diff --git a/GLUtil.cabal b/GLUtil.cabal
--- a/GLUtil.cabal
+++ b/GLUtil.cabal
@@ -1,5 +1,5 @@
 Name:                GLUtil
-Version:             0.6.1.1
+Version:             0.6.1.2
 Synopsis:            Miscellaneous OpenGL utilities.
 License:             BSD3
 License-file:        LICENSE
@@ -20,6 +20,11 @@
                     examples/shaders/hello-gl.frag,
                     examples/shaders/hello-gl.vert
 
+source-repository this
+  type:     git
+  tag:      0.6.1.2
+  location: http://github.com/acowley/GLUtil.git
+
 Library
   Exposed-modules:     Graphics.GLUtil,
                        Graphics.GLUtil.GLError,
@@ -45,8 +50,3 @@
   Build-tools:         cpphs
   GHC-Options:         -Odph -Wall
   HS-Source-Dirs:      src
-  
-source-repository this
-  type:     git
-  tag:      0.6.1
-  location: http://github.com/acowley/GLUtil.git
diff --git a/src/Graphics/GLUtil/JuicyTextures.hs b/src/Graphics/GLUtil/JuicyTextures.hs
--- a/src/Graphics/GLUtil/JuicyTextures.hs
+++ b/src/Graphics/GLUtil/JuicyTextures.hs
@@ -1,10 +1,15 @@
 {-# LANGUAGE RankNTypes #-}
+-- | Uses the @JuicyPixels@ package to load images that are then used
+-- to create OpenGL textuers.
 module Graphics.GLUtil.JuicyTextures where
 import Codec.Picture (readImage, DynamicImage(..), Image(..))
 import Control.Applicative ((<$>))
 import Graphics.GLUtil.Textures
 import Graphics.Rendering.OpenGL (TextureObject)
 
+-- | Load a 'TexInfo' value from an image file, and supply it to a
+-- user-provided function. Supported image formats include @png@,
+-- @jpeg@, @bmp@, and @gif@. See 'readTexture' for most uses.
 readTexInfo :: FilePath
             -> (forall a. IsPixelData a => TexInfo a -> IO b)
             -> IO (Either String b)
@@ -15,7 +20,9 @@
         aux (ImageRGB8 (Image w h p)) = Right <$> k (texInfo w h TexRGB p)
         aux (ImageRGBF (Image w h p)) = Right <$> k (texInfo w h TexRGB p)
         aux (ImageRGBA8 (Image w h p)) = Right <$> k (texInfo w h TexRGBA p)
-        aux (ImageYCbCr8 _) = return $ Left "YCbCr format not supported"
+        aux _ = return $ Left "Unsupported image format"
 
+-- | Load a 'TextureObject' from an image file. Supported formats
+-- include @png@, @jpeg@, @bmp@, and @gif@.
 readTexture :: FilePath -> IO (Either String TextureObject)
 readTexture f = readTexInfo f loadTexture
diff --git a/src/Graphics/GLUtil/Linear.hs b/src/Graphics/GLUtil/Linear.hs
--- a/src/Graphics/GLUtil/Linear.hs
+++ b/src/Graphics/GLUtil/Linear.hs
@@ -6,7 +6,6 @@
 import Foreign.Marshal.Array (withArray)
 import Foreign.Marshal.Utils (with)
 import Foreign.Ptr (Ptr, castPtr)
-import Foreign.Storable (Storable)
 import Graphics.Rendering.OpenGL (UniformLocation)
 import Graphics.Rendering.OpenGL.Raw.Core31
 import Linear
diff --git a/src/Graphics/GLUtil/ShaderProgram.hs b/src/Graphics/GLUtil/ShaderProgram.hs
--- a/src/Graphics/GLUtil/ShaderProgram.hs
+++ b/src/Graphics/GLUtil/ShaderProgram.hs
@@ -86,8 +86,10 @@
      throwError
      (attrs,unis) <- getActives p
      return $ ShaderProgram (fromList attrs) (fromList unis) p
-     
 
+-- | Get all attributes and uniforms used by a program. Note that
+-- unused parameters may be elided by the compiler, and so will not be
+-- considered as active.
 getActives :: Program -> 
               IO ( [(String, (AttribLocation, VariableType))]
                  , [(String, (UniformLocation, VariableType))] )
@@ -96,6 +98,8 @@
       <*> (get (activeUniforms p) >>= mapM (aux (uniformLocation p)))
   where aux f (_,t,name) = get (f name) >>= \l -> return (name, (l, t))
 
+-- | Get the attribute and uniform locations associated with a list of
+-- the names of each.
 getExplicits :: Program -> ([String], [String]) ->
                 IO ( [(String, (AttribLocation, VariableType))]
                    , [(String, (UniformLocation, VariableType))] )
@@ -113,6 +117,8 @@
           | otherwise = let Just i = findIndex isNothing xs
                         in error $ "Missing GLSL variable: " ++ anames !! i
 
+-- | Set a named uniform parameter associated with a particular shader
+-- program.
 setUniform :: Uniform a => ShaderProgram -> String -> a -> IO ()
 setUniform sp name = maybe (const (putStrLn warn >> return ()))
                            (\(u,_) -> let u' = uniform u
@@ -120,10 +126,14 @@
                            (lookup name $ uniforms sp)
   where warn = "WARNING: uniform "++name++" is not active"
 
+-- | Get the 'UniformLocation' associated with a named uniform
+-- parameter.
 getUniform :: ShaderProgram -> String -> UniformLocation
 getUniform sp n = maybe (error msg) fst . lookup n $ uniforms sp
   where msg = "Uniform "++show n++" is not active"
 
+-- | Set a named vertex attribute's 'IntegerHandling' and
+-- 'VertexArrayDescriptor'.
 setAttrib :: ShaderProgram -> String -> 
              IntegerHandling -> VertexArrayDescriptor a -> IO ()
 setAttrib sp name = maybe (\_ _ -> putStrLn warn >> return ())
@@ -132,10 +142,13 @@
                           (lookup name $ attribs sp)
   where warn = "WARNING: attrib "++name++" is not active"
 
+-- | Get the 'AttribLocation' associated with a named vertex
+-- attribute.
 getAttrib :: ShaderProgram -> String -> AttribLocation
 getAttrib sp n = maybe (error msg) fst . lookup n $ attribs sp
   where msg = "Attrib "++show n++" is not active"
 
+-- | Enable a named vertex attribute.
 enableAttrib :: ShaderProgram -> String -> IO ()
 enableAttrib sp name = maybe (return ())
                              (($= Enabled) . vertexAttribArray . fst)
diff --git a/src/Graphics/GLUtil/TypeMapping.hs b/src/Graphics/GLUtil/TypeMapping.hs
--- a/src/Graphics/GLUtil/TypeMapping.hs
+++ b/src/Graphics/GLUtil/TypeMapping.hs
@@ -11,6 +11,9 @@
 import Graphics.Rendering.OpenGL
 import Linear (V2, V3, V4, M22, M33, M44)
 
+-- | A mapping from Haskell types to values of 'VariableType'. This
+-- defines how Haskell values may be mapped to values that may be
+-- bound to GLSL variables.
 class HasVariableType a where
   variableType :: a -> VariableType
 
diff --git a/src/Graphics/GLUtil/VertexArrayObjects.hs b/src/Graphics/GLUtil/VertexArrayObjects.hs
--- a/src/Graphics/GLUtil/VertexArrayObjects.hs
+++ b/src/Graphics/GLUtil/VertexArrayObjects.hs
@@ -1,6 +1,5 @@
 -- | A thin layer over OpenGL 3.1+ vertex array objects.
 module Graphics.GLUtil.VertexArrayObjects (makeVAO, withVAO, VAO) where
-import Control.Applicative
 import Graphics.Rendering.OpenGL
 
 -- |Short alias for 'VertexArrayObject'.
diff --git a/src/Graphics/GLUtil/Viewport.hs b/src/Graphics/GLUtil/Viewport.hs
--- a/src/Graphics/GLUtil/Viewport.hs
+++ b/src/Graphics/GLUtil/Viewport.hs
@@ -1,6 +1,11 @@
+-- | Helpers for working with OpenGL viewports.
 module Graphics.GLUtil.Viewport where
 import Graphics.Rendering.OpenGL
 
+-- | @withViewport pos sz m@ runs the action @m@ after setting the
+-- viewport with the given 'Position' and 'Size'. The viewport is
+-- reset to its original state after the action is run, and the result
+-- of the action is returned.
 withViewport :: Position -> Size -> IO a -> IO a
 withViewport p s m = do oldVP <- get viewport
                         viewport $= (p,s)