abstract bindable stuff as typeclass

renderer-tutorial.cabal

@@ -26,8 +26,10 @@ executable renderer-tutorial
                      , bytestring
                      , monad-loops
                      , random
-  other-modules:       BufferClass
+  other-modules:       BindableClass
+                     , BufferClass
                      , VertexBuffer
+                     , VertexArray
                      , IndexBuffer
   hs-source-dirs:      src
   default-language:    Haskell2010

src/BindableClass.hs

@@ -0,0 +1,10 @@
+module BindableClass where
+
+-- | typeclass for bindabl eobjects like buffers, vertex arrays or shaders
+class Bindable a where
+
+  -- bind the object in context
+  bind :: a -> IO ()
+  
+  -- release object from context
+  unbind :: a -> IO ()

src/BufferClass.hs

@@ -5,10 +5,14 @@ import qualified Graphics.Rendering.OpenGL as GL
 
 import SDL (($=), get)
 
+-- internal imports
+
+import BindableClass
+
 -- this aims to be a typeclass for all used buffer objects throughout the
 -- tutorial.
 -- think of it as some kind of interface in the object oriented context
-class Buffer a where
+class (Bindable a) => Buffer a where
 
   type ObjName a :: *
 
@@ -20,11 +24,3 @@ class Buffer a where
 
   -- bind the buffer object and fill it with data
   initialize :: a -> IO ()
-
-  -- bind the buffer
-  bind :: a -> IO ()
-  -- bind buf = GL.bindBuffer (target buf) $= Just (glId buf)
-
-  -- unbind the buffer
-  unbind :: a -> IO ()
-  -- unbind buf = GL.bindBuffer (target buf) $= Nothing

src/IndexBuffer.hs

@@ -9,6 +9,7 @@ import Foreign
 
 -- internal imports
 
+import BindableClass
 import BufferClass
 
 -- layout of the IndexBuffer data object
@@ -40,6 +41,8 @@ instance Buffer (IndexBuffer a) where
     -- release the buffer using the default implementation of the typeclass
     unbind buf
 
+instance Bindable (IndexBuffer a) where
+
   -- bind the buffer
   bind buf = GL.bindBuffer (target buf) $= Just (glId buf)
 

src/Main.hs

@@ -31,6 +31,7 @@ import System.Random (randomRIO)
 
 -- internal imports
 
+import BindableClass
 import BufferClass
 import VertexArray
 import VertexBuffer

src/VertexArray.hs

@@ -11,6 +11,7 @@ import Control.Concurrent.MVar
 
 -- internal imports
 
+import BindableClass
 import BufferClass
 import VertexBuffer
 
@@ -29,6 +30,9 @@ instance Buffer VertexArray where
 
   initialize va = return ()
 
+
+instance Bindable VertexArray where
+
   bind va = GL.bindVertexArrayObject $= Just (vArrId va)
 
   unbind va = GL.bindVertexArrayObject $= Nothing

src/VertexBuffer.hs

@@ -9,6 +9,7 @@ import Foreign
 
 -- internal imports
 
+import BindableClass
 import BufferClass
 
 -- layout of the VertexBuffer data object
@@ -39,6 +40,9 @@ instance Buffer (VertexBuffer a) where
     -- release the buffer using the default implementation of the typeclass
     unbind buf
 
+
+instance Bindable (VertexBuffer a) where
+
   -- bind the buffer
   bind buf = GL.bindBuffer (target buf) $= Just (glId buf)