Dodge the Blocks HTML Game - Simple and Fun - 常规

<html>
<head>
  <title>Dodge the Blocks</title>
  <script>
    // Get the canvas element
    var canvas = document.getElementById('gameCanvas');
    canvas.width = 500;
    canvas.height = 300;
<pre><code>// Set up the game context
var ctx = canvas.getContext('2d');
var x = canvas.width/2;
var y = canvas.height-30;
var ballRadius = 10;
var dx = 2;
var dy = -2;
var paddleHeight = 10;
var paddleWidth = 75;
var paddleX = (canvas.width-paddleWidth)/2;
var rightPressed = false;
var leftPressed = false;
var brickRowCount = 3;
var brickColumnCount = 5;
var brickWidth = 75;
var brickHeight = 20;
var brickPadding = 10;
var brickOffsetTop = 30;
var brickOffsetLeft = 30;
var score = 0;
var lives = 3;

// Create the bricks
var bricks = [];
for(var c=0; c&lt;brickColumnCount; c++) {
    bricks[c] = [];
    for(var r=0; r&lt;brickRowCount; r++) {
        bricks[c][r] = { x: 0, y: 0, status: 1 };
    }
}

// Draw the bricks
function drawBricks() {
    for(var c=0; c&lt;brickColumnCount; c++) {
        for(var r=0; r&lt;brickRowCount; r++) {
            if(bricks[c][r].status == 1) {
                var brickX = (c*(brickWidth+brickPadding))+brickOffsetLeft;
                var brickY = (r*(brickHeight+brickPadding))+brickOffsetTop;
                bricks[c][r].x = brickX;
                bricks[c][r].y = brickY;
                ctx.beginPath();
                ctx.rect(brickX, brickY, brickWidth, brickHeight);
                ctx.fillStyle = '#0095DD';
                ctx.fill();
                ctx.closePath();
            }
        }
    }
}

// Draw the ball
function drawBall() {
    ctx.beginPath();
    ctx.arc(x, y, ballRadius, 0, Math.PI*2);
    ctx.fillStyle = '#0095DD';
    ctx.fill();
    ctx.closePath();
}

// Draw the paddle
function drawPaddle() {
    ctx.beginPath();
    ctx.rect(paddleX, canvas.height-paddleHeight, paddleWidth, paddleHeight);
    ctx.fillStyle = '#0095DD';
    ctx.fill();
    ctx.closePath();
}

// Handle keyboard input
document.addEventListener('keydown', keyDownHandler, false);
document.addEventListener('keyup', keyUpHandler, false);
function keyDownHandler(e) {
    if(e.keyCode == 39) {
        rightPressed = true;
    }
    else if(e.keyCode == 37) {
        leftPressed = true;
    }
}
function keyUpHandler(e) {
    if(e.keyCode == 39) {
        rightPressed = false;
    }
    else if(e.keyCode == 37) {
        leftPressed = false;
    }
}

// Collision detection
function collisionDetection() {
    for(var c=0; c&lt;brickColumnCount; c++) {
        for(var r=0; r&lt;brickRowCount; r++) {
            var b = bricks[c][r];
            if(b.status == 1) {
                if(x &gt; b.x &amp;&amp; x &lt; b.x+brickWidth &amp;&amp; y &gt; b.y &amp;&amp; y &lt; b.y+brickHeight) {
                    dy = -dy;
                    b.status = 0;
                    score++;
                    if(score == brickRowCount*brickColumnCount) {
                        alert('YOU WIN, CONGRATULATIONS!');
                        document.location.reload();
                    }
                }
            }
        }
    }
}

// Draw the score
function drawScore() {
    ctx.font = '16px Arial';
    ctx.fillStyle = '#0095DD';
    ctx.fillText('Score: '+score, 8, 20);
}

// Draw the lives
function drawLives() {
    ctx.font = '16px Arial';
    ctx.fillStyle = '#0095DD';
    ctx.fillText('Lives: '+lives, canvas.width-65, 20);
}

// Draw the game
function draw() {
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    drawBricks();
    drawBall();
    drawPaddle();
    drawScore();
    drawLives();
    collisionDetection();
    
    // Bounce the ball off the walls
    if(x + dx &gt; canvas.width-ballRadius || x + dx &lt; ballRadius) {
        dx = -dx;
    }
    if(y + dy &lt; ballRadius) {
        dy = -dy;
    }
    else if(y + dy &gt; canvas.height-ballRadius) {
        if(x &gt; paddleX &amp;&amp; x &lt; paddleX + paddleWidth) {
            dy = -dy;
        }
        else {
            lives--;
            if(!lives) {
                alert('GAME OVER');
                document.location.reload();
            }
            else {
                x = canvas.width/2;
                y = canvas.height-30;
                dx = 2;
                dy = -2;
                paddleX = (canvas.width-paddleWidth)/2;
            }
        }
    }
    
    // Move the paddle
    if(rightPressed &amp;&amp; paddleX &lt; canvas.width-paddleWidth) {
        paddleX += 7;
    }
    else if(leftPressed &amp;&amp; paddleX &gt; 0) {
        paddleX -= 7;
    }
    
    x += dx;
    y += dy;
    requestAnimationFrame(draw);
}

draw();
</code></pre>
  </script>
</head>
<body>
  <canvas id="gameCanvas" width="500" height="300"></canvas>
</body>
</html>