Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!julius.cs.uiuc.edu!ux1.cso.uiuc.edu!uxa.cso.uiuc.edu!jb10320 From: jb10320@uxa.cso.uiuc.edu (Desdinova) Newsgroups: comp.sys.apple2 Subject: Re: Stellar 7 re-release Message-ID: <1991Jan3.215930.16574@ux1.cso.uiuc.edu> Date: 3 Jan 91 21:59:30 GMT References: <60237@microsoft.UUCP> Sender: news@ux1.cso.uiuc.edu (News) Organization: University of Illinois at Urbana Lines: 34 In article <60237@microsoft.UUCP> brianw@microsoft.UUCP (Brian WILLOUGHBY) writes: >scottg@gnh-starport.cts.com (Scott Gentry) writes: >>The standard resolution are: Any Apple II graphic mode, PLUS, Super Hi Res in >>320x200 with 16 colors and 640x200 with 16 dithered colors (Four pure colors). >>A variant that doesn't require special programing to display but requires >>special programming to create is 320x200 with 256 colors (16 palettes), or >>640x200 with 256 colors (16 palettes). People should really look at what can >>be done with 16 properly used colors. I know I was stunned. > >I think that you are overlooking a detail in the design of the GS. >Multiple palettes are enabled by setting an interrupt bit for >individual scan lines. This interrupt does, in fact, take CPU time >to handle, as all 16 color registers must be loaded for the new >palette. Just because all of this is set up by the system and not by >your own code does not mean that it is totally free. There is a CPU >time price. Moving from 320X200 with 16 colors to 320X200 with 256 >colors takes CPU time. I hate to continue this pretty much pointless discussion, but I have to interject- each scan line on the GS has a 'palette nibble', which chooses one of 16 palettes for that scan line. Since each palette can have up to 16 colors, we can have 256 colors on the screen at once, without ANY extra effort by the software, it's all done in hardware, and it takes NO CPU time. 3200 color pictures constantly modify those 16 palettes on the fly, using scan-line interrupts. THIS requires massive CPU time. >Brian Willoughby -- Jawaid Bazyar | Being is Mathematics Senior/Computer Engineering | Love is Chemistry jb10320@uxa.cso.uiuc.edu | Sex is Physics Apple II Forever! | Babies are engineering