Atari 16/32-bit Panther articles - EGM - Game Players - GamePro

philipj · October 25, 2018

You're being harsh. The Jaguar has a pretty unique 3D hardware. It's the only one I know that can do Gouraud shading and Z-buffering, but can't draw a simple triangle.

Actually I was going to mention the 64bit blitter early on, but because of CyranoJ's work on the Raptor, I didn't quite know what kind of technobable he might come up with to dismiss my talking point for whatever reason he's doing it. I think if the GPU had more memory to work without issues with the Jump, or even a separate 30 or 60k of its own memory at-least, through software, it could borderline becoming a graphics accelerator. Even the 3DO had a full 1-MB or GPU space to work with.

It can DO! Just very very thin isosceles ones :D

What was it...? 4 pixel per 8-bit intensity calculation for shading and 2 pixels per 16-bit intensity using the Blitter via the JRISC?

There are different versions Jag and Panther story floating around. But from technical point of view, Panther's Object Processor is very similar to Jaguar's one

Same thing I heard or read... Would've gave the Genesis and the SNES a run for its money if they'd market the system right.

You say that, but.......

I got to start somewhere technobable or not... The Jaguar is a very different animal than the average 3D system so the approach making a good 3D engine will be very different and unconventional then the normal way and the only way figure out the angles is to look back at system before the Jag that rendered 3D in similar fashion, but I'm taking things off topic a little bit, but I feel very strongly about that opinion and have for a long time, which is probably why I bring it up so much.

More wall of text.

Edited October 25, 2018 by philipj

Cyprian · October 25, 2018

below file headers from Panther's documentation:

"MEMORY" file:

November 17, 1990
PANTHER MEMORY CHIPS
Flare Technology Ltd

"VIDEO" file:

November 17, 1990
PANTHER VIDEO
Flare Technology Ltd

Panther's Object Processor "Branch" instruction:

4. Branch object (0x81)

 31           24 23           16 15            8 7             0
├───────────────┼───────────────┼───────────────┴───────────────┤
│ type 0x81     │ Y position    │ unused                        │
├───────────────┴───────────────┼───────────────────────────────┤
│ unused                        │ link                          │
└───────────────────────────────┴───────────────────────────────┘

Y position     is a byte in the range 0-199 specifying the line of display on which
               the branch command is executed.  A position of 255 will cause the
               command to be executed every line.
Link           is the address of a longword containing the object to be branched to
               if the command is executed.

The branch object directs the object processor to the object at the link address if
the Y position matches the current line.  Otherwise execution continues with the
following object in memory.

Jaguar's Object Processor "Branch" instruction:

   63      56        48       40       32        24       16       8    3   0
  +--------^---------^-----+---^--------^--------+--------+--+-----^----+---+
  |        unused          |      Link-address   | unused |CC|   VCnt   |011|
  +------------------------+---------------------+--------+--+----------+---+
                               42..........24      23..16 15.14 13...3   2..0
                                    21bits           8bit  2bit 11bits   3bits

   The branch objects are used to compare the current scanline
   with the value stored in the branch object. Depending on the
   branch instructions comparison mode, the branch is taken
   either on < == != or >. The taken branch taken uses the information
   from the Linkinfo and branches to the phrase-indexed
   object. If the comparison fails it simply examines and handles
   the next object in the list.

   Link-address:
      See the bitmapped object for more infos on the link address.

   VCnt:    
      This is the value you compare the vertical scanline
      counter with (VC). For CC code 10 the operation goes:

more about Panther you can find there:
http://www.atarimuseum.com/videogames/consoles/jaguar/Panther/index.htm
Panther.zip
/Panther/Dev System - Atari England/PANTHER.ASC

and about Jaguar: https://www.mulle-kybernetik.com/jagdox/dox.html

Edited October 25, 2018 by Cyprian_K