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evert / Point-on-sphere

Last active 4 months ago

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Revision 91799eee434573fd444b483392cf59e5246ab4de

point-on-sphere.js Raw
1// Get angle on circle from mouse position
2function getAngleOnCircleFromOffsetMouse(evt) {
3 const x = (evt.pageX - element.offset().left);
4 const y = (evt.pageY - element.offset().top);
5
6 // https://math.stackexchange.com/a/127615
7 const center = { x: width / 2, y: width / 2 };
8 const xCenter = (x - center.x);
9 const yCenter = (y - center.y);
10 const circlePoint = {
11 x: center.x + radius * (xCenter / Math.sqrt(xCenter * xCenter + yCenter * yCenter)),
12 y: center.y + radius * (yCenter / Math.sqrt(xCenter * xCenter + yCenter * yCenter)),
13 };
14
15 const angle = Math.atan2(circlePoint.y - center.y, circlePoint.x - center.x) + Math.PI / 2;
16 return angle < 0 ? Math.PI * 2 - Math.abs(angle) : angle;
17}