cga/Parser/Meshparser.hs

47 lines
1.2 KiB
Haskell

{-# OPTIONS_HADDOCK ignore-exports #-}
module Parser.Meshparser where
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.
meshFaceVertices :: B.ByteString -> [[P2]]
meshFaceVertices str = fmap (fmap (\y -> meshVertices str !! (y - 1)))
(meshFaces str)
-- |Convert a text String with multiple vertices into
-- an array of float tuples.
meshVertices :: B.ByteString -- ^ the string to convert
-> [P2] -- ^ the resulting vertice table
meshVertices
= 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 :: (Integral a) => Parser [a]
parseFace = char 'f' *> many1' (many' space *> decimal)
meshFaces :: B.ByteString -> [[Int]]
meshFaces
= rights
. fmap (parseOnly parseFace)
. B.lines