bjw66 wrote:I am trying to figure out the PCS (PhotoChrome) format. From what I've been able to find, there are no public specs for that format. Are there specs for PCS? I don't want to spend a lot of time trying to figure it out, only to find that it has already been done. Does anyone who is "active" have the specs? If not, no problem. I'll spend the time and share the specs.
bjw66 wrote:However, there is one thing I have not yet figured out in this, and that is what to do when b = 0. I can successfully decompress the screen data for files that do not have count bytes with value 0, but I don't know what to do when I see a count byte with value 0.
bjw66 wrote:(4) STE PhotoChrome: 19200 colours out of 32768. (3 components of 5 bits for the colours.) This seems to mean that 96 colours per line are possible. (96*200 = 19200.)
MiggyMog wrote:There is an overscan variation of the PCS format too used in the Tobias Richter slideshow.
MiggyMog wrote:Does this mean we may get a new program with faster conversion to these formats
simonsunnyboy wrote:@Nyh: do you have working display code of this? I'm interested in such for use from GFABASIC....
bjw66 wrote:Yes, I found those "PCI" images too and I briefly looked at the format. It seemed to me that, instead of using 320x200, they use 352x278, but when it really seemed to be PCS format (apart from the dimensions) to me, I left that format alone for the time being to concentrate on PCS first. And then I got sidetracked by the variation of the IFF format that ONLY Deluxe Paint seems to use and THEN ONLY the ST version of Deluxe Paint... (ILBM compression type 2). Which I THINK I have figured out now by looking at those IFFs in a hex editor. I still have to write code though to see if I'm right...
Nyh wrote:simonsunnyboy wrote:A bit of a problem is who controls all the interrupts. The display routine uses VBL and HBL and disables all other routines. I don't know yet how much control I can give back to Gfa. Do you have an example with spectrum displaying code for Gfa?
Code: Select all
' Original GFABASIC 2.0 version by Charles Medley
' STatus Disk Magazine
' Volume 1, Issue 1, October 1989
' This GFABASIC 3.0 version by Jim Burton,
' not affiliated with STatus Magazine.
' Be sure to read STatus!
' Except where noted, all following comments by Medley
' Now I wanna allocate the memory for BOTH the compressed pic and the final
' displayable pic...
' Now, I'm gonna boot in the SPECTRUM 512 compressed pic, into the top most
' area of that reserved memory... what fun that will be...hehehehehe
' OK, so, anyways, we wanna have space for the TRIO code, for decompression
' and displaying of an .SPC pic...
' This INLINE contains TRIO's SHOW512.O code (Burton)
EXIT IF name$=""
' x is used to test for the existence of the file...
IF x<>-1 THEN
PRINT "The program needs to have ";name$;" present on the same path!"
PRINT " The program's execution has now been terminated..."
' Now, I run the decompression routine, supplied by TRIO Engineering...
' First we define the destinations for the bitmap and color data...
' Now we put the SPECTRUM pic onscreen until the user presses a key...
' We have to get the machine out of SPECTRUM mode...
' We give memory back that was used for the .SPC and decompressed SPECTRUM
' Amt is how much memory we are setting aside, ptr is the pointer to the start
' of this memory...
' Pg is used to calculate an address divisible for 256 that is appropriate...
' Checks to see if what we will reserve will be enough for what we wanted...
' If not, we increase it...
IF amt MOD 256<>0
' We set up how much we will actually reserve with Malloc...
' Reserves the memory, away from GFA Basic...
' Now we pass ptr to the GEMDOS Malloc() call that will reserve memory from
' the ST's OS...
' Adr is just the starting address of the area reserved...
' Er1 is used to determine if an error occurred with the use of Mfree...
' We also give back the RAM to the OS and GFA Basic...
PRINT "Mfree() error ->";er1
SoLo2 wrote:Seems like this PCS format
is also displayable in med res?
Looks very good.
bullis1 wrote:I would like to see a slideshow on Atari that utilized Photochrome images. It's a cool format and I hope you guys get it figured out!
SoLo2 wrote:I saw a presentation screen by
Sinister Development, raytraced,
in red is the logotype, and was
very incredible because it showed
more than 16 colors, but in
SoLo2 wrote:Would this be possible changing the
resolution to low at some concrete
point? The Atari XL had such tricks.
Cooper wrote:Hi, here is an example of Spectrum 512 pic displaying (SPU). GFA sourcecode attached, including the inline. If you want an other sourcecode, i have one from the SpriteWorks library, but if i recall correctly it's quite similar to this one.
More than 4 colors in a medium
resolution screen for Atari ST are
found in the presentation logotype of
Asteroids by Sinister Developments,
I could count more than 8 colors!
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