Adapted from http://bl.ocks.org/mbostock/2647924, to show one single moving dot
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August 29, 2015 14:09
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Perception of Movement
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <title>Movement</title> | |
| <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> | |
| <link type="text/css" rel="stylesheet" href="css/style.css"> | |
| </head> | |
| <body> | |
| <h1>Perception of movement</h1> | |
| <div id='circles'></div> | |
| <script src="http://d3js.org/d3.v3.min.js"></script> | |
| <script> | |
| var w = 1200, | |
| h = 500; | |
| var svg = d3.select("#circles").append("svg:svg") | |
| .attr("width", w) | |
| .attr("height", h); | |
| //d3.select("h1").on("click", startCircles); | |
| var circle = svg.selectAll("circle") | |
| .data(d3.range(50).map(function() { | |
| return { | |
| x: w * Math.random(), | |
| y: h * Math.random(), | |
| dx: Math.random() - .5, | |
| dy: Math.random() - .5 | |
| }; | |
| })) | |
| .enter().append("svg:circle") | |
| .attr("r", 2.5) | |
| .attr("cx", function(d) { d.x += d.dx; if (d.x > w) d.x -= w; else if (d.x < 0) d.x += w; return d.x; }) | |
| .attr("cy", function(d) { d.y += d.dy; if (d.y > h) d.y -= h; else if (d.y < 0) d.y += h; return d.y; }); | |
| var moving = svg.selectAll("moving") | |
| .data(d3.range(1).map(function() { | |
| return { | |
| x: w * Math.random(), | |
| y: h * Math.random(), | |
| dx: Math.random() - .5, | |
| dy: Math.random() - .5 | |
| }; | |
| })) | |
| .enter().append("svg:circle") | |
| .attr("class", "moving") | |
| .attr("r", 2.5); | |
| var start = Date.now(), | |
| frames = 0; | |
| d3.timer(function() { | |
| // Update the FPS meter. | |
| var now = Date.now(), duration = now - start; | |
| if (duration >= 1000) frames = 0, start = now; | |
| // Update the circle positions. | |
| moving | |
| .attr("cx", function(d) { d.x += d.dx; if (d.x > w) d.x -= w; else if (d.x < 0) d.x += w; return d.x; }) | |
| .attr("cy", function(d) { d.y += d.dy; if (d.y > h) d.y -= h; else if (d.y < 0) d.y += h; return d.y; }); | |
| }); | |
| </script> | |
| </body> | |
| </html> |
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