One PView-faithful portal-visibility pass replacing the abandoned two-pipe
(inside/outside) split (#103). Settled in brainstorm 2026-05-30:
- Full Phase U in one spec (indoor BFS + outdoor building-peering + dungeon
fixpoint + distance-priority ordering + reciprocal OtherPortalClip).
- Per-cell gate = hardware clip planes (gl_ClipDistance) + scissor pre-check
(retail's two-level model); structurally immune to the #103 global-mask flood.
- Terrain stays its own path, gated to OutsideView (retail-faithful; NOT the
handoff's "terrain as cells" sketch).
- Salvage = reuse the clip math (PortalView/ScreenPolygonClip/PortalProjection,
~36 tests), rework the builder (PortalViewBuilder), delete the stencil pipeline
+ GameWindow two-pipe orchestration. Audited keep-list preserves the real
EnvCellRenderer / BuildingId / camera-collision fixes.
Staged U.1-U.6 with three visual gates. Retail anchors + acdream file:line
injection points catalogued in the spec.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
