docs: screen-space overlays and activity distance

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/widescreen.md

@@ -115,16 +115,39 @@ only grows horizontally. `[widescreen] Height=0` renders natively 1:1
   game logic (camera follow `0x44d9f0`) converts world -> screen -> view with
   the device's current projection; unpatched it sent the camera off-world
 
+## Screen-space overlays
+
+- Alt object labels (`0x627260`) and floating texts / damage numbers (32
+  slots, drawn from the render loop at `0x60e940` via `0x41e460`) are packed
+  without overlap into a screen-sized area (`0x662300`, `push 300h / 400h`):
+  widened to the render size (`kLabelAreaPushes`).
+- More world -> screen conversions with integer centre immediates
+  (`x - camera + 200h`): the light/effect list at `+0xce14` (`0x41b1xx`)
+  and the floating texts (`0x41e560`, inverse `0x41eaf0`). Unpatched, lights
+  were offset from the player.
+- Left alone: `push 300h / 400h` at `0x4cc7d3`, `0x5d7bb7` (1024x768 textures),
+  `0x60e869` (GDI BitBlt), `0x613859..` (screenshot pixel conversion), and
+  200h/180h pairs at `0x52bab7`, `0x52c6c0`, `0x6c...-0x72...` (UI windows,
+  1024 layout).
+
+## Activity (simulation) distance
+
+The world is split into sectors of 64x64 tiles (`cSector`, manager
+`**0xad3bc0`, sector pointers at `+0x240`, flags `+0x30`: `0x10000` loaded,
+`0x800` active, tile origin `+0x44 / +0x48`). The 3x3 sectors around the
+player's sector are active (`Sector[%4d] Active (3x3 sectors)`, test
+`0x638ff0`); about 80 are loaded. Measured in game: 9 active sectors, origins
+64 tiles apart.
+
+With 96x48 px tiles, a sector spans 6144 px horizontally and 3072 px
+vertically, so the active block reaches at least that far beyond the player's
+sector in every direction. The widened view needs at most +-1835 x +-768 px
+(1835x768 at zoom 2), so everything visible is simulated; nothing to change.
+
 ## Open questions
 
 - Above ~2300 px render width (between 2304 and 2816) the player is not drawn
   although monsters are (`cCreature::vf14` still called). Not hit at the
   default size; some per-view limit of ~40 tile columns, not found yet.
-- HUD: drawn in the top-left 1024x768 of the render target; 3D belt items
-  use the scaled HUD projection and sit off their slots.
-
-- Activity radius: which creatures/objects are updated and animated
-  (`cWorld` / `cSector`, `0x00603e90` = player?, `0x005fe060` = object by id).
 - Fixed-size per-view buffers (e.g. `+0x80e40`, 5 vectors at `+0x96ad0` with
   capacity 0x200) - do they overflow at 3440x1440 (47 columns x 54 rows)?
-- Mouse picking (screen -> world).