Created
June 7, 2013 22:24
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Nebulabrot forked from Jeremy Ashkenas' Buddhabrot in coffeescript
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<!DOCTYPE html> | |
<html> | |
<head> | |
</head> | |
<body> | |
<canvas id="buddhabrot" width="1000" height="1000"></canvas> | |
<div id="images"></div> | |
<script type="text/javascript"> | |
var canvas = document.getElementById('buddhabrot'), | |
images = document.getElementById('images'); | |
var iterations = [1000, 10000, 5000], | |
points = 100000, | |
limit = 50; | |
var context = canvas.getContext('2d'), | |
N = canvas.width, | |
image = context.createImageData(N, N); | |
var exposures = [new Array(N * N), new Array(N * N), new Array(N * N)], | |
maxexposures = [0, 0, 0], | |
time = 0, | |
timer = null; | |
for (var i=0; i<exposures.length; i++) { | |
var exposure = exposures[i]; | |
for (var j=0; j<exposure.length; j++) { | |
exposure[j] = 0; | |
} | |
} | |
function draw() { | |
if (time > limit) clearInterval(timer); | |
time += 1; | |
plot(); | |
findMaxExposure(); | |
render(); | |
addImage(); | |
} | |
function plot() { | |
var x, y; | |
for (var n=0; n<points; n++) { | |
x = Math.random() * 3 - 2; | |
y = Math.random() * 3 - 1.5; | |
for (var i=0; i<3; i++) { | |
if (iterate(x, y, iterations[i], exposures[i], false)) | |
iterate(x, y, iterations[i], exposures[i], true); | |
} | |
} | |
} | |
function iterate(x0, y0, iterations, exposures, shouldDraw) { | |
var x = 0, | |
y = 0; | |
for (var i=0; i<iterations; i++) { | |
var xnew = x * x - y * y + x0, | |
ynew = 2 * x * y + y0; | |
if (shouldDraw && i > 3) { | |
var drawnX = Math.round(N * (xnew + 2.0) / 3.0), | |
drawnY = Math.round(N * (ynew + 1.5) / 3.0); | |
if ((0 <= drawnX < N) && (0 <= drawnY < N)) | |
exposures[drawnX * N + drawnY] += 1; | |
} | |
if ((xnew * xnew + ynew * ynew) > 4) | |
return true; | |
x = xnew; | |
y = ynew; | |
} | |
return false; | |
} | |
function render() { | |
var data = image.data; | |
for (var i=0; i<N; i++) { | |
for (var j=0; j<N; j++) { | |
var idx = (i * N + j) * 4; | |
for (var k=0; k<3; k++) { | |
var ramp = exposures[k][i * N + j] / (maxexposures[k] / 2.5); | |
if (ramp > 1) ramp = 1; | |
data[idx + k] = ramp * 255; | |
} | |
data[idx + 3] = 255 | |
} | |
} | |
context.putImageData(image, 0, 0); | |
} | |
function findMaxExposure() { | |
for (var i=0; i<3; i++) { | |
for (var j=0; j<exposures[i].length; j++) { | |
var value = exposures[i][j]; | |
if (value > maxexposures[i]) | |
maxexposures[i] = value; | |
} | |
} | |
} | |
function addImage() { | |
var dataUrl = canvas.toDataURL(), | |
image = document.createElement("img"); | |
image.setAttribute("src", dataUrl); | |
images.appendChild(image); | |
} | |
timer = setInterval(draw, 0); | |
</script> | |
</body> | |
</html> |
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