Monster (enemy) battle animation Confirmed

At a glance

Where

The monster archive, extraction PROT 0867 (CDNAME block monster_data), one block per enemy; per-action entries reached through the monster record's +0x4C offset array. The player battle files carry the same entry family

Size

Entry head 0x8C bytes, then [parts][frames] + frames × parts 9-byte keyframe records

Parser

legaia_asset::monster_archive (animations, idle_animation, action_tags, juggle_windows, animation_cue_tracks); playback engine-core::battle_anim; export monster_gltf

Confidence

Confirmed - decoder, draw, installer and commit routines all traced; the "contact" reading of the event-frame list is Inferred

Used by

Enemy table (idle loops + glb export), battle scene, battle action SM, battle formulas (juggle window)

Where it lives

Each monster's decoded archive block is: stat record with its +0x4C action-offset array, name, TMD mesh, the per-action entries, then the texture pool. The +0x4A count says how many entries there are. Each entry is an action descriptor - not just a spell - with a semantic tag, costs, effect and sound cue scripts, and a packed keyframe stream at +0x8C.

Keyframe records

Each part record is 9 bytes holding six 12-bit fields. Low bytes sit at [0,1,3,4,6,7]; the high nibbles pack into [2,5,8]:

tx = b0 | (b2 & 0x0f) << 8      ty = b1 | (b2 & 0xf0) << 4
tz = b3 | (b5 & 0x0f) << 8      rx = b4 | (b5 & 0xf0) << 4
ry = b6 | (b8 & 0x0f) << 8      rz = b7 | (b8 & 0xf0) << 4

• tx, ty, tz: sign-extended 12-bit translation (-2048..2047) in model units.
• rx, ry, rz: unsigned 12-bit Euler angles, 4096 = one full turn.
• One part = one TMD object. The part count equals the object count for over 98% of actions (one model carries an extra static object).
• The transform is absolute model-space, not a delta: world = Rz·Ry·Rx · v_local + t. Frame 0 is the assembled rest pose; a raw monster TMD drawn without it is a heap of parts piled at the origin.

Action tags and the reaction map

When a monster takes a hit, the game must find "the flinch" or "the knockdown" without knowing which entry index that is for this monster. The first byte of every entry is a semantic tag that makes the lookup possible:

At battle start the monster installer scans the entry table once and caches the entry index of each tag in {2, 3, 4, 5, 0x0B} into five actor bytes at +0x1EF..+0x1F3; the party installer hardcodes [2,3,4,5,0xB] because player files store that family in order. Rules of the scan:

• Single forward pass, no early exit - a duplicated tag resolves to the last match.
• "Absent" is zero; a monster with no knockdown entry reuses its light flinch.
• The damage primitive stages the target's reaction from this map; the anim commit chains a finished knockdown into the get-up while the actor lives.
• Attack animations (tags 0x20 / 1 / 0x21 / 0x22) use a different, first-match search with a 0xFF not-found sentinel (ported as find_action_by_tag). Do not build the reaction map from it.

The anim id is the entry index

Per actor, +0x1DA is the queued anim id and +0x1D9 the current one. The id is the entry index - the commit routine installs entry = offsets[id] with no remap table. Retail's idle id is 0. Party ids ≥ 0x10 take the dynamic-slot path of the player battle files.

Beats, effects and sound cues

Event frames (+0x10..+0x13)

Up to four ascending clip frame indices - the action's significant beats. The per-frame anim tick uses the first beat for two things: a queued clip commits mid-clip once beat + 2 < frame, and the actor byte +0x1F7 latches frame < beat - the battle's juggle window. Every flinch and block entry carries exactly one early beat; the attack band carries one to four. Reader monster_archive::juggle_windows.

Effect script (+0x14..+0x53)

Up to eight 8-byte records walked once per frame to place dust, impact flashes and emitter trains:

Port engine-core::action_effect_script::step_effect_script.

Sound cues (+0x54..+0x73)

Eight [u16 frame][u16 cue] pairs, truncated at the first zero cue - footsteps, swing whooshes, the per-punch impacts of the Delilas flurries. The per-frame player resumes at the actor's cue cursor and hands each cue to the sound ring (layout on sfx-table); cue ids ≥ 0x100 bypass the ring for the XA player. Reader monster_archive::animation_cue_tracks.

Playback

The battle draw keeps a 12.4 fixed-point phase per actor: frame index = phase >> 4, sub-frame fraction = phase & 0xF. The decoder interpolates between frame i and i+1 - linear for translation, shortest-path wrap for rotation - into a pose buffer of six shorts per object, which the draw loop applies per object through the GTE. Each tick advances phase += (frame_dt × speed_scale × rate) >> 1, where the actor's speed scale is normally 4 and rate is the entry's +0x78 byte.

The engine mirrors this: battle_anim::MonsterAnimPlayer decodes each monster's idle clip into a loop cursor whose tick() produces a PoseFrame - the same shape the field ANM player produces - and the renderer poses the mesh with R·v + T about each object's local origin. The reaction staging and the knockdown → get-up chain are played; the cross-blend into a queued clip is a known simplification.

Texture pool

The same archive block carries the model's colours: a 0x1E0-byte region of fifteen 16-colour palettes followed by a 4bpp index page (256 rows tall, 128 or 256 texels wide). Each TMD primitive picks its palette from the low six bits of its CBA and samples the page at its UVs - the same index-then-palette lookup the PSX GPU performs from VRAM (TIM, renderer). 186 of the 194 archive slots carry a clean mesh + pool; the rest are filler ids.

Export (glTF)

legaia_asset::monster_gltf::export_glb packs mesh, baked texture and every action into one .glb. The rigid-per-object model maps straight onto glTF node animation: each TMD object becomes a node, the keyframe translation and Euler rotation (recomposed as a quaternion in Rz·Ry·Rx order) drive its channels, and a root node rotates the rig 180° about X for glTF's Y-up. The per-primitive palettes are baked into a vertical atlas with each vertex's V remapped into its band.

The enemy table exposes the same export as a per-enemy download button.

How we know

Open: the caller of the anim-node tick is not in the dump corpus. Source of record: docs/formats/monster-animation.md.

See also