Path: chuka.playstation.co.uk!news From: "John \( QuietBloke \)" Newsgroups: scee.yaroze.freetalk.english Subject: Re: Have I mentioned this before... bgWorkArea? Date: Sat, 7 Jul 2001 23:03:47 +0100 Organization: PlayStation Net Yaroze (SCEE) Lines: 117 Message-ID: <9i810e$dor6@www.netyaroze-europe.com> References: <9i4n4l$b931@www.netyaroze-europe.com> <9i4sa2$b933@www.netyaroze-europe.com> <9i7ktj$dor5@www.netyaroze-europe.com> NNTP-Posting-Host: host213-122-12-53.btinternet.com X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Im not quite sure what your after Max.. The bg Work area is an area of memory you allocate which the Libraries need to use when displaying the tiled background. The formulae doesnt relate to number of pixels on the screen just like the size of a GsSPRITE doesnt relate to the number of pixels. Its merely how much space is required by the libraries to process and display your tileset. Also I cant see how the formulae can return a float. What your really after is an explanation of exactly what the libraries do in order to display a tileset and therefore why they need to use exactly that amount of space to do thier thing. Id be very interested to fnd out the exact details myslef but looking at the formulae you could make a fairly reasonable stab at some of it: My Rough guess work says the formulae is : (ScreenW/CellW+1) = maximum number of tiles which can appear on screen in the x direction (ScreenH/CellH+1+1) = maximum number of tiles which can appear on screen in the y direction + 1. I still have no idea why you need to add another one here. Multipy the two together to gives total number of tiles we need to be store information about. Multipy the result by 6 = For each tile the Library functions need this much work space to do its thing. I Guess this would be stuff like GsCell info + phsical screen position. Then add an additional 4 u_longs = I guess these are required to store additional information about the whole displayable tileset ( at a guess this might be to hold something like the x/y offset within the top/left tile corresponding to pixel 0,0) Muliply the result by 2 = A long shot but maybe just like the gpu_buffer we require 2 buffers. Finally add another 2 u_longs = Dunno.. Guess the tileset needs some more global information. Perhaps an offset where the second buffer exists within the workspace and which buffer we are currently working on ? Then again I could be way off and totally wrong.. In which case can someone give the real reason for the formulae ? It would be intersting to know how the formulae came to be. Cheers John ( QuietBloke ) With more insane ramblings "Max" wrote in message news:9i7ktj$dor5@www.netyaroze-europe.com... > Hmm.. > > Its really the +1s and +1+1s and *6+4 etc that I don't understand besides > this usually turns up a float value which is wierd considering the Yaroze is > a 32 bit integer machine and the value you get from this formula is always > FAR bigger that you actually need. > > I don't think I'll ever figure this out :( > > Max > > Alex Herbert wrote in message > news:9i4sa2$b933@www.netyaroze-europe.com... > > Hi Max, > > > > According to the Library Reference (page 142): > > > > size=(((ScreenW/CellW+1)*(ScreenH/CellH+1+1)*6+4)*2+2) > > > > Hope this helps. > > > > Alex > > > > > > > > "Max" wrote in message > > news:9i4n4l$b931@www.netyaroze-europe.com... > > > Hey all, > > > > > > I've started up again on the 2D tutorial and I'm puzzling over this > > > bgWorkArea size. Basically I have played around with it quite a bit. I > > have > > > 320 [16x16] tiles on the screen (20 tiles width x 16 tiles height) and > my > > > bgWorkArea is (20*16)*12 = 3840, now I get the 20*16 bit - the number of > > > tiles on the screen but 12 is just an arbitiary number I put in but it > > won't > > > work with anything less. I have also tried SCREEN_WIDTH (320) * > > > SCREEN_HEIGHT (256) = 81920 (the number of pixels on the screen) but > this > > > number far outweighs what I actually need as a bare minimum... because > it > > > works with 3840. > > > > > > Can anyone tell me what the bgWorkArea size is actually mean to be? - > > > please? > > > > > > Max > > > > > > > > > > > >