Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com From: Elliott Lee Newsgroups: scee.yaroze.beginners Subject: Re: Getting a sprite to leave a trail Date: Mon, 08 Jun 1998 13:24:40 -0700 Organization: Cisco Systems Lines: 30 Message-ID: <357C4888.396CF2E8@jps.net> References: <356C9B7A.C18CCEE4@easynet.co.uk> <3575B927.1D3140CD@mail.datasys.net> <3575C2B2.48A863A4@netmagic.net> <3577E3CF.5A90@writeme.com> Reply-To: tenchi@jps.net NNTP-Posting-Host: dhcp-e-39-201.cisco.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 4.03 [en] (Win95; U) True, but the reason you don't do that is while the GPU is rendering and the hardware is displaying the contents of that frame buffer, you'll either get screen full of flashing objects or static. Remember the old PC games that didn't sync properly with the vertical refresh rate? Same problem... :( It's usually better to have an area that's hidden from the user's view and only copy over/switch to the finished rendering. - e! James Rutherford wrote: > > > The only problem I see with this is that since you have 2 frame > > buffers, the amounts of trailing are going to be different because > > the updates to each frame only happen every other frame. One way > > to compensate for this is to let the Yaroze always display frame > > buffer 0 and only draw in frame buffer 1. Wait for the vsync > > interrupt and then do a MoveImage() from buffer 1 into buffer 0. > > This would ensure that you have a "perfect" copy of the workspace > > at the cost of the extra GPU cycles to copy memory... > > Or you could make both frame buffers point to the same display area. > > James (~mrfrosty). -- - e! tenchi@netmagic.net http://www.netmagic.net/~tenchi/yaroze/