Ok fixed it. I was not applying the transformation to the GLUshape model
type. But I have a new problem. It crashes I think I am overflowing the
stack with all of the matrices being passed around.
On Thu, Nov 11, 2010 at 8:27 AM, Ben Christy
I have a problem with implementing the transformations for my scene graph manually. After removing the opengl functions translate and rotate form my program and managing the matrix by hand my scene is no longer transformed correctly and I am at a loss. My guess is that it has something to do with the order I am doing something as my scene appears to be rotated and then translated. As I walk down the scene graph I multiply the current matrix by a series of translation matrices
SceneGraph = buildSSG = SimpleRootNode "HomeWork3" [ TransformNode "camera" (Rotate 0 0 0) (Translate 0 0 (-1)) [ TransformNode "ground" (Rotate 0 0 0) (Translate (-4) (-1.5) (-4)) [ ModelNode "groundModel" (Just groundModel) ], TransformNode "carousel" (Rotate 0 0 0) (Translate 0 0 0) [ TransformNode "carouselbase" (Rotate 90 0 0) (Translate 0 0 0) [ ModelNode "carouselbaseModel" (Just carouselBase) ], TransformNode "carouselRoof" (Rotate 90 0 0) (Translate 0 0.3 0) [ ModelNode "carouselRoofModel" (Just carouselRoof) ], TransformNode "carouselFloor" (Rotate 90 0 0) (Translate 0 0 0) [ ModelNode "carouselFloorModel" (Just carouselFloor), TransformNode "polls" (Rotate 0 0 0) (Translate 0 0 (-0.2)) [ OrbitalTransformNode "poll1"(Rotate 0 0 0 ) (Translate 0 0.45 0) [ ModelNode "poll1Model" (Just carouselPool), TransformNode "horse1" (Rotate 0 0 0 ) (Translate 0 0 0) [ ModelNode "horse1Model" (Just horseModel) ] ], OrbitalTransformNode "poll2" (Rotate 0 0 45) (Translate 0 0.45 0) [ ModelNode "poll2Model" (Just carouselPool), TransformNode "horse2" (Rotate 0 0 0) (Translate 0 0 0) [ ModelNode "horse2Model" (Just horseModel) ] ], OrbitalTransformNode "poll3" (Rotate 0 0 90) (Translate 0 0.45 0) [ ModelNode "poll3Model" (Just carouselPool), TransformNode "horse3" (Rotate 0 0 0) (Translate 0 0 0) [ ModelNode "horse3Model" (Just horseModel) ] ], OrbitalTransformNode "poll4" (Rotate 0 0 135) (Translate 0 0.45 0) [ ModelNode "poll4Model" (Just carouselPool), TransformNode "horse4" (Rotate 0 0 0) (Translate 0 0 0) [ ModelNode "horse4Model" (Just horseModel) ] ], OrbitalTransformNode "poll5" (Rotate 0 0 180) (Translate 0 0.45 0) [ ModelNode "poll5Model" (Just carouselPool), TransformNode "horse5" (Rotate 0 0 0) (Translate 0 0 0) [ ModelNode "horse5Model" (Just horseModel) ] ], OrbitalTransformNode "poll6" (Rotate 0 0 225) (Translate 0 0.45 0) [ ModelNode "poll6Model" (Just carouselPool), TransformNode "horse6" (Rotate 0 0 0) (Translate 0 0 0) [ ModelNode "horse6Model" (Just horseModel) ] ], OrbitalTransformNode "poll7" (Rotate 0 0 270) (Translate 0 0.45 0) [ ModelNode "poll7Model" (Just carouselPool), TransformNode "horse7" (Rotate 0 0 0) (Translate 0 0 0) [ ModelNode "horse7Model" (Just horseModel) ] ], OrbitalTransformNode "poll8" (Rotate 0 0 315) (Translate 0 0.45 0) [ ModelNode "poll8Model" (Just carouselPool), TransformNode "horse8" (Rotate 0 0 0) (Translate 0 0 0) [ ModelNode "horse8Model" (Just horseModel) ] ] ] ], TransformNode "carouselCeiling" (Rotate 90 0 0) (Translate 0 0.2 0) [ ModelNode "carouselCeilingModel" (Just carouselFloor) ] ] ] ] where groundModel = ClassicModel(0,0,0) (heightMapToVerts(genHeightMap 6 1 1.6 1.2 1.7) 0.1 0 3) carouselBase = GluShape (50,50,50) 0.55 0.550 0.55 0.550 0.550 0.550 1(Cylinder 0.5 0.5 0.05 20 20) (QuadricStyle(Just Smooth) NoTextureCoordinates Outside FillStyle) carouselRoof = GluShape (50,50,50) 0.55 0.55 0.55 0.550 0.550 0.550 1(Cylinder 0.001 0.5 0.1 20 20) (QuadricStyle(Just Smooth) NoTextureCoordinates Outside FillStyle) carouselPool = GluShape (50,50,50) 0.55 0.55 0.55 0.550 0.550 0.550 1(Cylinder 0.005 0.005 0.2 20 20) (QuadricStyle(Just Smooth) NoTextureCoordinates Outside FillStyle) carouselFloor = GluShape (50,50,50) 0.55 0.55 0.55 0.550 0.550 0.550 1(Disk 0 0.5 20 20) (QuadricStyle(Just Smooth) NoTextureCoordinates Outside FillStyle) horseModel = GluShape (50,50,50) 0.55 0.55 0.55 0.550 0.550 0.550 1(Sphere 0.03 20 20) (QuadricStyle(Just Smooth) NoTextureCoordinates Outside FillStyle)
SceneGraph module= module SimpleSceneGraph ( findNodeByID, updateSceneGraph, GraphChange(DeleteNode, AddNode, RotateNode, TranslateNode), Model(ClassicModel, ModernModel, GluShape), Translate(Translate), Rotate(Rotate), CameraPos(CameraPos), LookAt(LookAt), UpVector(UpVector), Vert(Vert), vertexTupleListToVertexList, initModelVBO, getChanges, identityMatrix, DrawSceneGraph, SimpleSceneGraph(SimpleRootNode,SimpleCameraNode, SimpleLightNode, ModelNode, TransformNode, OrbitalTransformNode), render, getColorAtPixel, pngToArray ) where import Graphics.Rendering.OpenGL import Data.IORef import Graphics.UI.GLUT import Foreign.Storable import Control.Monad.ST.Strict import Data.Array.MArray import Data.Array.Storable import Foreign.Ptr import qualified Data.Map as Map import qualified Data.HashTable as Hashtable import Graphics.Rendering.OpenGL.Raw.ARB.Compatibility import Graphics.Rendering.GLU.Raw import Graphics.Rendering.OpenGL.GLU import Data.Int import Prelude import Codec.Image.PNG
data OpenGLType = ClassicGL | ModernGL
openGLType = ModernGL
class DrawSceneGraph a where process:: a→ IO Bool
data Translate = Translate { tx::GLfloat, ty::GLfloat, tz::GLfloat } data Rotate = Rotate{ angleX::GLfloat, angleY::GLfloat, angleZ::GLfloat}
data CameraPos = CameraPos { cpx::GLdouble, cpy::GLdouble, cpz::GLdouble}
data LookAt = LookAt { lx::GLdouble, ly::GLdouble, lz::GLdouble}
data UpVector = UpVector { uvx::GLdouble, uvy::GLdouble, uvz::GLdouble}
data SimpleSceneGraph = SimpleRootNode { nid::String, children::[SimpleSceneGraph]} |TransformNode { nid::String, rotation::Rotate, translation::Translate, children::[SimpleSceneGraph]} |OrbitalTransformNode { nid::String, rotation::Rotate, translation::Translate, children::[SimpleSceneGraph] } | ModelNode { nid::String, model::(Maybe Model) } -- | SimpleNode { -- nid::String, -- model::(Maybe Model), -- rotation::Rotate, -- translation::Translate, -- children::[SimpleSceneGraph]}
| SimpleLightNode { nid::String, rotation::Rotate, translation::Translate, amb::Color4 GLfloat, diff::Color4 GLfloat, spec::Color4 GLfloat, children::[SimpleSceneGraph]}
-- | OrbitalNode { -- nid::String, -- model::(Maybe Model), -- rotation::Rotate, -- translation::Translate, -- children::[SimpleSceneGraph]} | SimpleCameraNode { nid::String, cameraPos::CameraPos, lookAT:: LookAt, upVector::UpVector, children::[SimpleSceneGraph]}
class RenderSimpleSceneGraph a where render :: Matrix4x4 → a → IO ()
data Matrix4x4 = Matrix4x4 { i1j1 ::GLfloat, i1j2 ::GLfloat, i1j3 ::GLfloat, i1j4 ::GLfloat, i2j1 ::GLfloat, i2j2 ::GLfloat, i2j3 ::GLfloat, i2j4 ::GLfloat, i3j1 ::GLfloat, i3j2 ::GLfloat, i3j3 ::GLfloat, i3j4 ::GLfloat, i4j1 ::GLfloat, i4j2 ::GLfloat, i4j3 ::GLfloat, i4j4 ::GLfloat } deriving (Show)
identityMatrix = Matrix4x4 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1
rotateX θ = if θ ≠ 0 then Matrix4x4 1 0 0 0 0 (cos rad) (-(sin rad)) 0 0 (sin rad) (cos rad) 0 0 0 0 1 else identityMatrix where rad = θ * pi / 180 rotateY θ = if θ ≠ 0 then Matrix4x4 (cos rad) 0 (sin rad) 0 0 1 0 0 (-(sin rad)) 0 (cos rad) 0 0 0 0 1 else identityMatrix where rad = θ * pi / 180 rotateZ θ = if θ ≠ 0 then Matrix4x4 (cos rad) (-(sin rad)) 0 0 (sin rad) (cos rad) 0 0 0 0 1 0 0 0 0 1 else identityMatrix where rad = θ * pi / 180 trans (Vector3 x y z) = Matrix4x4 1 0 0 x 0 1 0 y 0 0 1 z 0 0 0 1
mult:: Matrix4x4 → Matrix4x4 → Matrix4x4 mult mL mR = Matrix4x4 x1y1 x1y2 x1y3 x1y4 x2y1 x2y2 x2y3 x2y4 x3y1 x3y2 x3y3 x3y4 x4y1 x4y2 x4y3 x4y4 where x1y1 = (i1j1 mL) * (i1j1 mR) + (i1j2 mL) * (i2j1 mR) + (i1j3 mL) * (i3j1 mR) + (i1j4 mL) * (i4j1 mR) x1y2 = (i1j1 mL) * (i1j2 mR) + (i1j2 mL) * (i2j2 mR) + (i1j3 mL) * (i3j2 mR) + (i1j4 mL) * (i4j2 mR) x1y3 = (i1j1 mL) * (i1j3 mR) + (i1j2 mL) * (i2j3 mR) + (i1j3 mL) * (i3j3 mR) + (i1j4 mL) * (i4j3 mR) x1y4 = (i1j1 mL) * (i1j4 mR) + (i1j2 mL) * (i2j4 mR) + (i1j3 mL) * (i3j4 mR) + (i1j4 mL) * (i4j4 mR) x2y1 = (i2j1 mL) * (i1j1 mR) + (i2j2 mL) * (i2j1 mR) + (i2j3 mL) * (i3j1 mR) + (i2j4 mL) * (i4j1 mR) x2y2 = (i2j1 mL) * (i1j2 mR) + (i2j2 mL) * (i2j2 mR) + (i2j3 mL) * (i3j2 mR) + (i2j4 mL) * (i4j2 mR) x2y3 = (i2j1 mL) * (i1j3 mR) + (i2j2 mL) * (i2j3 mR) + (i2j3 mL) * (i3j3 mR) + (i2j4 mL) * (i4j3 mR) x2y4 = (i2j1 mL) * (i1j4 mR) + (i2j2 mL) * (i2j4 mR) + (i2j3 mL) * (i3j4 mR) + (i2j4 mL) * (i4j4 mR) x3y1 = (i3j1 mL) * (i1j1 mR) + (i3j2 mL) * (i2j1 mR) + (i3j3 mL) * (i3j1 mR) + (i3j4 mL) * (i4j1 mR) x3y2 = (i3j1 mL) * (i1j2 mR) + (i3j2 mL) * (i2j2 mR) + (i3j3 mL) * (i3j2 mR) + (i3j4 mL) * (i4j2 mR) x3y3 = (i3j1 mL) * (i1j3 mR) + (i3j2 mL) * (i2j3 mR) + (i3j3 mL) * (i3j3 mR) + (i3j4 mL) * (i4j3 mR) x3y4 = (i3j1 mL) * (i1j4 mR) + (i3j2 mL) * (i2j4 mR) + (i3j3 mL) * (i3j4 mR) + (i3j4 mL) * (i4j4 mR) x4y1 = (i4j1 mL) * (i1j1 mR) + (i4j2 mL) * (i2j1 mR) + (i4j3 mL) * (i3j1 mR) + (i4j4 mL) * (i4j1 mR) x4y2 = (i4j1 mL) * (i1j2 mR) + (i4j2 mL) * (i2j2 mR) + (i4j3 mL) * (i3j2 mR) + (i4j4 mL) * (i4j2 mR) x4y3 = (i4j1 mL) * (i1j3 mR) + (i4j2 mL) * (i2j3 mR) + (i4j3 mL) * (i3j3 mR) + (i4j4 mL) * (i4j3 mR) x4y4 = (i4j1 mL) * (i1j4 mR) + (i4j2 mL) * (i2j4 mR) + (i4j3 mL) * (i3j4 mR) + (i4j4 mL) * (i4j4 mR)
matrix4x4toList (Matrix4x4 i1j1 i1j2 i1j3 i1j4 i2j1 i2j2 i2j3 i2j4 i3j1 i3j2 i3j3 i3j4 i4j1 i4j2 i4j3 i4j4) = [i1j1, i1j2,i1j3,i1j4,i2j1,i2j2,i2j3,i2j4,i3j1,i3j2,i3j3,i3j4,i4j1,i4j2,i4j3,i4j4] matrix4x4toGLMatrix (Matrix4x4 i1j1 i1j2 i1j3 i1j4 i2j1 i2j2 i2j3 i2j4 i3j1 i3j2 i3j3 i3j4 i4j1 i4j2 i4j3 i4j4)= newMatrix RowMajor matList :: IO (GLmatrix GLfloat) where matList = [i1j1, i1j2,i1j3,i1j4,i2j1,i2j2,i2j3,i2j4,i3j1,i3j2,i3j3,i3j4,i4j1,i4j2,i4j3,i4j4]
classicTransform matrix = do matrixMode $= Modelview 0 loadIdentity print "classic matrix operation" m ← newMatrix RowMajor (matrix4x4toList matrix) :: IO (GLmatrix GLfloat) multMatrix m return ()
data GraphChange = DeleteNode { cid ::String} | RotateNode { cid ::String, cx ::GLfloat, cy ::GLfloat, cz ::GLfloat} | TranslateNode { cid ::String, cx ::GLfloat, cy ::GLfloat, cz ::GLfloat} | AddNode { parentid::String, newNode::SimpleSceneGraph}
data Vert = Vert { vertX::GLfloat, vertY::GLfloat, vertZ::GLfloat, colorR::GLfloat, colorG::GLfloat, colorB::GLfloat, specR::GLfloat, specG::GLfloat, specB::GLfloat, shiny::GLfloat} deriving (Show) data Model = ClassicModel{ colorID::(GLubyte,GLubyte,GLubyte), verts::[Vert]} | GluShape{ colorID::(GLubyte,GLubyte,GLubyte), shapeR::GLfloat, shapeG::GLfloat, shapeB::GLfloat, shapeSpecR::GLfloat, shapeSpecG::GLfloat, shapeSpecB::GLfloat, shapeShiny::GLfloat, shape ::(QuadricPrimitive), style :: QuadricStyle} | ModernModel{ vboData:: IO BufferObject, vertCount:: Int }
instance RenderSimpleSceneGraph Model where render matrix (ClassicModel (r,g,b) verts ) = do print "a model" classicTransform matrix --color $ Color3 r g b renderPrimitive Triangles $ mapM_ renderVert verts render matrix (GluShape (r, g ,b) r1 g1 b1 sR sG sB shiny shape style) = do color $ Color3 r1 g1 b1 materialAmbientAndDiffuse FrontAndBack $= (Color4 r1 g1 b1 1) materialSpecular FrontAndBack $= (Color4 sR sG sB 1) materialShininess FrontAndBack $= shiny renderQuadric style shape renderVert (Vert x y z r g b sR sG sB shiny) = do color $ Color3 r g b materialAmbientAndDiffuse FrontAndBack $= (Color4 r g b 1) materialSpecular FrontAndBack $= (Color4 sR sG sB 1) materialShininess FrontAndBack $= shiny vertex $ Vertex3 x y z instance RenderSimpleSceneGraph SimpleSceneGraph where render matrix (SimpleRootNode id children) = do --matrixMode $= Projection --loadIdentity --depthFunc $= Just Less --viewport $= (Position 0 0, Size 800 600) --perspective 60 1.333 1 120 clear [ColorBuffer, DepthBuffer] lighting $= Enabled light (Light 0) $= Enabled matrixMode $= Modelview 0 loadIdentity traverseChildren matrix children flush swapBuffers return () render matrix (ModelNode id model) = do --print $ "drawing" ⊕ id --show matrix case model of Nothing → return() Just model1 → render matrix model1
render matrix (OrbitalTransformNode id (Rotate aX aY aZ) (Translate x y z) children) = do print $ "drawing" ⊕ id print translatedMat traverseChildren translatedMat children return () where rotatedXMat = (rotateX aX) `mult` matrix rotatedYMat = (rotateY aY) `mult`rotatedXMat rotatedZMat = (rotateZ aZ) `mult`rotatedYMat translatedMat = (trans (Vector3 x y z)) `mult` rotatedZMat
render matrix (TransformNode id (Rotate aX aY aZ) (Translate x y z) children) = do print $ "drawing" ⊕ id print rotatedZMat traverseChildren rotatedZMat children return () where translatedMat = (trans (Vector3 x y z)) `mult` matrix rotatedXMat = (rotateX aX) `mult` translatedMat rotatedYMat = (rotateY aY) `mult` rotatedXMat rotatedZMat = (rotateZ aZ) `mult` rotatedYMat
render matrix (SimpleLightNode nid rotation translation amb diff spec children) = do ambient (Light 0) $= amb diffuse (Light 0) $= diff specular (Light 0) $= spec position (Light 0) $= (Vertex4 1 1 1 0) where transX = tx translation transY = ty translation transZ = tz translation --angleRot = rangle rotation --rotX = rx rotation --rotY = ry rotation --rotZ = rz rotation translateRotateDraw = do
--translate (Vector3 transX transY transZ) --rotate angleRot (Vector3 rotX rotY rotZ) traverseChildren matrix children --render matrix (SimpleNode id model rotation translation children) = do -- print $ "drawing" ⊕ id -- preservingMatrix translateRotateDraw -- return () -- where -- transX = tx translation -- transY = ty translation -- transZ = tz translation -- angleRot = rangle rotation -- rotX = rx rotation -- rotY = ry rotation -- rotZ = rz rotation -- translateRotateDraw = do -- -- translate (Vector3 transX transY transZ) -- rotate angleRot (Vector3 rotX rotY rotZ) -- traverseChildren matrix children -- case model of -- Nothing → return () -- Just m1 → render matrix m1 --render matrix (OrbitalNode id model rotation translation children) = do -- print $ "drawing" ⊕ id -- preservingMatrix translateRotateDraw -- return () -- where -- transX = tx translation -- transY = ty translation -- transZ = tz translation -- angleRot = rangle rotation -- rotX = rx rotation -- rotY = ry rotation -- rotZ = rz rotation -- translateRotateDraw = do -- rotate angleRot (Vector3 rotX rotY rotZ) -- translate (Vector3 transX transY transZ) -- traverseChildren matrix children -- case model of -- Nothing → return () -- Just m1 → render matrix m1 render matrix (SimpleCameraNode id (CameraPos posX posY posZ) (LookAt lookX lookY lookZ) (UpVector upX upY upZ) children) = do print $ "drawing" ⊕ id gluLookAt posX posY posZ lookX lookY lookZ upX upY upZ traverseChildren matrix children return () traverseChildren:: Matrix4x4 → [SimpleSceneGraph]→ IO () traverseChildren matrix (x:xs) = do render matrix x traverseChildren matrix xs traverseChildren _ [] = do return ()
initModelVBO :: [GLfloat] → IO BufferObject initModelVBO vertexList = do [models]← genObjectNames 1 :: IO [BufferObject] bindBuffer ArrayBuffer $= Just models tempArray ← newListArray (0, listLen - 1) vertexList :: IO(StorableArray Int GLfloat) withStorableArray tempArray (λptr -> bufferData ArrayBuffer $= (sizeOfList, ptr, StaticDraw)) bindBuffer ArrayBuffer $= Nothing return models where listLen = length vertexList elementSize = sizeOf $ head vertexList sizeOfList = toEnum $ listLen * elementSize vertexTupleListToVertexList::[(GLfloat,GLfloat,GLfloat)]→ [GLfloat] vertexTupleListToVertexList [] = [] vertexTupleListToVertexList ((x,y,z):verts) = x:y:z:vertexTupleListToVertexList verts
--Takes a list of changes, should be hashtable though, and a SceneGraph --It then recursivly rebuild the graph making any change in the changes --data structure updateSceneGraph :: Map.Map String [GraphChange]→ SimpleSceneGraph → SimpleSceneGraph
-- A root node can ¬ be changed or deleted and can only apear once as the ROOT --failing to follow these rules will result in undefined behaviors updateSceneGraph changes (SimpleRootNode id children) = SimpleRootNode id (updateChildren children changes)
updateSceneGraph changes graph = graph
findNodeByID id graph = if graphID ≡ id then Just graph else findNodeByIDChildren Nothing id (children graph) where graphID = nid graph
findNodeByIDChildren (Just graph) _ _ = Just graph
findNodeByIDChildren accum id (c:cs) = findNodeByIDChildren (findNodeByID id c) id cs
findNodeByIDChildren accum _ [] = accum
updateChildren :: [SimpleSceneGraph] → Map.Map String [GraphChange] → [SimpleSceneGraph]
updateChildren [] changes = []
updateChildren (n:ns) changes = case newN of Nothing → (updateChildren ns changes) Just node → node:(updateChildren ns changes) where nodeID = nid n newN = applyAllChanges (Just n) applicableChanges changes applicableChanges = getChanges nodeID changes
--Takes a String node id and returns all changes that apply to it getChanges::String→ Map.Map String [GraphChange]→ [GraphChange]
getChanges id map = case changes of Nothing → [] Just cs → cs where changes = Map.lookup id map
--Applies all changes for a node to that node applyAllChanges::(Maybe SimpleSceneGraph) → [GraphChange] → Map.Map String [GraphChange] → (Maybe SimpleSceneGraph) applyAllChanges Nothing _ _ = Nothing
applyAllChanges (Just node) (c:cs) allChanges = applyAllChanges (updateNode node c ) cs allChanges
applyAllChanges (Just (TransformNode id rotation trans children)) [] allChanges = Just (TransformNode id rotation trans (updateChildren children allChanges))
applyAllChanges (Just (OrbitalTransformNode id rotation trans children)) [] allChanges = Just (OrbitalTransformNode id rotation trans (updateChildren children allChanges))
applyAllChanges (Just (ModelNode id model)) [] allChanges = Just (ModelNode id model)
applyAllChanges (Just (SimpleCameraNode id pos look up children)) [] allChanges = Just (SimpleCameraNode id pos look up (updateChildren children allChanges))
applyAllChanges ( Just(SimpleLightNode id rot trans amb diff spec children)) [] allChanges = Just (SimpleLightNode id rot trans amb diff spec (updateChildren children allChanges)) --Updates a single node with a single Change --Returns Just Node or Nothing if a delete change was requested updateNode:: SimpleSceneGraph→ GraphChange→ (Maybe SimpleSceneGraph)
updateNode (SimpleCameraNode id pos lookat up children) (TranslateNode tId x y z)= Just (SimpleCameraNode id (CameraPos (realToFrac x) (realToFrac y) (realToFrac z)) lookat up children)
updateNode (TransformNode id rotation translation children) (TranslateNode tId x y z)= Just (TransformNode id rotation (Translate x y z) children)
updateNode (TransformNode id rotation translation children) (RotateNode tId x y z)= Just (TransformNode id (Rotate x y z) translation children)
updateNode (TransformNode id rotation translation children) _= Just (TransformNode id rotation translation children)
--updateNode (OrbitalNode id model rotation translation children) (TranslateNode tId x y z)= -- Just (OrbitalNode id model rotation (Translate x y z) children)
--updateNode (OrbitalNode id model rotation translation children) (RotateNode tId r x y z)= --Just (OrbitalNode id model (Rotate r x y z) translation children)
updateNode (OrbitalTransformNode id rotation translation children) _= Just (OrbitalTransformNode id rotation translation children) updateNode (ModelNode id model) _ = Just(ModelNode id model)
updateNode _ (DeleteNode id) = Nothing
pngToArray (Right png) = do Just (imageData png) pngToArray (Left error) = do Nothing
getColorAtPixel x y = do colorArray ← newArray (0, 2) 0 :: IO(StorableArray Int Int) vp ← get viewport adjustedY ← return $ adjustY vp withStorableArray colorArray (λptr -> readPixels (Position x (fromIntegral adjustedY)) (Size 1 1 ) (PixelData RGB UnsignedByte ptr)) touchStorableArray colorArray colors ← getElems colorArray return $ head colors where adjustY vp = (extractSizeY vp) - y extractSizeY (_, (Size x y)) = fromIntegral y :: GLint