Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com From: Scott Cartier Newsgroups: scee.yaroze.problems.pc Subject: Re: Backgrounds (BG) in interlaced mode Date: Thu, 11 Mar 1999 16:14:42 -0800 Organization: SCEA News Server Lines: 36 Message-ID: <36E85C72.7AAB1575@vmlabs.com> References: <9IMxzAAt5E62EwX8@cipher-ltd.demon.co.uk> NNTP-Posting-Host: vmlabs36.vmlabs.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 4.5 [en] (Win98; U) X-Accept-Language: en I encountered this too back when I was experimenting with the BG stuff. I suspect the built-in background routines don't work at hi-res. Since the tiles are 32x32, you'd need to draw 300 of them to form a background at 640x480. Could be that it just can't handle it. I ended up making my own background routines. The benefit with that is I'm not restricted to 32x32 tiles. It's been a while, but I think I'm using 64x64 tiles which are scaled 2x in both directions for an effective size of 128x128. That way I only need to draw 20 at a time. I'm not doing anything super fancy though - it's a simple star background. Scott > I have just started to dabble with my Yaroze and am trying out some of > its features. > > The manuals seem to infer that you can use BG functions in interlaced > mode: Page 142 of the Library Reference manual (GsInitFixBg16) makes > reference to NTSC interlaced mode vertical screen resolutions. > > When I try to use GsSortFixBg16 in PAL mode with PAL interlace mode at > 640x512 resolution, I get screen flicker. Further investigation shows > that the every other line (odd numbered lines - I think) of my BG data > is getting transmitted to the frame buffer, but not the rest, hence the > flicker. > > NB. The simple test that demonstrates this is to only register the BG in > the odd numbered OT (1). When the BG is only registered in the even > numbered OT (0) none of the BG is displayed and the screen is rock > solid. > > Any ideas? > > Tim.