Entry 134

Climbs move by their root keys

2026-10-165mplay

Filescrates/rugrats-data/src/anim.rscrates/rugrats/src/actors/animator.rsplayer.rs

The ANM key with bit 29 (Key::Lift) is the root's move over its frame, not a lift alone. 0x800557ec reads three fields:

• x: w0's bits 0-13;
• y: bits 14-27;
• z: w1's bits 0-13.

0x80055904 takes the frame's key in proportion to the time run. 0x80056834 adds the result into +0xda (y, always) and +0xd8 / +0xdc (x, z, for states whose ENDS word has 32). 0x80066e60 turns that vector by the body's matrix and moves the body by it (0x80066014). For bodies other than character 0x800c5680 (1, Tommy) the move is scaled by hierarchy +0x4c over 0x800c41dc. 0x800c41dc is -561, peeked in the hub.

The climbs' keys add up to their rises. For Tommy, by the climb picked:

So in the original the body starts at the foot of the ledge and is carried up and on to it by the animation.

The port puts the body on top at once. It used to play the climb there, hovering over the ledge. The physics stay as they are. Now Animator::root_progress gives the base track's root motion so far, and its whole, and Player::drawn_at draws the body, while the climb plays:

• back along the heading by the forward move still to come;
• down by the part of the rise still to come, in proportion to the animation's own y.

parts uses the same place, so a carried thing follows.

Checked in level 6's box setup (play test level_6_box_stack): the drawn root goes -2402, -2441, -2596, -2733, -2787, -2818, -2860 over the climb. The physics y is -2914 throughout.