Thank you for pointing out where the problem was.

On Fri, Nov 19, 2010 at 7:26 AM, Balazs Komuves <bkomuves@gmail.com> wrote:

Hi,

Still guessing (I can't try your code at the moment), but it seems that you want to use vertex arrays, however you set up the vertex *attribute* array pointer, which are two different things. Vertex attributes are arbitrary parameters associated with vertices, to be used by vertex shaders.

Balazs

On Fri, Nov 19, 2010 at 3:38 AM, Ben Christy <ben.christy@gmail.com> wrote:

Ok I stripped this down to the barest form and I still get segmentation faults here is the code. I am at a loss as this seems to be identical to C code posted in examples all over the web. Any thoughts?

main = do

  (progname, _) ← getArgsAndInitialize
  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 1 120
  changesRef ← newIORef Map.empty
  --sceneRef ← newIORef buildSSG
  sceneRef ← newIORef (SimpleRootNode "HomeWork3" [

   TransformNode "camera" (Rotate 0 90 0) (Translate 0 0 (-1))
   [
   TransformNode "ground" (Rotate 0 0 0) (Translate (-4) (-1.5) (-4))
   [

   ModelNode "groundModel" (Just (buildModel ModernGL (heightMapToVerts(genHeightMap 2 1 1.6 1.2 1.7) 0.1 0 3)
   (0,0,0) (buildShader defaultVertexShader defaultFragmentShader)))

   ]
   ]
   ])
  --pollsRot ← newIORef 0
  --evenState ← newIORef BackAgain
  --evenPos ← newIORef 0.25
  --oddState ← newIORef There

  --oddPos ← newIORef 0.15
  --balloonNumSteps ← newIORef 100
  reshapeCallback $= Just reshape
  displayCallback $= (displayScene sceneRef changesRef )
  --addTimerCallback 10 (animate sceneRef pollsRot changesRef evenState evenPos oddState oddPos)

  --keyboardMouseCallback $= Just (handleInput sceneRef changesRef)
  mainLoop

displayScene sceneRef changesRef= do
  --changes ← readIORef changesRef
  --oldSceneGraph ← readIORef sceneRef

  --sceneGraph ← return $ updateSceneGraph changes oldSceneGraph
  --render identityMatrix sceneGraph
  --writeIORef changesRef Map.empty
  --writeIORef sceneRef sceneGraph
   clear [ColorBuffer, DepthBuffer]

   lighting $= Enabled
   light (Light 0) $= Enabled
   matrixMode $= Modelview 0
   loadIdentity
   [vbo] ← genObjectNames 1 :: IO [BufferObject]
   bindBuffer ArrayBuffer $= Just vbo

   tempArray ← newListArray (0, 8) [0,0,0,0,0.5,0,0.5,0.5,0.5] :: IO(StorableArray Int GLfloat)
   withStorableArray tempArray (λptr ->
   bufferData ArrayBuffer $= ((fromIntegral (9*4), ptr, StaticDraw)))

   print " Setting attrib pointer"
   vertexAttribArray (AttribLocation 1) $= Enabled
   GLRaw.glVertexAttribPointer 1 3 GLRaw.gl_FLOAT 0 0 (plusPtr nullPtr (0))
   clientState VertexArray $= Enabled

   print "before draw"
   drawArrays Triangles 0 3
   print "after draw"
   --resetAttribPtr program
   bindBuffer ArrayBuffer $= Nothing

   clientState VertexArray $= Disabled

   return ()

reshape (Size w h) = do
  print "resize"
  matrixMode $= Projection
  loadIdentity
  depthFunc $= Just Less
  viewport $= (Position 0 0, Size w h)

  perspective 60 1.333 0.01 120
  matrixMode $= Modelview 0
  loadIdentity
  postRedisplay Nothing

On Thu, Nov 18, 2010 at 10:37 AM, Ben Christy <ben.christy@gmail.com> wrote:

I have tried
drawElements Triangles (fromIntegral 1) UnsignedInt nullPtr--(fromIntegral count)

Test.withArray [ (i) | i<-[0..count-1] ] $ \p -> drawElements Points10 UnsignedInt p


drawArrays Points 1 10

All three of which cause a segmentation thought. I am kind of at a loss, is it possible that the buffers are empty? If so what is the best way to check?