stephan@cup.portal.com (Stephen Derek Schaem) (07/22/89)
The reason for that posting is that to many people got the idea wrong, think
to complicated and try to create bugs where none exist.
The preview CCOP is now named CLUT (Color LookUp Table).
From BIX report by Peter Kaminski I saw that a couple of people where of
track.So Here is the latest news and happenings about the new 'COPPER' display
mode and format created by myself...
First an overview and why the format shouldn't be forgotten!
Current IFF viewer will only have to add a simple copper builder, just ask
your kid to put down is crayons and jump on the keyboard...
Second, for frame buffer: the format is taken the other way, you don't write
the body but the colormap or CLUT (more about it latter).The body is used as
pointer to the CLUT's, it would be EXACTLY like creating a 'video filter'.
you give it the lookup table (hardware register, here the corresponding
CLUTS) and the bitmap and you will have a RGB output...
Here again, couldn't be more simple.And no calculation involved, the work
is already chewed for you.Also a UNIVERSAL routine can be given for
de compacting the xbitplane lookup into xbitplane buffer on ANY system.
The format wont EVEN have one word about the COPPER.I cant imagine a
way more simple and more compact that fit all the needs of all 'existing'
system... If it can make people happy you could call it Extended IFF.
CLUT:
CLUT resemble alot like CMAP but will include a YPOS that will describe how
the line Y is coded.XPOS is also included to make everyone happy, even if
people shouldn't mess around with it and should keep it to 0.
So we got by mixing it all: number of color entry,Ypos,Xpos,color Entries
Is it that bad? I will do the filter routine on the IRIS and test how the
'new IFF' format work with 24 bitplanes.
Forgot to say, each color entry is 24bit 8bit Red, 8bit Green etc.
shift right by 4. to get you color entry, then shift Red left by 8, green
left by 4 and add Red,green,blue.My God its like CMAP:-).
A way to create the copper list, first do like you use to with the CAMG on
the CLUT, THEN, you make a CWAIT(cl,YPOS,0) and CMOVE(HCR[x],table[x]) x
representing the entry number.
The above is to give an idea, I already given routines for that?have I?
So in fact I only add CLUT's to the file... And it seem to be a very good
way to compress file using even 24bitplane with less.
If you want to include a 24-> bitplanes body, the CAMG is absolute.
It will also involve ALLOT more coding from the part of every viewer, I
think I show a good example of that at the BADGE meeting...
The file range around 600k! and half of it will be left unused by the amiga
in HAM and a great deal more in hires.
By including all the planes you get: MORE coding, allot longer to
render, huge file size, waist of data etc...(you can fill in the rest:-)
I hope the above prove my point on that subject.
To Leo Schaw: If you think CLUT change the meaning of IFF I should
point out that it doesn't change ANYTHING.You alway had to do the 'filtering'
with a hires screen with the CMAP.Only now you have a different colormap
for each scanline.You where also kind of worry about losing part of the
iff file and having everything screwed up:if the file is 'well' written, you
could still display it in B&W without any CMAP or the set of CLUT's.
you write the color entry by color intensity, with having in the
hardware color register (0=0x000,1=0x111 etc...).It wont look right in cases
where you have 0xf00 and 0x00f at the same time, but better than nothing.
So even 'old' (I'm living in the future here:-) viewer like ushow4.4(present)
will be able to display something that look like something...
NOTE:
I believe in not using bitplane 1&2:what do that mean?
Well, never changing color 0,1,2,3 it will enable amiga and other computer?
that do color change on the fly (during blanking gap) to implement window
system on the screen displaying the current image.Other system should care
about it, just do as usual for the decompaction...
You will tell me ,'that's only 12 different colors per scan line'.
what can I say:-) yes, but the copper limit is not fare from 12.Things' kind
of screw up a bit after 14 colors change.
Stephan.
I'm not on Portal anymore so...
if you want to reach me, give comment or whatever you fell like mail it
to the following address.Address available untill august8, after that how
knows...
stephan@velo.sgi.com