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Article #1564Page flipping (was What motion blur does for you)
From: Steven Eker
Date: Thu, 24 Dec 1992 10:35
Date: Thu, 24 Dec 1992 10:35
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In article <1992Dec22.202057.18233@blkbox>, collins@blkbox (Chad R. Collins) writes: [stuff deleted] |> |> Is there no other way to accomplish this? What you described in your |> previous post really isnt practical for me- there will be too many objects |> moving over an irregular background. My other choices have left me in a bit |> of a quandry- if I use page flipping, waiting for the vertical retrace slows |> things down too much, but if I dont, the animation is of course poor. |> If your frame redraw code takes longer than one video frame, one way of speeding things up is to use triple buffering rather than double buffering. With double buffering once your redraw is complete you have to waste cpu time waiting for the next vertical retrace so that you can flip pages. With triple buffering once your redraw is complete, you start drawing the next frame in the third buffer. You have an interupt routine tied to the vertical retrace which checks if the next frame is ready and does the page flip if so. Thus the extra buffer allows you to have complete synchronisation of page flipping without syncing (& therefore slowing) your redraw code. This is easy to do on ataris/amigas but I don't know about PCs. Incidently triple buffering also works well for sound generation if you're synthesizing/ pitch shifting your waveforms on the fly. Steven
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Path: arc1-ca.pugleaf.net!sparky!uunet!mcsun!julienas!loria!loria.fr!eker From: eker@loria.fr (Steven Eker) Newsgroups: rec.games.programmer Subject: Page flipping (was What motion blur does for you) Message-ID: <709@muller.loria.fr> Date: 24 Dec 92 10:35:09 GMT References: <1992Dec21.171731.26731@midway.uchicago.edu> <1992Dec22.202057.18233@blkbox> Sender: news@news.loria.fr Organization: CRIN (CNRS) Nancy - INRIA Lorraine Lines: 28