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| <script> | | <canvas id="canvas" height="142px" width="673px"></canvas> |
| // fork of
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| // http://jsfiddle.net/jonnyc/Ujz4P/5/
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| //
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| // Create an array to store our particles
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| var particles = [];
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| // The amount of particles to render
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| var particleCount = 60;
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| // The maximum velocity in each direction
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| var maxVelocity = 2;
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| // The target frames per second (how often do we want to update / redraw the scene)
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| var targetFPS = 33;
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| // Set the dimensions of the canvas as variables so they can be used.
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| var canvasWidth = window.innerWidth;
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| var canvasHeight = window.innerHeight;
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| // borders for particles on top and bottom
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| var borderTop = 0.01 * canvasHeight;
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| var borderBottom = 0.99 * canvasHeight;
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| // Create an image object (only need one instance)
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| var imageObj = new Image();
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| // Once the image has been downloaded then set the image on all of the particles
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| imageObj.onload = function() {
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| particles.forEach(function(particle) {
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| particle.setImage(imageObj);
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| });
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| };
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| // Once the callback is arranged then set the source of the image
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| imageObj.src = "http://www.blog.jonnycornwell.com/wp-content/uploads/2012/07/Smoke10.png";
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| // A function to create a particle object.
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| function Particle(context) {
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| // Set the initial x and y positions
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| this.x = 0;
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| this.y = 0;
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| // Set the initial velocity
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| this.xVelocity = 0;
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| this.yVelocity = 0;
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| // Set the radius
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| this.radius = 5;
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| // Store the context which will be used to draw the particle
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| this.context = context;
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| // The function to draw the particle on the canvas.
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| this.draw = function() {
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| // If an image is set draw it
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| if (this.image) {
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| this.context.drawImage(this.image, this.x - 128, this.y - 128);
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| // If the image is being rendered do not draw the circle so break out of the draw function
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| return;
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| }
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| // Draw the circle as before, with the addition of using the position and the radius from this object.
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| this.context.beginPath();
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| this.context.arc(this.x, this.y, this.radius, 0, 2 * Math.PI, false);
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| this.context.fillStyle = "rgba(0, 255, 255, 0.1)";
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| this.context.fill();
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| this.context.closePath();
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| };
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| // Update the particle.
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| this.update = function() {
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| // Update the position of the particle with the addition of the velocity.
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| this.x += this.xVelocity;
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| this.y += this.yVelocity;
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| // Check if has crossed the right edge
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| if (this.x >= canvasWidth) {
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| this.xVelocity = -this.xVelocity;
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| this.x = canvasWidth;
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| }
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| // Check if has crossed the left edge
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| else if (this.x <= 0) {
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| this.xVelocity = -this.xVelocity;
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| this.x = 0;
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| }
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| // Check if has crossed the bottom edge
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| if (this.y >= borderBottom) {
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| this.yVelocity = -this.yVelocity;
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| this.y = borderBottom;
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| }
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| // Check if has crossed the top edge
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| else if (this.y <= borderTop) {
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| this.yVelocity = -this.yVelocity;
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| this.y = borderTop;
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| }
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| };
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| // A function to set the position of the particle.
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| this.setPosition = function(x, y) {
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| this.x = x;
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| this.y = y;
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| };
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| // Function to set the velocity.
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| this.setVelocity = function(x, y) {
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| this.xVelocity = x;
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| this.yVelocity = y;
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| };
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| this.setImage = function(image) {
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| this.image = image;
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| };
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| }
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| // A function to generate a random number between 2 values
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| function generateRandom(min, max) {
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| return Math.random() * (max - min) + min;
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| }
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| // The canvas context if it is defined.
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| var context;
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| // Initialise the scene and set the context if possible
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| function init() {
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| var canvas = document.getElementById('myCanvas');
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| canvas.width = window.innerWidth;
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| canvas.height = window.innerHeight;
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| if (canvas.getContext) {
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| // Set the context variable so it can be re-used
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| context = canvas.getContext('2d');
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| // Create the particles and set their initial positions and velocities
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| for (var i = 0; i < particleCount; ++i) {
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| var particle = new Particle(context);
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| // Set the position to be inside the canvas bounds
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| particle.setPosition(generateRandom(0, canvasWidth), generateRandom(borderTop, borderBottom));
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| // Set the initial velocity to be either random and either negative or positive
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| particle.setVelocity(generateRandom(-maxVelocity, maxVelocity), generateRandom(-maxVelocity, maxVelocity));
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| particles.push(particle);
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| }
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| } else {
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| alert("Please use a modern browser");
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| }
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| }
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| // The function to draw the scene
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| function draw() {
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| // background image
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| context.globalAlpha = 1;
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| context.globalCompositeOperation = 'source-over';
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| context.drawImage(backImg, 0, 0, canvasWidth, canvasHeight);
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| context.globalAlpha = 0.75; context.globalCompositeOperation = 'soft-lights';
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| // Fog layer
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| // Go through all of the particles and draw them.
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| particles.forEach(function(particle) {
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| particle.draw();
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| });
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|
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| }
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| // Update the scene
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| function update() {
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| particles.forEach(function(particle) {
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| particle.update();
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| });
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| }
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| // Initialize the scene
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| init();
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| var backImg = document.getElementById("back");
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| // If the context is set then we can draw the scene (if not then the browser does not support canvas)
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| if (context) {
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| setInterval(function() {
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| // Update the scene befoe drawing
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| update();
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| // Draw the scene
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| draw();
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| }, 1000 / targetFPS);
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| }
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| </script>
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| <img id="back" width="100%" height="auto" src="https://lauracampbell89.files.wordpress.com/2014/12/e0bf35_1da77d8cc72b4028a5c0a40e8944884b.jpg" />
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| <div class="u-full-width">
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| <center>
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| <canvas id="myCanvas" width="900" height="600"></canvas>
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| </center>
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| </div>
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| <div id="headText">
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| I loved you<br /> at your darkest.
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| </div>
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