Path: chuka.playstation.co.uk!news From: James Russell Newsgroups: scee.yaroze.programming.2d_graphics Subject: Re: Caches Date: Mon, 17 Aug 1998 15:05:23 +0100 Organization: Sony Computer Entertainment Europe Lines: 26 Message-ID: <35D838A3.F8E6B876@scee.sony.co.uk> References: <35C81A30.4ACB@club-internet.fr> <35C82DDB.3E12E37C@scee.sony.co.uk> <01bdc061$2c186980$f30b0a0a@Angela1.intelligent-group.com> <35D2E01D.5CA1@mdx.ac.uk> <6r0vps$n7i6@chuka.playstation.co.uk> <35D43404.282A@mdx.ac.uk> <35D438D2.908C3316@ndirect.co.uk> <35D43F08.36BA@mdx.ac.uk> <35D44CBE.1FA95769@ndirect.co.uk> <35D46843.5DF5@mdx.ac.uk> <35D4750C.A4613436@ndirect.co.uk> <35D47AA8.4E80@mdx.ac.uk> <35D48242.CC86BE26@ndirect.co.uk> <35d51fb9.8182565@news.scea.sony.com> <35D7D900.39D7@mdx.ac.uk> <01bdc9c0$c2507b00$230b0a0a@Angela1.intelligent-group.com> NNTP-Posting-Host: mailgate.scee.sony.co.uk Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 4.5b1 [en] (Win95; I) X-Accept-Language: en Craig Graham wrote: > > Depends on whether you were GPU, CPU, or GTE bound in the first place. > Think like this....assume you were running out or GPU (draw) time. > Because of the way the GPU works, poly's that go over the edge or the draw area cause > a big performance hit. > But maybe you had a fair amount of GTE/CPU time spare. Setting subdivision > would make more of the display drop out in the trivial reject (all points > of a poly outside draw area after local->screen xform). So you'd quite possibly > improve performance in some cases (not all by any means) by subdividing. I don't understand those results at all, but Craig's answer sounds like the best to me. FYI, a poly that is to the top and/or left of the clip window will get drawn regardless, even if it's totally offscreen. Polys that lie completely to the right or bottom of the clip window get trivially rejected by the GPU. Subdivision may actually help the GPU speed in this case. Cheers, James -- == James_Russell@scee.sony.co.uk +44 (171) 447-1626 == Developer Support Engineer - Sony Computer Entertainment Europe A fail-safe circuit will destroy others.