Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!utah-gr!sunset.utah.edu!u-jmolse From: u-jmolse%sunset.utah.edu@utah-gr.UUCP (John M. Olsen) Newsgroups: comp.sys.amiga Subject: Re: Ideas for New Custom Chips (a SERIOUS one!) Summary: New ways to torture your Amiga Keywords: Chips HAM animation Message-ID: <2727@utah-gr.UUCP> Date: 8 Jul 88 15:01:58 GMT References: <3128@polya.Stanford.EDU> <14146@shemp.CS.UCLA.EDU> <613@myrias.UUCP> Sender: news@utah-gr.UUCP Reply-To: u-jmolse%sunset.utah.edu.UUCP@utah-gr.UUCP (John M. Olsen) Organization: University of Utah CS Dept Lines: 54 In article <613@myrias.UUCP> cg@myrias.UUCP (Chris Gray) writes: >Here's a suggestion for a very simple new mode in the custom chips. > [He describes current HAM] >What I would like to see is a HAM mode that would work with 2, 3, 4, and 5 >bit deep displays as follows: (example for 5 bits/pixel) > > 5-bits > 00000 - use same colour as previous pixel > xxxxx - select one of lower 32 colour table registers > (the 0th entry is not accessible, but is still used > as the border colour) > >The same pattern holds for other depths - all bits zero means use the same >colour as the horizontally previous pixel. Maybe HAM is a bad name for this, since it isn't really holding and modifying. How about something stupid like zero fill. ZF mode. Hmmm... This is really a slick idea. Access to the full 32 color registers (or however many your screen uses), and filled polygons as fast as just drawing a polygon outline. It would take a bit of care to make the borders of the polygons show up in the right places, but you also need to be careful with how you use things like the current HAM mode. >Chris Gray Myrias Research, Edmonton +1 403 428 1616 > {uunet!mnetor,ubc-vision,watmath,vax135}!alberta!myrias!cg And speaking of HAM: I was just thinking about a 3 plane HAM mode that Aaron Avery and I discovered. What you do is build a screen by hand, and assign the low 4 plane pointers all to the same plane, and have the top two planes just like normal HAM. This trick allows you to get up to 46 colors out of 3 bit planes. Since the first four bits of any color are always 0000 or 1111 depending on what you stick into the low plane, you can only use color registers 0 and 15. This also makes it so you can only modify the R, G or B to be full on or off. Still, 46 colors for 3 bit planes is not all that bad. If you think of lower case rgb as modifying to 0 and RGB as modifying to 15, then the color combinations possible are: base modified c0 r g b R G B rg rb rG rB gb gB Rg Rb RG RB Gb GB c15 r g b R G B rg rb rG rB gb gB Rg Rb RG RB Gb GB either rgb rgB rGb Rgb rGB RgB RGb RGB Any comments? Anybody warped enough to try it and see how it looks? /| | /||| /\| | John M. Olsen, 1547 Jamestown Drive | quote \|()|\|\_ |||. \/|/)@|\_ | Salt Lake City, UT 84121-2051 | from | u-jmolse%ug@cs.utah.edu or ...!utah-cs!utah-ug!u-jmolse | D. Merritt "(((c)<' ')?("^"[1]=(c)+'@',""[-2]):(((c)>'~')?"^?":(""[0]=(c),""[-1])))"