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Generating hex grid positions
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license: mit |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
<!DOCTYPE html> | |
<head> | |
<meta charset="utf-8"> | |
<script src="https://d3js.org/d3.v4.min.js"></script> | |
<style> | |
body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; } | |
</style> | |
</head> | |
<body> | |
<script> | |
console.clear() | |
var SQRT_3_2 = Math.sqrt(3)/2 | |
var SCALE = 10 | |
var toScreen = function(cube) { | |
var q = cube[0] | |
var r = cube[1] | |
var s = cube[2] | |
return { | |
x: SCALE * (r-q) * SQRT_3_2, | |
y: SCALE * (0.5*(r+q) - s) | |
} | |
} | |
// Feel free to change or delete any of the code you see in this editor! | |
var svg = d3.select("body").append("svg") | |
.attr("width", 960) | |
.attr("height", 500) | |
var g = svg.append('g') | |
.attr('transform', 'translate(480, 250)') | |
var hexPositionFactory = function() { | |
let i = 0 | |
let ring = 0 | |
let currentPosition = [0, 0, 0] | |
let currentDirection = 0 | |
let stepsInCurrentDirection = 0 | |
let directions = [ | |
[+1, -1, 0], [+1, 0, -1], [0, +1, -1], | |
[-1, +1, 0], [-1, 0, +1], [0, -1, +1] | |
] | |
let move = function(cur, dir) { | |
return [cur[0] + dir[0], cur[1] + dir[1], cur[2] + dir[2]] | |
} | |
return function() { | |
if (i === 0) { | |
i += 1 | |
ring = 1 | |
currentPosition = [0, 0, 0] | |
return currentPosition | |
} | |
let absoluteSum = currentPosition.reduce((c, p) => { | |
return Math.abs(p) + Math.abs(c) | |
}, 0) | |
if (absoluteSum / 2 < ring) { | |
stepsInCurrentDirection = 1 | |
currentPosition = [-ring, 0, ring] | |
} else { | |
currentPosition = move(currentPosition, directions[currentDirection]) | |
if (stepsInCurrentDirection >= ring) { | |
currentDirection = currentDirection + 1 | |
if (currentDirection > directions.length - 1) { | |
ring += 1 | |
currentDirection = 0 | |
currentPosition = [-ring, 0, ring] | |
} | |
stepsInCurrentDirection = 1 | |
} else { | |
stepsInCurrentDirection += 1 | |
} | |
} | |
i += 1 | |
return currentPosition.slice(0) | |
} | |
} | |
let mouseDistance = 0 | |
svg | |
.on("mousemove", function(e) { | |
let m = d3.mouse(this) | |
let dx = 480 - m[0] | |
let dy = 250 - m[1] | |
mouseDistance = Math.sqrt(dx * dx + dy * dy) | |
}) | |
let paint = function() { | |
let hexPosition = hexPositionFactory() | |
let numberOfCircles = Math.floor(mouseDistance) | |
let coordinates = d3.range(numberOfCircles).map((i) => { | |
return hexPosition() | |
}).map((cube, i) => { | |
return { | |
key: i, | |
cube: cube, | |
screen: toScreen(cube) | |
} | |
}) | |
let points = g.selectAll('circle') | |
.data(coordinates, function(d) { return d.key }) | |
points | |
.enter() | |
.append('circle') | |
.attr('r', 6) | |
.merge(points) | |
.attr('fill', function(d) { | |
let r = d.cube[0] * 5 + 150 | |
let g = d.cube[1] * 5 + 150 | |
let b = d.cube[2] * 5 + 150 | |
return 'rgb(' + r + ', ' + g + ', ' + b + ')' | |
}) | |
.attr('cx', function(d) { | |
return d.screen.x | |
}) | |
.attr('cy', function(d) { | |
return d.screen.y | |
}) | |
points.exit().remove() | |
window.requestAnimationFrame(paint) | |
} | |
window.requestAnimationFrame(paint) | |
</script> | |
</body> |
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