Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com From: pbureau@colba.net (Patrick Bureau) Newsgroups: scee.yaroze.programming.2d_graphics Subject: Re: Caches Date: Wed, 19 Aug 1998 03:43:25 GMT Organization: SCEA News Server Lines: 18 Message-ID: <35da46fd.5743320@news.scea.sony.com> 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> <35D84FAA.43FDFA48@ndirect.co.uk> NNTP-Posting-Host: e57.Dynamic-IP.Mlink.NET X-Newsreader: Forte Free Agent 1.1/32.230 On Mon, 17 Aug 1998 16:43:39 +0000, Alex Herbert >So, I'm suggesting that the GPU draw time is significantly less when each chunk of the >sub-divided texture fits in the cache, outweighing the CPU overheads of packet creation and the >sub-division itself. > >If I'm right, then it would seem that it is better to subdivide polygons with large textures. >But, you'd need to pay attention to the balance of CPU to GPU time. If the CPU time is already >overrunning the GPU time, sub-division will have a negative impact on performance. However, if >the GPU time is exceeding the CPU time, then why not cash in some of that CPU time and give it >to the GPU by sub-dividing? Okay, I tried a couple of things and I must have been on the limit of the balance between the CPU and GPU or GTE. I tried sub-dividing two other small, non-textured objects, and kept my big texture-mapped poly(with 8x8 sub-div) and it slowed down like crazy!(about 350 hsyncs!). I guess that I should use sub-division cautiously! Patrick Bureau