<!DOCTYPE html>
<html>
<head>
<title></title>
<style>
html, body {
height: 100%;
margin: 0;
}
body {
background: black;
display: flex;
align-items: center;
justify-content: center;
}
</style>
</head>
<body>
<canvas width="400" height="500" id="game"></canvas>
<script>
const canvas = document.getElementById('game');
const context = canvas.getContext('2d');
// each row is 14 bricks long. the level consists of 6 blank rows then 8 rows
// of 4 colors: red, orange, green, and yellow
const level1 = [
[],
[],
[],
[],
[],
[],
['R','R','R','R','R','R','R','R','R','R','R','R','R','R'],
['R','R','R','R','R','R','R','R','R','R','R','R','R','R'],
['O','O','O','O','O','O','O','O','O','O','O','O','O','O'],
['O','O','O','O','O','O','O','O','O','O','O','O','O','O'],
['G','G','G','G','G','G','G','G','G','G','G','G','G','G'],
['G','G','G','G','G','G','G','G','G','G','G','G','G','G'],
['Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y'],
['Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y']
];
// create a mapping between color short code (R, O, G, Y) and color name
const colorMap = {
'R': 'red',
'O': 'orange',
'G': 'green',
'Y': 'yellow'
};
// use a 2px gap between each brick
const brickGap = 2;
const brickWidth = 25;
const brickHeight = 12;
// the wall width takes up the remaining space of the canvas width. with 14 bricks
// and 13 2px gaps between them, thats: 400 - (14 * 25 + 2 * 13) = 24px. so each
// wall will be 12px
const wallSize = 12;
const bricks = [];
// create the level by looping over each row and column in the level1 array
// and creating an object with the bricks position (x, y) and color
for (let row = 0; row < level1.length; row++) {
for (let col = 0; col < level1[row].length; col++) {
const colorCode = level1[row][col];
bricks.push({
x: wallSize + (brickWidth + brickGap) * col,
y: wallSize + (brickHeight + brickGap) * row,
color: colorMap[colorCode],
width: brickWidth,
height: brickHeight
});
}
}
const paddle = {
// place the paddle horizontally in the middle of the screen
x: canvas.width / 2 - brickWidth / 2,
y: 440,
width: brickWidth,
height: brickHeight,
// paddle x velocity
dx: 0
};
const ball = {
x: 30,
y: 260,
width: 10,
height: 10,
// how fast the ball should go in either the x or y direction
speed: 1.5,
// ball velocity
dx: 0,
dy: 0
};
// check for collision between two objects using axis-aligned bounding box (AABB)
// @see https://developer.mozilla.org/en-US/docs/Games/Techniques/2D_collision_detection
function collides(obj1, obj2) {
return obj1.x < obj2.x + obj2.width &&
obj1.x + obj1.width > obj2.x &&
obj1.y < obj2.y + obj2.height &&
obj1.y + obj1.height > obj2.y;
}
// game loop
function loop() {
requestAnimationFrame(loop);
context.clearRect(0,0,canvas.width,canvas.height);
// move paddle by it's velocity
paddle.x += paddle.dx;
// prevent paddle from going through walls
if (paddle.x < wallSize) {
paddle.x = wallSize
}
else if (paddle.x + brickWidth > canvas.width - wallSize) {
paddle.x = canvas.width - wallSize - brickWidth;
}
// move ball by it's velocity
ball.x += ball.dx;
ball.y += ball.dy;
// prevent ball from going through walls by changing its velocity
// left & right walls
if (ball.x < wallSize) {
ball.x = wallSize;
ball.dx *= -1;
}
else if (ball.x + ball.width > canvas.width - wallSize) {
ball.x = canvas.width - wallSize - ball.width;
ball.dx *= -1;
}
// top wall
if (ball.y < wallSize) {
ball.y = wallSize;
ball.dy *= -1;
}
// reset ball if it goes below the screen
if (ball.y > canvas.height) {
ball.x = 230;
ball.y = 460;
ball.dx = 0;
ball.dy = 0;
}
// check to see if ball collides with paddle. if they do change y velocity
if (collides(ball, paddle)) {
ball.dy *= -1;
// move ball above the paddle otherwise the collision will happen again
// in the next frame
ball.y = paddle.y - ball.height;
}
// check to see if ball collides with a brick. if it does, remove the brick
// and change the ball velocity based on the side the brick was hit on
for (let i = 0; i < bricks.length; i++) {
const brick = bricks[i];
if (collides(ball, brick)) {
// remove brick from the bricks array
bricks.splice(i, 1);
// ball is above or below the brick, change y velocity
// account for the balls speed since it will be inside the brick when it
// collides
if (ball.y + ball.height - ball.speed <= brick.y ||
ball.y >= brick.y + brick.height - ball.speed) {
ball.dy *= -1;
}
// ball is on either side of the brick, change x velocity
else {
ball.dx *= -1;
}
break;
}
}
// draw walls
context.fillStyle = 'lightgrey';
context.fillRect(0, 0, canvas.width, wallSize);
context.fillRect(0, 0, wallSize, canvas.height);
context.fillRect(canvas.width - wallSize, 0, wallSize, canvas.height);
// draw ball if it's moving
if (ball.dx || ball.dy) {
context.fillRect(ball.x, ball.y, ball.width, ball.height);
}
// draw bricks
bricks.forEach(function(brick) {
context.fillStyle = brick.color;
context.fillRect(brick.x, brick.y, brick.width, brick.height);
});
// draw paddle
context.fillStyle = 'cyan';
context.fillRect(paddle.x, paddle.y, paddle.width, paddle.height);
}
// listen to keyboard events to move the paddle
document.addEventListener('keydown', function(e) {
// left arrow key
if (e.which === 37) {
paddle.dx = -3;
}
// right arrow key
else if (e.which === 39) {
paddle.dx = 3;
}
// space key
// if they ball is not moving, we can launch the ball using the space key. ball
// will move towards the bottom right to start
if (ball.dx === 0 && ball.dy === 0 && e.which === 32) {
ball.dx = ball.speed;
ball.dy = ball.speed;
}
});
// listen to keyboard events to stop the paddle if key is released
document.addEventListener('keyup', function(e) {
if (e.which === 37 || e.which === 39) {
paddle.dx = 0;
}
});
// start the game
requestAnimationFrame(loop);
</script>
</body>
</html>
Laxman Nepal
Laxman Nepal is a multi-talented individual with expertise in computer teaching, blogging, video editing, and more. With years of experience in his field, Laxman has established himself as a reliable source of knowledge and insight. He is enthusiastic about sharing his expertise with the world, and his work has been recognized by various organizations. Through his informative blog posts and engaging videos, Laxman aims to inspire and educate his readers and viewers. Join me as we explore the world of technology and education with Laxman Nepal!