Hi Haskell list,
Today I'm turning to you for the use of VBO (Vertex Buffer Object) in Haskell. I seem to be able to create one without any problem using the following code :
------------------------------------------------------ vboOfList :: Int -> [Float] -> IO BufferObject vboOfList size elems = let ptrsize = toEnum $ size * 4 arrayType = ElementArrayBuffer in do [array] <- genObjectNames 1 bindBuffer arrayType $= Just array arr <- newListArray (0, size - 1) elems withStorableArray arr (\ptr -> bufferData arrayType $= (ptrsize, ptr, StaticDraw)) bindBuffer ArrayBuffer $= Nothing reportErrors return array ------------------------------------------------------
However the problem arise when I try to draw primitives using this vbo :
------------------------------------------------------ displayVbo buff size = do let stride = toEnum sizeOfVertexInfo vxDesc = VertexArrayDescriptor 3 Float stride $ offset 0 colors = VertexArrayDescriptor 4 Float stride $ offset 12 texCoo = VertexArrayDescriptor 2 Float stride $ offset (12 + 16) filt = VertexArrayDescriptor 4 Float stride $ offset (12 + 16 +
First thanks you two for the reply.
Now for the solution, I'm a bit ashamed of myself, because I simply forgot
to put a
clientState VertexArray $= Enabled
The rest of the code is valid beside this 'little' miss
-----Message d'origine-----
De : mutantlemon@gmail.com [mailto:mutantlemon@gmail.com] De la part de Bit
Connor
Envoyé : lundi 25 août 2008 23:44
À : Twinside
Cc : haskell-cafe@haskell.org
Objet : Re: [Haskell-cafe] OpenGL's VBO with Haskell
Hi, I used VBO with haskell and I remember it being pretty
straightforward, pretty much the same as in C. This was a while ago
and I don't really remember how things work so I can't really comment
on your code. But I'll see if I can find my old haskell VBO code.
On Mon, Aug 25, 2008 at 8:43 PM, Twinside
bindBuffer ArrayBuffer $= Just buff
arrayPointer VertexArray $= vxDesc arrayPointer ColorArray $= colors arrayPointer TextureCoordArray $= texCoo arrayPointer SecondaryColorArray $= filt
drawArrays Quads 0 size bindBuffer ArrayBuffer $= Nothing ------------------------------------------------------
Nothing is displayed on screen.
As you can see, my VBO contain interleaved data : - 3 float for the vertex - 4 for the color - 2 for the texture coordinate - 4 for the secondary color)
The 'offset' function has type Int -> Ptr Float, and is used to forge a pointer from an Int, to mimic the C way of using VBO. As far as I've checked, the values in my list for VBO generation are valid and well displayed using other techniques.
So is there a workaround other method for my solution, preferably by keeping my data interleaved? Secondly, is there any sample for advanced features like VBOs in Haskell?
Regards, Vincent
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