debug wireframe: allowance areas option (off, floating spots, all edges) from an exact port of the engine floor test, capped by level memory

notes/debugviz.md

@@ -149,6 +149,40 @@ CutSceneTrigger camera moves only as points).
   (≤ 2000 extra vertices per tile model, on average ~1–2× as many triangles as the original).
 * Test level T1L9 (test world) has no debug version (the testlevel mod takes precedence).
 
+## Allowance areas (LlamaMod option `debug-wireframe.allowance`, 2026-11-08)
+
+Choice `off` (default) / `tips` ("Floating spots") / `all` ("All edges"). Shows the floor test's edge
+allowance: the engine accepts a floor polygon up to `tol = −0x40 − ((0x1000 − ny·32) >> 6)` (≈0.016–0.023)
+outside each edge plane; at sharp corners this becomes a sliver up to tol / sin(θ/2) long
+(geometry.md "Floor test: inclusion rule …"). Colour **pink 255,60,200**.
+
+* Code: `mods/debug/FloorTest` = bit-exact port of FUN_004036d0's floor branch (same as `tools/floortest.py`;
+  the sine table is `rint(sin(2πi/4096)·4096)`, identical to DAT_00574318), `mods/debug/AllowanceAreas`.
+  All geometry uses the engine's plane scale (n·p = d/32 with |n| = 127), not `Collision.decode`'s d/4096,
+  so the bands sit ~0.8 % further from the model origin than the green wireframe.
+* **tips**: for every placed tile and every up-facing collision polygon (not material 17 = skipped for the
+  llama, not 30 = no floor) and every corner whose tolerance corner lies ≥ `MIN_REACH` (0.05) beyond the
+  true corner, the area beyond the corner (tolerance region ∩ half-plane past the corner) is sampled in up to
+  40 rows × 7 points. A sample counts when the exact engine test, with the feet on that polygon's plane,
+  picks this polygon, the point is outside the polygon without tolerance, and no other passing floor of the
+  cell is less than `MIN_GAP` (0.05) below (material-30 floors count as none). Samples outside the tile's
+  cell are dropped (the engine only tests the cell's tiles). Kept when the winning samples reach ≥ 0.05
+  outside the polygon: translucent strip (alpha 150) through the winning part of each row + an opaque
+  centre line (4 mm), at the plane height + 0.012, in the tile's marker cell model (no collision).
+  Strat object collision (crates as strats, platforms) is not considered.
+* **all**: per TRAK model, every up-facing floor polygon (same material filter) gets an opaque ring from
+  its true corners to its tolerance corners (2n vertices, 2n triangles), appended to the model overlay like
+  the wireframe (tile transform, alt models free). Tolerance corners further than 1.5 out are clamped.
+* Budget: if TEXT+TRAK+MAP+STPC+LGPC would exceed 12 MB (16 MB level arena) the level is rebuilt without
+  allowance geometry and the apply log says "allowance areas left out: level too large". Not reached in
+  any original level; a model whose overlay would pass 7900 vertices keeps its wireframe without bands.
+* Numbers (all 33 levels): tips 0–1454 slivers per level (river t1l3m00x most, t1l4m002 394),
+  WAD +0–2.0 MB, ≤ 2 s per level; all: +0.02–2.9 MB, arena max 11.1 MB (t1l3m003).
+  t1l4m002 crate (tile 443): poly 15 corner 2 (reach 0.18, contains Kuzco's spot 57.204/43.733),
+  poly 11 corner 2 (0.175), polys 10/14 (0.11/0.13) on the other end, 12/13 barely (0.05).
+* Tests: `AllowanceAreasTest` (exact port vs. 44 floortest.py points, sine table vs. groove.exe,
+  slivers of t1l4m002, no slivers on the flat start ground, band counts, process in each mode).
+
 ## Statistics per level (build of 2026-11-06)
 
 Marker categories are the internal keys of `debugviz.py`: ausgang = exit, geheimnis = secret,