{- |

Module : $FreeCAD$

Description : Hets(Haskell) end-point of the interface with the OpenCascade

libraries. It reads the ouput of the C++ program "Brep_Reader"

and interprets it in order to generate the data for the basic

FreeCAD terms, which are not properly described in the file

"Document.xml"

Copyright : (c) Robert Savu and Uni Bremen 2011

License : GPLv2 or higher, see LICENSE.txt

Maintainer : Robert.Savu@dfki.de

Stability : experimental

Portability : portable

Haskell layer of the Brep-reader

-}

module FreeCAD.Brep where

import System.Process

import Text.XML.Light

import Data.Maybe

import Data.Set as Set

import FreeCAD.As

getBrep::(String, String) -> IO (BaseObject, Placement)

getBrep (address, "rectangle") =

fmap procRectangle $ getRectangle address

procRectangle::(Vector3, Vector3, Vector3, Vector3) -> (BaseObject, Placement)

procRectangle (a, b, c, d) = (Rectangle h l, place)

where

d1 = distance3 a b -- \

d2 = distance3 a c -- > values used to compute rectangle's properties

d3 = distance3 a d -- /

mn = min d1 (min d2 d3) -- heigth/small edge value

mx = max d1 (max d2 d3) -- diagonal length

md = if (d1 /= mn)&&(d1 /= mx) then d1 else --length value

if (d2 /= mn)&&(d2 /= mx) then d2 else

if (d3 /= mn)&&(d3 /= mx) then d3 else 0

h = d1

l = d3

hh = if mn == d1 then b else --w/o rotation is on the Oy axis

if mn == d2 then c else

if mn == d3 then d else (Vector3 0 0 0)

hpoint = subtract3 hh a

ll = if md == d1 then b else --w/o rotation is on the Ox axis

if md == d2 then c else

if md == d3 then d else (Vector3 0 0 0)

lpoint = subtract3 ll a

--obtain actual rotation by 2 intermediary rotations, matching points in

--space ( a = 0.0.0; first: hpoint = hpoint'; then: lpoint = lpoint' )

-- 0.0.0 --> X.Y.Z

-- first we rotate with regard to hpoint (and Oy axis)

rot1vec = v3VecProd (Vector3 0 1 0) hpoint -- rotation vector (for q1)

rot1vecn = scalarprod3 (norm3 rot1vec) rot1vec

cosAa1 = cos((acos((v3DotProd(Vector3 0 1 0)hpoint)/(norm3 hpoint)))/2)

sinAa1 = sqrt (1 - cosAa1**2)

quat1 = Vector4 (sinAa1*(x rot1vecn)) (sinAa1*(y rot1vecn))

(sinAa1*(z rot1vecn)) cosAa1

tmatrix = quat2matrix quat1

l2point = rotate tmatrix (Vector3 (norm3 lpoint) 0 0)

-- then we rotate l2point into lpoint

rot2vec = v3VecProd (l2point) lpoint

rot2vecn = scalarprod3 (norm3 rot2vec) rot2vec

cosAa2 = cos((acos ((v3DotProd l2point lpoint)/(norm3 lpoint)))/2)

sinAa2 = sqrt (1 - cosAa2**2)

quat2 = Vector4 (sinAa2*(x rot2vecn)) (sinAa2*(y rot2vecn))

(sinAa2*(z rot2vecn)) cosAa2

quaternion = quatProd quat1 quat2

pos = a

place = Placement pos quaternion

getRectangle:: String -> IO (Vector3, Vector3, Vector3, Vector3)

getRectangle address = fmap parseBrepXML $ readProcess

"./FreeCAD/brep_conversion/bin/brep_to_xml"

[concat ["/tmp/",address], "rectangle"] ""

--TODO fix this ^ (make it portable)

parseBrepXML:: String -> (Vector3, Vector3, Vector3, Vector3)

parseBrepXML a = getData $fromJust $parseXMLDoc a

quadFromList :: [a] -> (a,a,a,a)

quadFromList (d:b:c:[]) = error "List too short"

quadFromList (b:c:d:e) = (b,c,d, head e)

getData:: Element -> (Vector3, Vector3, Vector3, Vector3)

getData e = if (qName $elName e) == "rectangle" then

quadFromList (Prelude.map parseVertex (elChildren e))

else error "unsupported object type in the .brp file"

parseVertex:: Element -> Vector3

parseVertex e = Vector3 (getD "x") (getD "y") (getD "z") where

getD x = if ( findAttr (makeQName x) e) == Nothing then

error "erroneous input given by c++ module"

else read $fromJust (findAttr (makeQName x) e)

--getD x = 0

makeQName:: String -> QName

makeQName s = QName s Nothing Nothing