvas.height; y++) {
+        const rowStartPixelIndex = y * pixelsPerRow;
+        for (let x = 0; x < canvas.width; x++) {
+            const pixelIndex = rowStartPixelIndex + x;
+            const {byteIndex, bitInByteIndex} = getIndexes(pixelIndex);
+            const byte = pixels[byteIndex];
+            const mask = (1 << bitInByteIndex);
+            const bitCheck = byte & mask;
+            const isOn = bitCheck !== 0;
+
+            const dataIndex = pixelIndex * 4;
+            if (isOn) {
+                data[dataIndex] = 0; // r
+                data[dataIndex + 1] = 180; // g
+                data[dataIndex + 2] = 0; // b
+                data[dataIndex + 3] = 255; // a
+            } else {
+                data[dataIndex] = 0; // r
+                data[dataIndex + 1] = 0; // g
+                data[dataIndex + 2] = 0; // b
+                data[dataIndex + 3] = 255; // a
+            }
+        }
+    }
+
+    drawContext.putImageData(imageData, 0, 0);
+}
+
+export default function ClientScreen({}: {}) {
+    const canvasRef = useRef<HTMLCanvasElement>(null);
+
+    const {
+        readyState,
+        lastMessage,
+        sendMessage,
+        getWebSocket
+    } = useWebSocket(import.meta.env.VITE_TANK_SCREEN_URL, {
+        shouldReconnect: () => true,
+    });
+
+    const socket = getWebSocket();
+    if (socket)
+        (socket as WebSocket).binaryType = 'arraybuffer';
+
+    useEffect(() => {
+        if (lastMessage === null)
+            return;
+        if (canvasRef.current === null)
+            throw new Error('canvas null');
+
+        drawPixelsToCanvas(new Uint8Array(lastMessage.data), canvasRef.current);
+        sendMessage('');
+    }, [lastMessage, canvasRef.current]);
+
+    const connectionStatus = {
+        [ReadyState.CONNECTING]: 'Connecting',
+        [ReadyState.OPEN]: 'Open',
+        [ReadyState.CLOSING]: 'Closing',
+        [ReadyState.CLOSED]: 'Closed',
+        [ReadyState.UNINSTANTIATED]: 'Uninstantiated',
+    }[readyState];
+
+    return <>
+        <span>The WebSocket is currently {connectionStatus}</span>
+        <canvas ref={canvasRef} id="screen" width={pixelsPerRow} height={pixelsPerCol}/>
+    </>;
+}

tank-frontend/src/Controls.css

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+kbd {
+    background: hsl(0, 0%, 96%);
+    padding: 10px;
+    display: block;
+    border-radius: 5px;
+    margin: 5px;
+    width: 1.6em;
+    height: 1.3em;
+    text-align: center;
+    box-shadow: 0 1px rgba(0, 0, 0, .21);
+    user-select: none;
+    color: black;
+}
+
+kbd.up {
+    margin-left: calc(1.6em + 35px);
+}
+
+kbd.space {
+    margin-top: calc(1.3em + 35px);
+    width: 14em;
+}
+
+kbd:active {
+    position: relative;
+    top: 2px;
+    background: hsl(0, 0%, 94%);
+    box-shadow: 0 1px rgba(0, 0, 0, .13) inset;
+}
+
+.controls {
+    display: flex;
+    color: lightgray;
+}
+
+.control {
+    margin: 0 1em;
+}
+
+.control h3 {
+    text-align: center;
+}
+
+.row {
+    display: flex;
+}
+
+.splash {
+    position: absolute;
+    left: 0;
+    top: 0;
+    width: 100%;
+    height: 100%;
+    background: radial-gradient(transparent, red);
+    opacity: 0;
+    pointer-events: none;
+    transition: opacity 500ms;
+}
+
+.was-killed .splash {
+    opacity: 1;
+    transition: opacity 120ms;
+}

tank-frontend/src/Controls.tsx

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+import './Controls.css';
+import useWebSocket from 'react-use-websocket';
+import {useEffect} from 'react';
+
+export default function Controls({playerId}: {
+    playerId: string
+}) {
+    const url = new URL(import.meta.env.VITE_TANK_CONTROLS_URL);
+    url.searchParams.set('playerId', playerId);
+    const {
+        sendMessage,
+        getWebSocket
+    } = useWebSocket(url.toString(), {
+        shouldReconnect: () => true,
+    });
+
+    const socket = getWebSocket();
+    if (socket)
+        (socket as WebSocket).binaryType = 'arraybuffer';
+
+    const keyEventListener = (type: string) => (event: KeyboardEvent) => {
+        if (event.defaultPrevented)
+            return;
+
+        const controls = {
+            'ArrowLeft': 'left',
+            'ArrowUp': 'up',
+            'ArrowRight': 'right',
+            'ArrowDown': 'down',
+            'Space': 'shoot',
+            'KeyW': 'up',
+            'KeyA': 'left',
+            'KeyS': 'down',
+            'KeyD': 'right',
+        };
+
+        // @ts-ignore
+        const value = controls[event.code];
+        if (!value)
+            return;
+
+        sendMessage(JSON.stringify({type, value}));
+    };
+
+    useEffect(() => {
+        const up = keyEventListener('input-off');
+        const down = keyEventListener('input-on');
+        window.onkeyup = up;
+        window.onkeydown = down;
+        return () => {
+            window.onkeydown = null;
+            window.onkeyup = null;
+        };
+    }, []);
+
+    return <div className="controls">
+        <div className="control">
+            <div className="row">
+                <kbd className="up">▲</kbd>
+            </div>
+            <div className="row">
+                <kbd>◀</kbd>
+                <kbd>▼</kbd>
+                <kbd>▶</kbd>
+            </div>
+            <h3>Move</h3>
+        </div>
+        <div className="control">
+            <kbd className="space">Space</kbd>
+            <h3>Fire</h3>
+        </div>
+    </div>;
+}

tank-frontend/src/JoinForm.css

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+.JoinForm {
+    display: flex;
+    flex-direction: row;
+}

tank-frontend/src/JoinForm.tsx

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+import {useEffect, useState} from 'react';
+import './JoinForm.css';
+
+type PlayerResponse = {
+    readonly name: string;
+    readonly id: string;
+};
+
+export async function fetchPlayer(name: string, options: RequestInit) {
+    const url = new URL(import.meta.env.VITE_TANK_PLAYER_URL);
+    url.searchParams.set('name', name);
+
+    const response = await fetch(url, options);
+    if (!response.ok)
+        return null;
+
+    const json = await response.json() as PlayerResponse;
+    return json.id;
+}
+
+export default function JoinForm({onDone}: { onDone: (id: string) => void }) {
+    const [name, setName] = useState('');
+    const [clicked, setClicked] = useState(false);
+    const [data, setData] = useState<PlayerResponse | null>(null);
+
+    useEffect(() => {
+        if (!clicked || data)
+            return;
+
+        try {
+            fetchPlayer(name, {}).then((value: string | null) => {
+                if (value)
+                    onDone(value);
+                else
+                    setClicked(false);
+            });
+        } catch (e) {
+            console.log(e);
+            alert(e);
+        }
+    }, [clicked, setData, data]);
+
+    const disableButtons = clicked || name.trim() === '';
+    return <div className="JoinForm">
+        <input
+            type="text"
+            value={name}
+            onChange={e => setName(e.target.value)}
+        />
+        <button
+            onClick={() => setClicked(true)}
+            disabled={disableButtons}
+        >
+            join
+        </button>
+    </div>;
+}

tank-frontend/src/controls.js

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+import './controls.css';
+
+const body = document.querySelector('body');
+const splash = document.querySelector('.splash');
+
+if (!splash || !body)
+    throw new Error('required element not found');
+
+splash.addEventListener('transitionend', function () {
+    body.classList.remove('was-killed');
+});
+
+const connection = new WebSocket(`ws://${window.location.hostname}:3000`);
+connection.binaryType = 'blob';
+
+connection.onmessage = function (message) {
+    message = JSON.parse(message.data);
+    console.log('got message', {message});
+    if (message.type === 'shot')
+        body.classList.add('was-killed');
+};
+
+connection.onerror = event => {
+    console.log('error', event);
+    alert('connection error');
+};
+
+connection.onclose = event => {
+    console.log('closed', event);
+    alert('connection closed - maybe a player with this name is already connected');
+};
+
+const keyEventListener = (type) => (event) => {
+    if (event.defaultPrevented)
+        return;
+
+    const controls = {
+        'ArrowLeft': 'left',
+        'ArrowUp': 'up',
+        'ArrowRight': 'right',
+        'ArrowDown': 'down',
+        'Space': 'shoot',
+        'KeyW': 'up',
+        'KeyA': 'left',
+        'KeyS': 'down',
+        'KeyD': 'right',
+    };
+
+    const value = controls[event.code];
+    if (!value)
+        return;
+
+    send({type, value});
+};
+
+connection.onopen = () => {
+    let name = getPlayerName();
+    send({type: 'name', value: name});
+
+    window.onkeyup = keyEventListener('input-off');
+    window.onkeydown = keyEventListener('input-on');
+
+    console.log('connection opened, game ready');
+};
+
+function getPlayerName() {
+    let name;
+    while (!name)
+        name = prompt('Player Name');
+    return name;
+}
+
+function send(obj) {
+    connection.send(JSON.stringify(obj));
+}

tank-frontend/src/index.css

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+
+html, body {
+    height: 100%;
+}
+
+body {
+    font-family: sans-serif;
+    margin: 0;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+
+    background-color: white;
+}
+
+#root {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    width: 100%;
+    height: 100%;
+}

tank-frontend/src/index.tsx

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+import React, {useState} from 'react';
+import './index.css';
+import ClientScreen from './ClientScreen';
+import Controls from './Controls.tsx';
+import JoinForm from './JoinForm.tsx';
+import {createRoot} from 'react-dom/client';
+
+function App() {
+    const [id, setId] = useState<string | null>(null);
+
+    return <>
+        {id === null && <JoinForm onDone={name => setId(name)}/>}
+        <ClientScreen/>
+        {id == null || <Controls playerId={id}/>}
+    </>;
+}
+
+createRoot(document.getElementById('root')!).render(
+    <React.StrictMode>
+        <App/>
+    </React.StrictMode>
+);

tank-frontend/src/vite-env.d.ts

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+/// <reference types="vite/client" />