HTML5 Canvas 星空战机游戏开发全解析

发布于：2025-05-31 ⋅ 阅读:(22) ⋅ 点赞:(0)

HTML5 Canvas 星空战机游戏开发全解析

一、游戏介绍

这是一款基于HTML5 Canvas开发的2D射击游戏，具有以下特色功能：

  • 🚀 纯代码绘制的星空动态背景
  • ✈️ 三种不同特性的敌人类型
  • 🎮 键盘控制的玩家战机
  • 📊 完整的分数统计和排行榜系统
  • ⚙️ 三种难度可选
    在这里插入图片描述

二、核心代码解析

1. 游戏初始化

const canvas = document.getElementById('gameCanvas');
const ctx = canvas.getContext('2d');
let game = {
    // 游戏状态对象
    stars: [],      // 星星数组
    bullets: [],    // 玩家子弹
    enemies: [],    // 敌人数组
    score: 0,       // 当前分数
    level: 1,       // 当前关卡
    player: {       // 玩家对象
        x: canvas.width/2,
        y: canvas.height-100,
        width: 40,
        health: 100
    }
};

2. 游戏主循环

function gameLoop() {
    // 1. 清空画布
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    
    // 2. 更新游戏状态
    updateGame();
    
    // 3. 绘制所有元素
    drawBackground();
    drawPlayer();
    drawEnemies();
    drawBullets();
    
    // 4. 请求下一帧
    requestAnimationFrame(gameLoop);
}

3. 玩家控制实现

// 键盘事件监听
const keys = {};
window.addEventListener('keydown', e => keys[e.key] = true);
window.addEventListener('keyup', e => keys[e.key] = false);

// 玩家移动逻辑
function movePlayer() {
    if (keys['ArrowLeft']) {
        // 左移限制：不能超出左边界
        game.player.x = Math.max(game.player.width/2, game.player.x - 8);
    }
    if (keys['ArrowRight']) {
        // 右移限制：不能超出右边界
        game.player.x = Math.min(canvas.width-game.player.width/2, game.player.x + 8);
    }
    if (keys[' ']) {
        // 空格键射击
        fireBullet();
    }
}

三、关键技术点

1. 敌人系统设计

敌人类型 速度 生命值 分数 特性
基础型 3 1 10 普通移动
快速型 5 1 20 高速移动
坦克型 2 5 50 高生命值

2. 碰撞检测优化

采用圆形碰撞检测算法：

function checkCollision(bullet, enemy) {
    const dx = bullet.x - enemy.x;
    const dy = bullet.y - enemy.y;
    const distance = Math.sqrt(dx * dx + dy * dy);
    return distance < (bullet.radius + enemy.width/2);
}

3. 排行榜实现

使用localStorage存储数据：

function saveHighScore(name, score) {
    const scores = JSON.parse(localStorage.getItem('highScores')) || [];
    scores.push({ name, score });
    scores.sort((a, b) => b.score - a.score);
    localStorage.setItem('highScores', JSON.stringify(scores.slice(0, 10)));
}

在这里插入图片描述

四、完整代码

<!DOCTYPE html>
<html>
<head>
    <title>星空战机</title>
    <style>
        body { margin: 0; overflow: hidden; font-family: Arial, sans-serif; }
        canvas { display: block; }
        #ui {
            position: absolute;
            top: 20px;
            left: 20px;
            color: white;
            font-size: 16px;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
        }
        #menu {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            background: rgba(0, 0, 0, 0.8);
            padding: 20px;
            border-radius: 10px;
            color: white;
            text-align: center;
        }
        button {
            padding: 10px 20px;
            margin: 10px;
            font-size: 16px;
            cursor: pointer;
            border: none;
            border-radius: 5px;
            background: #3498db;
            color: white;
        }
    </style>
</head>
<body>
<canvas id="gameCanvas"></canvas>
<div id="ui"></div>
<div id="menu">
    <h1>星空战机</h1>
    <p>选择难度：</p>
    <button onclick="startGame('easy')">简单</button>
    <button onclick="startGame('normal')">普通</button>
    <button onclick="startGame('hard')">困难</button>
    <div id="highScores"></div>
</div>

<script>
// 初始化
const canvas = document.getElementById('gameCanvas');
const ctx = canvas.getContext('2d');
const ui = document.getElementById('ui');
const menu = document.getElementById('menu');
const highScores = document.getElementById('highScores');

let game = {
    stars: [],
    bullets: [],
    enemyBullets: [],
    enemies: [],
    powerups: [],
    explosions: [],
    score: 0,
    level: 1,
    difficulty: 'normal',
    player: {
        x: 0, // 初始位置会在 startGame 中设置
        y: 0, // 初始位置会在 startGame 中设置
        width: 40,
        height: 60,
        speed: 8,
        canShoot: true,
        health: 100,
        weapon: 'normal',
        shield: 0
    },
    running: false
};

// 调整画布大小
function resizeCanvas() {
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;
    if (game.running) {
        // 如果游戏运行中调整画布大小，重置玩家位置
        game.player.x = canvas.width / 2;
        game.player.y = canvas.height - 100;
    }
}
resizeCanvas();
window.addEventListener('resize', resizeCanvas);

// 显示高分榜
function showHighScores() {
    const scores = JSON.parse(localStorage.getItem('highScores')) || [];
    highScores.innerHTML = '<h2>高分榜</h2>' +
        scores.map((score, i) => 
            `<div>${i + 1}. ${score.name}: ${score.score}</div>`
        ).join('');
}

// 开始游戏
function startGame(difficulty) {
    game = {
        ...game,
        stars: [],
        bullets: [],
        enemyBullets: [],
        enemies: [],
        powerups: [],
        explosions: [],
        score: 0,
        level: 1,
        difficulty,
        player: {
            ...game.player,
            x: canvas.width / 2, // 初始位置在画布中央
            y: canvas.height - 100, // 初始位置在画布底部
            health: difficulty === 'easy' ? 150 : difficulty === 'normal' ? 100 : 75,
            weapon: 'normal',
            shield: 0
        },
        running: true
    };
    menu.style.display = 'none';
    createStars();
    gameLoop();
}

// 游戏结束
function gameOver() {
    game.running = false;
    const name = prompt('游戏结束！请输入你的名字：');
    if (name) {
        saveHighScore(name, game.score);
    }
    menu.style.display = 'block';
    showHighScores();
}

// 保存高分
function saveHighScore(name, score) {
    const scores = JSON.parse(localStorage.getItem('highScores')) || [];
    scores.push({ name, score });
    scores.sort((a, b) => b.score - a.score);
    localStorage.setItem('highScores', JSON.stringify(scores.slice(0, 10)));
}

// 生成星星
function createStars() {
    for (let i = 0; i < 200; i++) {
        game.stars.push({
            x: Math.random() * canvas.width,
            y: Math.random() * canvas.height,
            size: Math.random() * 3,
            alpha: Math.random()
        });
    }
}

// 绘制背景
function drawBackground() {
    const gradient = ctx.createLinearGradient(0, 0, 0, canvas.height);
    gradient.addColorStop(0, "#000428");
    gradient.addColorStop(1, "#004e92");
    ctx.fillStyle = gradient;
    ctx.fillRect(0, 0, canvas.width, canvas.height);

    ctx.fillStyle = "white";
    game.stars.forEach(star => {
        ctx.globalAlpha = star.alpha;
        ctx.beginPath();
        ctx.arc(star.x, star.y, star.size, 0, Math.PI * 2);
        ctx.fill();
    });
    ctx.globalAlpha = 1;
}

// 绘制玩家
function drawPlayer() {
    // 护盾
    if (game.player.shield > 0) {
        ctx.strokeStyle = `rgba(0, 255, 255, ${game.player.shield / 100})`;
        ctx.lineWidth = 2;
        ctx.beginPath();
        ctx.arc(game.player.x, game.player.y, 40, 0, Math.PI * 2);
        ctx.stroke();
    }

    // 机身
    ctx.fillStyle = "#4a90e2";
    ctx.beginPath();
    ctx.moveTo(game.player.x, game.player.y);
    ctx.lineTo(game.player.x - game.player.width / 2, game.player.y + game.player.height);
    ctx.lineTo(game.player.x + game.player.width / 2, game.player.y + game.player.height);
    ctx.closePath();
    ctx.fill();

    // 机翼
    ctx.fillStyle = "#2c3e50";
    ctx.fillRect(game.player.x - 25, game.player.y + 20, 50, 15);

    // 推进器火焰
    ctx.fillStyle = `hsl(${Math.random() * 30 + 30}, 100%, 50%)`;
    ctx.beginPath();
    ctx.ellipse(game.player.x, game.player.y + game.player.height + 5, 8, 15, 0, 0, Math.PI * 2);
    ctx.fill();
}

// 生成敌人
function createEnemy() {
    const enemyTypes = ['basic', 'fast', 'tank'];
    const type = enemyTypes[Math.floor(Math.random() * enemyTypes.length)];
    game.enemies.push({
        x: Math.random() * canvas.width,
        y: -50,
        width: 40,
        height: 40,
        speed: type === 'fast' ? 5 : type === 'tank' ? 2 : 3,
        health: type === 'tank' ? 5 : 1,
        type
    });
}

// 敌人射击
function enemyShoot() {
    game.enemies.forEach(enemy => {
        if (Math.random() < 0.02) {
            game.enemyBullets.push({
                x: enemy.x,
                y: enemy.y + enemy.height / 2,
                speed: 5
            });
        }
    });
}

// 碰撞检测
function checkCollisions() {
    // 玩家子弹击中敌人
    game.bullets.forEach((bullet, bIndex) => {
        game.enemies.forEach((enemy, eIndex) => {
            if (bullet.x > enemy.x - enemy.width / 2 &&
                bullet.x < enemy.x + enemy.width / 2 &&
                bullet.y > enemy.y - enemy.height / 2 &&
                bullet.y < enemy.y + enemy.height / 2) {
                game.score += 10;
                game.bullets.splice(bIndex, 1);
                enemy.health -= 1;
                if (enemy.health <= 0) {
                    game.enemies.splice(eIndex, 1);
                }
            }
        });
    });

    // 敌人子弹击中玩家
    game.enemyBullets.forEach((bullet, index) => {
        if (bullet.x > game.player.x - game.player.width / 2 &&
            bullet.x < game.player.x + game.player.width / 2 &&
            bullet.y > game.player.y - game.player.height / 2 &&
            bullet.y < game.player.y + game.player.height / 2) {
            game.player.health -= 10;
            game.enemyBullets.splice(index, 1);
            if (game.player.health <= 0) {
                gameOver();
            }
        }
    });
}

// 更新关卡
function updateLevel() {
    if (game.score >= game.level * 1000) {
        game.level++;
    }
}

// 游戏主循环
function gameLoop() {
    if (!game.running) return;

    // 更新游戏状态
    updateGame();

    // 绘制游戏元素
    drawBackground();
    drawPlayer();
    drawBullets();
    drawEnemies();
    drawUI();

    requestAnimationFrame(gameLoop);
}

// 更新游戏状态
function updateGame() {
    // 更新星星位置
    game.stars.forEach(star => {
        star.y += 2;
        if (star.y > canvas.height) {
            star.y = 0;
            star.x = Math.random() * canvas.width;
        }
    });

    // 更新子弹位置
    game.bullets.forEach(bullet => bullet.y -= 10);
    game.bullets = game.bullets.filter(bullet => bullet.y > 0);

    // 更新敌人子弹位置
    game.enemyBullets.forEach(bullet => bullet.y += bullet.speed);
    game.enemyBullets = game.enemyBullets.filter(bullet => bullet.y < canvas.height);

    // 更新敌人位置
    game.enemies.forEach(enemy => enemy.y += enemy.speed);
    game.enemies = game.enemies.filter(enemy => enemy.y < canvas.height + 50);

    // 生成敌人
    if (Math.random() < 0.03) {
        createEnemy();
    }

    // 敌人射击
    enemyShoot();

    // 碰撞检测
    checkCollisions();

    // 更新关卡
    updateLevel();
}

// 绘制UI
function drawUI() {
    ui.innerHTML = `
        <div>分数: ${game.score}</div>
        <div>生命值: ${game.player.health}</div>
        <div>护盾: ${game.player.shield}</div>
        <div>武器: ${game.player.weapon}</div>
        <div>关卡: ${game.level}</div>
    `;
}

// 绘制子弹
function drawBullets() {
    ctx.fillStyle = "#ffdd57";
    game.bullets.forEach(bullet => {
        ctx.beginPath();
        ctx.arc(bullet.x, bullet.y, 5, 0, Math.PI * 2);
        ctx.fill();
    });

    ctx.fillStyle = "#e74c3c";
    game.enemyBullets.forEach(bullet => {
        ctx.beginPath();
        ctx.arc(bullet.x, bullet.y, 5, 0, Math.PI * 2);
        ctx.fill();
    });
}

// 绘制敌人
function drawEnemies() {
    ctx.fillStyle = "#e74c3c";
    game.enemies.forEach(enemy => {
        ctx.beginPath();
        ctx.ellipse(enemy.x, enemy.y, enemy.width / 2, enemy.height / 2, 0, 0, Math.PI * 2);
        ctx.fill();
    });
}

// 键盘控制
const keys = {};
window.addEventListener('keydown', e => keys[e.key] = true);
window.addEventListener('keyup', e => keys[e.key] = false);

// 玩家移动
function movePlayer() {
    if (keys['ArrowLeft'] && game.player.x > game.player.width / 2) {
        game.player.x -= game.player.speed;
    }
    if (keys['ArrowRight'] && game.player.x < canvas.width - game.player.width / 2) {
        game.player.x += game.player.speed;
    }
    if (keys[' '] && game.player.canShoot) {
        game.bullets.push({ x: game.player.x, y: game.player.y });
        game.player.canShoot = false;
        setTimeout(() => game.player.canShoot = true, 200);
    }
}

// 运行游戏
setInterval(movePlayer, 1000 / 60);
showHighScores();
</script>
</body>
</html>

在这里插入图片描述

五、扩展方向

  1. 添加BOSS战系统
  2. 实现武器升级机制
  3. 加入粒子爆炸特效
  4. 添加背景音乐和音效

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