Entry 230

Every body's steps sound as the original's and the frames' events are the set-up's; the sweep compares the sounds

2026-10-181h 45mplay

Every body's steps now sound as the original's. The frames' events are rewritten as the original's set-up leaves them. The sweep tool compares the sounds each side keys on, and they match in every level it can run but golf's door phase and level 21's last notes.

The sound comparison (npc_check SOUNDS=1).

• The original's key-ons are hooked at 0x800a99a8: program, tone, and the note at sp + 0x10. Every effect (0x8006f26c, 0x8006f644), the crunch and the piano pass through it.
• The port's effects are mapped through the original's table (0x800b84fc, 3 bytes a sound).
• A sound a frame later in the original still counts, since the trigger pass runs after the oracle's frame ends.
• SOUNDRA=1 prints the callers.
• The tool now syncs the game's rand (0x800c3f94) and the doors' cycles (+0xa8..+0xac, +0x3c bit 2, +0xcc, +0xd2: Door::sync) at its frame 0.

The footstep (0x8007013c). Out of water a step keys program 0, tone 0, note 22 + (rand & 7), drawing the game's rand only when heard (0x8006f4c0: within 0xfffe across and 0x7fff up of the camera, whatever the volume). The port's comment had it as a table that is empty in play, so nothing played.

The step's sound by path (0x8005e1f4):

• Running (0x8005e830), by the player's character (0x800c5680):
  • Spike in water wades (57 on every fifth step in level 4), plays 176 in level 16, else 27.
  • Character 34 plays 108.
  • Others play 27 in water, but the footstep in the hub.
  • Out of water it is the footstep.
• Walking (0x8005e920), by the body's own character and template: character 34 plays 108, Reptar (template 8) puffs then steps, the rest step.

player::step_sound holds the rule.

The characters step too. Their bodies run the same handlers. Npc::stepped records a step in drive_body. npc::step sounds it before the next character's update, drawing a heard footstep's note from the rand there, as the original's body update does. Event::Step, Event::Wade and Event::Footstep go to Game::npc_steps. Npc::template is new. World gains the player's character and the listener (the camera).

The frames' events (0x800596e8, 0x800573b0). The player's set-up rewrites events in the shared frame table every level:

• animation 9: frame 2 none, frame 3 a step (256);
• animation 5: frame 2 none;
• animations 232-235: frame 2 none;
• animation 234: frame 8 a grab (2048).

The landing's entry (state 10, 0x8005b2d8) sets 190's frame 3 to a step. The port read the file's events, so level 11's runner stepped twice a stride. animator::set_up_events and landing_events do it now. With them the frame tables equal the oracle's in levels 1, 6, 11, 16 and 24 (npc_check FRAMES=1).

The sweep with SOUNDS (FAST, 300 frames). Every NPC track still matches.

• Level 11: all 40 sounds the same.
• Level 13: all 50 the same.
• Levels 1-7, 10, 12, 14-18, 23, 25, 27, 28, 30 and 31: no sound either side.

Found, not yet done. The generic object set-up (0x8004691c) changes the shared templates and models, as npc_check TEMPLATES=1 shows against the oracle's table (0x80118a0c). The golf door (770) runs at +0x1a 50 in level 24 where the file says 32, so its cycle is 72 frames, not 94. The next worklog takes the whole function on.

Tools. The oracle's bus stops on a write to a word (RUGRATS_STOPW=addr[:was]). That is how the golf door's 50 was traced to 0x80047418.