204 lines
4.6 KiB
HTML
204 lines
4.6 KiB
HTML
<!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="565" height="500" id="game"></canvas>
|
|
<script>
|
|
const canvas = document.getElementById('game');
|
|
const context = canvas.getContext('2d');
|
|
const grid = 15;
|
|
const playerHeight = grid * 3; // 45
|
|
const maxPlayerY = canvas.height - grid - playerHeight;
|
|
|
|
var playerSpeed = 4;
|
|
|
|
const leftPlayer = {
|
|
// start in the middle of the game on the left side
|
|
x: grid * 2,
|
|
y: canvas.height / 2 - playerHeight / 2,
|
|
width: grid,
|
|
height: playerHeight,
|
|
|
|
// shooting cooldown
|
|
cooldown: 0,
|
|
|
|
// player velocity
|
|
dy: 0
|
|
};
|
|
|
|
const rightPlayer = {
|
|
// start in the middle of the game on the right side
|
|
x: canvas.width - grid * 3,
|
|
y: canvas.height / 2 - playerHeight / 2,
|
|
width: grid,
|
|
height: playerHeight,
|
|
|
|
// shooting cooldown
|
|
cooldown: 0,
|
|
|
|
// player velocity
|
|
dy: 0
|
|
};
|
|
|
|
const bullets = {
|
|
speed: 5,
|
|
array: []
|
|
}
|
|
|
|
// 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);
|
|
|
|
// bullet cooldowns
|
|
// left player
|
|
if (leftPlayer.cooldown > 0) {
|
|
leftPlayer.cooldown--;
|
|
}
|
|
// right player
|
|
if (rightPlayer.cooldown > 0) {
|
|
rightPlayer.cooldown--;
|
|
}
|
|
|
|
// move players by their velocity
|
|
leftPlayer.y += leftPlayer.dy;
|
|
rightPlayer.y += rightPlayer.dy;
|
|
|
|
// prevent players from going through walls
|
|
if (leftPlayer.y < grid) {
|
|
leftPlayer.y = grid;
|
|
}
|
|
else if (leftPlayer.y > maxPlayerY) {
|
|
leftPlayer.y = maxPlayerY;
|
|
}
|
|
|
|
if (rightPlayer.y < grid) {
|
|
rightPlayer.y = grid;
|
|
}
|
|
else if (rightPlayer.y > maxPlayerY) {
|
|
rightPlayer.y = maxPlayerY;
|
|
}
|
|
|
|
// draw bullets
|
|
context.fillStyle = 'yellow';
|
|
bullets.array.forEach(function(bullet, index) {
|
|
context.fillRect(bullet.x, bullet.y, 10, 5);
|
|
|
|
// check if the bullet hits a player
|
|
// left player
|
|
if (collides(bullet, leftPlayer)) {
|
|
bullets.array.splice(index, 1);
|
|
leftPlayer.y = canvas.height / 2 - playerHeight / 2;
|
|
rightPlayer.y = canvas.height / 2 - playerHeight / 2;
|
|
bullets.array.length = 0;
|
|
}
|
|
// right player
|
|
else if (collides(bullet, rightPlayer)) {
|
|
bullets.array.splice(index, 1);
|
|
leftPlayer.y = canvas.height / 2 - playerHeight / 2;
|
|
rightPlayer.y = canvas.height / 2 - playerHeight / 2;
|
|
bullets.array.length = 0;
|
|
}
|
|
|
|
// move bullets
|
|
bullet.x += bullet.dx;
|
|
|
|
// remove bullets that leave the screen
|
|
if (bullet.x < 0 || bullet.x > canvas.width) {
|
|
bullets.array.splice(index, 1);
|
|
}
|
|
});
|
|
|
|
// draw paddles
|
|
context.fillStyle = 'gold';
|
|
context.fillRect(leftPlayer.x, leftPlayer.y, leftPlayer.width, leftPlayer.height);
|
|
context.fillRect(rightPlayer.x, rightPlayer.y, rightPlayer.width, rightPlayer.height);
|
|
|
|
// draw walls
|
|
context.fillStyle = 'lightgray';
|
|
context.fillRect(0, 0, canvas.width, grid);
|
|
context.fillRect(0, canvas.height - grid, canvas.width, canvas.height);
|
|
}
|
|
|
|
// listen to keyboard events to move the players
|
|
document.addEventListener('keydown', function(e) {
|
|
// up arrow key
|
|
if (e.which === 38) {
|
|
rightPlayer.dy = -playerSpeed;
|
|
}
|
|
// down arrow key
|
|
else if (e.which === 40) {
|
|
rightPlayer.dy = playerSpeed;
|
|
}
|
|
|
|
// w key
|
|
if (e.which === 87) {
|
|
leftPlayer.dy = -playerSpeed;
|
|
}
|
|
// a key
|
|
else if (e.which === 83) {
|
|
leftPlayer.dy = playerSpeed;
|
|
}
|
|
|
|
// shooting
|
|
// left arrow key
|
|
if (e.which === 37 && rightPlayer.cooldown === 0) {
|
|
bullets.array.push({
|
|
x: rightPlayer.x - 10,
|
|
y: rightPlayer.y + 20,
|
|
width: 10,
|
|
height: 5,
|
|
dx: -bullets.speed
|
|
});
|
|
rightPlayer.cooldown = 25;
|
|
}
|
|
// d key
|
|
if (e.which === 68 && leftPlayer.cooldown === 0) {
|
|
bullets.array.push({
|
|
x: leftPlayer.x + 15,
|
|
y: leftPlayer.y + 20,
|
|
width: 10,
|
|
height: 5,
|
|
dx: bullets.speed
|
|
});
|
|
leftPlayer.cooldown = 25;
|
|
}
|
|
});
|
|
// listen to keyboard events to stop the player if key is released
|
|
document.addEventListener('keyup', function(e) {
|
|
if (e.which === 38 || e.which === 40) {
|
|
rightPlayer.dy = 0;
|
|
}
|
|
|
|
if (e.which === 83 || e.which === 87) {
|
|
leftPlayer.dy = 0;
|
|
}
|
|
});
|
|
// start the game
|
|
requestAnimationFrame(loop);
|
|
</script>
|
|
</body>
|
|
</html> |