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August 29, 2015 14:04
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canvas + shadows-circles + ctx.rotate
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| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <link href="stars.css" rel="stylesheet"> | |
| </head> | |
| <body> | |
| <script src="http://d3js.org/d3.v3.min.js"></script> | |
| <script src="stars.js"></script> | |
| <script>d3.select(self.frameElement).style("height", "840px")</script> | |
| </body> | |
| </html> |
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| body { | |
| margin: 0; | |
| background: #000313; | |
| } |
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| var width = 960, | |
| height = 840 | |
| var projection = d3.geo.azimuthalEquidistant() | |
| .scale(width / 5) | |
| .translate([0, 0]) | |
| .rotate([-18 * 15, -66.56]) | |
| var canvas = d3.select("body").append("canvas") | |
| var ctx = canvas.node().getContext("2d") | |
| var offScreenCanvas = document.createElement('canvas') | |
| var offCtx = offScreenCanvas.getContext('2d') | |
| function getRetinaRatio() { | |
| var devicePixelRatio = window.devicePixelRatio || 1 | |
| var backingStoreRatio = ctx.webkitBackingStorePixelRatio || | |
| ctx.mozBackingStorePixelRatio || | |
| ctx.msBackingStorePixelRatio || | |
| ctx.oBackingStorePixelRatio || | |
| ctx.backingStorePixelRatio || 1 | |
| return devicePixelRatio / backingStoreRatio | |
| } | |
| var ratio = getRetinaRatio() | |
| var scaledWidth = width * ratio | |
| var scaledHeight = height * ratio | |
| canvas.node().width = scaledWidth | |
| canvas.node().height = scaledHeight | |
| canvas | |
| .style("width", width + 'px') | |
| .style("height", height + 'px') | |
| offScreenCanvas.width = scaledWidth | |
| offScreenCanvas.height = scaledHeight | |
| offCtx.scale(ratio, ratio) | |
| offCtx.translate(width / 2, height / 2) | |
| function addZodiacName(data) { | |
| var x1 = 0, y1 = -data.y / Math.sin(Math.atan2(data.y, data.x)) | |
| offCtx.save() | |
| offCtx.rotate(Math.atan2(data.y, data.x) + Math.PI / 2 ) | |
| offCtx.textAlign = "center" | |
| offCtx.font = "12px sans-serif" | |
| offCtx.strokeStyle = "#000313" | |
| offCtx.lineWidth = 3 | |
| offCtx.lineJoin = "round" | |
| offCtx.strokeText(data.name, x1, y1) | |
| offCtx.fillStyle = "white" | |
| offCtx.fillText(data.name, x1, y1) | |
| offCtx.restore() | |
| } | |
| function distance(x,y) { | |
| return Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2)) | |
| } | |
| function drawLine(line) { | |
| offCtx.strokeStyle = (line.zodiac) ? '#f2f237':'white' | |
| offCtx.lineWidth = (line.zodiac) ? 0.8 : 0.4 | |
| offCtx.beginPath() | |
| offCtx.moveTo(line.line[0][0], line.line[0][1]) | |
| offCtx.lineTo(line.line[1][0], line.line[1][1]) | |
| offCtx.stroke() | |
| } | |
| function drawStar(star) { | |
| offCtx.fillStyle = '#000313' | |
| offCtx.beginPath() | |
| offCtx.moveTo(star.projection[0], star.projection[1]); | |
| offCtx.arc(star.projection[0], star.projection[1], star.radius + 1.2, 0 ,Math.PI * 2 ,true); | |
| offCtx.fill() | |
| offCtx.fillStyle = star.color | |
| offCtx.beginPath() | |
| offCtx.moveTo(star.projection[0], star.projection[1]); | |
| offCtx.arc(star.projection[0], star.projection[1], star.radius, 0 ,Math.PI * 2 ,true); | |
| offCtx.fill() | |
| } | |
| function clearCtx(){ | |
| offCtx.clearRect(-width / 2, -height / 2, width, height) | |
| ctx.clearRect(0, 0, scaledWidth, scaledHeight) | |
| } | |
| d3.json("/erohinaelena/raw/ec635d68e8bf55586d40/starData.json", function(error, data) { | |
| var begin = performance.now() | |
| var constellationLines = [] | |
| var constellationStars = [] | |
| var zodiacNames = [] | |
| data.forEach(function (constellation) { | |
| var name = constellation.name | |
| var projections = constellation.stars.map(function (star) { | |
| var p = projection([star.ra, star.dec]) | |
| var out = (distance(p[0], p[1]) > width / 2.5) | |
| return { | |
| color: star.color, | |
| mag: star.mag, | |
| radius: Math.pow(1.2, 3 - star.mag), | |
| projection: p, | |
| out: out | |
| } | |
| }) | |
| var x = d3.mean(projections, function (d) { return d.projection[0] = -d.projection[0] }) | |
| var y = d3.mean(projections, function (d) { return d.projection[1] }) | |
| projections = projections.filter(function (star) { | |
| return !star.out && star.mag <= 6 | |
| }) | |
| if (distance(x, y) < width / 3 || constellation.zodiac){ | |
| var lines = constellation.lines.map(function (line) { | |
| var p1 = projection([line.ra1, line.dec1]) | |
| var p2 = projection([line.ra2, line.dec2]) | |
| p1[0] = -p1[0] | |
| p2[0] = -p2[0] | |
| var out = distance(p1[0], p1[1]) > width / 3 | |
| return {line: [p1, p2], zodiac: constellation.zodiac, out: out} | |
| }) | |
| lines = lines.filter(function (line) { | |
| return !line.out || line.zodiac | |
| }) | |
| constellationLines.push(lines) | |
| } | |
| constellationStars.push(projections) | |
| if (constellation.zodiac) | |
| zodiacNames.push({ | |
| name: name, | |
| x: x, | |
| y: y | |
| }) | |
| }) | |
| var angle = 0 | |
| var fps = 'fps' | |
| var frames = 0 | |
| function draw () { | |
| begin = performance.now() | |
| frames++ | |
| clearCtx() | |
| offCtx.fillStyle = '#fff' | |
| offCtx.fillText(fps, -width / 2 + 10, -height / 2 + 20) | |
| angle += 0.002 | |
| offCtx.save() | |
| offCtx.rotate(angle) | |
| constellationLines.forEach(function(lines){ | |
| lines.forEach(drawLine) | |
| }) | |
| constellationStars.forEach(function(projections){ | |
| projections.forEach(drawStar) | |
| }) | |
| zodiacNames.forEach(addZodiacName) | |
| offCtx.restore() | |
| ctx.drawImage(offScreenCanvas, 0, 0); | |
| } | |
| function animate(){ | |
| window.requestAnimationFrame(animate) | |
| draw() | |
| } | |
| animate() | |
| setInterval(function () { | |
| fps = frames / 10 + ' fps' | |
| console.log(fps) | |
| frames = 0 | |
| }, 10000) | |
| setTimeout(function () {console.log(performance.now() - begin,'ms') }) | |
| }) | |
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