paper
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The Swiss Army Knife of Vector Graphics Scripting
133 lines (116 loc) • 4.88 kB
HTML
<html>
<head>
<meta charset="UTF-8">
<title>Meta Balls</title>
<link rel="stylesheet" href="../css/style.css">
<script type="text/javascript" src="../../dist/paper-full.js"></script>
<script type="text/paperscript" canvas="canvas">
// Ported from original Metaball script by SATO Hiroyuki
// http://park12.wakwak.com/~shp/lc/et/en_aics_script.html
project.currentStyle = {
fillColor: 'black'
};
var ballPositions = [[255, 129], [610, 73], [486, 363],
[117, 459], [484, 726], [843, 306], [789, 615], [1049, 82],
[1292, 428], [1117, 733], [1352, 86], [92, 798]];
var handle_len_rate = 2.4;
var circlePaths = [];
var radius = 50;
for (var i = 0, l = ballPositions.length; i < l; i++) {
var circlePath = new Path.Circle({
center: ballPositions[i],
radius: 50
});
circlePaths.push(circlePath);
}
var largeCircle = new Path.Circle({
center: [676, 433],
radius: 100
});
circlePaths.push(largeCircle);
function onMouseMove(event) {
largeCircle.position = event.point;
generateConnections(circlePaths);
}
var connections = new Group();
function generateConnections(paths) {
// Remove the last connection paths:
connections.removeChildren();
for (var i = 0, l = paths.length; i < l; i++) {
for (var j = i - 1; j >= 0; j--) {
var path = metaball(paths[i], paths[j], 0.5, handle_len_rate, 300);
if (path) {
connections.appendTop(path);
path.removeOnMove();
}
}
}
}
generateConnections(circlePaths);
// ---------------------------------------------
function metaball(ball1, ball2, v, handle_len_rate, maxDistance) {
var center1 = ball1.position;
var center2 = ball2.position;
var radius1 = ball1.bounds.width / 2;
var radius2 = ball2.bounds.width / 2;
var pi2 = Math.PI / 2;
var d = center1.getDistance(center2);
var u1, u2;
if (radius1 == 0 || radius2 == 0)
return;
if (d > maxDistance || d <= Math.abs(radius1 - radius2)) {
return;
} else if (d < radius1 + radius2) { // case circles are overlapping
u1 = Math.acos((radius1 * radius1 + d * d - radius2 * radius2) /
(2 * radius1 * d));
u2 = Math.acos((radius2 * radius2 + d * d - radius1 * radius1) /
(2 * radius2 * d));
} else {
u1 = 0;
u2 = 0;
}
var angle1 = (center2 - center1).getAngleInRadians();
var angle2 = Math.acos((radius1 - radius2) / d);
var angle1a = angle1 + u1 + (angle2 - u1) * v;
var angle1b = angle1 - u1 - (angle2 - u1) * v;
var angle2a = angle1 + Math.PI - u2 - (Math.PI - u2 - angle2) * v;
var angle2b = angle1 - Math.PI + u2 + (Math.PI - u2 - angle2) * v;
var p1a = center1 + getVector(angle1a, radius1);
var p1b = center1 + getVector(angle1b, radius1);
var p2a = center2 + getVector(angle2a, radius2);
var p2b = center2 + getVector(angle2b, radius2);
// define handle length by the distance between
// both ends of the curve to draw
var totalRadius = (radius1 + radius2);
var d2 = Math.min(v * handle_len_rate, (p1a - p2a).length / totalRadius);
// case circles are overlapping:
d2 *= Math.min(1, d * 2 / (radius1 + radius2));
radius1 *= d2;
radius2 *= d2;
var path = new Path({
segments: [p1a, p2a, p2b, p1b],
style: ball1.style,
closed: true
});
var segments = path.segments;
segments[0].handleOut = getVector(angle1a - pi2, radius1);
segments[1].handleIn = getVector(angle2a + pi2, radius2);
segments[2].handleOut = getVector(angle2b - pi2, radius2);
segments[3].handleIn = getVector(angle1b + pi2, radius1);
return path;
}
// ------------------------------------------------
function getVector(radians, length) {
return new Point({
// Convert radians to degrees:
angle: radians * 180 / Math.PI,
length: length
});
}
</script>
</head>
<body>
<canvas id="canvas" resize></canvas>
</body>
</html>