Per docs/research/2026-07-30-ts4-116-oracle-plan.md Addendum (byte-proven
2026-07-30). Raw bytes of CPhysicsObj::calc_friction @ 0x0050ee70's
Sledding fast-sled branch (0x0050ef52-0x0050ef6a):
d9 86 38 01 00 00 fld dword [esi+0x138] ; contact_plane.Normal.Z
dd 05 28 6b 7c 00 fld qword [0x007c6b28] ; = 0.17453292519943295 (10 deg RADIANS)
d9 ff fcos ; st0 = cos(10 deg) = 0.984807753
de d9 fcompp
confirm a genuine fcos opcode over a real 10-degrees-in-radians double
literal -- not a BN misdecompile of a raw float load. Retail truly
computes cos(10 deg) ~ 0.9848078 at runtime; ACE's 0.99999536f equals
cos(0.1745 DEGREES) -- the same radian literal evaluated in degree mode,
a proven ACE porting error carried into this port provisionally.
PhysicsBody.calc_friction's Sledding near-flat override now compares
GroundNormal.Z > 0.98480775f (cos 10 deg). Feel impact: retail's 0.2f
fast-sled friction override engages on any ground within 10 degrees of
flat; the old constant engaged only within ~0.175 degrees (never, in
practice).
Tests: two new boundary pins
(calc_friction_sledding_fast_override_engages_at_5_degrees_from_flat /
..._does_not_engage_at_15_degrees_from_flat) construct a tilted
GroundNormal with velocity purely orthogonal to the tilt plane (dot=0
exactly, isolating the Sledding-band friction value from the outer 0.25f
gate and the normal-removal step) and assert the exact pow(1-friction, dt)
decay on each side of the new 10-degree boundary.
Register: AD-55 retired (struck through, retirement note with the byte
decode).
Full AcDream.Core.Tests suite: 4063 passed / 1 skipped, no regressions.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
252e806804