Entry 137

The animation engine's loose ends: F_Obj, texture offsets, cameras, lights and frame speed

2026-09-26engine

Filescrates/piney-data/src/anim.rscrates/piney-world/src/foe.rscrates/piney-data/tests/anim.rsdocs/engine/animation.md

The animation page had three open items (32). A scan of every Anime chunk in DATA.BIN, counting its records by kind and file, settled them.

What was found

• Texture offsets (ccMaterial.u/v). The draw applies them through the model packet's STROW, (u >> 4) & 0xff in 1/256 of the texture. render.md and desktop.md already said so, and the port already does it (uv_rows in piney-desktop's anm.rs and piney-world's pose.rs). The 21 files that animate them are:

  • the Chaos Gate;
  • the fields' waters (field_a, field_c);
  • Aura's body and the virus cores;
  • a few enemies;
  • the desktop and the title.

• F_Obj (0x0101). This was a real gap. Four files use it:

  • Three enemies, eex1, eii1 and elgx, move their body with it in their damage, down and magic clips: one record a frame, with no controller on the body.
  • The desktop's xddesk01 has some as well.

  ccStream::DecodeF_Obj (main 0x0014e950) sets the object's matrix through ccCoord::SetMatrix_PosRotZYXScale (0x00138120): T(pos) · sceVu0RotMatrix(π · deg / 180) · S(scale). It also sets localtp to the transparency, clamped to 0..1. The port skipped these records, so those enemies did not flinch or fall.

• Cameras and lights. These records are read where they are played, not by the pose:

  • the streams' scenes and the desktop's clips read F_Camera;
  • town::anim_lights reads F_Ambient and the distant and omni controllers, for the towns, the gate, the story maps and the dungeons' special rooms;
  • the fields read frame 0's ambient and distant light.

• frameSpd. The field does change it:

  • Kite's AnimCtrl, by act;
  • the town player's motion;
  • the enemies' and members' motion;
  • the Administrator's act -5 (384).

The port

• Reading. piney_data::anim reads F_Obj into Animation::objs, as ObjRecord: object, ExtObj target, position, degrees, scale, transparency, flags.
• Posing. obj_poses_at(time) gives each driven object the last record read by then, from frame 1, as the per-frame reader does. locals_at and transforms_at use it for objects no controller drives, and Foe::node_alphas takes its transparency.
• The check. f_obj_records_pose_the_body checks ANM_eex1dmg0. It has 31 records on OBJ_eex1body and none at frame 0. At frame 3 the body is 7.75 up, turned by the record's degrees, and it holds there through that frame and past the end.
• Other readers. The other list now counts only F_Camera and the lights.