Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com
From: "Ed Federmeyer" <fedeedw@charlie.cns.iit.edu>
Newsgroups: scea.yaroze.programming.2d_graphics,scea.yaroze.programming.3d_graphics,scee.yaroze.programming.2d_graphics,scee.yaroze.programming.3d_graphics
Subject: Re: inside Ordering Tables
Date: Sun, 25 Oct 1998 00:21:29 -0500
Organization: Ed Federmeyer
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Message-ID: <70ubsd$dnq16@scea>
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Angel Sastre wrote in message <70u292$5iq5@chuka.playstation.co.uk>...
>this is a question regarding how ordering tables work.  It seems that a bit
>of information is given on the green book but not as much as one would
like.


I think the biggest problem you are going to face is that the 'TMD' format
is specced out (not the printed manuals, look in the Web page for the
"file formats" document and get that (along with Adobe Acrobat, to read the
.PDF format doc, if you don't already have Acrobat).

You can then give these 'TMD' format objects to the Yaroze library and it
will translate all the coords and all that and create "packets" that gets
put into the Ordering Tables....  You can use DOS/Macintosh tools to
create "TMD" format objects or you can create the TMD objects dynamically
at runtime for fine control over the TMD, and to deform it in real-time.

The "Packets" are the actual hardware drawing commands that tell the
GPU to draw your primitives (triangles, lines, whatever) into the frame
buffer.

The big "problem" is that the format of the packets is not disclosed by
Sony.  Apparently, its even a big pain for "Pro" developers to get this
"packet" format.  (Something I'll never fully understand, coming from a
device driver background where chipmakers fall all overthemselvs to
give you all the info you need to make thier chips work with your
products!!  :-)

So, even if you do all your own coord conversions, it's kinda all for
nothing,
since you can't directly create the drawing commands (packets).

Now, if someone can please tell me I'm wrong and point us to a solution,
that would be very cool!  :-)

>also don't forget:
>-How does it know how many packets there are in a given GsOT_TAG ?
>-Why the need to have different packets in different GSOT_TAG ?  why just
>not shove them all to the same one.


I think "one OT_TAG" equals "one packet", and are used by the library
routines
to keep the primitives sorted properly.  The packets themselves are created
into the PACKET area, (hence you'll see PACKETMAX*24 often used to
define that space, the *average* size of a packet is 24 bytes, but simpler
primitives (single color lines) are smaller than complex ones (shaded,
textured
quads for example).  I'm guessing that the final "draw" of the OT actually
goes
through the PACKET area and makes all those packets presentable to the
GPU and tells the GPU to actually get to work on the packets.

(Again, corrections are very welcome!  :-)
EdF