Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!ucsd!ucbvax!decwrl!mejac!gryphon!jdow From: jdow@gryphon.CTS.COM (J. Dow) Newsgroups: comp.sys.amiga Subject: Re: graphics chips ideas Message-ID: <5490@gryphon.CTS.COM> Date: 12 Aug 88 07:09:10 GMT References: <0Wz-V=Au8k-083IFce@andrew.cmu.edu> Reply-To: jdow@gryphon.CTS.COM (J. Dow) Organization: Trailing Edge Technology, Redondo Beach, CA Lines: 34 In article <0Wz-V=Au8k-083IFce@andrew.cmu.edu> bader+@andrew.cmu.edu (Miles Bader) writes: >Currently, as I understand it, in instances where you want a >background to show through (like with sprites, or in dual-playfield >mode), a particular color register indicates "see-through." > >I think a neat way to do it would to be eliminate the special >behavior of that register, and add another 4 bits to ALL the color >registers (for a total of 16 bits each), which would be "opaqueness": >a value of 0 would mean "completely transparent," and a value of 15 >would mean completely opaque. The color of a pixel would be >(fg*op)+(bg*(15-op)) for each of red, blue and green, where op is the >opaqueness, fg is the intensity of this layer, and bg is the >intensity of the underlying layer. > Um, Miles, wanna tell me what the Amiga is going to use for bus bandwidth to do all this? Hires 4 bitplanes currently burns ALL the CHIP ram bandwidth durning the active portions of the frame. 4 more bitplanes MIGHT be possible if you go to 32 bit buses in the Amiga. I kinda wish they would. We could well use that added bandwidth. (And it'd be fun to listen to the HW vendors scream in anguish over the chaned bus yet again.(I'm feeling nasty tonite!) >-Miles -- Sometimes a bird in the hand leaves a sticky deposit. Perhaps it were best it remain there in the bush with the other one. {@_@} jdow@bix (where else?) Sometimes the dragon wins. Sometimes jdow@gryphon.CTS.COM the knight. Does the fair maiden ever {backbone}!gryphon!jdow win? Surely both the knight and dragon stink. Maybe the maiden should suicide? Better yet - she should get an Amiga and quit playing with dragons and knights.