79 lines
2.4 KiB
Haskell
79 lines
2.4 KiB
Haskell
module Grid where
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import Geometry
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import Bound
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--import Data.Function (on)
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import Data.List
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import Data.Bifunctor
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--import Data.Maybe
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import qualified Data.Tuple.Extra as Tup
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import qualified Streaming.Prelude as S
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--import qualified Control.Foldl as L
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--import qualified Data.Set as S
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gridInPolygon :: Float -> [Point2] -> [Point2]
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gridInPolygon gap ps = filter (`pointInPolygon` ps)
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. maybe [] (boundedGrid gap) . boundPoints . S.each $ ps
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boundedGrid :: Float -> (Float,Float,Float,Float) -> [Point2]
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boundedGrid gap (n,s,e,w) = gridPointsOff w s gap nx gap ny
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where
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nx = floor $ (e-w) / gap
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ny = floor $ (n-s) / gap
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shiftedGrid
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:: Float -- ^ x min
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-> Float -- ^ x max
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-> Float -- ^ y min
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-> Float -- ^ y max
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-> [(Point2,Point2)]
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shiftedGrid xmin xmax ymin ymax = grid
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where
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xd = xmax - xmin
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yd = ymax - ymin
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xsteps = ceiling $ (xd - 40) / 60
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ysteps = ceiling $ (yd - 40) / 60
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shift p = bimap (p +.+) (p +.+)
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grid = map (shift (V2 (xmin + 20) (ymin+20))) $ makeGrid 60 xsteps 60 ysteps
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-- creates a rectangular grid starting at (0,0) in the positive orthant
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-- needs fixing in degenerate (xstep or ystep == 0) cases
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makeGrid
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:: Float -- ^ horizontal step size
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-> Int -- ^ number of horizontal steps
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-> Float -- ^ vertical step size
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-> Int -- ^ number of vertical steps
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-> [(Point2,Point2)]
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makeGrid x nx y ny
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= nub
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. concatMap doublePair
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. concatMap (\p -> map (Tup.both (p +.+)) $ makeRect x y)
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$ gridPoints x nx y ny
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gridPointsOff :: Float -> Float -> Float -> Int -> Float -> Int -> [Point2]
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gridPointsOff xoff yoff x nx y ny = map f $ gridPoints' nx ny
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where
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f (a,b) = V2 (xoff + fromIntegral a * x) (yoff + fromIntegral b * y)
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gridPoints :: Float -> Int -> Float -> Int -> [Point2]
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gridPoints = gridPointsOff 0 0
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-- map f $ gridPoints' nx ny
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-- where
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-- f (a,b) = V2 (fromIntegral a * x) (fromIntegral b * y)
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gridPoints'' :: Float -> Int -> Float -> Int -> [(Point2,(Int,Int))]
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gridPoints'' x nx y ny = map f $ gridPoints' nx ny
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where
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f (a,b) = (V2 (fromIntegral a * x) (fromIntegral b * y), (a,b))
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gridPoints' :: Int -> Int -> [(Int,Int)]
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gridPoints' nx ny = [(x,y) | x <- [0..nx-1], y <- [0..ny-1]]
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makeRect :: Float -> Float -> [(Point2,Point2)]
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makeRect x y = map (bimap toV2 toV2)
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[((0,0),(x,0))
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,((0,0),(0,y))
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,((x,y),(x,0))
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,((x,y),(0,y))
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]
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