Partial implementation of interleaving VBO

src/Shader.hs

@@ -146,9 +146,45 @@ setupVAO :: [(GLuint,Int)] -> IO VAO
 setupVAO ps = do
     theVAO <- genObjectName
     bindVertexArrayObject $= Just theVAO
+    theVBO <- setupVBO $ map snd ps
     vbos <- forM ps setupArrayBuffer
     ptrs <- forM (zip vbos $ map snd ps) setupVBOPointers
-    return $ VAO theVAO ptrs
+    return $ VAO 
+        { _vao = theVAO
+        , _vaoBufferTargets = ptrs
+        , _vaoVBO = theVBO
+        }
+
+setupVBO :: [Int] -> IO VBO
+setupVBO sizes = do
+    vboName <- genObjectName
+    bindBuffer ArrayBuffer $= Just vboName
+    forM_ (zip3 [0..] sizes offs) $ \(loc,siz,off) -> do
+        setupVertexAttribPointer loc siz strd off
+    thePtr <- mallocArray (strd * numDrawableElements)
+    return $ VBO
+        { _vbo = vboName
+        , _vboPoint = thePtr
+        , _vboAttribSizes = sizes
+        }
+  where
+    strd = sum sizes
+    offs = scanl (+) 0 sizes
+    
+{- | Assumes the correct VBO is bound -}
+setupVertexAttribPointer 
+    :: Int  -- ^ Atrib location
+    -> Int  -- ^ Size
+    -> Int  -- ^ Stride 
+    -> Int  -- ^ Offset
+    -> IO ()
+setupVertexAttribPointer loc siz strd off = do
+    vertexAttribPointer (AttribLocation (fi loc)) $=
+        (ToFloat, VertexArrayDescriptor (fi' siz) Float (fi'' $ floatSize * strd) (bufferOffset off))
+  where
+    fi = fromIntegral
+    fi' = fromIntegral
+    fi'' = fromIntegral
 
 setupVBOPointers :: (BufferObject,Int) -> IO (BufferObject,Ptr Float,Int)
 setupVBOPointers (vbo,vsize) = do

src/Shader/Data.hs

@@ -4,6 +4,7 @@ Datatypes used to setup and pass data to shaders.
 -}
 module Shader.Data
     ( VAO (..)
+    , VBO (..)
     , FullShader (..)
     , ShaderTexture (..)
 -- | Lens functions
@@ -28,7 +29,18 @@ and its buffer targets.  -}
 data VAO = VAO
     { _vao :: VertexArrayObject
     , _vaoBufferTargets :: [(BufferObject,Ptr Float,Int)]
+    , _vaoVBO :: VBO
     }
+{- | Vertex buffer object: contains the reference to the object,
+a pointer to a location with space that can be written to the buffer,
+and a list of attribute pointer sizes.
+Vertex attributes are interleaved within the vbo. -}
+data VBO = VBO
+    { _vbo      :: BufferObject
+    , _vboPoint :: Ptr Float
+    , _vboAttribSizes :: [Int]  -- ^ It is not clear to me if this is necessary to store or not
+    }
+
 {- | Datatype containing the necessary information for a single shader.  -}
 data FullShader a = FullShader
     { _shaderProgram :: Program