SCORE: 0

HIGH SCORE: 0

SNAKE

矢印キーまたはスワイプで操作

GAME OVER

最終スコア: 0

PAUSED

ゲームルール
ソースコード(HTML/CSS/Javascript)

ゲームルール

定番のスネークゲームです。キーボードの矢印キーで自機を上下左右に操作し、壁や自分の壁に当たらないように赤いマークを集めていくシンプルなゲームです。試しに作ってみたので掲載しています。スマホからでもタップでプレイできるようにしていますが、操作性はそこまでよくありませんのでPCからのプレイをおすすめします。

ソースコード(HTML/CSS/Javascript)

ソースコードも載せておきます。サイトに掲載の都合上、idやclassなどが出来るだけ重複しないように割り当ててます。使用の際は適宜調整してください。

<!DOCTYPE html>
<html lang="ja">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
    <title>スネークゲーム・エボリューション</title>
    <link rel="preconnect" href="https://fonts.googleapis.com">
    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
    <link href="https://fonts.googleapis.com/css2?family=Poppins:wght@400;600&display=swap" rel="stylesheet">
    <style>
        /* Reset and Base Styles */
        :root {
            --bg-color-snakegame: #121212;
            --surface-color-snakegame: #1e1e1e;
            --primary-color-snakegame: #4CAF50;
            --primary-light-color-snakegame: #81C784;
            --accent-color-snakegame: #FF5722;
            --text-color-snakegame: #ffffff;
            --shadow-color-snakegame: rgba(0, 0, 0, 0.5);
            --glow-color-snakegame: rgba(76, 175, 80, 0.4);
        }

        /* Scoped body styles to the game wrapper */
        .game-wrapper-snakegame {
            background-color: var(--bg-color-snakegame);
            color: var(--text-color-snakegame);
            font-family: 'Poppins', sans-serif;
            -webkit-tap-highlight-color: transparent; /* Disable tap highlight on mobile */
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 15px;
            width: 100%;
            height: 100%;
            padding: 10px;
            box-sizing: border-box;
        }

        .score-board-snakegame {
            display: flex;
            justify-content: space-between;
            width: 100%;
            max-width: 600px;
            font-size: clamp(1rem, 4vw, 1.2rem);
            font-weight: 600;
        }

        #current-score-snakegame, #high-score-snakegame {
            color: var(--primary-color-snakegame);
            font-weight: 600;
        }

        .game-container-snakegame {
            position: relative;
            width: 90vw;
            height: 90vw;
            max-width: 600px;
            max-height: 600px;
        }

        #gameCanvas-snakegame {
            background-color: var(--surface-color-snakegame);
            border-radius: 10px;
            box-shadow: 0 0 25px var(--shadow-color-snakegame);
            width: 100%;
            height: 100%;
        }

        /* Overlays (Start, Game Over, Pause) */
        .game-overlay-snakegame {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-color: rgba(0, 0, 0, 0.8);
            border-radius: 10px;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            text-align: center;
            z-index: 10;
            backdrop-filter: blur(5px);
            animation: fadeIn-snakegame 0.3s ease-in-out;
        }

        @keyframes fadeIn-snakegame {
            from { opacity: 0; }
            to { opacity: 1; }
        }
        
        .game-overlay-snakegame h1 {
            font-size: clamp(2.5rem, 10vw, 3.5rem);
            margin: 0;
            text-shadow: 0 0 15px var(--primary-color-snakegame);
        }

        .game-overlay-snakegame p {
            font-size: clamp(1rem, 4vw, 1.2rem);
            margin: 20px 0;
        }

        .game-overlay-snakegame button {
            background: linear-gradient(45deg, var(--primary-color-snakegame), var(--primary-light-color-snakegame));
            border: none;
            color: white;
            padding: 15px 32px;
            text-align: center;
            font-size: 16px;
            font-family: 'Poppins', sans-serif;
            font-weight: 600;
            cursor: pointer;
            border-radius: 8px;
            transition: transform 0.2s, box-shadow 0.2s;
            box-shadow: 0 4px 15px var(--shadow-color-snakegame);
        }

        .game-overlay-snakegame button:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 20px var(--glow-color-snakegame);
        }

        /* Pause Button */
        #pause-button-snakegame {
            position: absolute;
            top: 15px;
            right: 15px;
            width: 40px;
            height: 40px;
            background: rgba(255, 255, 255, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 50%;
            cursor: pointer;
            z-index: 11;
            display: flex;
            justify-content: center;
            align-items: center;
            backdrop-filter: blur(2px);
            transition: background-color 0.2s;
        }
        #pause-button-snakegame:hover {
            background: rgba(255, 255, 255, 0.2);
        }
        #pause-icon-snakegame, #play-icon-snakegame {
            color: var(--text-color-snakegame);
            font-size: 20px;
        }
        #play-icon-snakegame { display: none; }

        /* Touch Controls */
        #touch-controls-snakegame {
            position: absolute;
            bottom: 20px;
            left: 50%;
            transform: translateX(-50%);
            width: 150px;
            height: 150px;
            display: none; /* Hidden by default, shown on touch devices */
            z-index: 5;
            opacity: 0.5;
        }
        @media (hover: none) and (pointer: coarse) {
            #touch-controls-snakegame {
                display: grid;
                grid-template-columns: 1fr 1fr 1fr;
                grid-template-rows: 1fr 1fr 1fr;
            }
        }
        .touch-btn-snakegame {
            display: flex;
            justify-content: center;
            align-items: center;
            -webkit-user-select: none; /* Safari */
            -ms-user-select: none; /* IE 10+ */
            user-select: none; /* Standard syntax */
        }
        .touch-btn-snakegame::before {
            content: '';
            width: 0;
            height: 0;
            border-style: solid;
        }
        #touch-up-snakegame::before { border-width: 0 15px 25px 15px; border-color: transparent transparent var(--text-color-snakegame) transparent; }
        #touch-down-snakegame::before { border-width: 25px 15px 0 15px; border-color: var(--text-color-snakegame) transparent transparent transparent; }
        #touch-left-snakegame::before { border-width: 15px 25px 15px 0; border-color: transparent var(--text-color-snakegame) transparent transparent; }
        #touch-right-snakegame::before { border-width: 15px 0 15px 25px; border-color: transparent transparent transparent var(--text-color-snakegame); }

        #touch-up-snakegame { grid-area: 1 / 2 / 2 / 3; }
        #touch-left-snakegame { grid-area: 2 / 1 / 3 / 2; }
        #touch-right-snakegame { grid-area: 2 / 3 / 3 / 4; }
        #touch-down-snakegame { grid-area: 3 / 2 / 4 / 3; }
    </style>
</head>
<body>
    <!-- The main wrapper for the game to isolate it -->
    <div class="game-wrapper-snakegame">
        <div class="score-board-snakegame">
            <div>SCORE: <span id="current-score-snakegame">0</span></div>
            <div>HIGH SCORE: <span id="high-score-snakegame">0</span></div>
        </div>
        <div class="game-container-snakegame">
            <canvas id="gameCanvas-snakegame"></canvas>
            
            <!-- Overlays -->
            <div id="start-screen-snakegame" class="game-overlay-snakegame">
                <h1>SNAKE</h1>
                <p>矢印キーまたはスワイプで操作</p>
                <button id="start-button-snakegame">ゲーム開始</button>
            </div>
            <div id="game-over-screen-snakegame" class="game-overlay-snakegame" style="display: none;">
                <h1>GAME OVER</h1>
                <p>最終スコア: <span id="final-score-snakegame">0</span></p>
                <button id="restart-button-snakegame">もう一度プレイ</button>
            </div>
            <div id="pause-screen-snakegame" class="game-overlay-snakegame" style="display: none;">
                <h1>PAUSED</h1>
                <button id="resume-button-snakegame">ゲーム再開</button>
            </div>

            <!-- Controls -->
            <div id="pause-button-snakegame" style="display: none;">
                <div id="pause-icon-snakegame">❚❚</div>
                <div id="play-icon-snakegame">&#x25b6;</div>
            </div>
            <div id="touch-controls-snakegame">
                <div id="touch-up-snakegame" class="touch-btn-snakegame"></div>
                <div id="touch-left-snakegame" class="touch-btn-snakegame"></div>
                <div id="touch-right-snakegame" class="touch-btn-snakegame"></div>
                <div id="touch-down-snakegame" class="touch-btn-snakegame"></div>
            </div>
        </div>
    </div>

    <script>
        // Wrap the entire game logic in a function to avoid global scope pollution
        (function() {
            // DOM Elements
            const canvas = document.getElementById('gameCanvas-snakegame');
            const ctx = canvas.getContext('2d');
            const currentScoreElem = document.getElementById('current-score-snakegame');
            const highScoreElem = document.getElementById('high-score-snakegame');
            const finalScoreElem = document.getElementById('final-score-snakegame');
            const startScreen = document.getElementById('start-screen-snakegame');
            const gameOverScreen = document.getElementById('game-over-screen-snakegame');
            const pauseScreen = document.getElementById('pause-screen-snakegame');
            const startButton = document.getElementById('start-button-snakegame');
            const restartButton = document.getElementById('restart-button-snakegame');
            const resumeButton = document.getElementById('resume-button-snakegame');
            const pauseButton = document.getElementById('pause-button-snakegame');
            const pauseIcon = document.getElementById('pause-icon-snakegame');
            const playIcon = document.getElementById('play-icon-snakegame');

            // Game Settings
            let gridSize = 20;
            const snakeSpeed = 10; // moves per second

            // Game State
            let snake, food, score, highScore, direction, changingDirection, gameLoop;
            let particles = [];
            let gameState = 'start'; // 'start', 'playing', 'paused', 'gameOver'
            
            // Audio
            let audioContext;
            let eatSound, gameOverSound;

            function initAudio() {
                if (audioContext) return;
                audioContext = new (window.AudioContext || window.webkitAudioContext)();
                
                function createSound(freq, type = 'sine', duration = 0.5) {
                    return () => {
                        if (!audioContext) return;
                        const oscillator = audioContext.createOscillator();
                        const gainNode = audioContext.createGain();
                        oscillator.connect(gainNode);
                        gainNode.connect(audioContext.destination);
                        oscillator.type = type;
                        oscillator.frequency.setValueAtTime(freq, audioContext.currentTime);
                        gainNode.gain.setValueAtTime(0.1, audioContext.currentTime);
                        gainNode.gain.exponentialRampToValueAtTime(0.0001, audioContext.currentTime + duration);
                        oscillator.start(audioContext.currentTime);
                        oscillator.stop(audioContext.currentTime + duration);
                    };
                }
                eatSound = createSound(440, 'square', 0.2);
                gameOverSound = createSound(110, 'sawtooth', 0.5);
            }

            // Canvas Sizing
            function resizeCanvas() {
                const container = document.querySelector('.game-container-snakegame');
                const size = Math.min(container.clientWidth, container.clientHeight);
                canvas.width = size;
                canvas.height = size;
                gridSize = Math.floor(size / 30); // Keep grid size relative
                if (gameState !== 'playing') {
                    draw(); // Redraw static elements on resize
                }
            }

            // Game Initialization
            function init() {
                gameState = 'playing';
                changingDirection = false;
                direction = { x: gridSize, y: 0 };
                score = 0;
                particles = [];

                const startX = Math.floor(canvas.width / 2 / gridSize) * gridSize;
                const startY = Math.floor(canvas.height / 2 / gridSize) * gridSize;

                snake = [
                    { x: startX, y: startY },
                    { x: startX - gridSize, y: startY },
                    { x: startX - gridSize * 2, y: startY }
                ];

                highScore = localStorage.getItem('snakeHighScore') || 0;
                currentScoreElem.textContent = score;
                highScoreElem.textContent = highScore;

                startScreen.style.display = 'none';
                gameOverScreen.style.display = 'none';
                pauseScreen.style.display = 'none';
                pauseButton.style.display = 'flex';

                generateFood();
                
                if(gameLoop) cancelAnimationFrame(gameLoop);
                lastRenderTime = 0;
                gameLoop = requestAnimationFrame(main);
            }
            
            // Main Game Loop
            let lastRenderTime = 0;
            function main(currentTime) {
                if (gameState !== 'playing') return;

                gameLoop = requestAnimationFrame(main);
                const secondsSinceLastRender = (currentTime - lastRenderTime) / 1000;
                if (secondsSinceLastRender < 1 / snakeSpeed) return;
                
                lastRenderTime = currentTime;
                
                update();
                draw();
            }
            
            // Update Game State
            function update() {
                changingDirection = false;
                const head = { x: snake[0].x + direction.x, y: snake[0].y + direction.y };
                snake.unshift(head);

                if (checkCollision()) {
                    setGameState('gameOver');
                    return;
                }

                if (head.x === food.x && head.y === food.y) {
                    score += 10;
                    currentScoreElem.textContent = score;
                    if (score > highScore) {
                        highScore = score;
                        highScoreElem.textContent = highScore;
                        localStorage.setItem('snakeHighScore', highScore);
                    }
                    createParticles(food.x, food.y);
                    eatSound();
                    generateFood();
                } else {
                    snake.pop();
                }

                updateParticles();
            }

            // Drawing Functions
            function draw() {
                ctx.clearRect(0, 0, canvas.width, canvas.height);
                ctx.fillStyle = getComputedStyle(document.documentElement).getPropertyValue('--surface-color-snakegame').trim();
                ctx.fillRect(0, 0, canvas.width, canvas.height);

                if (gameState === 'start') {
                    return;
                }
                
                drawFood();
                drawSnake();
                drawParticles();
            }

            function drawSnake() {
                const primaryColor = getComputedStyle(document.documentElement).getPropertyValue('--primary-color-snakegame').trim();
                const primaryLightColor = getComputedStyle(document.documentElement).getPropertyValue('--primary-light-color-snakegame').trim();

                snake.forEach((part, index) => {
                    if (index === 0) {
                        const headGradient = ctx.createLinearGradient(part.x, part.y, part.x + gridSize, part.y + gridSize);
                        headGradient.addColorStop(0, primaryLightColor);
                        headGradient.addColorStop(1, primaryColor);
                        ctx.fillStyle = headGradient;
                    } else {
                        const scale = (snake.length - index) / snake.length;
                        // Manually create rgba from hex `primaryColor`
                        const r = parseInt(primaryColor.slice(1, 3), 16);
                        const g = parseInt(primaryColor.slice(3, 5), 16);
                        const b = parseInt(primaryColor.slice(5, 7), 16);
                        ctx.fillStyle = `rgba(${r}, ${g}, ${b}, ${0.6 + scale * 0.4})`;
                    }
                    ctx.fillRect(part.x, part.y, gridSize, gridSize);
                });
            }

            function drawFood() {
                ctx.fillStyle = getComputedStyle(document.documentElement).getPropertyValue('--accent-color-snakegame').trim();
                ctx.shadowColor = 'rgba(255, 87, 34, 0.7)';
                ctx.shadowBlur = 15;
                ctx.fillRect(food.x, food.y, gridSize, gridSize);
                ctx.shadowBlur = 0;
            }

            // Particle System
            function createParticles(x, y) {
                for (let i = 0; i < 20; i++) {
                    particles.push({
                        x: x + gridSize / 2,
                        y: y + gridSize / 2,
                        vx: (Math.random() - 0.5) * 4,
                        vy: (Math.random() - 0.5) * 4,
                        size: Math.random() * 3 + 1,
                        life: 50,
                        color: `hsl(${Math.random() * 20 + 10}, 100%, 60%)` // Orange/Yellow hues
                    });
                }
            }

            function updateParticles() {
                for (let i = particles.length - 1; i >= 0; i--) {
                    const p = particles[i];
                    p.x += p.vx;
                    p.y += p.vy;
                    p.life--;
                    if (p.life <= 0) {
                        particles.splice(i, 1);
                    }
                }
            }

            function drawParticles() {
                particles.forEach(p => {
                    ctx.fillStyle = p.color;
                    ctx.globalAlpha = p.life / 50;
                    ctx.beginPath();
                    ctx.arc(p.x, p.y, p.size, 0, Math.PI * 2);
                    ctx.fill();
                });
                ctx.globalAlpha = 1.0;
            }

            // Food Generation
            function generateFood() {
                food = {
                    x: Math.floor(Math.random() * (canvas.width / gridSize)) * gridSize,
                    y: Math.floor(Math.random() * (canvas.height / gridSize)) * gridSize
                };
                if (snake.some(part => part.x === food.x && part.y === food.y)) {
                    generateFood();
                }
            }

            // Collision Detection
            function checkCollision() {
                const head = snake[0];
                if (head.x < 0 || head.x >= canvas.width || head.y < 0 || head.y >= canvas.height) {
                    return true;
                }
                for (let i = 1; i < snake.length; i++) {
                    if (head.x === snake[i].x && head.y === snake[i].y) {
                        return true;
                    }
                }
                return false;
            }
            
            // Game State Management
            function setGameState(newState) {
                gameState = newState;
                switch(newState) {
                    case 'gameOver':
                        gameOverSound();
                        cancelAnimationFrame(gameLoop);
                        finalScoreElem.textContent = score;
                        gameOverScreen.style.display = 'flex';
                        pauseButton.style.display = 'none';
                        break;
                    case 'paused':
                        cancelAnimationFrame(gameLoop);
                        pauseScreen.style.display = 'flex';
                        pauseIcon.style.display = 'none';
                        playIcon.style.display = 'block';
                        break;
                    case 'playing':
                         if(gameLoop) cancelAnimationFrame(gameLoop);
                         lastRenderTime = performance.now();
                         gameLoop = requestAnimationFrame(main);
                         pauseScreen.style.display = 'none';
                         pauseIcon.style.display = 'block';
                         playIcon.style.display = 'none';
                        break;
                }
            }

            function togglePause() {
                if (gameState === 'playing') {
                    setGameState('paused');
                } else if (gameState === 'paused') {
                    setGameState('playing');
                }
            }

            // Event Handlers
            function handleKeyDown(event) {
                if (gameState !== 'playing' || changingDirection) return;

                const keyPressed = event.key;
                const goingUp = direction.y === -gridSize;
                const goingDown = direction.y === gridSize;
                const goingRight = direction.x === gridSize;
                const goingLeft = direction.x === -gridSize;

                let newDirection = null;

                if ((keyPressed === 'ArrowLeft' || keyPressed.toLowerCase() === 'a') && !goingRight) {
                    newDirection = { x: -gridSize, y: 0 };
                } else if ((keyPressed === 'ArrowUp' || keyPressed.toLowerCase() === 'w') && !goingDown) {
                    newDirection = { x: 0, y: -gridSize };
                } else if ((keyPressed === 'ArrowRight' || keyPressed.toLowerCase() === 'd') && !goingLeft) {
                    newDirection = { x: gridSize, y: 0 };
                } else if ((keyPressed === 'ArrowDown' || keyPressed.toLowerCase() === 's') && !goingUp) {
                    newDirection = { x: 0, y: gridSize };
                } else if (keyPressed === ' ' || keyPressed === 'p') {
                    togglePause();
                }

                if (newDirection) {
                    direction = newDirection;
                    changingDirection = true;
                }
            }

            // Touch Controls
            let touchStartX = 0;
            let touchStartY = 0;
            
            function handleTouchStart(e) {
                e.preventDefault();
                touchStartX = e.touches[0].clientX;
                touchStartY = e.touches[0].clientY;
            }

            function handleTouchMove(e) {
                if (!touchStartX || !touchStartY || gameState !== 'playing' || changingDirection) {
                    return;
                }
                e.preventDefault();
                const touchEndX = e.touches[0].clientX;
                const touchEndY = e.touches[0].clientY;

                const diffX = touchEndX - touchStartX;
                const diffY = touchEndY - touchStartY;
                
                const goingUp = direction.y === -gridSize;
                const goingDown = direction.y === gridSize;
                const goingRight = direction.x === gridSize;
                const goingLeft = direction.x === -gridSize;

                let newDirection = null;

                if (Math.abs(diffX) > Math.abs(diffY)) { // Horizontal swipe
                    if (diffX > 0 && !goingLeft) {
                        newDirection = { x: gridSize, y: 0 };
                    } else if (diffX < 0 && !goingRight) {
                        newDirection = { x: -gridSize, y: 0 };
                    }
                } else { // Vertical swipe
                    if (diffY > 0 && !goingUp) {
                        newDirection = { x: 0, y: gridSize };
                    } else if (diffY < 0 && !goingDown) {
                        newDirection = { x: 0, y: -gridSize };
                    }
                }

                if (newDirection) {
                    direction = newDirection;
                    changingDirection = true;
                    touchStartX = 0; // Reset after a successful swipe
                    touchStartY = 0;
                }
            }
            
            // Setup
            window.addEventListener('resize', resizeCanvas);
            document.addEventListener('keydown', handleKeyDown);
            canvas.addEventListener('touchstart', handleTouchStart, { passive: false });
            canvas.addEventListener('touchmove', handleTouchMove, { passive: false });
            
            // Button Listeners
            startButton.addEventListener('click', () => {
                initAudio();
                init();
            });
            restartButton.addEventListener('click', init);
            pauseButton.addEventListener('click', togglePause);
            resumeButton.addEventListener('click', togglePause);
            
            // Touch control buttons
            document.getElementById('touch-up-snakegame').addEventListener('click', () => handleKeyDown({key: 'ArrowUp'}));
            document.getElementById('touch-down-snakegame').addEventListener('click', () => handleKeyDown({key: 'ArrowDown'}));
            document.getElementById('touch-left-snakegame').addEventListener('click', () => handleKeyDown({key: 'ArrowLeft'}));
            document.getElementById('touch-right-snakegame').addEventListener('click', () => handleKeyDown({key: 'ArrowRight'}));

            // Initial call
            resizeCanvas();
            setGameState('start');
            highScore = localStorage.getItem('snakeHighScore') || 0;
            highScoreElem.textContent = highScore;
        })();
    </script>
</body>
</html>

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<!DOCTYPE html>

<head>

<title>スネークゲーム・エボリューション</title>

<style>

/* Reset and Base Styles */

:root {

--bg-color-snakegame: #121212;

--surface-color-snakegame: #1e1e1e;

--primary-color-snakegame: #4CAF50;

--primary-light-color-snakegame: #81C784;

--accent-color-snakegame: #FF5722;

--text-color-snakegame: #ffffff;

--shadow-color-snakegame: rgba(0, 0, 0, 0.5);

--glow-color-snakegame: rgba(76, 175, 80, 0.4);

}

/* Scoped body styles to the game wrapper */

.game-wrapper-snakegame {

background-color: var(--bg-color-snakegame);

color: var(--text-color-snakegame);

font-family: 'Poppins', sans-serif;

-webkit-tap-highlight-color: transparent; /* Disable tap highlight on mobile */

display: flex;

flex-direction: column;

align-items: center;

gap: 15px;

width: 100%;

height: 100%;

padding: 10px;

box-sizing: border-box;

}

.score-board-snakegame {

display: flex;

justify-content: space-between;

width: 100%;

max-width: 600px;

font-size: clamp(1rem, 4vw, 1.2rem);

font-weight: 600;

}

#current-score-snakegame, #high-score-snakegame {

color: var(--primary-color-snakegame);

font-weight: 600;

}

.game-container-snakegame {

position: relative;

width: 90vw;

height: 90vw;

max-width: 600px;

max-height: 600px;

}

#gameCanvas-snakegame {

background-color: var(--surface-color-snakegame);

border-radius: 10px;

box-shadow: 0 0 25px var(--shadow-color-snakegame);

width: 100%;

height: 100%;

}

/* Overlays (Start, Game Over, Pause) */

.game-overlay-snakegame {

position: absolute;

top: 0;

left: 0;

width: 100%;

height: 100%;

background-color: rgba(0, 0, 0, 0.8);

border-radius: 10px;

display: flex;

flex-direction: column;

justify-content: center;

align-items: center;

text-align: center;

z-index: 10;

backdrop-filter: blur(5px);

animation: fadeIn-snakegame 0.3s ease-in-out;

}

@keyframes fadeIn-snakegame {

from { opacity: 0; }

to { opacity: 1; }

}

.game-overlay-snakegame h1 {

font-size: clamp(2.5rem, 10vw, 3.5rem);

margin: 0;

text-shadow: 0 0 15px var(--primary-color-snakegame);

}

.game-overlay-snakegame p {

font-size: clamp(1rem, 4vw, 1.2rem);

margin: 20px 0;

}

.game-overlay-snakegame button {

background: linear-gradient(45deg, var(--primary-color-snakegame), var(--primary-light-color-snakegame));

border: none;

color: white;

padding: 15px 32px;

text-align: center;

font-size: 16px;

font-family: 'Poppins', sans-serif;

font-weight: 600;

cursor: pointer;

border-radius: 8px;

transition: transform 0.2s, box-shadow 0.2s;

box-shadow: 0 4px 15px var(--shadow-color-snakegame);

}

.game-overlay-snakegame button:hover {

transform: translateY(-3px);

box-shadow: 0 6px 20px var(--glow-color-snakegame);

}

/* Pause Button */

#pause-button-snakegame {

position: absolute;

top: 15px;

right: 15px;

width: 40px;

height: 40px;

background: rgba(255, 255, 255, 0.1);

border: 1px solid rgba(255, 255, 255, 0.2);

border-radius: 50%;

cursor: pointer;

z-index: 11;

display: flex;

justify-content: center;

align-items: center;

backdrop-filter: blur(2px);

transition: background-color 0.2s;

}

#pause-button-snakegame:hover {

background: rgba(255, 255, 255, 0.2);

}

#pause-icon-snakegame, #play-icon-snakegame {

color: var(--text-color-snakegame);

font-size: 20px;

}

#play-icon-snakegame { display: none; }

/* Touch Controls */

#touch-controls-snakegame {

position: absolute;

bottom: 20px;

left: 50%;

transform: translateX(-50%);

width: 150px;

height: 150px;

display: none; /* Hidden by default, shown on touch devices */

z-index: 5;

opacity: 0.5;

}

@media (hover: none) and (pointer: coarse) {

#touch-controls-snakegame {

display: grid;

grid-template-columns: 1fr 1fr 1fr;

grid-template-rows: 1fr 1fr 1fr;

}

.touch-btn-snakegame {

display: flex;

justify-content: center;

align-items: center;

-webkit-user-select: none; /* Safari */

-ms-user-select: none; /* IE 10+ */

user-select: none; /* Standard syntax */

}

.touch-btn-snakegame::before {

content: '';

width: 0;

height: 0;

border-style: solid;

}

#touch-up-snakegame::before { border-width: 0 15px 25px 15px; border-color: transparent transparent var(--text-color-snakegame) transparent; }

#touch-down-snakegame::before { border-width: 25px 15px 0 15px; border-color: var(--text-color-snakegame) transparent transparent transparent; }

#touch-left-snakegame::before { border-width: 15px 25px 15px 0; border-color: transparent var(--text-color-snakegame) transparent transparent; }

#touch-right-snakegame::before { border-width: 15px 0 15px 25px; border-color: transparent transparent transparent var(--text-color-snakegame); }

#touch-up-snakegame { grid-area: 1 / 2 / 2 / 3; }

#touch-left-snakegame { grid-area: 2 / 1 / 3 / 2; }

#touch-right-snakegame { grid-area: 2 / 3 / 3 / 4; }

#touch-down-snakegame { grid-area: 3 / 2 / 4 / 3; }

</style>

</head>

<body>

<div>SCORE: <span id="current-score-snakegame">0</span></div>

<div>HIGH SCORE: <span id="high-score-snakegame">0</span></div>

</div>

<h1>SNAKE</h1>

<p>矢印キーまたはスワイプで操作</p>

<button id="start-button-snakegame">ゲーム開始</button>

</div>

<p>最終スコア: <span id="final-score-snakegame">0</span></p>

<button id="restart-button-snakegame">もう一度プレイ</button>

</div>

<h1>PAUSED</h1>

<button id="resume-button-snakegame">ゲーム再開</button>

</div>

</div>

</div>

// Wrap the entire game logic in a function to avoid global scope pollution

(function() {

// DOM Elements

const canvas = document.getElementById('gameCanvas-snakegame');

const ctx = canvas.getContext('2d');

const currentScoreElem = document.getElementById('current-score-snakegame');

const highScoreElem = document.getElementById('high-score-snakegame');

const finalScoreElem = document.getElementById('final-score-snakegame');

const startScreen = document.getElementById('start-screen-snakegame');

const gameOverScreen = document.getElementById('game-over-screen-snakegame');

const pauseScreen = document.getElementById('pause-screen-snakegame');

const startButton = document.getElementById('start-button-snakegame');

const restartButton = document.getElementById('restart-button-snakegame');

const resumeButton = document.getElementById('resume-button-snakegame');

const pauseButton = document.getElementById('pause-button-snakegame');

const pauseIcon = document.getElementById('pause-icon-snakegame');

const playIcon = document.getElementById('play-icon-snakegame');

// Game Settings

let gridSize = 20;

const snakeSpeed = 10; // moves per second

// Game State

let snake, food, score, highScore, direction, changingDirection, gameLoop;

let particles = [];

let gameState = 'start'; // 'start', 'playing', 'paused', 'gameOver'

// Audio

let audioContext;

let eatSound, gameOverSound;

function initAudio() {

if (audioContext) return;

audioContext = new (window.AudioContext || window.webkitAudioContext)();

function createSound(freq, type = 'sine', duration = 0.5) {

return () => {

if (!audioContext) return;

const oscillator = audioContext.createOscillator();

const gainNode = audioContext.createGain();

oscillator.connect(gainNode);

gainNode.connect(audioContext.destination);

oscillator.type = type;

oscillator.frequency.setValueAtTime(freq, audioContext.currentTime);

gainNode.gain.setValueAtTime(0.1, audioContext.currentTime);

gainNode.gain.exponentialRampToValueAtTime(0.0001, audioContext.currentTime + duration);

oscillator.start(audioContext.currentTime);

oscillator.stop(audioContext.currentTime + duration);

};

}

eatSound = createSound(440, 'square', 0.2);

gameOverSound = createSound(110, 'sawtooth', 0.5);

}

// Canvas Sizing

function resizeCanvas() {

const container = document.querySelector('.game-container-snakegame');

const size = Math.min(container.clientWidth, container.clientHeight);

canvas.width = size;

canvas.height = size;

gridSize = Math.floor(size / 30); // Keep grid size relative

if (gameState !== 'playing') {

draw(); // Redraw static elements on resize

}

// Game Initialization

function init() {

gameState = 'playing';

changingDirection = false;

direction = { x: gridSize, y: 0 };

score = 0;

particles = [];

const startX = Math.floor(canvas.width / 2 / gridSize) * gridSize;

const startY = Math.floor(canvas.height / 2 / gridSize) * gridSize;

snake = [

{ x: startX, y: startY },

{ x: startX - gridSize, y: startY },

{ x: startX - gridSize * 2, y: startY }

];

highScore = localStorage.getItem('snakeHighScore') || 0;

currentScoreElem.textContent = score;

highScoreElem.textContent = highScore;

startScreen.style.display = 'none';

gameOverScreen.style.display = 'none';

pauseScreen.style.display = 'none';

pauseButton.style.display = 'flex';

generateFood();

if(gameLoop) cancelAnimationFrame(gameLoop);

lastRenderTime = 0;

gameLoop = requestAnimationFrame(main);

}

// Main Game Loop

let lastRenderTime = 0;

function main(currentTime) {

if (gameState !== 'playing') return;

gameLoop = requestAnimationFrame(main);

const secondsSinceLastRender = (currentTime - lastRenderTime) / 1000;

if (secondsSinceLastRender < 1 / snakeSpeed) return;

lastRenderTime = currentTime;

update();

draw();

}

// Update Game State

function update() {

changingDirection = false;

const head = { x: snake[0].x + direction.x, y: snake[0].y + direction.y };

snake.unshift(head);

if (checkCollision()) {

setGameState('gameOver');

return;

}

if (head.x === food.x && head.y === food.y) {

score += 10;

currentScoreElem.textContent = score;

if (score > highScore) {

highScore = score;

highScoreElem.textContent = highScore;

localStorage.setItem('snakeHighScore', highScore);

}

createParticles(food.x, food.y);

eatSound();

generateFood();

} else {

snake.pop();

}

updateParticles();

}

// Drawing Functions

function draw() {

ctx.clearRect(0, 0, canvas.width, canvas.height);

ctx.fillStyle = getComputedStyle(document.documentElement).getPropertyValue('--surface-color-snakegame').trim();

ctx.fillRect(0, 0, canvas.width, canvas.height);

if (gameState === 'start') {

return;

}

drawFood();

drawSnake();

drawParticles();

}

function drawSnake() {

const primaryColor = getComputedStyle(document.documentElement).getPropertyValue('--primary-color-snakegame').trim();

const primaryLightColor = getComputedStyle(document.documentElement).getPropertyValue('--primary-light-color-snakegame').trim();

snake.forEach((part, index) => {

if (index === 0) {

const headGradient = ctx.createLinearGradient(part.x, part.y, part.x + gridSize, part.y + gridSize);

headGradient.addColorStop(0, primaryLightColor);

headGradient.addColorStop(1, primaryColor);

ctx.fillStyle = headGradient;

} else {

const scale = (snake.length - index) / snake.length;

// Manually create rgba from hex `primaryColor`

const r = parseInt(primaryColor.slice(1, 3), 16);

const g = parseInt(primaryColor.slice(3, 5), 16);

const b = parseInt(primaryColor.slice(5, 7), 16);

ctx.fillStyle = `rgba(${r}, ${g}, ${b}, ${0.6 + scale * 0.4})`;

}

ctx.fillRect(part.x, part.y, gridSize, gridSize);

});

}

function drawFood() {

ctx.fillStyle = getComputedStyle(document.documentElement).getPropertyValue('--accent-color-snakegame').trim();

ctx.shadowColor = 'rgba(255, 87, 34, 0.7)';

ctx.shadowBlur = 15;

ctx.fillRect(food.x, food.y, gridSize, gridSize);

ctx.shadowBlur = 0;

}

// Particle System

function createParticles(x, y) {

for (let i = 0; i < 20; i++) {

particles.push({

x: x + gridSize / 2,

y: y + gridSize / 2,

vx: (Math.random() - 0.5) * 4,

vy: (Math.random() - 0.5) * 4,

size: Math.random() * 3 + 1,

life: 50,

color: `hsl(${Math.random() * 20 + 10}, 100%, 60%)` // Orange/Yellow hues

});

}

function updateParticles() {

for (let i = particles.length - 1; i >= 0; i--) {

const p = particles[i];

p.x += p.vx;

p.y += p.vy;

p.life--;

if (p.life <= 0) {

particles.splice(i, 1);

}

function drawParticles() {

particles.forEach(p => {

ctx.fillStyle = p.color;

ctx.globalAlpha = p.life / 50;

ctx.beginPath();

ctx.arc(p.x, p.y, p.size, 0, Math.PI * 2);

ctx.fill();

});

ctx.globalAlpha = 1.0;

}

// Food Generation

function generateFood() {

food = {

x: Math.floor(Math.random() * (canvas.width / gridSize)) * gridSize,

y: Math.floor(Math.random() * (canvas.height / gridSize)) * gridSize

};

if (snake.some(part => part.x === food.x && part.y === food.y)) {

generateFood();

}

// Collision Detection

function checkCollision() {

const head = snake[0];

if (head.x < 0 || head.x >= canvas.width || head.y < 0 || head.y >= canvas.height) {

return true;

}

for (let i = 1; i < snake.length; i++) {

if (head.x === snake[i].x && head.y === snake[i].y) {

return true;

}

return false;

}

// Game State Management

function setGameState(newState) {

gameState = newState;

switch(newState) {

case 'gameOver':

gameOverSound();

cancelAnimationFrame(gameLoop);

finalScoreElem.textContent = score;

gameOverScreen.style.display = 'flex';

pauseButton.style.display = 'none';

break;

case 'paused':

cancelAnimationFrame(gameLoop);

pauseScreen.style.display = 'flex';

pauseIcon.style.display = 'none';

playIcon.style.display = 'block';

break;

case 'playing':

if(gameLoop) cancelAnimationFrame(gameLoop);

lastRenderTime = performance.now();

gameLoop = requestAnimationFrame(main);

pauseScreen.style.display = 'none';

pauseIcon.style.display = 'block';

playIcon.style.display = 'none';

break;

}

function togglePause() {

if (gameState === 'playing') {

setGameState('paused');

} else if (gameState === 'paused') {

setGameState('playing');

}

// Event Handlers

function handleKeyDown(event) {

if (gameState !== 'playing' || changingDirection) return;

const keyPressed = event.key;

const goingUp = direction.y === -gridSize;

const goingDown = direction.y === gridSize;

const goingRight = direction.x === gridSize;

const goingLeft = direction.x === -gridSize;

let newDirection = null;

if ((keyPressed === 'ArrowLeft' || keyPressed.toLowerCase() === 'a') && !goingRight) {

newDirection = { x: -gridSize, y: 0 };

} else if ((keyPressed === 'ArrowUp' || keyPressed.toLowerCase() === 'w') && !goingDown) {

newDirection = { x: 0, y: -gridSize };

} else if ((keyPressed === 'ArrowRight' || keyPressed.toLowerCase() === 'd') && !goingLeft) {

newDirection = { x: gridSize, y: 0 };

} else if ((keyPressed === 'ArrowDown' || keyPressed.toLowerCase() === 's') && !goingUp) {

newDirection = { x: 0, y: gridSize };

} else if (keyPressed === ' ' || keyPressed === 'p') {

togglePause();

}

if (newDirection) {

direction = newDirection;

changingDirection = true;

}

// Touch Controls

let touchStartX = 0;

let touchStartY = 0;

function handleTouchStart(e) {

e.preventDefault();

touchStartX = e.touches[0].clientX;

touchStartY = e.touches[0].clientY;

}

function handleTouchMove(e) {

if (!touchStartX || !touchStartY || gameState !== 'playing' || changingDirection) {

return;

}

e.preventDefault();

const touchEndX = e.touches[0].clientX;

const touchEndY = e.touches[0].clientY;

const diffX = touchEndX - touchStartX;

const diffY = touchEndY - touchStartY;

const goingUp = direction.y === -gridSize;

const goingDown = direction.y === gridSize;

const goingRight = direction.x === gridSize;

const goingLeft = direction.x === -gridSize;

let newDirection = null;

if (Math.abs(diffX) > Math.abs(diffY)) { // Horizontal swipe

if (diffX > 0 && !goingLeft) {

newDirection = { x: gridSize, y: 0 };

} else if (diffX < 0 && !goingRight) {

newDirection = { x: -gridSize, y: 0 };

}

} else { // Vertical swipe

if (diffY > 0 && !goingUp) {

newDirection = { x: 0, y: gridSize };

} else if (diffY < 0 && !goingDown) {

newDirection = { x: 0, y: -gridSize };

}

if (newDirection) {

direction = newDirection;

changingDirection = true;

touchStartX = 0; // Reset after a successful swipe

touchStartY = 0;

}

// Setup

window.addEventListener('resize', resizeCanvas);

document.addEventListener('keydown', handleKeyDown);

canvas.addEventListener('touchstart', handleTouchStart, { passive: false });

canvas.addEventListener('touchmove', handleTouchMove, { passive: false });

// Button Listeners

startButton.addEventListener('click', () => {

initAudio();

init();

});

restartButton.addEventListener('click', init);

pauseButton.addEventListener('click', togglePause);

resumeButton.addEventListener('click', togglePause);

// Touch control buttons

document.getElementById('touch-up-snakegame').addEventListener('click', () => handleKeyDown({key: 'ArrowUp'}));

document.getElementById('touch-down-snakegame').addEventListener('click', () => handleKeyDown({key: 'ArrowDown'}));

document.getElementById('touch-left-snakegame').addEventListener('click', () => handleKeyDown({key: 'ArrowLeft'}));

document.getElementById('touch-right-snakegame').addEventListener('click', () => handleKeyDown({key: 'ArrowRight'}));

// Initial call

resizeCanvas();

setGameState('start');

highScore = localStorage.getItem('snakeHighScore') || 0;

highScoreElem.textContent = highScore;

})();

</script>

</body>

</html>