385 lines
12 KiB
Haskell
385 lines
12 KiB
Haskell
{-
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The module YGL will contains most boilerplate
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And display details.
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To make things even nicer, we should separate
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this file in many different parts.
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Typically separate the display function.
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-}
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module YGL (
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-- Here is declared our interface with external files
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-- that will include our YGL module
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-- Declarations related to data types
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Point -- the 1 dimension point type
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, Time -- the type for the time
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, Scalar -- the type for scalar values
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, Color -- the type for color (3 scalars)
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, Point3D (..) -- A 3D point type (3 Points)
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, makePoint3D -- helper (x,y,z) -> Point3D
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, (-*<) -- scalar product on Point3D a -*< (x,y,z) = (ax,ay,az)
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, Function3D -- Point -> Point -> Maybe (Point,Color)
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, xpoint, ypoint, zpoint
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, Atom (..) -- The Atom object (colored triangles for now)
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-- Your world state must be an instance
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-- of the DisplayableWorld type class
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, DisplayableWorld (..)
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-- Datas related to DisplayableWorld
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, Camera (..)
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, YObject (..) -- 3D Objects to display
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, Box3D (..) -- Some bounded 3D box
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, getObject3DFromShapeFunction
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, makeBox -- helper to make a box
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, hexColor -- Color from hexadecimal string
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, makeColor -- make color from RGB values
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-- Interface related to user input
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, InputMap
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, UserInput (Press,Ctrl,Alt,CtrlAlt)
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, inputMapFromList
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-- The main loop function to call
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, yMainLoop
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) where
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-- A bunch of imports
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import Numeric (readHex) -- to read hexadecimal values
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-- Import of OpenGL and GLUT
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-- but, I use my own Color type, therefore I hide the definition
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-- of Color inside GLUT and OpenGL packages
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import Graphics.Rendering.OpenGL hiding (Color)
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import Graphics.UI.GLUT hiding (Color)
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import Data.IORef
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-- I use Map to deal with user interaction
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import qualified Data.Map as Map
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-- Some standard stuff
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import Control.Monad (when)
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import Data.Maybe (isNothing)
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{-- Things start to be complex here.
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- Just take the time to follow me.
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--}
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-- | A 1D point
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type Point = GLfloat
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-- | A Scalar value
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type Scalar = GLfloat
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-- | The time type (currently its Int)
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type Time = Int
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-- | A 3D Point mainly '(x,y,z)'
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data Point3D = P (Point,Point,Point) deriving (Eq,Show,Read)
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type Color = Color3 Scalar
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-- Get x (resp. y, z) coordinate of a 3D point
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xpoint :: Point3D -> Point
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xpoint (P (x,_,_)) = x
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ypoint :: Point3D -> Point
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ypoint (P (_,y,_)) = y
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zpoint :: Point3D -> Point
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zpoint (P (_,_,z)) = z
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-- Create a Point3D element from a triplet
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makePoint3D :: (Point,Point,Point) -> Point3D
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makePoint3D = P
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-- Make Point3D an instance of Num
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instance Num Point3D where
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(+) (P (ax,ay,az)) (P (bx,by,bz)) = P (ax+bx,ay+by,az+bz)
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(-) (P (ax,ay,az)) (P (bx,by,bz)) = P (ax-bx,ay-by,az-bz)
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(*) (P (ax,ay,az)) (P (bx,by,bz)) = P ( ay*bz - az*by
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, az*bx - ax*bz
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, ax*by - ay*bx )
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abs (P (x,y,z)) = P (abs x,abs y, abs z)
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signum (P (x,y,z)) = P (signum x, signum y, signum z)
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fromInteger i = P (fromInteger i, 0, 0)
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-- The scalar product
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infixr 5 -*<
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(-*<) :: Scalar -> Point3D -> Point3D
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(-*<) s p = P (s*xpoint p, s*ypoint p, s*zpoint p)
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-- Used internally to convert point3D to different types
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toGLVector3 :: Point3D -> Vector3 GLfloat
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toGLVector3 (P(x,y,z)) = Vector3 x y z
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toGLVertex3 :: Point3D -> Vertex3 GLfloat
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toGLVertex3 (P(x,y,z)) = Vertex3 x y z
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toGLNormal3 :: Point3D -> Normal3 GLfloat
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toGLNormal3 (P(x,y,z)) = Normal3 x y z
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-- | The Box3D type represent a 3D bounding box
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-- | Note if minPoint = (x,y,z) and maxPoint = (x',y',z')
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-- | Then to have a non empty box you must have
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-- | x<x' & y<y' & z<z'
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data Box3D = Box3D {
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minPoint :: Point3D
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, maxPoint :: Point3D
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, resolution :: Scalar }
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-- | An helper to make a Box3D
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makeBox :: (Point,Point,Point) -> (Point,Point,Point) -> Scalar -> Box3D
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makeBox mini maxi res = Box3D {
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minPoint = makePoint3D mini
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, maxPoint = makePoint3D maxi
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, resolution = res }
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-- | A Triangle3D is simply 3 points and a color
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type Triangle3D = (Point3D,Point3D,Point3D,Color)
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-- | The type Atom is the atom for our display here we'll only use triangles.
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-- | For a general purpose library we should add many other different atoms
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-- | corresponding to Quads for example.
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data Atom = ColoredTriangle Triangle3D
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-- | A Function3D is simply a function for each x,y associate a z and a color
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-- | If undefined at point (x,y), it returns Nothing.
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type Function3D = Point -> Point -> Maybe (Point,Color)
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-- | Our objects that will be displayed
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-- | Wether a function3D delimited by a Box
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-- | or a list of Atoms
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data YObject = XYFunc Function3D Box3D
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| Atoms [Atom]
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-- | The function atoms retrieve the list of atoms from an YObject
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atoms :: YObject -> [Atom]
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atoms (XYFunc f b) = getObject3DFromShapeFunction f b
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atoms (Atoms atomList) = atomList
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-- | We decalre the input map type we need here
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-- | It is our API
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-- | I don't use Mouse but it can be easily added
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type InputMap worldType = Map.Map UserInput (worldType -> worldType)
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data UserInput = Press Char | Ctrl Char | Alt Char | CtrlAlt Char
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deriving (Eq,Ord,Show,Read)
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-- | A displayable world is a type for which
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-- | ther exists a function that provide sufficient informations
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-- | to provide a camera, lights, objects and a window title.
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class DisplayableWorld world where
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camera :: world -> Camera
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camera _ = defaultCamera
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lights :: world -> [Light]
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lights _ = []
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objects :: world -> [YObject]
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objects _ = []
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winTitle :: world -> String
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winTitle _ = "YGL"
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-- | the Camera type to know how to
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-- | Transform the scene to see the right view.
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data Camera = Camera {
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camPos :: Point3D
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, camDir :: Point3D
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, camZoom :: Scalar }
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-- | A default initial camera
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defaultCamera :: Camera
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defaultCamera = Camera {
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camPos = makePoint3D (0,0,0)
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, camDir = makePoint3D (0,0,0)
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, camZoom = 1 }
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-- | Given a shape function and a delimited Box3D
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-- | return a list of Atoms (here only colored triangles) to be displayed
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getObject3DFromShapeFunction :: Function3D -> Box3D -> [Atom]
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getObject3DFromShapeFunction shape box = do
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x <- [xmin,xmin+res..xmax]
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y <- [ymin,ymin+res..ymax]
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let
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neighbors = [(x,y),(x+res,y),(x+res,y+res),(x,y+res)]
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-- zs are 3D points with found depth and color
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-- zs :: [ (Point,Point,Point,Maybe (Point,Color) ]
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zs = map (\(u,v) -> (u,v,shape u v)) neighbors
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-- ps are 3D opengl points + color value
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ps = zs
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-- If the point diverged too fast, don't display it
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if any (\(_,_,z) -> isNothing z) zs
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then []
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-- Draw two triangles
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-- 3 - 2
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-- | / |
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-- 0 - 1
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-- The order is important
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else
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[ makeAtom (ps!!0) (ps!!2) (ps!!1)
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, makeAtom (ps!!0) (ps!!3) (ps!!2) ]
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where
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makeAtom (p0x,p0y,Just (p0z,c0)) (p1x,p1y,Just (p1z,_)) (p2x,p2y,Just (p2z,_)) =
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ColoredTriangle (makePoint3D (p0x,p0y,p0z)
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,makePoint3D (p1x,p1y,p1z)
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,makePoint3D (p2x,p2y,p2z)
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,c0)
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makeAtom _ _ _ = error "Somethings wrong here"
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-- some naming to make it
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-- easier to read
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xmin = xpoint $ minPoint box
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xmax = xpoint $ maxPoint box
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ymin = ypoint $ minPoint box
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ymax = ypoint $ maxPoint box
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res = resolution box
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-- | Get the user input map from a list
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inputMapFromList :: (DisplayableWorld world) =>
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[(UserInput,world -> world)] -> InputMap world
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inputMapFromList = Map.fromList
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{--
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- We set our mainLoop function
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- As you can see the code is _not_ pure
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- and not even functionnal friendly!
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- But when called,
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- it will look like a pure functional function.
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--}
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yMainLoop :: (DisplayableWorld worldType) =>
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-- the mapping user input / world
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InputMap worldType
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-- function that modify the world
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-> (Time -> worldType -> worldType)
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-- the world state of type worldType
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-> worldType
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-- into IO () for obvious reason
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-> IO ()
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yMainLoop inputActionMap
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worldTranformer
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world = do
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-- The boilerplate
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_ <- getArgsAndInitialize
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initialDisplayMode $=
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[WithDepthBuffer,DoubleBuffered,RGBMode]
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_ <- createWindow $ winTitle world
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depthFunc $= Just Less
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windowSize $= Size 500 500
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-- The state variables for the world (I know it feels BAD)
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worldRef <- newIORef world
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-- Action to call when waiting
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idleCallback $= Just (idle worldTranformer worldRef)
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-- the keyboard will update the world
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keyboardMouseCallback $=
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Just (keyboardMouse inputActionMap worldRef)
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-- We generate one frame using the callback
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displayCallback $= display worldRef
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-- let OpenGL resize normal vectors to unity
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normalize $= Enabled
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shadeModel $= Smooth
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-- Lights (in a better version should be put elsewhere)
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lighting $= Enabled
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ambient (Light 0) $= Color4 0.5 0.5 0.5 1
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diffuse (Light 0) $= Color4 1 1 1 1
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light (Light 0) $= Enabled
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pointSmooth $= Enabled
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colorMaterial $= Just (Front,AmbientAndDiffuse)
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materialAmbient Front $= Color4 0.0 0.0 0.0 1
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materialDiffuse Front $= Color4 0.0 0.0 0.0 1
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materialSpecular Front $= Color4 1 1 1 1
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materialEmission Front $= Color4 0.0 0.0 0.0 1
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materialShininess Front $= 96
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-- We enter the main loop
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mainLoop
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-- When no user input entered do nothing
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idle :: (Time -> worldType -> worldType) -> IORef worldType -> IO ()
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idle worldTranformer world = do
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w <- get world
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t <- get elapsedTime
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world $= worldTranformer t w
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postRedisplay Nothing
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-- | Get User Input
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-- | both cleaner, terser and more expendable than the preceeding code
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keyboardMouse :: InputMap a -> IORef a
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-> Key -> KeyState -> Modifiers -> Position -> IO()
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keyboardMouse input world key state _ _ =
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when (state == Down) $
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let
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charFromKey (Char c) = c
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-- To complete if you want to finish it
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charFromKey _ = '#'
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transformator = Map.lookup (Press (charFromKey key)) input
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in
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mayTransform transformator
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where
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mayTransform Nothing = return ()
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mayTransform (Just transform) = do
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w <- get world
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world $= transform w
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-- | The function that will display datas
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display :: (HasGetter g, DisplayableWorld world) =>
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g world -> IO ()
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display worldRef = do
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-- BEWARE UGLINESS!!!!
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-- SHOULD NEVER MODIFY worldRef HERE!!!!
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--
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-- I SAID NEVER.
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w <- get worldRef
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-- NO REALLY, NEVER!!!!
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-- If someone write a line starting by
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-- w $= ... Shoot him immediately in the head
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-- and refere to competent authorities
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let cam = camera w
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-- set the background color (dark solarized theme)
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-- Could also be externalized to world state
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clearColor $= Color4 0 0.1686 0.2117 1
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clear [ColorBuffer,DepthBuffer]
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-- Transformation to change the view
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loadIdentity -- reset any transformation
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-- tranlate
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translate $ toGLVector3 (camPos cam)
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-- zoom
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scale (camZoom cam) (camZoom cam) (camZoom cam)
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-- rotate
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rotate (xpoint (camDir cam)) $ Vector3 1.0 0.0 (0.0::GLfloat)
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rotate (ypoint (camDir cam)) $ Vector3 0.0 1.0 (0.0::GLfloat)
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rotate (zpoint (camDir cam)) $ Vector3 0.0 0.0 (1.0::GLfloat)
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-- Now that all transformation were made
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-- We create the object(s)
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_ <- preservingMatrix $ mapM drawObject (objects w)
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swapBuffers -- refresh screen
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-- Hexa style colors
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scalarFromHex :: String -> Scalar
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scalarFromHex = (/256) . fst . head . readHex
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-- | Color from CSS style color string
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hexColor :: String -> Color
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hexColor ('#':rd:ru:gd:gu:bd:bu:[]) = Color3 (scalarFromHex [rd,ru])
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(scalarFromHex [gd,gu])
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(scalarFromHex [bd,bu])
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hexColor ('#':r:g:b:[]) = hexColor ['#',r,r,g,g,b,b]
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hexColor _ = error "Bad color!!!!"
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-- | Helper to make a color from RGB scalar values
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makeColor :: Scalar -> Scalar -> Scalar -> Color
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makeColor = Color3
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-- | Where the drawing occurs
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drawObject :: YObject -> IO()
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drawObject shape = renderPrimitive Triangles $
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mapM_ drawAtom (atoms shape)
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-- simply draw an Atom
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drawAtom :: Atom -> IO ()
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drawAtom atom@(ColoredTriangle (p0,p1,p2,c)) = do
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color c
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normal $ toGLNormal3 (getNormal atom)
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vertex $ toGLVertex3 p0
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vertex $ toGLVertex3 p1
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vertex $ toGLVertex3 p2
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-- | get the normal vector of an Atom
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-- I don't normalize it; it is done by OpenGL
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-- in main with 'normalize $= Enabled'
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getNormal :: Atom -> Point3D
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getNormal (ColoredTriangle (p0,p1,p2,_)) = (p1 - p0) * (p2 - p0)
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