    --------------------------------------------------------------------------------
    -- |
    -- Module      :  Graphics.Rendering.OpenGL.GL.PixelRectangles.Rasterization
    -- 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 a part of section 3.6.4 (Rasterization of Pixel
    -- Rectangles) of the OpenGL 2.1 specs.
    --
    --------------------------------------------------------------------------------

    module Graphics.Rendering.OpenGL.GL.PixelRectangles.Rasterization (
       PixelData(..), PixelFormat(..), drawPixels, pixelZoom
    ) where

    import Control.Monad ( liftM2 )
    import Foreign.Ptr ( Ptr )
    import Graphics.Rendering.OpenGL.GL.BasicTypes ( GLenum, GLsizei, GLfloat )
    import Graphics.Rendering.OpenGL.GL.CoordTrans ( Size(..) )
    import Graphics.Rendering.OpenGL.GL.PixelData ( PixelData(..), withPixelData )
    import Graphics.Rendering.OpenGL.GL.PixelFormat ( PixelFormat(..) )
    import Graphics.Rendering.OpenGL.GL.QueryUtils (
       GetPName(GetZoomX,GetZoomY), getFloat1 )
    import Graphics.Rendering.OpenGL.GL.StateVar ( StateVar, makeStateVar )

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

    drawPixels :: Size -> PixelData a -> IO ()
    drawPixels (Size w h) pd = withPixelData pd $ glDrawPixels w h

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

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

    pixelZoom :: StateVar (GLfloat, GLfloat)
    pixelZoom =
       makeStateVar
          (liftM2 (,) (getFloat1 id GetZoomX) (getFloat1 id GetZoomY))
          (uncurry glPixelZoom)

    foreign import CALLCONV unsafe "glPixelZoom" glPixelZoom ::
       GLfloat -> GLfloat -> IO ()