I am making a clone of agar.io and I am stuck in my code. I can't understand why my camera's position is not correctly calculated. I want my camera's position to half the vector between the farthest blob and the closest blob.
Below is a picture and my code:
<html>
<head>
<title>Play Agario Clone</title>
<style>
body {
margin: 0;
padding: 0;
}
</style>
</head>
<body>
<canvas id="game">
kindly update your browser.
</canvas>
<script>
var
canvas,
ctx,
width = innerWidth,
height = innerHeight,
mouseX = 0,
mouseY = 0;
var
camera = {
x: 0,
y: 0,
// camera
update: function(obj) {
var farthestBlobX = Math.max.apply(0, obj.blobs.map(function(cell) { return cell.x }));
var farthestBlobY = Math.max.apply(0, obj.blobs.map(function(cell) { return cell.y }));
var closestBlobX = Math.min.apply(0, obj.blobs.map(function(cell) { return cell.x }));
var closestBlobY = Math.min.apply(0, obj.blobs.map(function(cell) { return cell.y }));
var x = farthestBlobX - closestBlobX;
var y = farthestBlobY - closestBlobY;
var length = Math.sqrt(x * x + y * y);
this.x = length/2 - width/2;
this.y = length/2 - height/2;
}
},
player = {
defaultMass: 54,
x: 0,
y: 0,
blobs: [],
update: function () {
for (var i = 0; i < this.blobs.length; i ++) {
var x = mouseX + camera.x - this.blobs[i].x;
var y = mouseY + camera.y - this.blobs[i].y;
var length = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
var speed = 54/this.blobs[i].mass;
this.blobs[i].velX = x/length * speed * Math.min(1, Math.pow(x / this.blobs[i].mass, 2));
this.blobs[i].velY = y/length * speed * Math.min(1, Math.pow(x / this.blobs[i].mass, 2));
this.blobs[i].x += this.blobs[i].velX;
this.blobs[i].y += this.blobs[i].velY;
for (var j = 0; j < this.blobs.length; j ++) {
if (j != i && this.blobs[i] !== undefined) {
var blob1 = this.blobs[i];
var blob2 = this.blobs[j];
var x = blob2.x - blob1.x;
var y = blob2.y - blob1.y;
var dist = Math.sqrt(x * x + y * y);
if (dist < blob1.mass + blob2.mass) {
x /= dist;
y /= dist;
blob1.x = blob2.x - x * (blob1.mass + blob2.mass);
blob1.y = blob2.y - y * (blob1.mass + blob2.mass);
}
}
}
}
this.x += (mouseX - width/2)/(width/2) * 1;
this.y += (mouseY - height/2)/(height/2) * 1
},
split: function (cell) {
cell.mass /= 2;
this.blobs.push({
x: cell.x,
y: cell.y,
mass: cell.mass
});
},
draw: function () {
for (var i = 0; i < this.blobs.length; i ++) {
ctx.fillStyle = "red";
ctx.beginPath();
ctx.arc(-camera.x + this.blobs[i].x, -camera.y + this.blobs[i].y, this.blobs[i].mass, 0, Math.PI*2);
ctx.fill();
ctx.closePath();
}
}
};
function handleMouseMove (e) {
mouseX = e.clientX;
mouseY = e.clientY;
}
function setup () {
canvas = document.getElementById("game");
ctx = canvas.getContext("2d");
canvas.width = width;
canvas.height = height;
addEventListener("mousemove", handleMouseMove);
player.blobs.push({
x: 0,
y: 0,
mass: player.defaultMass
});
player.blobs.push({
x: 100,
y: 100,
mass: player.defaultMass/2
});
player.blobs.push({
x: 100,
y: 100,
mass: player.defaultMass*2
});
var loop = function () {
update();
draw();
requestAnimationFrame(loop);
}
requestAnimationFrame(loop);
}
function update () {
camera.update(player);
player.update();
}
function draw () {
ctx.fillStyle = "#fff";
ctx.fillRect(0, 0, width, height);
player.draw();
}
setup();
</script>
</body>
</html>
Instead of computing everything relative to your camera, use your camera to set the global transformation matrix of your canvas, and only for this.
This way, your blobs' updates will be cleaner, and your camera easier to manage.
Now to get the middle position between two points, do (pt1 + pt2) / 2.
You were not clear in your question, if fartherstX and fartherstY should represent the same blob. In your code it wasn't, so I didn't change it.
Also, I didn't gone into all your logics, but beware NaN values, I got some while doing the edit.
function draw() {
var cw = ctx.canvas.width / 2;
var ch = ctx.canvas.height / 2;
// reset transform to clear the canvas
ctx.setTransform(1, 0, 0, 1, 0, 0);
ctx.fillStyle = "#fff";
ctx.fillRect(0, 0, width, height);
// here we really set the camera position
ctx.setTransform(1, 0, 0, 1, -camera.x + cw, -camera.y + ch);
ctx.strokeRect(0, 0, width, height); // just to show the original area
player.draw();
}
var
canvas,
ctx,
width = innerWidth,
height = innerHeight,
mouseX = 0,
mouseY = 0;
var camera = {
x: 0,
y: 0,
// camera
update: function(obj) {
var farthestBlobX = Math.max.apply(0, obj.blobs.map(function(cell) {
return cell.x
}));
var farthestBlobY = Math.max.apply(0, obj.blobs.map(function(cell) {
return cell.y
}));
var closestBlobX = Math.min.apply(0, obj.blobs.map(function(cell) {
return cell.x
}));
var closestBlobY = Math.min.apply(0, obj.blobs.map(function(cell) {
return cell.y
}));
this.x = (closestBlobX + farthestBlobX) / 2 || 0;
this.y = (closestBlobY + farthestBlobY) / 2 || 0;
}
},
player = {
defaultMass: 54,
x: 0,
y: 0,
blobs: [],
update: function() {
for (var i = 0; i < this.blobs.length; i++) {
var x = mouseX - this.blobs[i].x || 0;
var y = mouseY - this.blobs[i].y || 0;
var length = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
var speed = 54 / this.blobs[i].mass;
this.blobs[i].velX = x / length * speed * Math.min(1, Math.pow(x / this.blobs[i].mass, 2));
this.blobs[i].velY = y / length * speed * Math.min(1, Math.pow(x / this.blobs[i].mass, 2));
this.blobs[i].x += this.blobs[i].velX;
this.blobs[i].y += this.blobs[i].velY;
for (var j = 0; j < this.blobs.length; j++) {
if (j != i && this.blobs[i] !== undefined) {
var blob1 = this.blobs[i];
var blob2 = this.blobs[j];
var x = blob2.x - blob1.x;
var y = blob2.y - blob1.y;
var dist = Math.sqrt(x * x + y * y);
if (dist < blob1.mass + blob2.mass) {
x /= dist;
y /= dist;
blob1.x = blob2.x - x * (blob1.mass + blob2.mass);
blob1.y = blob2.y - y * (blob1.mass + blob2.mass);
}
}
}
}
this.x += (mouseX - width / 2) / (width / 2) * 1;
this.y += (mouseY - height / 2) / (height / 2) * 1;
},
split: function(cell) {
cell.mass /= 2;
this.blobs.push({
x: cell.x,
y: cell.y,
mass: cell.mass
});
},
draw: function() {
for (var i = 0; i < this.blobs.length; i++) {
ctx.fillStyle = "red";
ctx.beginPath();
ctx.arc(this.blobs[i].x, this.blobs[i].y, this.blobs[i].mass, 0, Math.PI * 2);
ctx.fill();
ctx.closePath();
}
}
};
function handleMouseMove(e) {
mouseX = e.clientX;
mouseY = e.clientY;
}
function setup() {
canvas = document.getElementById("game");
ctx = canvas.getContext("2d");
canvas.width = width;
canvas.height = height;
addEventListener("mousemove", handleMouseMove);
player.blobs.push({
x: 10,
y: 10,
mass: player.defaultMass
});
player.blobs.push({
x: 100,
y: 100,
mass: player.defaultMass / 2
});
player.blobs.push({
x: 100,
y: 100,
mass: player.defaultMass * 2
});
var loop = function() {
update();
draw();
requestAnimationFrame(loop);
}
requestAnimationFrame(loop);
}
function update() {
camera.update(player);
player.update();
}
setup();
body {
margin: 0;
padding: 0;
}
<canvas id="game">kindly update your browser.</canvas>
I see there is an answer already..
var canvas;
var ctx;
var width = innerWidth;
var height = innerHeight;
var mouseX = 0;
var mouseY = 0;
const camera = {
x : 0,
y : 0,
update(obj) { // camera
this.x = (obj.blobsExtent.minx + obj.blobsExtent.maxx) / 2;
this.y = (obj.blobsExtent.miny + obj.blobsExtent.maxy) / 2;
this.x -= width / 2;
this.y -= height / 2;
}
};
const player = {
defaultMass : 54,
blobs : [],
blobsExtent : { // get the extent while updating the blobs save you having to iterate all the objects a second time to get extent
minx :0,
miny : 0,
maxx : 0,
maxy : 0,
},
update () {
var be = this.blobsExtent; // be for Blob Extent alias to save typing and make code easier to read
for (var i = 0; i < this.blobs.length; i++) {
var blob1 = this.blobs[i];
var x = mouseX - blob1.x;
var y = mouseY - blob1.y;
// to stop the divide by zero propigating NaN set length to 1 if less than 1
var length = Math.max(1,Math.sqrt(x * x + y * y)); // x * x is quicker than Math.pow(x,2)
var speed = 54 / blob1.mass;
blob1.velX = x / length * speed * Math.min(1, Math.pow(x / blob1.mass, 2));
blob1.velY = y / length * speed * Math.min(1, Math.pow(x / blob1.mass, 2));
blob1.x += blob1.velX;
blob1.y += blob1.velY;
for (var j = 0; j < this.blobs.length; j++) {
if (j != i) {
var blob2 = this.blobs[j];
var x = blob2.x - blob1.x;
var y = blob2.y - blob1.y;
var dist = Math.sqrt(x * x + y * y);
var radTotal = blob1.mass + blob2.mass;
if (dist < radTotal) {
x /= dist;
y /= dist;
blob1.x = blob2.x - x * radTotal;
blob1.y = blob2.y - y * radTotal;
}
}
}
if(i === 0){ // use first blob to setup min max
be.maxx = be.minx = blob1.x;
be.maxy = be.miny = blob1.y;
}else{
be.maxx = Math.max(be.maxx, blob1.x);
be.maxy = Math.max(be.maxy, blob1.y);
be.minx = Math.min(be.minx, blob1.x);
be.miny = Math.min(be.miny, blob1.y);
}
}
},
split (cell) {
cell.mass /= 2;
this.blobs.push(createBlob(cell.x, cell.y, cell.mass));
},
draw () {
var b; // alias for blob
ctx.fillStyle = "red"; // all the same colour then can render as one path
ctx.setTransform(1,0,0,1,-camera.x,-camera.y);
ctx.beginPath();
for (var i = 0; i < this.blobs.length; i++) {
b = this.blobs[i];
ctx.arc( b.x, b.y, b.mass, 0, Math.PI * 2);
ctx.closePath();
}
ctx.fill();
ctx.setTransform(1,0,0,1,0,0); // restore default transform
}
};
function handleMouseMove(e) {
mouseX = e.clientX + camera.x;
mouseY = e.clientY + camera.y;
}
function createBlob(x,y,mass){ return {x,y,mass} }
function setup() {
canvas = document.getElementById("game");
ctx = canvas.getContext("2d");
canvas.width = width;
canvas.height = height;
addEventListener("mousemove", handleMouseMove);
player.blobs.push(createBlob(0,0,player.defaultMass));
player.blobs.push(createBlob(100,100,player.defaultMass / 2));
player.blobs.push(createBlob(100,100,player.defaultMass * 2));
}
function update() {
camera.update(player);
player.update();
}
function draw() {
ctx.fillStyle = "#fff";
ctx.fillRect(0, 0, width, height);
player.draw();
}
function loop() {
update();
draw();
requestAnimationFrame(loop);
}
setup();
requestAnimationFrame(loop);
body {
margin: 0;
padding: 0;
}
<canvas id="game"></canvas>
Related
The code is different, I apologize may I didn't ask the question the right way, you can understand well in principle, When I'm hovering the dots get colours and connect to each other, other dots are invisible, I want that all dots should be visible all time. live example available on codepen, https://codepen.io/tati420/pen/RwBamQo?editors=1111
(function () {
var width,
height,
largeHeader,
canvas,
ctx,
points,
target,
animateHeader = true;
// Main
initHeader();
initAnimation();
addListeners();
function initHeader() {
width = window.innerWidth;
height = window.innerHeight;
target = { x: width / 2, y: height / 2 };
largeHeader = document.getElementById("large-header");
largeHeader.style.height = height + "px";
canvas = document.getElementById("demo-canvas");
canvas.width = width;
canvas.height = height;
ctx = canvas.getContext("2d");
// create points
points = [];
for (var x = 0; x < width; x = x + width / 20) {
for (var y = 0; y < height; y = y + height / 20) {
var px = x + (Math.random() * width) / 20;
var py = y + (Math.random() * height) / 20;
var p = { x: px, originX: px, y: py, originY: py };
points.push(p);
}
}
// for each point find the 5 closest points
for (var i = 0; i < points.length; i++) {
var closest = [];
var p1 = points[i];
for (var j = 0; j < points.length; j++) {
var p2 = points[j];
if (!(p1 == p2)) {
var placed = false;
for (var k = 0; k < 5; k++) {
if (!placed) {
if (closest[k] == undefined) {
closest[k] = p2;
placed = true;
}
}
}
for (var k = 0; k < 5; k++) {
if (!placed) {
if (getDistance(p1, p2) < getDistance(p1, closest[k])) {
closest[k] = p2;
placed = true;
}
}
}
}
}
p1.closest = closest;
}
// assign a circle to each point
for (var i in points) {
var c = new Circle(
points[i],
2 + Math.random() * 2,
"rgba(0,255,255,0.3)"
);
points[i].circle = c;
}
}
// Event handling
function addListeners() {
if (!("ontouchstart" in window)) {
window.addEventListener("mousemove", mouseMove);
}
window.addEventListener("scroll", scrollCheck);
window.addEventListener("resize", resize);
}
function mouseMove(e) {
var posx = (posy = 0);
if (e.pageX || e.pageY) {
posx = e.pageX;
posy = e.pageY;
} else if (e.clientX || e.clientY) {
posx =
e.clientX +
document.body.scrollLeft +
document.documentElement.scrollLeft;
posy =
e.clientY +
document.body.scrollTop +
document.documentElement.scrollTop;
}
target.x = posx;
target.y = posy;
}
function scrollCheck() {
if (document.body.scrollTop > height) animateHeader = false;
else animateHeader = true;
}
function resize() {
width = window.innerWidth;
height = window.innerHeight;
largeHeader.style.height = height + "px";
canvas.width = width;
canvas.height = height;
}
// animation
function initAnimation() {
animate();
for (var i in points) {
shiftPoint(points[i]);
}
}
function animate() {
if (animateHeader) {
ctx.clearRect(0, 0, width, height);
for (var i in points) {
// detect points in range
if (Math.abs(getDistance(target, points[i])) < 4000) {
points[i].active = 0.3;
points[i].circle.active = 0.6;
} else if (Math.abs(getDistance(target, points[i])) < 20000) {
points[i].active = 0.1;
points[i].circle.active = 0.3;
} else if (Math.abs(getDistance(target, points[i])) < 40000) {
points[i].active = 0.02;
points[i].circle.active = 0.1;
} else {
points[i].active = 0;
points[i].circle.active = 0;
}
drawLines(points[i]);
points[i].circle.draw();
}
}
requestAnimationFrame(animate);
}
function shiftPoint(p) {
TweenLite.to(p, 1 + 1 * Math.random(), {
x: p.originX - 50 + Math.random() * 100,
y: p.originY - 50 + Math.random() * 100,
ease: Circ.easeInOut,
onComplete: function () {
shiftPoint(p);
},
});
}
ctx.strokeStyle = "rgba(255,0,0," + p.active + ")";
// Canvas manipulation
function drawLines(p) {
if (!p.active) return;
for (var i in p.closest) {
ctx.beginPath();
ctx.moveTo(p.x, p.y);
ctx.lineTo(p.closest[i].x, p.closest[i].y);
ctx.strokeStyle = "rgba(0,255,255," + p.active + ")";
ctx.stroke();
}
}
function Circle(pos, rad, color) {
var _this = this;
// constructor
(function () {
_this.pos = pos || null;
_this.radius = rad || null;
_this.color = color || null;
})();
this.draw = function () {
if (!_this.active) return;
ctx.beginPath();
ctx.arc(_this.pos.x, _this.pos.y, _this.radius, 0, 2 * Math.PI, false);
ctx.fillStyle = "rgba(0,255,0," + _this.active + ")";
ctx.fill();
};
}
// Util
function getDistance(p1, p2) {
return Math.pow(p1.x - p2.x, 2) + Math.pow(p1.y - p2.y, 2);
}
})();
If I understand your question correctly, you just want to make sure that every point.active = 1 and point.circle.active = 1:
function animate() {
if (animateHeader) {
ctx.clearRect(0, 0, width, height);
for (var i in points) {
points[i].active = 1;
points[i].circle.active = 1;
drawLines(points[i]);
points[i].circle.draw();
}
}
requestAnimationFrame(animate);
}
I have tried all the jQuery tricks as well as the CSS tricks, but none of them work.. I don't really know anything about <canvas> but I've been trying to solve this for a day now.. can anybody help?
I am trying not mess up the code and just make the black background transparent so that I could use this canvas over a carousal..
// helper functions
const PI2 = Math.PI * 2
const random = (min, max) => Math.random() * (max - min + 1) + min | 0
const timestamp = _ => new Date().getTime()
// container
class Birthday {
constructor() {
this.resize()
// create a lovely place to store the firework
this.fireworks = []
this.counter = 0
}
resize() {
this.width = canvas.width = window.innerWidth
let center = this.width / 2 | 0
this.spawnA = center - center / 4 | 0
this.spawnB = center + center / 4 | 0
this.height = canvas.height = window.innerHeight
this.spawnC = this.height * .1
this.spawnD = this.height * .5
}
onClick(evt) {
let x = evt.clientX || evt.touches && evt.touches[0].pageX
let y = evt.clientY || evt.touches && evt.touches[0].pageY
let count = random(3, 5)
for (let i = 0; i < count; i++) this.fireworks.push(new Firework(
random(this.spawnA, this.spawnB),
this.height,
x,
y,
random(0, 260),
random(30, 110)))
this.counter = -1
}
update(delta) {
ctx.globalCompositeOperation = 'hard-light'
ctx.fillStyle = `rgba(20,20,20,${ 7 * delta })`
ctx.fillRect(0, 0, this.width, this.height)
ctx.globalCompositeOperation = 'lighter'
for (let firework of this.fireworks) firework.update(delta)
// if enough time passed... create new new firework
this.counter += delta * 3 // each second
if (this.counter >= 1) {
this.fireworks.push(new Firework(
random(this.spawnA, this.spawnB),
this.height,
random(0, this.width),
random(this.spawnC, this.spawnD),
random(0, 360),
random(30, 110)))
this.counter = 0
}
// remove the dead fireworks
if (this.fireworks.length > 1000) this.fireworks = this.fireworks.filter(firework => !firework.dead)
}
}
class Firework {
constructor(x, y, targetX, targetY, shade, offsprings) {
this.dead = false
this.offsprings = offsprings
this.x = x
this.y = y
this.targetX = targetX
this.targetY = targetY
this.shade = shade
this.history = []
}
update(delta) {
if (this.dead) return
let xDiff = this.targetX - this.x
let yDiff = this.targetY - this.y
if (Math.abs(xDiff) > 3 || Math.abs(yDiff) > 3) { // is still moving
this.x += xDiff * 2 * delta
this.y += yDiff * 2 * delta
this.history.push({
x: this.x,
y: this.y
})
if (this.history.length > 20) this.history.shift()
} else {
if (this.offsprings && !this.madeChilds) {
let babies = this.offsprings / 2
for (let i = 0; i < babies; i++) {
let targetX = this.x + this.offsprings * Math.cos(PI2 * i / babies) | 0
let targetY = this.y + this.offsprings * Math.sin(PI2 * i / babies) | 0
birthday.fireworks.push(new Firework(this.x, this.y, targetX, targetY, this.shade, 0))
}
}
this.madeChilds = true
this.history.shift()
}
if (this.history.length === 0) this.dead = true
else if (this.offsprings) {
for (let i = 0; this.history.length > i; i++) {
let point = this.history[i]
ctx.beginPath()
ctx.fillStyle = 'hsl(' + this.shade + ',100%,' + i + '%)'
ctx.arc(point.x, point.y, 1, 0, PI2, false)
ctx.fill()
}
} else {
ctx.beginPath()
ctx.fillStyle = 'hsl(' + this.shade + ',100%,50%)'
ctx.arc(this.x, this.y, 1, 0, PI2, false)
ctx.fill()
}
}
}
let canvas = document.getElementById('birthday')
let ctx = canvas.getContext('2d')
let then = timestamp()
let birthday = new Birthday
window.onresize = () => birthday.resize()
document.onclick = evt => birthday.onClick(evt)
document.ontouchstart = evt => birthday.onClick(evt)
;
(function loop() {
requestAnimationFrame(loop)
let now = timestamp()
let delta = now - then
then = now
birthday.update(delta / 1000)
})()
<canvas id="birthday"></canvas>
All you need to do is replace fillRect with clearRect in the update method of the Birthday class like this:
ctx.clearRect(0, 0, this.width, this.height)
You may need to make further adjustments to the color of the firework trail though, since it seems like it was supposed to match the background color.
If your canvas still isn't transparent, check your css to ensure that you're not setting the background color that way.
const PI2 = Math.PI * 2
const random = (min, max) => Math.random() * (max - min + 1) + min | 0
const timestamp = _ => new Date().getTime()
// container
class Birthday {
constructor() {
this.resize()
// create a lovely place to store the firework
this.fireworks = []
this.counter = 0
}
resize() {
this.width = canvas.width = window.innerWidth
let center = this.width / 2 | 0
this.spawnA = center - center / 4 | 0
this.spawnB = center + center / 4 | 0
this.height = canvas.height = window.innerHeight
this.spawnC = this.height * .1
this.spawnD = this.height * .5
}
onClick(evt) {
let x = evt.clientX || evt.touches && evt.touches[0].pageX
let y = evt.clientY || evt.touches && evt.touches[0].pageY
let count = random(3, 5)
for (let i = 0; i < count; i++) this.fireworks.push(new Firework(
random(this.spawnA, this.spawnB),
this.height,
x,
y,
random(0, 260),
random(30, 110)))
this.counter = -1
}
update(delta) {
ctx.globalCompositeOperation = 'hard-light'
ctx.fillStyle = `rgba(20,20,20,${ 7 * delta })`
ctx.clearRect(0, 0, this.width, this.height)
ctx.globalCompositeOperation = 'lighter'
for (let firework of this.fireworks) firework.update(delta)
// if enough time passed... create new new firework
this.counter += delta * 3 // each second
if (this.counter >= 1) {
this.fireworks.push(new Firework(
random(this.spawnA, this.spawnB),
this.height,
random(0, this.width),
random(this.spawnC, this.spawnD),
random(0, 360),
random(30, 110)))
this.counter = 0
}
// remove the dead fireworks
if (this.fireworks.length > 1000) this.fireworks = this.fireworks.filter(firework => !firework.dead)
}
}
class Firework {
constructor(x, y, targetX, targetY, shade, offsprings) {
this.dead = false
this.offsprings = offsprings
this.x = x
this.y = y
this.targetX = targetX
this.targetY = targetY
this.shade = shade
this.history = []
}
update(delta) {
if (this.dead) return
let xDiff = this.targetX - this.x
let yDiff = this.targetY - this.y
if (Math.abs(xDiff) > 3 || Math.abs(yDiff) > 3) { // is still moving
this.x += xDiff * 2 * delta
this.y += yDiff * 2 * delta
this.history.push({
x: this.x,
y: this.y
})
if (this.history.length > 20) this.history.shift()
} else {
if (this.offsprings && !this.madeChilds) {
let babies = this.offsprings / 2
for (let i = 0; i < babies; i++) {
let targetX = this.x + this.offsprings * Math.cos(PI2 * i / babies) | 0
let targetY = this.y + this.offsprings * Math.sin(PI2 * i / babies) | 0
birthday.fireworks.push(new Firework(this.x, this.y, targetX, targetY, this.shade, 0))
}
}
this.madeChilds = true
this.history.shift()
}
if (this.history.length === 0) this.dead = true
else if (this.offsprings) {
for (let i = 0; this.history.length > i; i++) {
let point = this.history[i]
ctx.beginPath()
ctx.fillStyle = 'hsl(' + this.shade + ',100%,' + i + '%)'
ctx.arc(point.x, point.y, 1, 0, PI2, false)
ctx.fill()
}
} else {
ctx.beginPath()
ctx.fillStyle = 'hsl(' + this.shade + ',100%,50%)'
ctx.arc(this.x, this.y, 1, 0, PI2, false)
ctx.fill()
}
}
}
let canvas = document.getElementById('birthday')
let ctx = canvas.getContext('2d')
let then = timestamp()
let birthday = new Birthday
window.onresize = () => birthday.resize()
document.onclick = evt => birthday.onClick(evt)
document.ontouchstart = evt => birthday.onClick(evt)
;
(function loop() {
requestAnimationFrame(loop)
let now = timestamp()
let delta = now - then
then = now
birthday.update(delta / 1000)
})()
div {
height : 100vh;
width : 100vw;
display : flex;
flex-direction : center;
align-items : center;
justify-content : center;
}
canvas {
position : absolute;
top : 0;
left : 0;
}
<div>Content Underneath</div>
<canvas id="birthday"></canvas>
i'm trying to use this Fireworks javascript. But when i write some text in the middle of the HTML page, the fireworks will not go over it and is limited by the text position...how can i override this and keep the fireworks go up to the top of the page ?
i tryed to fix the SCREEN_WIDTH and SCREEN_HEIGHT position but it doesn't work...
var SCREEN_WIDTH = window.innerWidth,
SCREEN_HEIGHT = window.innerHeight,
mousePos = {
x: 400,
y: 300
},
// create canvas
canvas = document.createElement('canvas'),
context = canvas.getContext('2d'),
particles = [],
rockets = [],
MAX_PARTICLES = 400,
colorCode = 0;
// init
$(document).ready(function() {
document.body.appendChild(canvas);
canvas.width = SCREEN_WIDTH;
canvas.height = SCREEN_HEIGHT;
setInterval(launch, 800);
setInterval(loop, 1000 / 50);
});
// update mouse position
$(document).mousemove(function(e) {
e.preventDefault();
mousePos = {
x: e.clientX,
y: e.clientY
};
});
// launch more rockets!!!
$(document).mousedown(function(e) {
for (var i = 0; i < 5; i++) {
launchFrom(Math.random() * SCREEN_WIDTH * 2 / 3 + SCREEN_WIDTH / 6);
}
});
function launch() {
launchFrom(mousePos.x);
}
function launchFrom(x) {
if (rockets.length < 10) {
var rocket = new Rocket(x);
rocket.explosionColor = Math.floor(Math.random() * 360 / 10) * 10;
rocket.vel.y = Math.random() * -3 - 4;
rocket.vel.x = Math.random() * 6 - 3;
rocket.size = 8;
rocket.shrink = 0.999;
rocket.gravity = 0.01;
rockets.push(rocket);
}
}
function loop() {
// update screen size
if (SCREEN_WIDTH != window.innerWidth) {
canvas.width = SCREEN_WIDTH = window.innerWidth;
}
if (SCREEN_HEIGHT != window.innerHeight) {
canvas.height = SCREEN_HEIGHT = window.innerHeight;
}
// clear canvas
context.fillStyle = "rgba(0, 0, 0, 0.05)";
context.fillRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
var existingRockets = [];
for (var i = 0; i < rockets.length; i++) {
// update and render
rockets[i].update();
rockets[i].render(context);
// calculate distance with Pythagoras
var distance = Math.sqrt(Math.pow(mousePos.x - rockets[i].pos.x, 2) + Math.pow(mousePos.y - rockets[i].pos.y, 2));
// random chance of 1% if rockets is above the middle
var randomChance = rockets[i].pos.y < (SCREEN_HEIGHT * 2 / 3) ? (Math.random() * 100 <= 1) : false;
/* Explosion rules
- 80% of screen
- going down
- close to the mouse
- 1% chance of random explosion
*/
if (rockets[i].pos.y < SCREEN_HEIGHT / 5 || rockets[i].vel.y >= 0 || distance < 50 || randomChance) {
rockets[i].explode();
} else {
existingRockets.push(rockets[i]);
}
}
rockets = existingRockets;
var existingParticles = [];
for (var i = 0; i < particles.length; i++) {
particles[i].update();
// render and save particles that can be rendered
if (particles[i].exists()) {
particles[i].render(context);
existingParticles.push(particles[i]);
}
}
// update array with existing particles - old particles should be garbage collected
particles = existingParticles;
while (particles.length > MAX_PARTICLES) {
particles.shift();
}
}
function Particle(pos) {
this.pos = {
x: pos ? pos.x : 0,
y: pos ? pos.y : 0
};
this.vel = {
x: 0,
y: 0
};
this.shrink = .97;
this.size = 2;
this.resistance = 1;
this.gravity = 0;
this.flick = false;
this.alpha = 1;
this.fade = 0;
this.color = 0;
}
Particle.prototype.update = function() {
// apply resistance
this.vel.x *= this.resistance;
this.vel.y *= this.resistance;
// gravity down
this.vel.y += this.gravity;
// update position based on speed
this.pos.x += this.vel.x;
this.pos.y += this.vel.y;
// shrink
this.size *= this.shrink;
// fade out
this.alpha -= this.fade;
};
Particle.prototype.render = function(c) {
if (!this.exists()) {
return;
}
c.save();
c.globalCompositeOperation = 'lighter';
var x = this.pos.x,
y = this.pos.y,
r = this.size / 2;
var gradient = c.createRadialGradient(x, y, 0.1, x, y, r);
gradient.addColorStop(0.1, "rgba(255,255,255," + this.alpha + ")");
gradient.addColorStop(0.8, "hsla(" + this.color + ", 100%, 50%, " + this.alpha + ")");
gradient.addColorStop(1, "hsla(" + this.color + ", 100%, 50%, 0.1)");
c.fillStyle = gradient;
c.beginPath();
c.arc(this.pos.x, this.pos.y, this.flick ? Math.random() * this.size : this.size, 0, Math.PI * 2, true);
c.closePath();
c.fill();
c.restore();
};
Particle.prototype.exists = function() {
return this.alpha >= 0.1 && this.size >= 1;
};
function Rocket(x) {
Particle.apply(this, [{
x: x,
y: SCREEN_HEIGHT}]);
this.explosionColor = 0;
}
Rocket.prototype = new Particle();
Rocket.prototype.constructor = Rocket;
Rocket.prototype.explode = function() {
var count = Math.random() * 10 + 80;
for (var i = 0; i < count; i++) {
var particle = new Particle(this.pos);
var angle = Math.random() * Math.PI * 2;
// emulate 3D effect by using cosine and put more particles in the middle
var speed = Math.cos(Math.random() * Math.PI / 2) * 15;
particle.vel.x = Math.cos(angle) * speed;
particle.vel.y = Math.sin(angle) * speed;
particle.size = 10;
particle.gravity = 0.2;
particle.resistance = 0.92;
particle.shrink = Math.random() * 0.05 + 0.93;
particle.flick = true;
particle.color = this.explosionColor;
particles.push(particle);
}
};
Rocket.prototype.render = function(c) {
if (!this.exists()) {
return;
}
c.save();
c.globalCompositeOperation = 'lighter';
var x = this.pos.x,
y = this.pos.y,
r = this.size / 2;
var gradient = c.createRadialGradient(x, y, 0.1, x, y, r);
gradient.addColorStop(0.1, "rgba(255, 255, 255 ," + this.alpha + ")");
gradient.addColorStop(1, "rgba(0, 0, 0, " + this.alpha + ")");
c.fillStyle = gradient;
c.beginPath();
c.arc(this.pos.x, this.pos.y, this.flick ? Math.random() * this.size / 2 + this.size / 2 : this.size, 0, Math.PI * 2, true);
c.closePath();
c.fill();
c.restore();
};
body {
background-color: #000000;
margin: 0px;
overflow: hidden;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Fireworks!</title>
</head>
<body/>
</html>
The problem is the canvas used by the script is positioned relative by default. To make it always visible completely on screen we have to make it fixed and set the top and left CSS values to 0.
Now because its fixed the canvas renders on top of everything. To get it in the background set z-index to -1.
All additions together:
canvas.style.position="fixed";
canvas.style.top="0";
canvas.style.left="0";
canvas.style.zIndex="-1";
Complete Source:
var SCREEN_WIDTH = window.innerWidth,
SCREEN_HEIGHT = window.innerHeight,
mousePos = {
x: 400,
y: 300
},
// create canvas
canvas = document.createElement('canvas'),
context = canvas.getContext('2d'),
particles = [],
rockets = [],
MAX_PARTICLES = 400,
colorCode = 0;
// init
$(document).ready(function() {
document.body.appendChild(canvas);
canvas.width = SCREEN_WIDTH;
canvas.height = SCREEN_HEIGHT;
canvas.style.position = "fixed";
canvas.style.top = "0";
canvas.style.left = "0";
canvas.style.zIndex = "-1";
setInterval(launch, 800);
setInterval(loop, 1000 / 50);
});
// update mouse position
$(document).mousemove(function(e) {
e.preventDefault();
mousePos = {
x: e.clientX,
y: e.clientY
};
});
// launch more rockets!!!
$(document).mousedown(function(e) {
for (var i = 0; i < 5; i++) {
launchFrom(Math.random() * SCREEN_WIDTH * 2 / 3 + SCREEN_WIDTH / 6);
}
});
function launch() {
launchFrom(mousePos.x);
}
function launchFrom(x) {
if (rockets.length < 10) {
var rocket = new Rocket(x);
rocket.explosionColor = Math.floor(Math.random() * 360 / 10) * 10;
rocket.vel.y = Math.random() * -3 - 4;
rocket.vel.x = Math.random() * 6 - 3;
rocket.size = 8;
rocket.shrink = 0.999;
rocket.gravity = 0.01;
rockets.push(rocket);
}
}
function loop() {
// update screen size
if (SCREEN_WIDTH != window.innerWidth) {
canvas.width = SCREEN_WIDTH = window.innerWidth;
}
if (SCREEN_HEIGHT != window.innerHeight) {
canvas.height = SCREEN_HEIGHT = window.innerHeight;
}
// clear canvas
context.fillStyle = "rgba(0, 0, 0, 0.05)";
context.fillRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
var existingRockets = [];
for (var i = 0; i < rockets.length; i++) {
// update and render
rockets[i].update();
rockets[i].render(context);
// calculate distance with Pythagoras
var distance = Math.sqrt(Math.pow(mousePos.x - rockets[i].pos.x, 2) + Math.pow(mousePos.y - rockets[i].pos.y, 2));
// random chance of 1% if rockets is above the middle
var randomChance = rockets[i].pos.y < (SCREEN_HEIGHT * 2 / 3) ? (Math.random() * 100 <= 1) : false;
/* Explosion rules
- 80% of screen
- going down
- close to the mouse
- 1% chance of random explosion
*/
if (rockets[i].pos.y < SCREEN_HEIGHT / 5 || rockets[i].vel.y >= 0 || distance < 50 || randomChance) {
rockets[i].explode();
} else {
existingRockets.push(rockets[i]);
}
}
rockets = existingRockets;
var existingParticles = [];
for (var i = 0; i < particles.length; i++) {
particles[i].update();
// render and save particles that can be rendered
if (particles[i].exists()) {
particles[i].render(context);
existingParticles.push(particles[i]);
}
}
// update array with existing particles - old particles should be garbage collected
particles = existingParticles;
while (particles.length > MAX_PARTICLES) {
particles.shift();
}
}
function Particle(pos) {
this.pos = {
x: pos ? pos.x : 0,
y: pos ? pos.y : 0
};
this.vel = {
x: 0,
y: 0
};
this.shrink = .97;
this.size = 2;
this.resistance = 1;
this.gravity = 0;
this.flick = false;
this.alpha = 1;
this.fade = 0;
this.color = 0;
}
Particle.prototype.update = function() {
// apply resistance
this.vel.x *= this.resistance;
this.vel.y *= this.resistance;
// gravity down
this.vel.y += this.gravity;
// update position based on speed
this.pos.x += this.vel.x;
this.pos.y += this.vel.y;
// shrink
this.size *= this.shrink;
// fade out
this.alpha -= this.fade;
};
Particle.prototype.render = function(c) {
if (!this.exists()) {
return;
}
c.save();
c.globalCompositeOperation = 'lighter';
var x = this.pos.x,
y = this.pos.y,
r = this.size / 2;
var gradient = c.createRadialGradient(x, y, 0.1, x, y, r);
gradient.addColorStop(0.1, "rgba(255,255,255," + this.alpha + ")");
gradient.addColorStop(0.8, "hsla(" + this.color + ", 100%, 50%, " + this.alpha + ")");
gradient.addColorStop(1, "hsla(" + this.color + ", 100%, 50%, 0.1)");
c.fillStyle = gradient;
c.beginPath();
c.arc(this.pos.x, this.pos.y, this.flick ? Math.random() * this.size : this.size, 0, Math.PI * 2, true);
c.closePath();
c.fill();
c.restore();
};
Particle.prototype.exists = function() {
return this.alpha >= 0.1 && this.size >= 1;
};
function Rocket(x) {
Particle.apply(this, [{
x: x,
y: SCREEN_HEIGHT
}]);
this.explosionColor = 0;
}
Rocket.prototype = new Particle();
Rocket.prototype.constructor = Rocket;
Rocket.prototype.explode = function() {
var count = Math.random() * 10 + 80;
for (var i = 0; i < count; i++) {
var particle = new Particle(this.pos);
var angle = Math.random() * Math.PI * 2;
// emulate 3D effect by using cosine and put more particles in the middle
var speed = Math.cos(Math.random() * Math.PI / 2) * 15;
particle.vel.x = Math.cos(angle) * speed;
particle.vel.y = Math.sin(angle) * speed;
particle.size = 10;
particle.gravity = 0.2;
particle.resistance = 0.92;
particle.shrink = Math.random() * 0.05 + 0.93;
particle.flick = true;
particle.color = this.explosionColor;
particles.push(particle);
}
};
Rocket.prototype.render = function(c) {
if (!this.exists()) {
return;
}
c.save();
c.globalCompositeOperation = 'lighter';
var x = this.pos.x,
y = this.pos.y,
r = this.size / 2;
var gradient = c.createRadialGradient(x, y, 0.1, x, y, r);
gradient.addColorStop(0.1, "rgba(255, 255, 255 ," + this.alpha + ")");
gradient.addColorStop(1, "rgba(0, 0, 0, " + this.alpha + ")");
c.fillStyle = gradient;
c.beginPath();
c.arc(this.pos.x, this.pos.y, this.flick ? Math.random() * this.size / 2 + this.size / 2 : this.size, 0, Math.PI * 2, true);
c.closePath();
c.fill();
c.restore();
};
body {
background-color: #000000;
margin: 0px;
overflow: hidden;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Fireworks!</title>
</head>
<body>
<p>
test
</p>
<br />
<p>
test2
</p>
</body>
</html>
I'm trying to make a blackhole simulation, and although I'm almost done, I wish to make disappear the dots that are drawn on the blackhole progressively, here is my code:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<title>test trou noir</title>
<script>
var canvas, ctx;
var blackhole;
var circle;
var circles = new Array();
var G = 6.67e-11,//gravitational constant
pixel_G = G/1e-11,
c = 3e8, //speed of light (m/s)
M = 12e31,// masseof the blackhole in kg (60 solar masses)
pixel_M = M/1e32
Rs = (2 * G * M) / 9e16, //Schwarzchild radius
pixel_Rs = Rs/1e3, // scaled radius
ccolor=128;
function update() {
var pos, i, distance, somethingMoved = false;
for (i = 0; i < circles.length; i++) {
pos = circles[i].position;
distance = Math.sqrt(((pos.x - 700) * (pos.x - 700)) + ((pos.y - 400) * (pos.y - 400)));
if (distance > pixel_Rs && visible(circles[i])) {
var delta = new Vector2D(0, 0);
var forceDirection = Math.atan2(pos.y - 400, pos.x - 700);
var evelocity = Math.sqrt( (2*pixel_G*pixel_M)/(distance*1e-2));
delta.x += Math.cos(forceDirection) * evelocity;
delta.y += Math.sin(forceDirection) * evelocity;
pos.x += delta.x;
pos.y += delta.y;
somethingMoved = true;
}
}
if (somethingMoved) {
drawEverything();
requestAnimationFrame(update);
} else {
ccolor -=10;
};
}
function visible(ball) {
return ball.position.x > ball.radius && ball.position.x < canvas.width - ball.radius &&
ball.position.y > ball.radius && ball.position.y < canvas.height - ball.radius;
}
function drawEverything() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
blackhole.draw(ctx);
for (var i = 0; i < circles.length; i++) {
if (visible(circles[i])) {
circles[i].draw(ctx);
}
}
}
function init() {
canvas = document.getElementById("space");
ctx = canvas.getContext('2d');
blackhole = new Ball(pixel_Rs, {
x: 700,
y: 400
}, "black");
for (var i = 0; i < 200; i++) {
var vec2D = new Vector2D(Math.floor(Math.random() * 1400), Math.floor(Math.random() * 800));
circle = new Ball(5, vec2D, 'rgba('+ccolor+','+ccolor+','+ccolor+',1)');
circles.push(circle);
}
drawEverything();
requestAnimationFrame(update);
}
function Ball(radius, position, color) {
this.radius = radius;
this.position = position;
this.color = color;
}
Ball.prototype.draw = function(ctx) {
ctx.fillStyle = this.color;
ctx.beginPath();
ctx.arc(this.position.x, this.position.y, this.radius, 0, 2 * Math.PI);
ctx.closePath();
ctx.fill();
};
function Vector2D(x, y) {
this.x = x;
this.y = y;
}
window.onload = init;
</script>
<style>
body {
background-color: #021c36;
margin: 0px;
}
</style>
</head>
<body>
<canvas id="space" , width="1400" , height="800">
</canvas>
</body>
</html>
now as you can see, I created a variable called ccolor which is integrated in the rgba code, but I don't know why the colors don't tend to zero, so the circles that are inside the blackhole gradually disappear, if someone could lend me a hand it'd be great
In update, if any circles[i] is captured by the Blackhole you decrement its this.color. It might be easier if you change this.color to an integer that you use to create a fillStyle:
ctx.fillStyle='rgba(' + this.color + ',' + this.color + ',' + this.color + ',1)'.
Here's a quick demo:
View this demo Full Page or the black hole is off-screen
var canvas, ctx;
var blackhole;
var circle;
var circles = new Array();
var G = 6.67e-11, //gravitational constant
pixel_G = G / 1e-11,
c = 3e8, //speed of light (m/s)
M = 12e31, // masseof the blackhole in kg (60 solar masses)
pixel_M = M / 1e32
Rs = (2 * G * M) / 9e16, //Schwarzchild radius
pixel_Rs = Rs / 1e3, // scaled radius
ccolor = 128;
function update() {
var pos, i, distance, somethingMoved = false;
for (i = 0; i < circles.length; i++) {
pos = circles[i].position;
distance = Math.sqrt(((pos.x - 700) * (pos.x - 700)) + ((pos.y - 400) * (pos.y - 400)));
if (distance > pixel_Rs && visible(circles[i])) {
var delta = new Vector2D(0, 0);
var forceDirection = Math.atan2(pos.y - 400, pos.x - 700);
var evelocity = Math.sqrt((2 * pixel_G * pixel_M) / (distance * 1e-2));
delta.x += Math.cos(forceDirection) * evelocity;
delta.y += Math.sin(forceDirection) * evelocity;
pos.x += delta.x;
pos.y += delta.y;
somethingMoved = true;
} else {
circles[i].color -= 0.50;
}
}
if (somethingMoved) {
drawEverything();
requestAnimationFrame(update);
};
}
function visible(ball) {
return ball.position.x > ball.radius && ball.position.x < canvas.width - ball.radius &&
ball.position.y > ball.radius && ball.position.y < canvas.height - ball.radius;
}
function drawEverything() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
blackhole.draw(ctx);
for (var i = 0; i < circles.length; i++) {
if (visible(circles[i])) {
circles[i].draw(ctx);
}
}
}
function init() {
canvas = document.getElementById("space");
ctx = canvas.getContext('2d');
blackhole = new Ball(pixel_Rs, {
x: 700,
y: 400
}, 0);
for (var i = 0; i < 200; i++) {
var vec2D = new Vector2D(Math.floor(Math.random() * 1400), Math.floor(Math.random() * 800));
circle = new Ball(5, vec2D, ccolor);
circles.push(circle);
}
drawEverything();
requestAnimationFrame(update);
}
function Ball(radius, position, color) {
this.radius = radius;
this.position = position;
this.color = color;
}
//
Ball.prototype.draw = function(ctx) {
var c=parseInt(this.color);
ctx.fillStyle = 'rgba(' + c + ',' + c + ',' + c + ',1)';
ctx.beginPath();
ctx.arc(this.position.x, this.position.y, this.radius, 0, 2 * Math.PI);
ctx.closePath();
ctx.fill();
};
function Vector2D(x, y) {
this.x = x;
this.y = y;
}
init();
body{ background-color: #021c36; margin: 0px; }
<canvas id="space" width=1400 height=800></canvas>
Simple solution:
In drawEverything() function move blackhole.draw(ctx) to be the last step
Not so simple: Use one of the many JS particle systems
When I run this script on Safari, everything works fine. However when I open it up in Chrome or Firefox it does not execute correctly. In the Chrome console it says that there are Uncaught type errors for:
ctx.drawImage(img, x + 1, y + 1, iwh, iwh);
and
function renderStarField() {
ctx.fillStyle = '#000000';
ctx.fillRect(0, 0, WIDTH, HEIGHT);
for (var i = 0; i < stars.length; i++) {
stars[i].plot();
}
}
Here is my entire script, thanks for the help!
<script type="text/javascript">
var starField = (function () {
var browserWIDTH = $(document).width(),
browserHEIGHT = $(document).height(),
WIDTH = browserWIDTH + 500,
HEIGHT = 400,
FIELD_DEPTH = 15,
DISTANCE = 500,
STAR_DIAMETER = 45,
STAR_SPEED = 0.003,
canvas,
ctx,
numStars = 2000,
stars = [];
function Star() {
this.calcPosition();
var RANDSTAR = Math.floor(Math.random() * 3) + 1;
}
Star.prototype.calcPosition = function (reset) {
this.x = this.randomise(-25, 50);
this.y = this.randomise(-25, 50);
this.z = reset ? FIELD_DEPTH : this.randomise(1, FIELD_DEPTH);
};
Star.prototype.randomise = function (min, max) {
return Math.floor((Math.random() * max) + min);
};
Star.prototype.plot = function () {
//calculate 3d to 2d using perspective projection with the screen as the origin
var x = this.x * (DISTANCE / this.z) + WIDTH / 2,
y = this.y * (DISTANCE / this.z) + HEIGHT / 2;
if ((x >= 0 && x <= WIDTH) && (y >= 0 && y <= HEIGHT)) {
ctx.beginPath();
var img = document.createElement('image');
img.src ='Star1.png';
var iwh = this.calcSize(this.z);
ctx.moveTo(x, y);
ctx.drawImage(img, x + 1, y + 1, iwh, iwh);
}
this.z -= STAR_SPEED;
if (this.z <= 0) {
this.calcPosition(true);
}
};
Star.prototype.calcColor = function (z) {
var rgb = Math.abs((z * 5) - 255).toFixed(0),
a = (1 - ((z / (FIELD_DEPTH / 100)) / 100)).toFixed(1);
return 'rgba(' + rgb + ', ' + rgb + ', ' + rgb + ', ' + a + ')';
};
Star.prototype.calcSize = function (z) {
return Math.abs(((z / (FIELD_DEPTH / 100)) * (STAR_DIAMETER / 100)) - STAR_DIAMETER);
};
function setUpCanvas() {
canvas = document.querySelector('#stage');
canvas.width = WIDTH;
canvas.height = HEIGHT;
ctx = canvas.getContext('2d');
}
function buildStars() {
for (var i = 0; i < numStars; i++) {
stars.push(new Star());
}
}
function renderStarField() {
ctx.fillStyle = '#000000';
ctx.fillRect(0, 0, WIDTH, HEIGHT);
for (var i = 0; i < stars.length; i++) {
stars[i].plot();
}
}
function initialise() {
setUpCanvas();
buildStars();
setInterval(renderStarField, 20);
}
return {
init: initialise
}
})();
document.addEventListener('DOMContentLoaded', function () {
starField.init();
});
</script>
if ((x >= 0 && x <= WIDTH) && (y >= 0 && y <= HEIGHT)) {
ctx.beginPath();
var img = document.createElement('image');
img.src ='Star1.png';
var iwh = this.calcSize(this.z);
ctx.moveTo(x, y);
ctx.drawImage(img, x + 1, y + 1, iwh, iwh);
}
This code has some error
img.src = 'Star1.png' is not working, try img.setAttribute('src','Star1.png');
and Create <img> tag code is not document.createElement('image')
try document.createElement('img');
Change To
if ((x >= 0 && x <= WIDTH) && (y >= 0 && y <= HEIGHT)) {
ctx.beginPath();
var img = document.createElement('img');
img.setAttribute('src','Star1.png');
var iwh = this.calcSize(this.z);
ctx.moveTo(x, y);
ctx.drawImage(img, x + 1, y + 1, iwh, iwh);
}