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POSort points in clockwise order?
 

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    <p>Given an array of x,y points, how do I sort the points of this array in clockwise order (around their overall average center point)? My goal is to pass the points to a line-creation function to end up with something looking rather "solid", as convex as possible with no lines intersecting.</p> <p>For what it's worth, I'm using Lua, but any pseudocode would be appreciated. Thanks so much for any help!</p> <p><strong>Update:</strong> For reference, this is the Lua code based on Ciamej's excellent answer (ignore my "app" prefix):</p> <pre><code>function appSortPointsClockwise(points) local centerPoint = appGetCenterPointOfPoints(points) app.pointsCenterPoint = centerPoint table.sort(points, appGetIsLess) return points end function appGetIsLess(a, b) local center = app.pointsCenterPoint if a.x &gt;= 0 and b.x &lt; 0 then return true elseif a.x == 0 and b.x == 0 then return a.y &gt; b.y end local det = (a.x - center.x) * (b.y - center.y) - (b.x - center.x) * (a.y - center.y) if det &lt; 0 then return true elseif det &gt; 0 then return false end local d1 = (a.x - center.x) * (a.x - center.x) + (a.y - center.y) * (a.y - center.y) local d2 = (b.x - center.x) * (b.x - center.x) + (b.y - center.y) * (b.y - center.y) return d1 &gt; d2 end function appGetCenterPointOfPoints(points) local pointsSum = {x = 0, y = 0} for i = 1, #points do pointsSum.x = pointsSum.x + points[i].x; pointsSum.y = pointsSum.y + points[i].y end return {x = pointsSum.x / #points, y = pointsSum.y / #points} end </code></pre> <p></p>
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    1. USPhilipp Lenssen
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    1. COThink about compute the angle of the radial line through that point. Then sort by angle.
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      1. USJames K Polk
    2. CO+1 Fabulous that you also shared the Lua code.
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    3. COIn case you didn't know, lua has a builtin function `ipairs(tbl)` that iterates over the indices *and values* of tbl from 1 to #tbl. So for the sum calculation, you can do this, which most people find looks cleaner: `for _, p in ipairs(points) do pointsSum.x = pointsSum.x + p.x; pointsSum.y = pointsSum.y + p.y end`
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