Tactical Kneeling mod v2.0 addon - SWAT 3

Tactical Kneeling mod by [furrycat]
Version 2.0, 2002-04-09
Latest version available from Swat3.furrycat.net

This is an updated version of probably my most popular mod. It combines the
famous kneeling animation with a modified version of the fixed mirroring
animation which doesn't suffer from the levitation bug.

Tech notes
----------
The GSA (GSkinAnimation) format was fairly easy to figure out for two
reasons. One: a large part of it is identical or at least similar to the GSM
(GSkinMesh) format. Two: Sierra's 3D Studio MAX plugin gives quite desriptive
progress reports while it does its work, enabling one to make an accurate guess
as to what to expect.

A detailed description is available at Swat3.furrycat.net.
In a nutshell, the GSA format looks like this:

Header
Framerate
Skeleton and bone data (identical to GSM)
Animated bone list
Number of frames
The frames

Fairly straightforward but what is an animated bone list? When you create an
animation for SWAT3 you are describing bone positions at each frame. However
you might not want to consider ALL the bones in the mesh. For example, the
"Suspect reeling from shock of a flashbang" animation only applies to the
suspect's upper body, which means it can be played when the suspect is crouched
or standing. The animated bone list is simple a list of bones that are
affected by the animation. If all bones are affected, the list is null.

Each frame is defined as follows:

Frame position
Frame orientation
Root bone position
A bunch of quaternions
Events

The "frame position" and "frame orientation" define a new co-ordinate system
relative to the actual. All co-ordinates in the frame are relative to the new
system. Since in the GSM world, the root bone is the model's origin, ITS
position relative to the frame co-ordinate base is also defined. Then the
"bunch of quaternions" is a group of quaternions defining EACH BONE's location
in the frame.

So the animation format is quite straightforward. No keyframing or anything
fancy, just a list of each bone's position at each frame. If you have a 52-
-bone SWT animation with 30 frames, you need 52x30 quaternions to describe it.

Events are described in more detail on the GSA file format page linked above.

Making the mod
--------------
Armed with the above information it is very easy to convert animations. To
convert a 37-bone TAC animation to a 52-bone SWT animation, we first simply rip
out the TAC skeleton and replace it with a SWT one. Next we make a new
animated bones list and add only those bones that are present in both
skeletons.

For example, both skeletons have a bone called Biped Pelvis so we put the bone
ID for the pelvis bone in the animated bones list. TAC models have Ponytail
bones which SWT models do not have, so we ignore that bone when constructing
the list.

Once that's done, we remove unnecessary bone position data from the frames and
write out a new animation.

Basically, given a 37-bone "animate all bones" animation, we construct a new
52-bone animation and say "we're only going to animate 37 of them."

The Mirror Crack'd
------------------
The big problem with the first kneel mod was that officers would levitate when
mirroring. This happens without kneel as well. It's a bug in the optiwand
animation. The mirror mod fixes this bug for the standard animations but won't
work with kneel because the root bone position is lower for the kneeling
animation than for the standard crouch. For this reason you SHOULD NOT USE
mirror with kneel. Instead use this updated kneel mod in preference to the old
kneel and use it AS WELL as any mods which include kneel.

Licence
-------
You may distribute this mod freely. You may modify it without asking my
permission. You may include it in compilation mods. You may use the
any or all of the animations in your own mod. You do not have to give me
credit if you do not wish to. You can do anything else with this mod that I
didn't think about. It is public domain.