横スクロールゲーム

// HTML Structure
const body = document.body;
body.style.margin = ‘0’;
body.style.overflow = ‘hidden’;
const canvas = document.createElement(‘canvas’);
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
body.appendChild(canvas);
const ctx = canvas.getContext(‘2d’);
// Game Variables
let player = {
x: 50,
y: canvas.height / 2 – 25,
width: 50,
height: 50,
color: ‘blue’,
speed: 5
};
let obstacles = [];
let score = 0;
let gameSpeed = 3;
// Helper Functions
function createObstacle() {
const height = Math.random() * (canvas.height / 2) + 50;
const gap = 150;
obstacles.push({
x: canvas.width,
y: 0,
width: 50,
height: height
});
obstacles.push({
x: canvas.width,
y: height + gap,
width: 50,
height: canvas.height – height – gap
});
}
function detectCollision(player, obstacle) {
return (
player.x obstacle.x &&
player.y obstacle.y
);
}
// Event Listener
window.addEventListener(‘keydown’, (e) => {
if (e.key === ‘ArrowUp’) {
player.y -= player.speed * 10;
} else if (e.key === ‘ArrowDown’) {
player.y += player.speed * 10;
}
});
// Game Loop
function update() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
// Draw Player
ctx.fillStyle = player.color;
ctx.fillRect(player.x, player.y, player.width, player.height);
// Draw Obstacles
ctx.fillStyle = ‘red’;
for (let i = obstacles.length – 1; i >= 0; i–) {
const obs = obstacles[i];
obs.x -= gameSpeed;
ctx.fillRect(obs.x, obs.y, obs.width, obs.height);
// Remove off-screen obstacles
if (obs.x + obs.width < 0) {
obstacles.splice(i, 1);
score++;
}
// Check for collision
if
(detectCollision(player, obs)) {
alert(`Game Over! Your score: ${score}`);
document.location.reload();
}
}
// Add new obstacles
if (obstacles.length === 0 || obstacles[obstacles.length – 1].x < canvas.width – 300) {
createObstacle();
}
// Display Score
ctx.fillStyle = 'black';
ctx.font = '20px Arial';
ctx.fillText(`Score: ${score}`, 10, 30);
requestAnimationFrame(update);
}
// Start Game
update();