User-reported: "still don't slide down steep roofs" after the previous
trigger-gate fix (52e257d). Traced through the EdgeSlide dispatcher:
the gate IS firing now, but ValidateTransition's L.2.3i FloorZ test
clears OnWalkable as soon as the player is on a steep surface. So
EdgeSlideAfterStepDownFailed enters Branch 1 (`!OnWalkable → restore
+ OK`) and stops the player BEFORE Branch 2's steep-ContactPlane
CliffSlide can fire.
Re-order: check the steep-ContactPlane condition FIRST, before the
Branch 1 OnWalkable gate. If the surface is too steep AND we have a
contact plane on it AND the EdgeSlide flag is set, run CliffSlide
regardless of OnWalkable state. The cross-product deflection plus
gravity produces continuous downhill drift, frame after frame.
Branch 1's "stop at edge" still fires for the original case it was
meant for: walked off into thin air with no contact plane at all.
That should still stop (or fall normally) rather than CliffSlide
against nothing.
Tests: 1491 still pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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