最佳答案
按顺时针顺序排序？
给定一个由 x，y 点组成的数组，我如何按顺时针方向(围绕它们的总平均中心点)对这个数组的点排序？我的目标是将这些点传递给一个直线创建函数，使其最终看起来相当“实心”，尽可能凸，没有直线相交。
不管怎样，我正在使用 Lua，但是任何伪代码都是值得的。
更新: 作为参考，这是基于 Ciamej 出色回答的 Lua 代码(忽略我的“ app”前缀) :
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 >= 0 and b.x < 0 then return true
elseif a.x == 0 and b.x == 0 then return a.y > b.y
end
local det = (a.x - center.x) * (b.y - center.y) - (b.x - center.x) * (a.y - center.y)
if det < 0 then return true
elseif det > 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 > 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
