Path: chuka.playstation.co.uk!news From: "Russ Williams" Newsgroups: scea.yaroze.programming.2d_graphics,scee.yaroze.programming.2d_graphics Subject: Re: high-res? Date: Sat, 20 Dec 1997 00:04:28 -0000 Organization: PlayStation Net Yaroze (SCEE) Lines: 47 Message-ID: <67f1lg$9ij1@chuka.playstation.co.uk> References: <63vuoq$852@scea> <34638347.16036238@205.149.189.29> <3464C9CB.F465379D@msu.edu> <01bd03ed$65a53420$6c0b0a0a@newcastle.twowaytv.co.uk> NNTP-Posting-Host: algorithm.demon.co.uk X-Newsreader: Microsoft Outlook Express 4.71.1712.3 X-MimeOLE: Produced By Microsoft MimeOLE V4.71.1712.3 Xref: chuka.playstation.co.uk scea.yaroze.programming.2d_graphics:299 scee.yaroze.programming.2d_graphics:203 CRAIG GRAHAM wrote in message <01bd03ed$65a53420$6c0b0a0a@newcastle.twowaytv.co.uk>... >Charles Henrich wrote in article ><3464C9CB.F465379D@msu.edu>... >> Mario Perdue wrote: >> >> > Yes, this is true. >> > >> > > Would it be hard to keep a *simple* 2d game at 60fps? >> > >> > It's not to hard as long as you keep the sprite count down. >> >> I really dont know why exactly people arent using Hi-Res more often, >> the only thing I can think of is to conserve frame buffer space so that >> more sprite-data can be present. Just for grins I took the demo >> bouncing-balls w/ midi music thats on the Yaroze CD and Hi-Res'd it >> (640x480). I could up the ball count to 1200 before I the code was >> taking more than 1/60th of a second > >Using Hi-res, you don't get a 1/60th sec to draw a screen - that's the >whole problem. Yes, you do. >What you actually get is solely the vertical retrace time. No, you get 1/60s to draw 1 field. The odd/even lines are drawn alternately and you update them independently. >If you were double buffering you could have the whole 1/60th sec to draw >your screen (that's the point, you can be drawing as the screen is >displaying). Unless you set the dfe bit, you get 1/60s to update half of the scanlines. >Without the double buffer there is a much smaller time to generate a >screen in (amount's to approx. 1500 gourard polys on 50Hz PAL) OK. If you can do all your drawing (in hires mode) in <240 hsyncs, then it will work fine. The drawing is (IME) about 40% quicker in interleaved mode. To keep up with the interlace, you really need to be drawing from a VSync callback. --- Russ