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<!DOCTYPE html> |
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<head> |
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<meta charset="utf-8"> |
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<script src="https://d3js.org/d3.v4.min.js"></script> |
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<script src="https://d3js.org/d3-queue.v2.min.js"></script> |
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<style> |
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body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; } |
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circle.main { |
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fill: none; |
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stroke: #111; |
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stroke-width: 2; |
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} |
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</style> |
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</head> |
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<body> |
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<script> |
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var width = window.innerWidth || 960; |
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var height = window.innerHeight || 500; |
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var Ra = 20; // starting radius |
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var Rb = 20; |
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var maxRadius = Ra; |
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//var ratio = 0.8; //how much to decay radius |
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var ratio = [0.8, 1.4]; |
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//var ratio = [1, 1] |
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var maxLevel = 20; |
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var adam = { x: width/2 - Ra, y: height/2, r: Ra, color: "#111", level: 0 }; |
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var eve = { x: width/2 + Rb, y: height/2, r: Rb, color: "#111", level: 0}; |
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var data = [adam, eve]; |
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var quadtree = d3.quadtree() |
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.x(function(d) { return d.x }) |
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.y(function(d) { return d.y }) |
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.extent([[-1, -1], [width + 1, height + 1]]); |
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quadtree.add(adam) |
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quadtree.add(eve) |
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var svg = d3.select("body").append("svg") |
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.attr("width", width) |
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.attr("height", height) |
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function addCircle(a,b, ROTATE) { |
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//console.log("a,b", a,b) |
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// create a new circle given parents a & b |
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var child = { r: a.r }; |
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var randomRatio = Math.random() * (ratio[1] - ratio[0]) + ratio[0] |
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//var randomRatio = 0.9 |
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child.r = randomRatio * child.r; |
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// we want to find our child's center by |
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// finding the 3rd point in the triangle |
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// with the base defined by the parents centers |
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var AC = a.r + child.r; |
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var AB = a.r + b.r; |
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var BC = child.r + b.r; |
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// SSS rule to find the angle between parents segment and a -> child segment |
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var atheta = Math.acos((AC*AC + AB*AB - BC*BC)/(2*AC*AB)); |
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// base of the right triangle made by dropping perpendicular line from child |
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// down to the segment between a and b |
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var base = Math.cos(atheta) * AC; |
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// length of the above mentioned line segment that is perpendicular |
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var altitude = Math.sin(atheta) * AC; |
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var dx = b.x - a.x; |
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var dy = b.y - a.y; |
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var magnitude = Math.sqrt(dx*dx + dy*dy); |
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var normalized = { |
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x: dx/magnitude, |
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y: dy/magnitude |
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} |
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// the angle between the parent segment (connection between a and b) |
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// and the x-axis (we essentially rotate our altitude) |
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var ptheta = -Math.acos(dx/magnitude) * (dy<0 ? -1 : 1); |
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var rotate = ptheta |
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if(ptheta < -Math.PI/2) rotate += Math.PI; |
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rotate += ROTATE |
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// we find the point perpendicular |
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var perp = { |
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x: a.x + normalized.x * base, |
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y: a.y + normalized.y * base |
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} |
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/* |
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svg.append("circle") |
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.attr("cx", perp.x) |
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.attr("cy", perp.y) |
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.attr("r", 5) |
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.style("fill", b.color) |
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*/ |
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child.x = perp.x - Math.sin(rotate)*altitude; |
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child.y = perp.y - Math.cos(rotate)*altitude; |
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return child; |
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} |
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function recurseCircle(a,b) { |
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if(a.level > maxLevel) return; |
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var c1 = addCircle(a,b, 0); |
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c1.level = a.level + 1; |
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if(c1.r > maxRadius) maxRadius = c1.r; |
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// check if new circle collides |
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var hits = []; |
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quadtree.visit(nearest(c1, maxRadius, hits)) |
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if(!hits.length && c1.x > c1.r + 2 && c1.x < width - 2 - c1.r && c1.y > c1.r + 2 && c1.y < height - 2 - c1.r ) { |
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data.push(c1) |
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quadtree.add(c1) |
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render(); |
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setTimeout(function() { |
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recurseCircle(c1, a); |
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}, 150) |
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setTimeout(function() { |
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recurseCircle(c1, b) |
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}, 300) |
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}; |
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var c2 = addCircle(a,b, Math.PI); |
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c2.level = a.level + 1; |
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if(c2.r > maxRadius) maxRadius = c2.r; |
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// check if new circle collides |
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var hits = []; |
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quadtree.visit(nearest(c2, maxRadius, hits)) |
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if(!hits.length && c2.x > c2.r + 2 && c2.x < width - 2 - c2.r && c2.y > c2.r + 2 && c2.y < height - 2 - c2.r ) { |
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data.push(c2) |
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quadtree.add(c2) |
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render(); |
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setTimeout(function() { |
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recurseCircle(c2, a); |
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}, 150) |
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setTimeout(function() { |
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recurseCircle(c2, b) |
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}, 300) |
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}; |
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} |
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recurseCircle(adam, eve) |
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function render() { |
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var circles = svg.selectAll("circle.main").data(data); |
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circles = circles.enter().append("circle") |
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.classed("main", true) |
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.on("click", function(d) { console.log(d)}) |
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.merge(circles); |
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circles |
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.attr("cx", function(d) { return d.x}) |
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.attr("cy", function(d) { return d.y}) |
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.attr("r", function(d) { return d.r}) |
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.style("stroke", function(d) { return d.color || "#111" }) |
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} |
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render(); |
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function nearest(node, radius, hits) { |
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if(!hits) hits = []; |
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// we want to find everything within radius |
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var nx1 = node.x - radius; |
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var nx2 = node.x + radius; |
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var ny1 = node.y - radius; |
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var ny2 = node.y + radius; |
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return function(quad, x1, y1, x2, y2) { |
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if (quad.data && (quad.data !== node)) { |
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var x = node.x - quad.data.x, |
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y = node.y - quad.data.y, |
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l = Math.sqrt(x * x + y * y) + 1e-7, |
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r = node.r + quad.data.r; |
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if (l < r) { |
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hits.push(quad.data) |
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} else { |
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} |
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} |
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return x1 > nx2 || x2 < nx1 || y1 > ny2 || y2 < ny1; |
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} |
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} |
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</script> |
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</body> |
