cga/Parser/Meshparser.hs

44 lines
1.2 KiB
Haskell

{-# OPTIONS_HADDOCK ignore-exports #-}
module Parser.Meshparser (meshToArr, facesToArr) where
import Algebra.Vector(PT)
import Control.Applicative
import Data.Attoparsec.ByteString.Char8
import Data.Either
import qualified Data.ByteString.Char8 as B
import Diagrams.TwoD.Types
-- |Convert a text String with multiple vertices and faces into
-- a list of vertices, ordered by the faces specification.
facesToArr :: B.ByteString -> [[PT]]
facesToArr str = fmap (fmap (\y -> meshs str !! (fromIntegral y - 1)))
(faces str)
where
meshs = meshToArr
faces = rights . fmap (parseOnly parseFace) . B.lines
-- |Convert a text String with multiple vertices into
-- an array of float tuples.
meshToArr :: B.ByteString -- ^ the string to convert
-> [PT] -- ^ the resulting vertice table
meshToArr =
fmap p2
. rights
. fmap (parseOnly parseVertice)
. B.lines
-- |Creates a Parser that accepts a single vertice, such as 'v 1.0 2.0'.
parseVertice :: Parser (Double, Double)
parseVertice =
(,)
<$> (char 'v' *> many' space *> double)
<*> (many' space *> double)
parseFace :: Parser [Integer]
parseFace = char 'f' *> many1' (many' space *> decimal)