Replace the ad-hoc movement simulation with the ported retail physics:
- PlayerMovementController now owns a PhysicsBody (gravity, friction, Euler
integration with sub-stepping) and a MotionInterpreter (motion state machine,
speed constants from retail dat).
- Orientation quaternion is synced from Yaw each frame (Yaw=0 → +X, matching
the cos/sin convention the camera and outbound messages expect).
- Horizontal velocity is composed from MotionInterpreter.get_state_velocity()
speeds (WalkAnimSpeed=3.12, RunAnimSpeed=4.0, SidestepAnimSpeed=1.25 from
decompiled globals) then pushed via PhysicsBody.set_local_velocity so the
orientation quaternion rotates them into world space correctly.
- Vertical velocity (gravity / jump / fall) is snapshot before DoMotion calls
so apply_current_movement's set_local_velocity(0,0,0) can't clobber it.
- Jump delegates to MotionInterpreter.jump() + LeaveGround() which calls
get_leave_ground_velocity() → DefaultJumpVz=10.0 (retail value).
- PhysicsEngine.Resolve is still called each frame with zero delta to sample
terrain/cell Z under the body and set Contact+OnWalkable accordingly.
- Drive UpdatePhysicsInternal(dt) directly instead of update_object(wallClock)
to avoid the MinQuantum (~33ms) guard that would silently drop 60fps frames.
Test update: jump loop extended from 30→50 frames to cover the longer flight
time from retail DefaultJumpVz=10 (≈2.04s) vs old JumpImpulse=5 (≈1.02s).
303 tests green.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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