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module Data.Obj3D.Parser ( Vertex
, VertexNormal
, TexCoords
, FaceVertex
, Face
, ObjLine(..)
, parseObj
, SourceName
, ParseError
) where
import Control.Monad
import Text.ParserCombinators.Parsec hiding (space, spaces, Parser)
type Vertex = (Float, Float, Float)
type VertexNormal = (Float, Float, Float)
type TexCoords = (Float, Float)
type FaceVertex = (Integer, Maybe Integer, Maybe Integer)
type Face = (FaceVertex, FaceVertex, FaceVertex)
data ObjLine = VertexLine Vertex | TexCoordsLine TexCoords | VertexNormalLine VertexNormal | FaceLine Face | ObjectLine String | UnknownLine String | EmptyLine
deriving Show
data ParserState = ParserState
{ vertexCount :: Integer
, texCoordsCount :: Integer
, vertexNormalCount :: Integer
}
type Parser a = GenParser Char ParserState a
noNewline :: Parser Char
noNewline = noneOf "\n"
validChar :: Parser Char
validChar = noneOf "\n#"
space :: Parser Char
space = oneOf " \t"
spaces :: Parser String
spaces = many1 space
float :: Parser Float
float = ( do
sign <- option "" $ string "-"
intpart <- many1 digit
fracpart <- option "0" $ do
char '.'
many1 digit
return $ read $ sign ++ intpart ++ "." ++ fracpart
) <?> "float"
integer :: Parser Integer
integer = ( do
sign <- option "" $ string "-"
digits <- many1 digit
return $ read $ sign ++ digits
) <?> "integer"
relativeInteger :: Integer -> Parser Integer
relativeInteger rel = do
value <- integer
let absval = if value < 0 then (rel + value + 1) else value
when (absval <= 0 || absval > rel) $ fail $ "invalid index " ++ show value
return absval
faceVertex :: Parser FaceVertex
faceVertex = do
state <- getState
v <- liftM (subtract 1) $ relativeInteger $ vertexCount state
(t, n) <- option (Nothing, Nothing) $ do
char '/'
t <- option Nothing $ liftM (Just . subtract 1) $ relativeInteger $ texCoordsCount state
n <- option Nothing $ do
char '/'
option Nothing $ liftM (Just . subtract 1) $ relativeInteger $ vertexNormalCount state
return (t, n)
return (v, t, n)
comment :: Parser String
comment = do
char '#'
many noNewline
vertexLine :: Parser ObjLine
vertexLine = do
try $ do
string "v"
spaces
x <- float
spaces
y <- float
spaces
z <- float
optional $ do
spaces
float
updateState $ \state -> state {vertexCount = 1 + vertexCount state}
return $ VertexLine (x, y, z)
texCoordsLine :: Parser ObjLine
texCoordsLine = do
try $ do
string "vt"
spaces
u <- float
spaces
v <- float
optional $ do
spaces
float
updateState $ \state -> state {texCoordsCount = 1 + texCoordsCount state}
return $ TexCoordsLine (u, v)
vertexNormalLine :: Parser ObjLine
vertexNormalLine = do
try $ do
string "vn"
spaces
x <- float
spaces
y <- float
spaces
z <- float
updateState $ \state -> state {vertexNormalCount = 1 + vertexNormalCount state}
return $ VertexNormalLine (x, y, z)
faceLine :: Parser ObjLine
faceLine = do
try $ do
string "f"
spaces
v1 <- faceVertex
spaces
v2 <- faceVertex
spaces
v3 <- faceVertex
return $ FaceLine (v1, v2, v3)
objectLine :: Parser ObjLine
objectLine = do
try $ do
string "o"
spaces
name <- many1 (alphaNum <|> oneOf "._")
return $ ObjectLine name
anyLine :: Parser ObjLine
anyLine = liftM UnknownLine $ many1 validChar
emptyLine :: Parser ObjLine
emptyLine = return EmptyLine
line :: Parser ObjLine
line = do
optional spaces
l <- vertexLine <|> texCoordsLine <|> vertexNormalLine <|> faceLine <|> objectLine <|> anyLine <|> emptyLine
optional spaces
optional comment
newline
return l
obj :: Parser [ObjLine]
obj = do
lines <- many line
eof
return lines
parseObj :: SourceName -> String -> Either ParseError [ObjLine]
parseObj = runParser obj (ParserState 0 0 0)
|
