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Floating Particles
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title></title> | |
| <style> | |
| body { | |
| background-color: black; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <script src="//d3js.org/d3.v3.min.js" charset="utf-8"></script> | |
| <script> | |
| var width = 960, | |
| height = 500; | |
| var scale = { | |
| x: d3.scale.linear().domain([0, 1]).range([0, width]), | |
| y: d3.scale.linear().domain([0, 1]).range([height, 0]), | |
| r: d3.scale.linear().domain([0, 1]).range([1, 4]), | |
| a: d3.scale.linear().domain([0, 1]).range([.1, .6]) | |
| }; | |
| var canvas = d3.select("body").append("canvas") | |
| .attr("width", width) | |
| .attr("height", height); | |
| var context = canvas.node().getContext("2d"); | |
| var particles = d3.range(1000) | |
| .map(function() { | |
| return { | |
| x: Math.random(), | |
| y: Math.random(), | |
| r: Math.random(), | |
| t: Math.random()*2*Math.PI | |
| }; | |
| }); | |
| draw(particles); | |
| setInterval(function() { | |
| particles = tick(particles); | |
| draw(particles); | |
| }, 66); | |
| function tick(particles) { | |
| return particles.map(function(d) { | |
| d.t += Math.random()*.5 - .25; | |
| d.x += .001*Math.cos(d.t); | |
| d.y += .001*Math.sin(d.t); | |
| d.r += Math.random()*.01 - .005; | |
| if (d.x < 0 || d.x > width) { | |
| d.x = .5; | |
| d.r = .1; | |
| } | |
| if (d.y < 0 || d.y > height) { | |
| d.y = .5; | |
| d.r = .1; | |
| } | |
| if (d.r <= 0) d.r = .1; | |
| return d; | |
| }); | |
| } | |
| function draw(particles) { | |
| context.clearRect(0, 0, width, height); | |
| particles.forEach(function(d) { | |
| var x = scale.x(d.x), | |
| y = scale.y(d.y), | |
| r = scale.r(d.r), | |
| a = scale.a(d.r); | |
| context.beginPath() | |
| context.arc(x, y, r, 0, 2*Math.PI); | |
| context.fillStyle = "rgba(255, 255, 255," + a + ")"; | |
| context.fill(); | |
| }); | |
| } | |
| </script> | |
| </body> | |
| </html> |
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