KEY Files

KEY Files General

KEY files (or Keyframe files) are used to animate the various nodes of a 3DO in accordance to an action the 3DO is making. Other uses of Keyframes include moving the camera around (such as at the start of each boss level when Rahn talks to you) and to create ships's flying sequences (such as the TIE Bomber, Crow and 8t88's Shuttle).

KEYs are broken into two sections, with a possible third.

SECTION: HEADER 

FLAGS      # 32-bit value specifying properties of this Keyframe
TYPE       # 32-bit value specifying the type of Keyframe
FRAMES     # The number of frames in the animation sequence
FPS        # Frame rate, in frames per second
JOINTS     # The number of 3DO nodes that are to be animated

SECTION: MARKERS 

MARKERS 2

16.000000 9
112.000000 8

This section is only present in some KEY files, and has an unknown purpose.

SECTION: KEYFRAME NODES 

NODES N

N is the number of nodes that are animated in this sequence. Note: This number is usually equal to the number of nodes in the 3DO (each part moves, or, at least has an entry).

A Node has a simple header: 

NODE          # The index of this node
MESH NAME     # The name of the Hierarchy node in the 3DO that it transforms
ENTRIES       # The number of entries this node has

Note: Entries are in fact "waypoints" of sorts, and each entry does not actually represent a single frame of the animation. The game engine interpolates values to create additional frames of animation between two entries, to make the animations smoother.

The header is followed by the entries. Each entry consists of these parts: 

num         The index of this entry
frame       The number of the frame which this entry defines
flags       32-bit value specifying the properties of this frame
              0x0001 = position (x,y,z) changes between current frame and next
              0x0002 = orientation (P,Y,R) changes between current frame and next

x, y, z     Spatial coordinates by which to offset the Node
p, y, r     Orientation (Pitch, Yaw and Roll) of node
dx, dy, dz  Change in x / y / z value between current frame and the next
dp, dy, dr  Change in pitch / yaw / roll between current frame and the next

Note: if frame definitions are skipped, the 'delta' values (dx, dy etc.) of the last entry are retained until the next frame is reached. See the example below : 

#num:  frame  flags 	  x    ...
#                        dx    ...

 0:    0      0x0003     0.00  ...
                         0.25
 1:    5      0x0003     1.25
                         0.40
 2:    6      0x0003     1.65
                         0.55
...

Frames 1 - 4 are not defined, so the dx value of 0.25 (from frame 0) will be retained until frame 5. i.e. the 3D object's X offset will move through 0.25, 0.50, 0.75 and 1.00 in frames 1 - 4.


Flag Values 

0x00  Looping
0x14  Stops at last frame until another event occurs
0x2c  Stops after reaching last frame