    --------------------------------------------------------------------------------
    -- |
    -- Module      :  Graphics.Rendering.OpenGL.GLU.Mipmapping
    -- Copyright   :  (c) Sven Panne 2002-2006
    -- License     :  BSD-style (see the file libraries/OpenGL/LICENSE)
    --
    -- Maintainer  :  sven.panne@aedion.de
    -- Stability   :  stable
    -- Portability :  portable
    --
    -- This module corresponds to chapter 3 (Mipmapping) of the GLU specs.
    --
    --------------------------------------------------------------------------------

    module Graphics.Rendering.OpenGL.GLU.Mipmapping (
       scaleImage, build1DMipmaps, build2DMipmaps
    ) where

    import Foreign.Ptr ( Ptr )
    import Graphics.Rendering.OpenGL.GL.BasicTypes ( GLsizei, GLint, GLenum )
    import Graphics.Rendering.OpenGL.GL.CoordTrans ( Size(..) )
    import Graphics.Rendering.OpenGL.GL.PixelData ( PixelData, withPixelData )
    import Graphics.Rendering.OpenGL.GL.Texturing.PixelInternalFormat (
       PixelInternalFormat, marshalPixelInternalFormat )
    import Graphics.Rendering.OpenGL.GL.Texturing.TextureTarget (
       TextureTarget, marshalTextureTarget )
    import Graphics.Rendering.OpenGL.GLU.ErrorsInternal ( recordInvalidValue )

    --------------------------------------------------------------------------------
    -- Section 3.1 (Image Scaling)

    scaleImage :: Size -> PixelData a -> Size -> PixelData b -> IO ()
    scaleImage (Size widthIn  heightIn)  pdIn (Size widthOut heightOut) pdOut =
       withPixelData pdIn $ \fIn dIn pIn ->
          withPixelData pdOut $ \fOut dOut pOut ->
             if fIn == fOut
                then gluScaleImage
                        fIn widthIn heightIn dIn pIn widthOut heightOut dOut pOut
                else recordInvalidValue

    foreign import CALLCONV unsafe "gluScaleImage" gluScaleImage ::
       GLenum -> GLsizei -> GLsizei -> GLenum -> Ptr a
              -> GLsizei -> GLsizei -> GLenum -> Ptr b -> IO ()

    --------------------------------------------------------------------------------
    -- Section 3.2 (Automatic Mipmapping)
    -- Missing for GLU 1.3: gluBuild3DMipmaps, gluBuild{1,2,3}DMipmapLevels

    build1DMipmaps ::
       TextureTarget -> PixelInternalFormat -> GLsizei -> PixelData a -> IO ()
    build1DMipmaps target internalFormat height pd = do
       withPixelData pd $
          gluBuild1DMipmaps
             (marshalTextureTarget target)
             (marshalPixelInternalFormat internalFormat)
             height
       return ()   -- TODO: Should we use the return value?

    foreign import CALLCONV unsafe "gluBuild1DMipmaps" gluBuild1DMipmaps ::
          GLenum -> GLint -> GLsizei -> GLenum -> GLenum -> Ptr a -> IO GLint

    --------------------------------------------------------------------------------

    build2DMipmaps :: TextureTarget -> PixelInternalFormat -> GLsizei -> GLsizei
                   -> PixelData a -> IO ()
    build2DMipmaps target internalFormat width height pd = do
       withPixelData pd $
          gluBuild2DMipmaps
             (marshalTextureTarget target)
             (marshalPixelInternalFormat internalFormat)
             width height
       return ()   -- TODO: Should we use the return value?

    foreign import CALLCONV unsafe "gluBuild2DMipmaps" gluBuild2DMipmaps ::
          GLenum -> GLint -> GLsizei -> GLsizei -> GLenum -> GLenum -> Ptr a -> IO GLint