diff --git a/GLUtil.cabal b/GLUtil.cabal
--- a/GLUtil.cabal
+++ b/GLUtil.cabal
@@ -1,5 +1,5 @@
 Name:                GLUtil
-Version:             0.7.4
+Version:             0.7.5
 Synopsis:            Miscellaneous OpenGL utilities.
 License:             BSD3
 License-file:        LICENSE
@@ -52,7 +52,8 @@
                        linear >= 1.1.3,
                        JuicyPixels >= 3,
                        OpenGLRaw >= 1.1,
-                       OpenGL >= 2.9,
+                       OpenGL >= 2.9.2 && < 2.10,
+                       transformers >= 0.3,
                        vector >= 0.7
   Build-tools:         cpphs
   GHC-Options:         -Odph -Wall
diff --git a/src/Graphics/GLUtil/Shaders.hs b/src/Graphics/GLUtil/Shaders.hs
--- a/src/Graphics/GLUtil/Shaders.hs
+++ b/src/Graphics/GLUtil/Shaders.hs
@@ -29,10 +29,10 @@
   ok <- get (compileStatus shader)
   infoLog <- get (shaderInfoLog shader)
   unless (null infoLog)
-         (mapM_ putStrLn 
+         (mapM_ putStrLn
                 ["Shader info log for '" ++ filePath ++ "':", infoLog, ""])
   unless ok $ do
-    deleteObjectNames [shader]
+    deleteObjectName shader
     ioError (userError "shader compilation failed")
   return shader
 
diff --git a/src/Graphics/GLUtil/Textures.hs b/src/Graphics/GLUtil/Textures.hs
--- a/src/Graphics/GLUtil/Textures.hs
+++ b/src/Graphics/GLUtil/Textures.hs
@@ -99,11 +99,13 @@
   where loadTex TexMono = case pixelType of
                             GL.UnsignedShort -> loadAux Luminance16 Luminance
                             GL.Float         -> loadAux R32F Red
+                            GL.HalfFloat     -> loadAux R16F Red
                             GL.UnsignedByte  -> loadAux R8 Red
                             _                -> loadAux Luminance' Luminance
         loadTex TexRG = case pixelType of
                           GL.UnsignedShort -> loadAux RG16 RGInteger
                           GL.Float -> loadAux RG32F RG
+                          GL.HalfFloat -> loadAux RG16F RG
                           GL.UnsignedByte -> loadAux RG8UI RGInteger
                           GL.Byte -> loadAux RG8I RGInteger
                           GL.Int -> loadAux RG32I RGInteger
@@ -139,6 +141,7 @@
 withTextures tt ts m = do mapM_ aux (zip ts [0..])
                           r <- m
                           cleanup 0 ts
+                          activeTexture $= TextureUnit 0
                           return r
   where aux (t,i) = do activeTexture $= TextureUnit i
                        textureBinding tt $= Just t
@@ -166,14 +169,3 @@
                        textureBinding tt $= Just t
         cleanup i = do activeTexture $= TextureUnit i
                        textureBinding tt $= Nothing
-
-class MipMappable t where
-  -- | Generate a complete set of mipmaps for the currently bound
-  -- texture object.
-  generateMipmap' :: t -> IO ()
-
-instance MipMappable TextureTarget2D where
-  generateMipmap' _ = glGenerateMipmap gl_TEXTURE_2D
-
-instance MipMappable TextureTargetCubeMap where
-  generateMipmap' _ = glGenerateMipmap gl_TEXTURE_CUBE_MAP
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
@@ -1,14 +1,16 @@
 -- | Helpers for working with OpenGL viewports.
 module Graphics.GLUtil.Viewport where
+import Control.Monad.IO.Class
 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)
+withViewport :: MonadIO m => Position -> Size -> m a -> m a
+withViewport p s m = do oldVP <- liftIO $ do oldVP <- get viewport
+                                             viewport $= (p,s)
+                                             return oldVP
                         r <- m
-                        viewport $= oldVP
+                        liftIO $ viewport $= oldVP
                         return r