Path: chuka.playstation.co.uk!news From: James Russell Newsgroups: scee.yaroze.programming.2d_graphics Subject: Re: Scrolling backgrounds Date: Sun, 12 Jul 1998 14:55:37 +0100 Organization: Sony Computer Entertainment Europe Lines: 30 Message-ID: <35A8C059.F4CE9E15@scee.sony.co.uk> References: <6nvfvm$9o1@chuka.playstation.co.uk> <35A34842.A7B6E58C@scee.sony.co.uk> <35a3f513.14718586@news.scea.sony.com> <35A47C17.4266BE24@scee.sony.co.uk> <35A75EF1.C28E7C0B@compuserve.com> 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) Nick Slaven wrote: > > James Russell wrote: > > > Does this mean that using only one DrawOT, as I've seen in many yaroze programs, > will cause a major bottleneck, as this call will block until GPU can cope with > it? No. DrawOT simply puts the head of the OT into the queue of commands for the GPU. The call WILL block if the queue is full (very unlikely). The functions you can call to put things in the queue are DrawOT, LoadImage, ClearImage and MoveImage. That means you can have up to 64 of any combination of those functions queued up for the GPU. Most people only have one (DrawOT). > Does this also mean that to get the best performance that we have to chop up the > final OT into 64 command long chunks & draw these sequentially whilst processing the > rest of the game logic? No - The queue for the GPU is made up of pointers to _linked_lists_ of commands, not commands themselves. You can have up to 64 _linked_lists_ in the queue before it will block. A single OT is a single linked list. Cheers, James -- == James_Russell@scee.sony.co.uk +44 (171) 447-1626 == Developer Support Engineer - Sony Computer Entertainment Europe Bigamist : A large Italian fog.