Clip the demote+promote passes in updateVisibility() to an AABB sized to
fov_radius instead of two full-W*H walks per entity. A prev_fov window cache
demotes last tick's promoted rect (not the current one) so a moving entity
leaves no trailing "ghost vision". On a 1000x1000 grid the Phase 5.2 benchmark's
flat ~25-36 ms/entity writeback overhead collapses to single-digit microseconds
(384x-6577x speedup on the cheap algorithms; below timing noise on the rest).
Adversarial verify caught a regression the happy-path test missed: the
documented from_bytes -> assign -> update_visibility() load/resume path left
permanent ghost-VISIBLE cells, because prev_fov only bounds engine-promoted
cells. Fixed with a one-shot perspective_full_demote_pending flag (full demote
only on the tick after an external assignment; per-turn hot path stays
windowed). Documented the engine-owned demote contract on the perspective_map
property.
- src/UIEntity.cpp/.h: windowed demote/promote, prev_fov cache, demote flag
- src/DiscreteMap.cpp/.h: demoteVisibleRect(x0, y0, x1, y1)
- tests/regression/issue_316_sparse_perspective_test.py: 7-section regression
(equivalence matrix, radius-0, moving disjoint, trailing-edge, grid resize,
load/resume assignment, AABB margin lock)
- docs regenerated for the perspective_map docstring change
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KnywUddaFRhkxo5kijxJnv
John McCardle
265425321c