Entry 197

"The party's weapon trails and element particles: ccSpcChar::ArmsEffect on ccLattice"

2026-09-26battle

Filescrates/piney-world/src/arms.rscrates/piney-world/src/lattice.rscrates/piney-world/src/combat/mod.rscrates/piney-world/src/combat/cast.rscrates/piney-world/src/combat/stage.rscrates/piney-world/src/field_world.rscrates/piney-battle/src/skill.rscrates/piney-battle/src/kite.rscrates/piney-effect/src/lib.rscrates/piney-effect/examples/boss_probe.rscrates/piney-game/src/fx.rscrates/piney-game/src/session.rscrates/piney-game/src/session/tests/weapon.rstools/test_boss_effect_rs.pydocs/engine/battle.mddocs/engine/boss.mddocs/engine/field-game.md

0195 left one gap: the party's weapon trails. Kite's and the members' frames already emitted four outputs, and nothing consumed them:

• ArmsEffect and ClearArmsEffect;
• SetArmsEffectColor;
• StartArmsEffect (Kite's as ArmsParticles).

So no one in the party left a ribbon behind a swing, and a fire art did not light the blades.

What the game does

battle.md, "The party's weapon trails", has the tables. In short:

• EquipWeapon (0x0059d650) reads the weapon file's DMY_xdummy_w01-w04 besides its models. Decode_DummyPos (0x0014d4d0) gives each a place with w 1.0. It also makes the job's lattices: two ccLattice(2, 0) for the twin blades, one for most jobs, and a 3-column one for job 4.
• ArmsEffect (0x0059ddd0), every drawn frame, runs ClearCnt first. It puts the weapon points weaponEffPos at the hands' matrices times the dummies. It lays a row only while swinging (trajectorySW) or when the weapon has an aura (ccEquipmentParam +8). The aura is the colour, outside a swing or on the normal attack. Then Disp.
• StartArmsEffect (0x0059e530) starts, for an art with an element, particleEffectTbl[40 + element] between two weapon points while armsEffectSW holds.

The lattice

piney_world::lattice held 2 columns only. It now holds up to 3, as job 4 needs. ccLattice::Disp then sends two strips in one packet (columns 0-1, then 1-2), each starting with ADC. The z sum counts a middle vertex once (MakePacket's made flags), and the key is the sum over twice the pairs. The lattice also has:

• ClearCnt (0x00579c50) with its +0x72c flag;
• the colour type as the i32 _SetArmsEffectColor writes. MakePacket reads +4 each time, so a change shows at once.

test_boss_effect_rs.py's test_weapon_trails drives the game's own ccLattice(2, 0) and (3, 0) in eemu as ArmsEffect does:

• ClearCnt every frame;
• ClearArmsEffect's flag and colour types set at random between frames.

Against the probe: 0 mismatches over 600 frames each, in every row, life, flag, type, strip vertex and sort key. The cross's check still passes.

The port

• piney_world::arms::Arms is the state: the dummies, the lattices, the points and the frame's strips. Each Actor keeps one as weapon. It is made at the actor's first call, from the file hung on its hands, and re-read by change_equip.
• Combat::arms_shown runs the frame's calls in order, before ccThEffect. It poses the hands as the actor stands.
• field_world draws the strips as it draws the cross's (trail_packet).
• piney_battle::skill::start_arms_effect is StartArmsEffect. Kite's AnimCtrl now calls it (test_battle_kite_rs.py anim_ctrl and small still pass). The combat runs it for a member's fellow::Out::StartArmsEffect, which was dropped before.
• Effects::arms_particles starts the particles. The battle host answers weaponEffPos from the actor's Arms (char_vec +0x160) and armsEffectSW from the character (char_int +0xe4).

Tests:

• kites_blades_leave_trails: all four dummies on Kite's blades; the trails after 16 rows; the aura's colour; the clear. Every weapon's aura is -1 or 0-7.
• orcas_swings_leave_trails: Orca's heavy blade leaves a white trail on 30 frames against event 3's goblin, and Kite, standing, none. party_trail_shots shows the ribbon following the blade.
• flame_dance_lights_his_blades: Kite's Flame Dance (art 9) turns armsEffectSW on and starts row 42's generators on both blades. Their particles follow the weapon points, and both trails turn red. flame_dance_shots shows the fire on his blades.