Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!rochester!kodak!elmgate!jeh From: jeh@elmgate.UUCP (Ed J Hanway CUST) Newsgroups: comp.sys.amiga Subject: Re: 4096 colors in HIRES Summary: Let's keep custom copper lists flexible. Message-ID: <1102@elmgate.UUCP> Date: 6 Jul 89 22:58:16 GMT References: <20069@cup.portal.com> <409@xdos.UUCP> <20112@cup.portal.com> <412@xdos.UUCP> <1166@atanasoff.cs.iastate.edu> <8721@thorin.cs.unc.edu> <421@xdos.UUCP> Reply-To: jeh@elmgate.UUCP (Ed J Hanway CUST) Distribution: usa Organization: Eastman Kodak Company, Rochester, NY Lines: 35 In article <421@xdos.UUCP> doug@xdos.UUCP (Doug Merritt) writes: (speculating why screen drags with a custom copper list are slow) >Right, the only time the processor can get anything done is during vertical >retrace. Perhaps it would be a good idea to leave some more time slots >open so that *some* things can still happen during horizontal retrace. Actually, I think screen drags are slow because Intuition must rebuild its master copper list whenever a screen is dragged. For normal screens, the copper lists are trivial, and the rebuilding is quick enough that screen dragging is smooth, but a custom list that has a few instructions per scan line can take a while to sort. Sure, the extra copper instructions will steal cycles that would have gone to the CPU, but the real slowdown happens because the computations necessary for screen dragging are much harder. >For instance, if you restricted it to 8 color register changes per scan >line, then presumably system response would be much snappier, and background >tasks would be able to run sometimes, yet you'd still have lots of colors >to play with (one complete palette switch every two scan lines). Why place any restrictions on it at all? I'd much rather see a scheme where I could redefine one color for line 1, then 12 for line 2, then 3 for line 3, and so on. On the average, this would probably result in less copper instructions but would allow more flexibility. >-- >Doug Merritt {pyramid,apple}!xdos!doug >Member, Crusaders for a Better Tomorrow Professional Wildeyed Visionary -- Ed Hanway Eastman Kodak Company ...!rochester!kodak!elmgate!jeh #include