More file format musing

doc/formats/ani.md

@@ -1,18 +1,71 @@
 # `Anim/WarHammer.ani`
 
-This turns out to simply be an [`obj`](obj.md#WarHammer.ani) file. However, some
-other files are implicated in its interpretation:
+This turns out to simply be an [`obj`](obj.md) file.
 
-- `Data/AniObDef.dat`
+The first 1,064 sprites are all of the same Ultramarine, carryng a bolter. There
+are eight "facing" orientations:
+
+* North
+* Northeast
+* East
+* Southeast
+* South
+* Southwest
+* West
+* Northwest
+
+For each orientation, an action is pictured in a variable number of frames. The
+final frame for each action appears to be "stationary".
+
+* Walk (13 frames)
+* Run (9 frames)
+* Crouch down (8 frames)
+* Stand up (8 frames)
+* Take aim (standing) (6 frames)
+* Fire (standing) (6 frames)
+* Relax aim (standing) (6 frames) 
+* Throw grenade (standing) (18 frames)
+* Take aim (crouched) (5 frames)
+* Fire (crouched) (5 frames)
+* Relax aim (crouched) (5 frames)
+* Throw grenade (crouched) (17 frames)
+* Draw melee weapon (standing) (10 frames)
+* Strike down with melee weapon (standing) (8 frames)
+* Stab with melee weapon (standing) (9 frames)
+
+Added together and multiplied by 87, that's 1064.
+
+The next sprite is a walking-north action for an ultramarine with a flamer. The
+total number of frames for this character is 1120 - 56 additional frames, or 7
+per orientation. Could be an extra action, or an extra frame per action.
+
+Also notable is that while the bolter showed muzzle flash in the animation, the
+flamer only showed a tiny hint of fire. I think the animation for spewing flame
+is held elsewhere.
+
+I strongly suspect the actions and the number of frames in each action are
+configurable. So, what other files are implicated in its interpretation? Here's
+a few possibilities:
+
+* `Data/AniObDef.dat`
+* `Data/Coordinates.dat`
+* `Data/HasAction.dat`
+* `Data/VehicDef.dat`
+* `Data/WeapDef.dat`
 - `Idx/WarHammer.idx`
 
-Including comments, the former is 4098 lines, giving approx. 45 lines for each
+## `Data/AniObDef.dat`
+
+Including comments, this is 4098 lines, giving approx. 45 lines for each
 of the ~188 characters in the `ani`. That doesn't seem many, and there's no
 obvious correspondence between the commented-on names (`SMOKE01`?) and the
 viewed frames... but then, I've not viewed all the frames.
 
-Still, I think a focus in `WarHammer.idx` (1,880,078 bytes, binary, so around
-10KiB per character, in theory) is more reasonable.
+
+## `Idx/WarHammer.idx`
+
+`WarHammer.idx` (1,880,078 bytes, binary, so around 10KiB per character, in
+theory) is more reasonable.
 
 Here's a list of operations on the file when `WH40K_TD.EXE` is instructed to
 place an Ultramarine squad:
@@ -310,22 +363,15 @@ read(<WarHammer.ani>, "\xbe\xe5\xb6\x09\x0c\x0f\x00\x00", 8) = 8
 
 </details>
 
-Notable is that we still load 5 type 2 records, even though there's just a
-single librarian, and 8 compass points. Why 5?
+Notable is that we read from `idx` **before** we read from `ani` - so it does
+seem like the former should tell us where to pull from the latter.
 
-Also notable is that we read from `idx` **before** we read from `ani`.
+We still load 5 type 2 records, even though there's just a single librarian, and
+8 compass points. Why 5? After looking in `idx`, we load 10 sprites from `ani`,
+which is at least a multiple. Do any of the records we load from `idx` specify
+sprite directory offsets that match?
 
-Other data may be loaded at program start, of course. What other files seem
-relevant?
-
-* `Data/AniObDef.dat`
-* `Data/HasAction.dat`
-* `Data/VehicDef.dat`
-* `Data/WeapDef.dat`
-
-These all reference animations in one way or another.
-
-## `HasAction.dat`
+## `Data/HasAction.dat`
 
 This file seems relevant as it says whether or not particular animations exist
 for the different types of character, which maps directly to what is stored in