I've been making a simple game just with the HTML5 canvas and plain JavaScript. Most recently I tried adding a feature to shoot bullets which would then destroy obstacles but I've come upon a problem. Whenever you shoot a bullet it doesn't move until another is shot. Even when it starts moving and collides with one of the obstacles nothing happens. I've done some troubleshooting and I can't seem to get to the bottom of it. Any help and/or suggestions would be greatly appreciated.
Collision handling code:
for(var i = 0; i < this.bullets.length - 1; i++) { // -1 is present because whenever I remove it I get an error. I have a feeling this may be related to the order of how everything updates, will be fixed
this.bullets[i].x += this.bullets[i].speed;
if(this.bullets[i].x > cvs.width) {
this.bullets.splice(i, 1);
}
for(var j = 0; j < obstacles.length - 1; j++) { // Same here
if(rectanglesColliding(this.bullets[i], obstacles[j])) {
console.log("Collision");
}
}
}
Full player object:
var player = {
score: 0,
x: 50,
y: 150,
radius: 10,
jumping: false,
bullets: [],
velocityX: 0,
velocityY: 1,
angle: 90,
update: function() {
this.draw();
this.score++;
if(this.y + this.radius + 2 > cvs.height - 50 && this.jumping === false || this.y - this.radius + 2 < 0 + 50 && this.jumping === true) {
this.velocityY = 0;
} else if(this.jumping === false){
this.velocityY = 4;
} else {
this.velocityY = -4;
}
obstacles.forEach((obstacle) => {
if(colliding(this, obstacle)) {
gameEnded = true;
}
});
this.x += this.velocityX;
this.y += this.velocityY;
for(var i = 0; i < this.bullets.length - 1; i++) { // -1 is present because whenever I remove it I get an error. I have a feeling this may be related to the order of how everything updates, will be fixed
this.bullets[i].x += this.bullets[i].speed;
if(this.bullets[i].x > cvs.width) {
this.bullets.splice(i, 1);
}
for(var j = 0; j < obstacles.length - 1; j++) { // Same here
if(rectanglesColliding(this.bullets[i], obstacles[j])) {
console.log("Collision");
}
}
}
},
draw: function() {
this.bullets.forEach((bullet) => {
ctx.fillStyle = 'green';
ctx.fillRect(bullet.x, bullet.y, 7, 2);
});
ctx.fillStyle = 'blue';
ctx.beginPath();
ctx.arc(this.x, this.y, this.radius, 0, 2 * Math.PI);
ctx.fill();
}
};
Collision Detection Function:
function rectanglesColliding(rect1, rect2) {
if(rect1.x < rect2.x + rect2.width &&
rect1.x + rect1.width > rect2.x && // Found on Mozilla.com: https://developer.mozilla.org/en-US/docs/Games/Techniques/2D_collision_detection
rect1.y < rect2.y + rect2.height &&
rect1.y + rect1.height > rect2.y) return true;
else return false;
}
Shoot Function:
function shoot() {
player.bullets.push({ x: player.x + 10, y: player.y, speed: 6 });
}
Object of the game: Survive as long as you can by avoiding the obstacles.
Controls: Space: Go up W: Shoot Bullet
Full code snippet:
var cvs = document.getElementById('canvas');
var ctx = cvs.getContext("2d");
var gameEnded = false;
var player = {
score: 0,
x: 50,
y: 150,
radius: 10,
jumping: false,
bullets: [],
velocityX: 0,
velocityY: 1,
angle: 90,
update: function() {
this.draw();
this.score++;
if(this.y + this.radius + 2 > cvs.height - 50 && this.jumping === false || this.y - this.radius + 2 < 0 + 50 && this.jumping === true) {
this.velocityY = 0;
} else if(this.jumping === false){
this.velocityY = 4;
} else {
this.velocityY = -4;
}
obstacles.forEach((obstacle) => {
if(colliding(this, obstacle)) {
gameEnded = true;
}
});
this.x += this.velocityX;
this.y += this.velocityY;
for(var i = 0; i < this.bullets.length - 1; i++) {
this.bullets[i].x += this.bullets[i].speed;
if(this.bullets[i].x > cvs.width) {
this.bullets.splice(i, 1);
}
for(var j = 0; j < obstacles.length - 1; j++) {
if(rectanglesColliding(this.bullets[i], obstacles[j])) {
console.log("Collision");
// obstacles.splice(i, 1);
}
}
}
},
draw: function() {
this.bullets.forEach((bullet) => {
ctx.fillStyle = 'green';
ctx.fillRect(bullet.x, bullet.y, 7, 2);
});
ctx.fillStyle = 'blue';
ctx.beginPath();
ctx.arc(this.x, this.y, this.radius, 0, 2 * Math.PI);
ctx.fill();
}
};
var obstacles = [{ x: 150, y: 60, width: 10, height: 20 }];
document.addEventListener('keydown', (event) => {
if(event.key === ' ') {
player.jumping = true;
}
if(event.key === 'w') {
shoot();
}
});
document.addEventListener('keyup', (event) => {
if(event.key === ' ') {
player.jumping = false;
}
});
function randomIntFromRange(min, max) {
return Math.floor(Math.random() * (max - min + 1) + min);
}
function getWidth() {
return Math.max(
document.body.scrollWidth,
document.documentElement.scrollWidth,
document.body.offsetWidth,
document.documentElement.offsetWidth,
document.documentElement.clientWidth
);
}
function getHeight() {
return Math.max(
document.body.scrollHeight,
document.documentElement.scrollHeight,
document.body.offsetHeight,
document.documentElement.offsetHeight,
document.documentElement.clientHeight
);
}
function colliding(circle, rect) {
var distX = Math.abs(circle.x - rect.x - rect.width / 2);
var distY = Math.abs(circle.y - rect.y - rect.height / 2);
if(distX > (rect.width / 2 + circle.radius)) return false;
if(distY > (rect.height / 2 + circle.radius)) return false;
if(distX <= (rect.width / 2)) return true;
if(distY <= (rect.height / 2)) return true;
}
function rectanglesColliding(rect1, rect2) {
if(rect1.x < rect2.x + rect2.width &&
rect1.x + rect1.width > rect2.x &&
rect1.y < rect2.y + rect2.height &&
rect1.y + rect1.height > rect2.y) {
return true;
}
}
function distance(x1, y1, x2, y2) {
const xDist = x2 - x1;
const yDist = y2 - y1;
return Math.sqrt(Math.pow(xDist, 2) + Math.pow(yDist, 2));
}
function shoot() {
player.bullets.push({ x: player.x + 10, y: player.y, speed: 6 });
}
function generateObstacle() {
var obstacle = {
x: obstacles[0].x + randomIntFromRange(cvs.width - 100, cvs.width + 70),
y: 0 + randomIntFromRange(20, 550),
width: randomIntFromRange(25, 35),
height: randomIntFromRange(10, 25)
};
for(var i = 0; i < obstacles.length; i++) {
if(distance(obstacle.x, obstacle.y, obstacles[i].x, obstacles[i].y) < 65) {
obstacle = {
x: obstacles[0].x + randomIntFromRange(cvs.width - 100, cvs.width + 70),
y: 0 + randomIntFromRange(20, 550),
width: randomIntFromRange(25, 35),
height: randomIntFromRange(10, 25)
};
i = -1;
}
}
obstacles.push({ x: obstacle.x, y: obstacle.y, width: obstacle.width, height: obstacle.height });
}
function removeBadObstacles() {
for(var i = 0; i < obstacles.length; i++) {
if(obstacles[i].x < 0) {
obstacles.splice(i, 1);
}
}
}
function updateObstacles() {
if(obstacles[obstacles.length - 1].x < cvs.width + 5) {
generateObstacle();
generateObstacle();
}
obstacles.forEach((obstacle) => {
obstacle.x -= 10;
ctx.fillStyle = 'red';
ctx.fillRect(obstacle.x, obstacle.y, obstacle.width, obstacle.height);
});
}
function init() {
cvs.width = getWidth();
cvs.height = getHeight();
update();
}
function update() {
if(gameEnded) {
ctx.font = '50px Verdana';
return ctx.fillText('Game Over', 110, cvs.height / 2);
}
requestAnimationFrame(update);
removeBadObstacles();
ctx.fillStyle = 'black';
ctx.fillRect(0, 0, cvs.width, cvs.height);
updateObstacles();
player.update();
ctx.font = '30px Impact';
ctx.fillText("Score: " + player.score, 20, 40);
}
init();<!DOCTYPE html>
<html>
<head>
<title>Game</title>
</head>
<body>
<canvas id="canvas"></canvas>
<script type="text/javascript" src="./JS/main.js"></script>
</body>
</html>
i < this.bullets.length2. your bullet object has nowidth. – apple apple