    --------------------------------------------------------------------------------
    -- |
    -- Module      :  Graphics.Rendering.OpenGL.GL.FlushFinish
    -- Copyright   :  (c) Sven Panne 2002-2009
    -- License     :  BSD-style (see the file libraries/OpenGL/LICENSE)
    --
    -- Maintainer  :  sven.panne@aedion.de
    -- Stability   :  stable
    -- Portability :  portable
    --
    -- This module corresponds to section 5.5 (Flush and Finish) of the OpenGL 2.1
    -- specs.
    --
    --------------------------------------------------------------------------------

    module Graphics.Rendering.OpenGL.GL.FlushFinish (
       flush, finish
    ) where

    import Graphics.Rendering.OpenGL.Raw.Core31

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

    -- | Different GL implementations buffer commands in several different
    -- locations, including network buffers and the graphics accelerator itself.
    -- 'flush' empties all of these buffers, causing all issued commands to be
    -- executed as quickly as they are accepted by the actual rendering engine.
    -- Though this execution may not be completed in any particular time period, it
    -- does complete in finite time.
    --
    -- Because any GL program might be executed over a network, or on an accelerator
    -- that buffers commands, all programs should call 'flush' whenever they count
    -- on having all of their previously issued commands completed. For example,
    -- call 'flush' before waiting for user input that depends on the generated
    -- image.
    --
    -- Note that 'flush' can return at any time. It does not wait until the
    -- execution of all previously issued GL commands is complete.

    flush :: IO ()
    flush = glFlush

    -- | 'finish' does not return until the effects of all previously called GL
    -- commands are complete. Such effects include all changes to GL state, all
    -- changes to connection state, and all changes to the frame buffer contents.
    --
    -- Note that 'finish' requires a round trip to the server.

    finish :: IO ()
    finish = glFinish