Related
https://codepen.io/deathshadow8123/pen/KKNaLXq That is my pen from codepen, however when I create an html doc, and put the js into a tag and the css into a tag it doesn't show up on the webpage I also put the in there. Pls help me I do not know how to make this work. Any ideas?
if you can't access codepen here is my code:
var w = c.width = window.innerWidth,
h = c.height = window.innerHeight,
ctx = c.getContext( '2d' ),
opts = {
chars: '\1234567890ìqwertyuiopè+asdfghjklòàù<zxcvbnm,.-|!"£$%&/()=?^QWERTYUIOPé*ASDFGHJKLç°§>ZXCVBNM;:_[]##€{}'.split(''), // every key in the italian keyboard layout. It sucks, we don't even have a backtick!
font: '12px monospace',
charSize: 14,
lineHeight: 14,
hueSpeed: 1,
repaintAlpha: .1,
stripesParXxY: .1,
stripeSpeed: .5,
beforeSpawning: 50
},
tick = 0,
endX = ( w / opts.charSize + 1 ) |0,
endY = ( h / opts.lineHeight + 1 ) |0,
sum = w + h,
stripes = [];
ctx.font = opts.font;
ctx.fillStyle = '#111';
ctx.fillRect( 0, 0, w, h );
function loop() {
window.requestAnimationFrame( loop );
tick += opts.hueSpeed;
ctx.fillStyle = 'rgba(0,0,0,alp)'.replace( 'alp', opts.repaintAlpha );
ctx.fillRect( 0, 0, w, h );
stripes.map( function( stripe ){ stripe.step(); } );
}
function Stripe(){
this.reset();
}
Stripe.prototype.reset = function() {
this.x = ( Math.random() * endX ) |0;
this.y = -Math.random() * opts.beforeSpawning;
}
Stripe.prototype.step = function() {
this.y += opts.stripeSpeed;
drawLetter( this.x, this.y|0 );
if( this.y > endX )
this.reset();
}
function drawLetter( x, y ){
x *= opts.charSize;
y *= opts.lineHeight;
ctx.fillStyle = 'hsl(hue,80%,50%)'.replace( 'hue', ( x + y ) / sum * 360 + tick );
ctx.fillText( opts.chars[ ( Math.random() * opts.chars.length ) |0 ], x, y );
}
for( var i = 0; i < endX*endX * opts.stripesParXxY; ++i )
stripes.push( new Stripe );
loop();
window.addEventListener( 'resize', function(){
w = c.width = window.innerWidth;
h = c.height = window.innerHeight;
ctx.fillStyle = '#111';
ctx.fillRect( 0, 0, w, h );
ctx.font = opts.font;
endX = ( w / opts.charSize + 1 ) |0;
endY = ( h / opts.lineHeight + 1 ) |0;
sum = w + h;
stripes.length = 0;
for( var i = 0; i < endX*endY * opts.stripesParXxY; ++i )
stripes.push( new Stripe );
})
canvas {
position: absolute;
top: 0;
left: 0;
}
<canvas id=c></canvas>
Once the DOM is loaded, you need to get a reference to your canvas DOM element at the top of your script or load handler function.
const c = document.getElementById("c");
Also its best to use quotes in your html.
e.g.
<canvas id="c"></canvas>
The problem of your code is that you have not put your canvas' id inside "", putting t
I have seen the code. There is a small error in html file and this is the cause of the project not working. It is simple, Just put your canvas id in "" doublequotes.
<canvas id="c"></canvas>
Thanks, Hope it helps
I'm starting to work with some canvas animations and am having trouble understanding what's happening in a CodePen. Here is the animation in question: https://codepen.io/towc/pen/mJzOWJ
var w = c.width = window.innerWidth,
h = c.height = window.innerHeight,
ctx = c.getContext( '2d' ),
opts = {
len: 20,
count: 50,
baseTime: 10,
addedTime: 10,
dieChance: .05,
spawnChance: 1,
sparkChance: .1,
sparkDist: 10,
sparkSize: 2,
color: 'hsl(hue,100%,light%)',
baseLight: 50,
addedLight: 10, // [50-10,50+10]
shadowToTimePropMult: 6,
baseLightInputMultiplier: .01,
addedLightInputMultiplier: .02,
cx: w / 2,
cy: h / 2,
repaintAlpha: .04,
hueChange: .1
},
tick = 0,
lines = [],
dieX = w / 2 / opts.len,
dieY = h / 2 / opts.len,
baseRad = Math.PI * 2 / 6;
ctx.fillStyle = 'black';
ctx.fillRect( 0, 0, w, h );
function loop() {
window.requestAnimationFrame( loop );
++tick;
ctx.globalCompositeOperation = 'source-over';
ctx.shadowBlur = 0;
ctx.fillStyle = 'rgba(0,0,0,alp)'.replace( 'alp', opts.repaintAlpha );
ctx.fillRect( 0, 0, w, h );
ctx.globalCompositeOperation = 'lighter';
if( lines.length < opts.count && Math.random() < opts.spawnChance )
lines.push( new Line );
lines.map( function( line ){ line.step(); } );
}
function Line(){
this.reset();
}
Line.prototype.reset = function(){
this.x = 0;
this.y = 0;
this.addedX = 0;
this.addedY = 0;
this.rad = 0;
this.lightInputMultiplier = opts.baseLightInputMultiplier + opts.addedLightInputMultiplier * Math.random();
this.color = opts.color.replace( 'hue', tick * opts.hueChange );
this.cumulativeTime = 0;
this.beginPhase();
}
Line.prototype.beginPhase = function(){
this.x += this.addedX;
this.y += this.addedY;
this.time = 0;
this.targetTime = ( opts.baseTime + opts.addedTime * Math.random() ) |0;
this.rad += baseRad * ( Math.random() < .5 ? 1 : -1 );
this.addedX = Math.cos( this.rad );
this.addedY = Math.sin( this.rad );
if( Math.random() < opts.dieChance || this.x > dieX || this.x < -dieX || this.y > dieY || this.y < -dieY )
this.reset();
}
Line.prototype.step = function(){
++this.time;
++this.cumulativeTime;
if( this.time >= this.targetTime )
this.beginPhase();
var prop = this.time / this.targetTime,
wave = Math.sin( prop * Math.PI / 2 ),
x = this.addedX * wave,
y = this.addedY * wave;
ctx.shadowBlur = prop * opts.shadowToTimePropMult;
ctx.fillStyle = ctx.shadowColor = this.color.replace( 'light', opts.baseLight + opts.addedLight * Math.sin( this.cumulativeTime * this.lightInputMultiplier ) );
ctx.fillRect( opts.cx + ( this.x + x ) * opts.len, opts.cy + ( this.y + y ) * opts.len, 2, 2 );
if( Math.random() < opts.sparkChance )
ctx.fillRect( opts.cx + ( this.x + x ) * opts.len + Math.random() * opts.sparkDist * ( Math.random() < .5 ? 1 : -1 ) - opts.sparkSize / 2, opts.cy + ( this.y + y ) * opts.len + Math.random() * opts.sparkDist * ( Math.random() < .5 ? 1 : -1 ) - opts.sparkSize / 2, opts.sparkSize, opts.sparkSize )
}
loop();
window.addEventListener( 'resize', function(){
w = c.width = window.innerWidth;
h = c.height = window.innerHeight;
ctx.fillStyle = 'black';
ctx.fillRect( 0, 0, w, h );
opts.cx = w / 2;
opts.cy = h / 2;
dieX = w / 2 / opts.len;
dieY = h / 2 / opts.len;
});
canvas {
position: absolute;
top: 0;
left: 0;
}
<canvas id=c></canvas>
If you let the animation run for a while so the "sparks" spread out they leave behind a faint gray-ish trail. What is causing this trail and is it possible to prevent it?
Thank you!
Consider the following snippet: Why are there visible points outside the rectangle?
Is the switching of the context color slower than the drawing of the rectangle?
const templateCanvas = document.getElementById( "template" );
const tctx = templateCanvas.getContext( "2d" );
tctx.fillStyle = "red";
tctx.fillRect( 300, 300, 200, 200 )
const canvas = document.getElementById( "canvas" );
const ctx = canvas.getContext( "2d" );
const max = {
x: 800,
y: 800
};
const sites = [];
const points = 10000;
for ( let i = 0; i < points; i++ ) sites.push( {
x: Math.floor( Math.random() * max.x ),
y: Math.floor( Math.random() * max.y )
} );
const c = ( alpha ) => 'rgba(255,0,0,' + alpha + ')';
const c2 = ( alpha ) => {
let colors = [
'rgba(78,9,12,' + alpha + ')',
'rgba(161,34,19,' + alpha + ')',
'rgba(171,95,44,' + alpha + ')',
'rgba(171,95,44,' + alpha + ')',
'rgba(252,160,67,' + alpha + ')'
]
return colors[ Math.round( Math.random() * colors.length ) ];
}
sites.forEach( p => {
let imgData = tctx.getImageData( p.x, p.y, 1, 1 ).data;
ctx.fillStyle = ( imgData[ 0 ] == 255 ) ? c2( 1 ) : c2( 0 );
ctx.fillRect( p.x, p.y, 2, 2 )
} );
<canvas id="canvas" width="800" height="800"></canvas>
<canvas id="template" width="800" height="800"></canvas>
I think what's happening is that your random color function sometimes returns an invalid color, because it's fetching from an undefined array element. That's caused by the use of Math.round() instead of Math.floor():
return colors[ Math.round( Math.random() * colors.length ) ];
Because of that, every once in a while a bad color expression will be used for the fill style, and that will be ignored by the canvas mechanism. Thus you get some dots outside the area covered by red pixels (the square).
I have a canvas
(check in Chrome only)
$(function() {
var Fire = function(){
this.canvas = document.getElementById('fire');
this.ctx = this.canvas.getContext('2d');
this.canvas.height = window.innerHeight;
this.canvas.width = window.innerWidth;
this.aFires = [];
this.aSpark = [];
this.aSpark2 = [];
this.mouse = {
x : this.canvas.width * .5,
y : this.canvas.height * .75,
}
this.init();
}
Fire.prototype.init = function()
{
//this.canvas.addEventListener('mousemove', this.updateMouse.bind( this ), false);
}
Fire.prototype.run = function(){
this.update();
this.draw();
if( this.bRuning )
requestAnimationFrame( this.run.bind( this ) );
}
Fire.prototype.start = function(){
this.bRuning = true;
this.run();
}
Fire.prototype.update = function(){
this.aFires.push( new Flame( this.mouse ) );
this.aSpark.push( new Spark( this.mouse ) );
this.aSpark2.push( new Spark( this.mouse ) );
for (var i = this.aFires.length - 1; i >= 0; i--) {
if( this.aFires[i].alive )
this.aFires[i].update();
else
this.aFires.splice( i, 1 );
}
for (var i = this.aSpark.length - 1; i >= 0; i--) {
if( this.aSpark[i].alive )
this.aSpark[i].update();
else
this.aSpark.splice( i, 1 );
}
for (var i = this.aSpark2.length - 1; i >= 0; i--) {
if( this.aSpark2[i].alive )
this.aSpark2[i].update();
else
this.aSpark2.splice( i, 1 );
}
}
Fire.prototype.draw = function(){
this.ctx.globalCompositeOperation = "source-over";
this.ctx.fillStyle = "rgba( 15, 5, 2, 1 )";
this.ctx.fillRect( 0, 0, window.innerWidth, window.innerHeight );
this.grd = this.ctx.createRadialGradient( this.mouse.x, this.mouse.y - 200,200,this.mouse.x, this.mouse.y - 100,0 );
this.grd.addColorStop(0,"rgb( 15, 5, 2 )");
this.grd.addColorStop(1,"rgb(30, 10, 2 )");
this.ctx.beginPath();
this.ctx.arc( this.mouse.x, this.mouse.y - 100, 200, 0, 2*Math.PI );
this.ctx.fillStyle= this.grd;
this.ctx.fill();
this.ctx.globalCompositeOperation = "overlay";//or lighter or soft-light
for (var i = this.aFires.length - 1; i >= 0; i--) {
this.aFires[i].draw( this.ctx );
}
this.ctx.globalCompositeOperation = "soft-light";//"soft-light";//"color-dodge";
for (var i = this.aSpark.length - 1; i >= 0; i--) {
if( ( i % 2 ) === 0 )
this.aSpark[i].draw( this.ctx );
}
this.ctx.globalCompositeOperation = "color-dodge";//"soft-light";//"color-dodge";
for (var i = this.aSpark2.length - 1; i >= 0; i--) {
this.aSpark2[i].draw( this.ctx );
}
}
// Flame
var Flame = function( mouse ){
this.cx = mouse.x;
this.cy = mouse.y;
this.x = rand( this.cx - 600, this.cx + 600);
this.y = rand( this.cy - -200, this.cy + 5);
this.vy = rand( 1, 3 );
this.vx = rand( -1, 1 );
this.r = rand( 20, 30 );
this.life = rand( 3, 6 );
this.alive = true;
this.c = {
h : Math.floor( rand( 2, 40) ),
s : 1000,
l : rand( 80, 100 ),
a : 0,
ta : rand( 0.8, 0.9 )
}
}
Flame.prototype.update = function()
{
this.y -= this.vy;
this.vy += 0.05;
this.x += this.vx;
if( this.x < this.cx )
this.vx += 0.1;
else
this.vx -= 0.1;
if( this.r > 0 )
this.r -= 0.1;
if( this.r <= 0 )
this.r = 0;
this.life -= 0.15;
if( this.life <= 0 ){
this.c.a -= 0.05;
if( this.c.a <= 0 )
this.alive = false;
}else if( this.life > 0 && this.c.a < this.c.ta ){
this.c.a += .08;
}
}
Flame.prototype.draw = function( ctx ){
ctx.beginPath();
ctx.arc( this.x, this.y, this.r * 3, 0, 2*Math.PI );
ctx.fillStyle = "hsla( " + this.c.h + ", " + this.c.s + "%, " + this.c.l + "%, " + (this.c.a/20) + ")";
ctx.fill();
ctx.beginPath();
ctx.arc( this.x, this.y, this.r, 0, 2*Math.PI );
ctx.fillStyle = "hsla( " + this.c.h + ", " + this.c.s + "%, " + this.c.l + "%, " + this.c.a + ")";
ctx.fill();
}
// Spark
var Spark = function( mouse ){
this.cx = mouse.x;
this.cy = mouse.y;
this.x = rand( this.cx -600, this.cx + 600);
this.y = rand( this.cy - -200, this.cy + 5);
this.lx = this.x;
this.ly = this.y;
<!-- Edit Value -->
this.vy = rand( 1, 3 );
this.vx = rand( -4, 4 );
this.r = rand( 0, 1 );
this.life = rand( 4, 5 );
this.alive = true;
this.c = {
h : Math.floor( rand( 2, 40) ),
s : 100,
l : rand( 40, 100 ),
a : rand( 0.8, 0.9 )
}
}
Spark.prototype.update = function()
{
this.lx = this.x;
this.ly = this.y;
this.y -= this.vy;
this.x += this.vx;
if( this.x < this.cx )
this.vx += 0.2;
else
this.vx -= 0.2;
this.vy += 0.08;
this.life -= 0.1;
if( this.life <= 0 ){
this.c.a -= 0.05;
if( this.c.a <= 0 )
this.alive = false;
}
}
Spark.prototype.draw = function( ctx ){
ctx.beginPath();
ctx.moveTo( this.lx , this.ly);
ctx.lineTo( this.x, this.y);
ctx.strokeStyle = "hsla( " + this.c.h + ", " + this.c.s + "%, " + this.c.l + "%, " + (this.c.a / 2) + ")";
ctx.lineWidth = this.r * 2;
ctx.lineCap = 'round';
ctx.stroke();
ctx.closePath();
ctx.beginPath();
ctx.moveTo( this.lx , this.ly);
ctx.lineTo( this.x, this.y);
ctx.strokeStyle = "hsla( " + this.c.h + ", " + this.c.s + "%, " + this.c.l + "%, " + this.c.a + ")";
ctx.lineWidth = this.r;
ctx.stroke();
ctx.closePath();
}
rand = function( min, max ){ return Math.random() * ( max - min) + min; };
onresize = function () { oCanvas.canvas.width = window.innerWidth; oCanvas.canvas.height = window.innerHeight; };
var oCanvas;
init = function()
{
oCanvas = new Fire();
oCanvas.start();
}
window.onload = init;
});
h1
{
position:relative;
z-index:1;
float:right;
width:100%;
color:#fff;
}
#fire
{
position:fixed;
height:100%;
top:0;
right:0;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.2.3/jquery.min.js"></script>
<canvas id="fire"></canvas>
<h1>Hover Me!</h1>
I want to change the amount of canvas every time the Hover Me! is hoverd.
For example, this value is this.vy = rand (1, 3); To this value this.vy = rand (1, 30); When the hover changes.
Another thing to note is why the Mozilla browser is extremely difficult to execute and the colors in the Internet Explorer are not supported.
please help me!
I'm trying to wrap my head around the globalCompositeOperation property by attempting to combine these two examples: JSFiddle and Codepen.
The former is using destination-outand the latter is using source-over. Would it be possible to use the fiery cursor in the Codepen, but also have it remove the portion of the overlay fill that the user clicks on, as in the Fiddle?
Any assistance would be most appreciated. I can combine the demos on Codepen to use the same methods if necessary.
Relevant Fiddle code:
function drawDot(mouseX,mouseY){
bridgeCanvas.beginPath();
bridgeCanvas.arc(mouseX, mouseY, brushRadius, 0, 2*Math.PI, true);
bridgeCanvas.fillStyle = '#000';
bridgeCanvas.globalCompositeOperation = "destination-out";
bridgeCanvas.fill();
}
Relevant Codepen code:
Fire.prototype.clearCanvas = function(){
this.ctx.globalCompositeOperation = "source-over";
this.ctx.fillStyle = "rgba( 15, 5, 2, 1 )";
this.ctx.fillRect( 0, 0, window.innerWidth, window.innerHeight );
this.ctx.globalCompositeOperation = "lighter";
this.ctx.rect(0, 0, this.canvas.width, this.canvas.height);
this.ctx.fillStyle = this.pattern;
this.ctx.fill();/**/
}
As I said in comments, you'll have to divide your code in at least two parts.
The cropper function uses "destination-out" compositing operation to remove the already drawn pixels of the canvas where the new ones should be drawn. In your version, it uses a background-image, and once the foreground pixels are removed, you can see this background since in the now transparent areas of the canvas.
The flame one in the other hand, uses '"lighter"', "color-dodge" and "soft-light" blending operations. This will add the colors of both the already there and the new drawn pixels.
At least the first one, if used on a transparent area, will be the same as the default "source-over" composite operation. So you need to have the background image drawn onto the canvas to be able to use it in the blending.
For this, you've got to use a second, off-screen canvas, where you will only apply the eraser "destination-out" operation. Then, on the visible canvas, at each new eraser frame, you'll have to draw the background image on your visible canvas, then the eraser one, with the holes, and finally the blending one, which will mix all together.
Here is a quick code dump, where I rewrote a bit the eraser, and modified the Fire one, in order to make our main function handles both events and animation loop.
function MainDrawing(){
this.canvas = document.getElementById('main');
this.ctx = this.canvas.getContext('2d');
this.background = new Image();
this.background.src = "https://s3-us-west-2.amazonaws.com/s.cdpn.io/4273/calgary-bridge-1943.jpg"
this.eraser = new Eraser(this.canvas);
this.fire = new Fire(this.canvas);
this.attachEvents();
}
MainDrawing.prototype = {
anim: function(){
if(this.stopped)
return;
this.ctx.globalCompositeOperation = 'source-over';
this.ctx.drawImage(this.background, 0,0);
this.ctx.drawImage(this.eraser.canvas, 0,0);
this.fire.run();
requestAnimationFrame(this.anim.bind(this));
},
stop: function(){
this.stopped = true;
},
attachEvents: function(){
var mouseDown = false;
this.canvas.onmousedown = function(){
mouseDown = true;
};
this.canvas.onmouseup = function(){
mouseDown = false;
};
this.canvas.onmousemove = function(e){
if(mouseDown){
this.eraser.handleClick(e);
}
this.fire.updateMouse(e);
}.bind(this);
}
};
function Eraser(canvas){
this.main = canvas;
this.canvas = canvas.cloneNode();
var ctx = this.ctx = this.canvas.getContext('2d');
this.img = new Image();
this.img.onload = function(){
ctx.drawImage(this, 0, 0);
ctx.globalCompositeOperation = 'destination-out';
};
this.img.src = "https://s3-us-west-2.amazonaws.com/s.cdpn.io/4273/calgary-bridge-2013.jpg";
this.getRect();
}
Eraser.prototype = {
getRect: function(){
this.rect = this.main.getBoundingClientRect();
},
handleClick: function(evt){
var x = evt.clientX - this.rect.left;
var y = evt.clientY - this.rect.top;
this.draw(x,y);
},
draw: function(x, y){
this.ctx.beginPath();
this.ctx.arc(x, y, 30, 0, Math.PI*2);
this.ctx.fill();
}
};
var Fire = function(canvas){
this.canvas = canvas;
this.ctx = this.canvas.getContext('2d');
this.aFires = [];
this.aSpark = [];
this.aSpark2 = [];
this.mouse = {
x : this.canvas.width * .5,
y : this.canvas.height * .75,
}
}
Fire.prototype.run = function(){
this.update();
this.draw();
}
Fire.prototype.start = function(){
this.bRuning = true;
this.run();
}
Fire.prototype.stop = function(){
this.bRuning = false;
}
Fire.prototype.update = function(){
this.aFires.push( new Flame( this.mouse ) );
this.aSpark.push( new Spark( this.mouse ) );
this.aSpark2.push( new Spark( this.mouse ) );
for (var i = this.aFires.length - 1; i >= 0; i--) {
if( this.aFires[i].alive )
this.aFires[i].update();
else
this.aFires.splice( i, 1 );
}
for (var i = this.aSpark.length - 1; i >= 0; i--) {
if( this.aSpark[i].alive )
this.aSpark[i].update();
else
this.aSpark.splice( i, 1 );
}
for (var i = this.aSpark2.length - 1; i >= 0; i--) {
if( this.aSpark2[i].alive )
this.aSpark2[i].update();
else
this.aSpark2.splice( i, 1 );
}
}
Fire.prototype.draw = function(){
this.drawHalo();
this.ctx.globalCompositeOperation = "overlay";//or lighter or soft-light
for (var i = this.aFires.length - 1; i >= 0; i--) {
this.aFires[i].draw( this.ctx );
}
this.ctx.globalCompositeOperation = "soft-light";//"soft-light";//"color-dodge";
for (var i = this.aSpark.length - 1; i >= 0; i--) {
if( ( i % 2 ) === 0 )
this.aSpark[i].draw( this.ctx );
}
this.ctx.globalCompositeOperation = "color-dodge";//"soft-light";//"color-dodge";
for (var i = this.aSpark2.length - 1; i >= 0; i--) {
this.aSpark2[i].draw( this.ctx );
}
}
Fire.prototype.updateMouse = function( e ){
this.mouse.x = e.clientX;
this.mouse.y = e.clientY;
}
Fire.prototype.drawHalo = function(){
var r = rand( 300, 350 );
this.ctx.globalCompositeOperation = "lighter";
this.grd = this.ctx.createRadialGradient( this.mouse.x, this.mouse.y,r,this.mouse.x, this.mouse.y, 0 );
this.grd.addColorStop(0,"transparent");
this.grd.addColorStop(1,"rgb( 50, 2, 0 )");
this.ctx.beginPath();
this.ctx.arc( this.mouse.x, this.mouse.y - 100, r, 0, 2*Math.PI );
this.ctx.fillStyle= this.grd;
this.ctx.fill();
}
var Flame = function( mouse ){
this.cx = mouse.x;
this.cy = mouse.y;
this.x = rand( this.cx - 25, this.cx + 25);
this.y = rand( this.cy - 5, this.cy + 5);
this.lx = this.x;
this.ly = this.y;
this.vy = rand( 1, 3 );
this.vx = rand( -1, 1 );
this.r = rand( 30, 40 );
this.life = rand( 2, 7 );
this.alive = true;
this.c = {
h : Math.floor( rand( 2, 40) ),
s : 100,
l : rand( 80, 100 ),
a : 0,
ta : rand( 0.8, 0.9 )
}
}
Flame.prototype.update = function()
{
this.lx = this.x;
this.ly = this.y;
this.y -= this.vy;
this.vy += 0.08;
this.x += this.vx;
if( this.x < this.cx )
this.vx += 0.2;
else
this.vx -= 0.2;
if( this.r > 0 )
this.r -= 0.3;
if( this.r <= 0 )
this.r = 0;
this.life -= 0.12;
if( this.life <= 0 ){
this.c.a -= 0.05;
if( this.c.a <= 0 )
this.alive = false;
}else if( this.life > 0 && this.c.a < this.c.ta ){
this.c.a += .08;
}
}
Flame.prototype.draw = function( ctx ){
this.grd1 = ctx.createRadialGradient( this.x, this.y, this.r*3, this.x, this.y, 0 );
this.grd1.addColorStop( 0.5, "hsla( " + this.c.h + ", " + this.c.s + "%, " + this.c.l + "%, " + (this.c.a/20) + ")" );
this.grd1.addColorStop( 0, "transparent" );
this.grd2 = ctx.createRadialGradient( this.x, this.y, this.r, this.x, this.y, 0 );
this.grd2.addColorStop( 0.5, "hsla( " + this.c.h + ", " + this.c.s + "%, " + this.c.l + "%, " + this.c.a + ")" );
this.grd2.addColorStop( 0, "transparent" );
ctx.beginPath();
ctx.arc( this.x, this.y, this.r * 3, 0, 2*Math.PI );
ctx.fillStyle = this.grd1;
//ctx.fillStyle = "hsla( " + this.c.h + ", " + this.c.s + "%, " + this.c.l + "%, " + (this.c.a/20) + ")";
ctx.fill();
ctx.globalCompositeOperation = "overlay";
ctx.beginPath();
ctx.arc( this.x, this.y, this.r, 0, 2*Math.PI );
ctx.fillStyle = this.grd2;
ctx.fill();
ctx.beginPath();
ctx.moveTo( this.lx , this.ly);
ctx.lineTo( this.x, this.y);
ctx.strokeStyle = "hsla( " + this.c.h + ", " + this.c.s + "%, " + this.c.l + "%, 1)";
ctx.lineWidth = rand( 1, 2 );
ctx.stroke();
ctx.closePath();
}
var Spark = function( mouse ){
this.cx = mouse.x;
this.cy = mouse.y;
this.x = rand( this.cx -40, this.cx + 40);
this.y = rand( this.cy, this.cy + 5);
this.lx = this.x;
this.ly = this.y;
this.vy = rand( 1, 3 );
this.vx = rand( -4, 4 );
this.r = rand( 0, 1 );
this.life = rand( 4, 8 );
this.alive = true;
this.c = {
h : Math.floor( rand( 2, 40) ),
s : 100,
l : rand( 40, 100 ),
a : rand( 0.8, 0.9 )
}
}
Spark.prototype.update = function()
{
this.lx = this.x;
this.ly = this.y;
this.y -= this.vy;
this.x += this.vx;
if( this.x < this.cx )
this.vx += 0.2;
else
this.vx -= 0.2;
this.vy += 0.08;
this.life -= 0.1;
if( this.life <= 0 ){
this.c.a -= 0.05;
if( this.c.a <= 0 )
this.alive = false;
}
}
Spark.prototype.draw = function( ctx ){
ctx.beginPath();
ctx.moveTo( this.lx , this.ly);
ctx.lineTo( this.x, this.y);
ctx.strokeStyle = "hsla( " + this.c.h + ", " + this.c.s + "%, " + this.c.l + "%, " + (this.c.a / 2) + ")";
ctx.lineWidth = this.r * 2;
ctx.lineCap = 'round';
ctx.stroke();
ctx.closePath();
ctx.beginPath();
ctx.moveTo( this.lx , this.ly);
ctx.lineTo( this.x, this.y);
ctx.strokeStyle = "hsla( " + this.c.h + ", " + this.c.s + "%, " + this.c.l + "%, " + this.c.a + ")";
ctx.lineWidth = this.r;
ctx.stroke();
ctx.closePath();
}
rand = function( min, max ){ return Math.random() * ( max - min) + min; };
var app = new MainDrawing();
app.anim();
<canvas id="main" width="750" height="465"></canvas>