Ports the seal half of retail's invisible portal depth writes
(D3DPolyRender::DrawPortalPolyInternal, Ghidra 0x0059bc90; dispatched by
PView::DrawCells loop 1, Ghidra 0x005a4840 pc:432783-432786):
- NEW PortalDepthMaskRenderer: draws a portal polygon as a color-masked
triangle fan, depth-test ALWAYS + depth-write ON, at the polygon's TRUE
projected depth (retail maxZ2 seal) or forced to far-z 0.99999988
(retail maxZ1 punch - the constant from 0x0059bc90's tail; punch wiring
lands in BR-2 commit 2). Where retail software-clips the fan against
the installed view (polyClipFinish), we apply the SAME slice region via
gl_ClipDistance from the slice's <=8 clip-space half-planes. GL state
fully self-contained (set -> draw -> restore, no early-outs).
- DrawExitPortalMasks is now WIRED in production (was a null-callback
no-op since birth): for interior roots, every visible cell's portals
with OtherCellId==0xFFFF get their world-space polygon sealed per view
slice, far-to-near, after the landscape slices.
- ClearDepthSlice (per-slice scissored AABB clear - wrong shape, wrong
scope, no seal after it) is REPLACED by ClearDepthForInterior: ONE
full-buffer depth clear between the outside stage and the interior
stage, gated on any outside slice having drawn (retail's
portalsDrawnCount gate semantics staged as an open question, marked
inline). DepthMask(true) asserted at the clear site (c4df241 lesson).
Outdoor roots: no clear, no seals (interiors must depth-test against
terrain until the commit-2 punch).
Closes the mechanism behind #108 (outdoor grass sweeping across the
upstairs door opening - terrain depth seen through the doorway is now
re-stamped at the door plane so farther interior geometry z-fails inside
the aperture). Visual gate: BR-2/BR-3 batched checklist (cellar doorway
+ cottage wall + tower stairs near/far).
Suites: build green, App 226 green, Core 1398 + 4 pre-existing #99-era
failures + 1 skip.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
