[HOpenGL] Depth problem

Nate Young youngnh at gmail.com
Mon Oct 25 21:01:46 EDT 2010


Hi, I couldn't get your code running to verify you didn't include enough to
run the whole program, but I did notice that `main` and `reshape` methods
set different zNear values: 1 and 0.01 respectively.  How are you
translating the object?


> I am taking a graphics class and I have a problem I have not been able to
> resolve. When I translate along the Z axis objects are clipped before their
> size changes. It almost seems likes its stuck using a ortho prjojection
> some
> how. That being said the clip plan is very close and to me does not
> resemble
> the one I set in gluPerspective. It starts to clip after being translated
> -0.6 units down the z axis.
>
> Attached is the code that I use to setup the projection matrix.
>
> main = do
>  (progname, _) ←  getArgsAndInitialize
>  --initialContextVersion 3 0
>  createWindow "Ben Christy Assignment 2"
>  windowSize $= Size 800 600
>  matrixMode $= Projection
>  loadIdentity
>  depthFunc $= Just Less
>  viewport   $= (Position 0 0, Size 800 600)
>  perspective 60 1.333 1 1200
>  --tableModel ←  initModelVBO (vertexTupleListToVertexList table)
>  changesRef ←  newIORef Map.empty
>  sceneRef ←  newIORef buildSSG
>  balloonState ←  newIORef There
>  balloonZTarget ←  newIORef 4
>  balloonZStart ←  newIORef 0
>  balloonStep ←  newIORef 0
>  balloonNumSteps ←  newIORef 0
>  reshapeCallback $= Just reshape
>  displayCallback $= (displayScene sceneRef changesRef )
>  --addTimerCallback  10 (animate sceneRef changesRef balloonState
> balloonZTarget balloonZStart balloonStep balloonNumSteps)
>  keyboardMouseCallback $= Just (handleInput sceneRef changesRef)
>  mainLoop
> reshape (Size w h) = do
>  print "resize"
>  matrixMode $= Projection
>  loadIdentity
>  depthFunc $= Just Less
>  viewport   $= (Position 0 0, Size w h)
>  perspective 60 1.333 0.01 1200
>  matrixMode $= Modelview 1
>  loadIdentity
>  postRedisplay Nothing
>
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