53 lines
1.1 KiB
Haskell
53 lines
1.1 KiB
Haskell
{-# OPTIONS_HADDOCK ignore-exports #-}
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module Algebra.Polygon where
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import Algebra.Vector
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import Data.Maybe
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import MyPrelude
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{- import Diagrams.Coordinates -}
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splitPoly :: [PT]
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-> Segment
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-> [[PT]]
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splitPoly pts (a, b)
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| elem a pts && elem b pts =
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[b : takeWhile (/= b) shiftedPoly, a : dropWhile (/= b) shiftedPoly]
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| otherwise = [[]]
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where
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shiftedPoly = shiftM' a pts
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polySegments :: [PT] -> [Segment]
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polySegments p@(x':_:_:_) = go p ++ [(last p, x')]
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where
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go (x:y:xs) = (x, y) : go (y:xs)
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go _ = []
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polySegments _ = []
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isInsidePoly :: [PT] -> Segment -> Bool
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isInsidePoly pts seg =
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null
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. catMaybes
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. fmap (intersectSeg'' seg)
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$ polySegments pts
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adjacent :: PT -> PT -> [PT] -> Bool
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adjacent u v = any (\x -> x == (u, v) || x == (v, u)) . polySegments
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isTrianglePoly :: [PT] -> Bool
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isTrianglePoly [_, _, _] = True
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isTrianglePoly _ = False
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triangleOnly :: [[PT]] -> [[PT]]
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triangleOnly = filter isTrianglePoly
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nonTriangleOnly :: [[PT]] -> [[PT]]
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nonTriangleOnly = filter (not . isTrianglePoly)
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