Огненно-радужный шторм на HTML5 Canvas
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<canvas id="c"></canvas> <script> /* * The design was completely made by @jackrugile in his other pen: * http://codepen.io/jackrugile/pen/AokpF * This is just a recreation of that pen * */ //==//==============// // canvas setup // //==//==============// var ctx = c.getContext('2d'), width = c.width = window.innerWidth, height = c.height = window.innerHeight, //==//==================// // a few parameters // //==//==================// particleCount = (width / 2) | 0, obstacleCount = ((width + height) / 20) | 0, obstacleRadius = 100, gravity = .1, //==//========================// // other needed variables // //==//========================// particles = [], obstacles = [], frame = 0, tau = Math.PI * 2, //==//=========================// // initialization function // //==//=========================// init = function() { // initial fade to cancel repaint leftover lines, pointed out by the great lemon ctx.fillStyle = '#222'; ctx.fillRect(0, 0, width, height); while (--particleCount) particles.push(new Particle); while (--obstacleCount) obstacles.push(new Obstacle); anim(); }, //==//===================================// // animation loop and main functions // //==//===================================// anim = function() { window.requestAnimationFrame(anim); step(); draw(); }, step = function() { particles.map(function(particle) { particle.step(); }); obstacles.map(function(obstacle) { obstacle.step(); }); }, draw = function() { ctx.globalCompositeOperation = 'destination-out'; ctx.shadowBlur = 0; ctx.fillStyle = 'rgba(0, 0, 0, .1)'; ctx.fillRect(0, 0, width, height); ctx.globalCompositeOperation = 'lighter'; particles.map(function(particle) { particle.draw(); }); ctx.globalCompositeOperation = 'source-over'; ctx.fillStyle = 'rgba(25, 25, 25, .2)'; // purposely didn't change ctx.shadowColor obstacles.map(function(obstacle) { obstacle.draw(); }); }, spawnNew = function(x, y) { var part = new Particle; part.x = x; part.y = y; particles.push(part); }, //==//===================// // utility functions // //==//===================// checkDistance = function(par, obs) { var x = par.x - obs.x, y = par.y - obs.y, d = obs.radius; return d * d >= x * x + y * y; }, rand = function(min, max) { return Math.random() * (max - min) + min; }, validateObstacleResize = function(obs) { obs.validateResize(); }, //==//====================================// // Particle and Obstacle constructors // //==//====================================// Particle = function() { this.reset(); }, Obstacle = function() { this.reset(); }; Particle.prototype = { reset: function() { this.x = rand(0, width) | 0; this.y = rand(-obstacleRadius, 0) | 0; this.vx = this.vy = this.shine = 0; this.last = { x: this.x, y: this.y }; this.color = 'hsla(hue, 80%, 50%, alp)'.replace('hue', (frame + 360 * this.x / width) | 0); }, step: function() { if (this.shine)--this.shine; this.last.x = this.x; this.last.y = this.y; this.x += this.vx; this.y += this.vy += gravity; if ((this.x < 0 || this.x > width) && Math.random() < .4) this.vx *= -1; if (this.y < -obstacleRadius || this.y > height) { frame += .3; this.reset(); } var len = obstacles.length; while (--len + 1) { if (checkDistance(this, obstacles[len])) { this.hit(obstacles[len]); len = 0; } } }, hit: function(obs) { this.vx = (this.x - obs.x) * rand(.02, .03); this.vy = (this.y - obs.y) * rand(.02, .03); this.shine = 2; ++obs.toRemove; }, draw: function() { ctx.strokeStyle = this.color.replace('alp', .4); ctx.beginPath(); ctx.moveTo(this.last.x, this.last.y); ctx.lineTo(this.x, this.y); ctx.stroke(); if (this.shine) { ctx.shadowColor = ctx.strokeStyle; ctx.shadowBlur = this.shine * 3; ctx.fillStyle = this.color.replace('alp', .05); ctx.beginPath(); ctx.arc(this.x | 0, this.y | 0, this.shine * 8, 0, tau); ctx.fill(); } else ctx.shadowBlur = 0; } } Obstacle.prototype = { reset: function() { this.x = rand(0, width) | 0; this.y = rand(obstacleRadius * 2, height) | 0; this.maxRadius = rand(obstacleRadius / 2, obstacleRadius) | 0; this.radius = rand(this.maxRadius / 2, this.maxRadius); this.new = 30; this.toRemove = 0; }, step: function() { if (this.new) this.new -= 5; if (this.toRemove) { --this.radius; --this.toRemove; if (this.radius < 0) this.reset(); } else if (this.radius < this.maxRadius)++this.radius; }, draw: function() { ctx.shadowBlur = this.new; ctx.beginPath(); ctx.arc(this.x, this.y, this.radius, 0, tau); ctx.fill(); }, validateResize: function() { if (this.x > width || this.y > height) this.reset(); } } //==//=================// // and here we go! // //==//=================// init(); //==//================// // resize handler // //==//================// window.addEventListener('resize', function() { width = c.width = window.innerWidth; height = c.height = window.innerHeight; ctx.fillStyle = '#222'; ctx.fillRect(0, 0, width, height); obstacles.map(validateObstacleResize); }); //==//==============// // add on click // //==//==============// window.addEventListener('click', function() { for (var i = 0; i < 10; ++i) particles.push(new Particle); }); </script> |
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