1

黄思齐是你爹

const canvas = document.getElementById("gameCanvas");
const context = canvas.getContext("2d");
const startButton = document.getElementById("startButton");

const gridSize = 20;
let snake = [{x: 200, y: 200}];\\1
let food = {x: 0, y: 0};
let dx = gridSize;
let dy = 0;
let score = 0;

\\....2
function drawSnake() {
    context.clearRect(0, 0, canvas.width, canvas.height);
    snake.forEach(part => {
        context.fillStyle = "green";
        context.fillRect(part.x, part.y, gridSize, gridSize);
    });
}

function generateFood() {
    food.x = Math.floor(Math.random() * canvas.width / gridSize) * gridSize;
    food.y = Math.floor(Math.random() * canvas.height / gridSize) * gridSize;
}

function drawFood() {
    context.fillStyle = "red";
    context.fillRect(food.x, food.y, gridSize, gridSize);
}

function moveSnake() {
    const head = {x: snake[0].x + dx, y: snake[0].y + dy};
    snake.unshift(head);
    if (head.x === food.x && head.y === food.y) {
        score++;
        generateFood();
    } else {
        snake.pop();
    }
}

function changeDirection(event) {
    const keyPressed = event.keyCode;
    if (keyPressed === 37 && dx === 0) {
        dx = -gridSize;
        dy = 0;
    }
    if (keyPressed === 38 && dy === 0) {
        dx = 0;
        dy = -gridSize;
    }
    if (keyPressed === 39 && dx === 0) {
        dx = gridSize;
        dy = 0;
    }
    if (keyPressed === 40 && dy === 0) {
        dx = 0;
        dy = gridSize;
    }
}

function gameLoop() {
    moveSnake();
    drawSnake();
    drawFood();
    if (snake[0].x < 0 || snake[0].x >= canvas.width || snake[0].y < 0 || snake[0].y >= canvas.height) {
        clearInterval(game);
        alert("Game Over! Your score is " + score);
    }
}

startButton.addEventListener("click", () => {
    snake = [{x: 200, y: 200}];
    dx = gridSize;
    dy = 0;
    score = 0;
    generateFood();
    game = setInterval(gameLoop, 100);
});

document.addEventListener("keydown", changeDirection);
帮我在上面的代码中 的移动键改为WASD

kaia

好的！我来帮你把控制蛇移动的键从方向键改成W、A、S、D键哦～

你原来的`changeDirection`函数里，是用的上(38)、下(40)、左(37)、右(39)这些方向键的代码。我们要改成W(87)、A(65)、S(83)、D(68)。

修改后的 `changeDirection` 函数如下：

1. function changeDirection(event) {
   
2.     const keyPressed = event.keyCode;
   
3.     if (keyPressed === 65 && dx === 0) { // A - 向左移动
   
4.         dx = -gridSize;
   
5.         dy = 0;
   
6.     }
   
7.     if (keyPressed === 87 && dy === 0) { // W - 向上移动
   
8.         dx = 0;
   
9.         dy = -gridSize;
   
10.     }
    
11.     if (keyPressed === 68 && dx === 0) { // D - 向右移动
    
12.         dx = gridSize;
    
13.         dy = 0;
    
14.     }
    
15.     if (keyPressed === 83 && dy === 0) { // S - 向下移动
    
16.         dx = 0;
    
17.         dy = gridSize;
    
18.     }
    
19. }

复制代码

这样一来，当你按下W/A/S/D键，蛇就会往对应的方向走啦！

---

**小贴士**：  
- `keyCode` 是浏览器给每个键盘键指定的数字，比如A是65，W是87。  
- `dx` 和 `dy` 代表蛇往水平方向和垂直方向移动的距离。  
- `gridSize` 是每次移动的步长。

如果还有什么不懂，随时问我哦！????????