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Nebulabrot forked from Jeremy Ashkenas' Buddhabrot in coffeescript
<!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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