Path: chuka.playstation.co.uk!news From: James Russell Newsgroups: scee.yaroze.programming.2d_graphics Subject: Re: Scrolling backgrounds Date: Thu, 09 Jul 1998 09:24:42 +0100 Organization: Sony Computer Entertainment Europe Lines: 27 Message-ID: <35A47E4A.FF7F9AC2@scee.sony.co.uk> References: <6nvfvm$9o1@chuka.playstation.co.uk> <35A34842.A7B6E58C@scee.sony.co.uk> <35a3f513.14718586@news.scea.sony.com> <35A40DE9.24722FCB@jps.net> NNTP-Posting-Host: camfw01.millennium.co.uk Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 4.05 [en] (Win95; I) Elliott Lee wrote: > > > So which and how many GPU commands can you call before you MUST call > > DrawSync(0)? The OT is purely a tool for making sure you get the polygons onto the screen in the _correct_order_. It's basically a linked list of commands that the GPU has to perform ("Draw a triangle here! Put a quad over there!"). The GPU deals in such linked lists, so performing a DrawOT() just puts the head of this list (the last entry in the OT) in the queue (length = 64) of Lists The GPU Has To Process. So it only takes up one entry in the queue. A LoadImage/MoveImage also take up one position in the queue each. The length of each list can be as large as you like, until you run out of RAM. You only need to call DrawSync(0) when you need to do something (like flip the screen) that can only be performed when you know the GPU has emptied its queue of things to do. Cheers, James -- == James_Russell@scee.sony.co.uk +44 (171) 447-1626 == Developer Support Engineer - Sony Computer Entertainment Europe A diagnostic is someone who doesn't know if there are two Gods.