| 1 | export function ccw(polygon) {
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| 2 |
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| 3 | var _p = polygon.slice(0), sum = 0;
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| 4 |
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| 5 | _p.push(_p[0]);
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| 6 |
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| 7 | for (var i = 0; i <= polygon.length - 1; i++) {
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| 8 |
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| 9 | var j = i + 1;
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| 10 | var p1 = _p[i].rotated;
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| 11 | var p2 = _p[j].rotated;
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| 12 |
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| 13 | sum += (p2.x - p1.x) * (p2.y + p1.y);
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| 14 | }
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| 15 | // if the area is positive
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| 16 | // the curve is counter-clockwise
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| 17 | // because of the flipped y-Axis in the browser
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| 18 | return sum > 0 ? true : false;
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| 19 | }
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