function FizzyText(message) { var that = this; // These are the variables that we manipulate with gui-dat. // Notice they're all defined with "this". That makes them public. // Otherwise, gui-dat can't see them. this.growthSpeed = 0.2; // how fast do particles change size? this.minSize = 1; this.maxSize = 5.59; // how big can they get? this.noiseStrength = 10; // how turbulent is the flow? this.speed = 0.4; // how fast do particles move? this.displayOutline = true; // should we draw the message as a stroke? this.framesRendered = 0; //////////////////////////////////////////////////////////////// var _this = this; var width = 550; var height = 200; var textAscent = 101; var textOffsetLeft = 80; var noiseScale = 300; var frameTime = 30; var colors = ["#00aeff", "#0fa954", "#54396e", "#e61d5f"]; // This is the context we use to get a bitmap of text using // the getImageData function. var r = document.createElement('canvas'); var s = r.getContext('2d'); // This is the context we actually use to draw. var c = document.createElement('canvas'); var g = c.getContext('2d'); r.setAttribute('width', width); c.setAttribute('width', width); r.setAttribute('height', height); c.setAttribute('height', height); // Add our demo to the HTML document.getElementById('fizzytext').appendChild(c); // Stores bitmap image var pixels = []; // Stores a list of particles var particles = []; // Set g.font to the same font as the bitmap canvas, incase we // want to draw some outlines. s.font = g.font = "800 82px helvetica, arial, sans-serif"; // Instantiate some particles for (var i = 0; i < 1000; i++) { particles.push(new Particle(Math.random() * width, Math.random() * height)); } // This function creates a bitmap of pixels based on your message // It's called every time we change the message property. var createBitmap = function (msg) { s.fillStyle = "#fff"; s.fillRect(0, 0, width, height); s.fillStyle = "#222"; s.fillText(msg, textOffsetLeft, textAscent); // Pull reference var imageData = s.getImageData(0, 0, width, height); pixels = imageData.data; }; // Called once per frame, updates the animation. var render = function () { that.framesRendered ++; g.clearRect(0, 0, width, height); if (_this.displayOutline) { g.globalCompositeOperation = "source-over"; g.strokeStyle = "#000"; g.lineWidth = .5; g.strokeText(message, textOffsetLeft, textAscent); } g.globalCompositeOperation = "darker"; for (var i = 0; i < particles.length; i++) { g.fillStyle = colors[i % colors.length]; particles[i].render(); } }; // Returns x, y coordinates for a given index in the pixel array. var getPosition = function (i) { return { x: (i - (width * 4) * Math.floor(i / (width * 4))) / 4, y: Math.floor(i / (width * 4)) }; }; // Returns a color for a given pixel in the pixel array. var getColor = function (x, y) { var base = (Math.floor(y) * width + Math.floor(x)) * 4; var c = { r: pixels[base + 0], g: pixels[base + 1], b: pixels[base + 2], a: pixels[base + 3] }; return "rgb(" + c.r + "," + c.g + "," + c.b + ")"; }; this.message = message; createBitmap(message); var loop = function() { requestAnimationFrame(loop); render(); } // This calls the render function every 30 milliseconds. loop(); // This class is responsible for drawing and moving those little // colored dots. function Particle(x, y, c) { // Position this.x = x; this.y = y; // Size of particle this.r = 1; // This velocity is used by the explode function. this.vx = 0; this.vy = 0; this.constrain = function (v, o1, o2) { if (v < o1) v = o1; else if (v > o2) v = o2; return v; }; // Called every frame this.render = function () { // What color is the pixel we're sitting on top of? var c = getColor(this.x, this.y); // Where should we move? var angle = noise(this.x / noiseScale, this.y / noiseScale) * _this.noiseStrength; // var angle = -Math.PI/2; // Are we within the boundaries of the image? var onScreen = this.x > 0 && this.x < width && this.y > 0 && this.y < height; var isBlack = c != "rgb(255,255,255)" && onScreen; // If we're on top of a black pixel, grow. // If not, shrink. if (isBlack) { this.r += _this.growthSpeed; } else { this.r -= _this.growthSpeed; } // This velocity is used by the explode function. this.vx *= 0.5; this.vy *= 0.5; // Change our position based on the flow field and our // explode velocity. this.x += Math.cos(angle) * _this.speed + this.vx; this.y += -Math.sin(angle) * _this.speed + this.vy; // this.r = 3; // debugger // console.log(DAT.GUI.constrain(this.r, 0, _this.maxSize)); this.r = this.constrain(this.r, _this.minSize, _this.maxSize); // If we're tiny, keep moving around until we find a black // pixel. // if (this.r <= 0) { // this.x = Math.random() * width; // this.y = Math.random() * height; // return; // Don't draw! // } // If we're off the screen, go over to other side if(this.x < 0) this.x = width; if(this.x > width) this.x = 0; if(this.y < 0) this.y = height; if(this.y > height) this.y = 0; // Draw the circle. g.beginPath(); g.arc(this.x, this.y, this.r, 0, Math.PI * 2, false); g.fill(); } } }