Maphack: real wall transparency via a second layered window

[imm0r]

Summary

In labyrinth-style map layouts (many nested narrow corridors) the memory maphack draws so many wall outlines in a small screen area that real in-game enemies underneath become hard to see. Every border pixel is fully opaque, because the radar overlay uses colour-key transparency (LWA_COLORKEY + one global LWA_ALPHA) — there is no per-pixel alpha, and lowering the one global alpha would also dim the radar dots and labels.

This PR adds the one form of real transparency the model does offer: per-layer alpha via a second layered window. RadarOverlay now owns a second click-through layered window kept directly below the radar window in the topmost band. When the new wall alpha (g_mapHackAlpha, 20–255) is below 255, the map layers (wall borders + unexplored wash) render into that window's own back-buffer and genuinely alpha-blend with the game underneath — enemies stay visible through dense wall clusters — while dots, labels and paths on the radar window keep full opacity. At the default 255 nothing changes: the layers draw into the radar back-buffer exactly as before (zero extra cost), and any window/buffer creation failure falls back to the classic path.

Changes

• ahk/RadarOverlay.ahk — new _Ml* helpers (lazily created layer window, back-buffer, present/hide/destroy); the large-map layer draw routes into the layer window when g_mapHackAlpha < 255; _DrawMapLayersCached / _DrawMapLayersDirect gained an optional target-DC parameter (shared scroll cache untouched); HUD + loot-label clip exclusions are collected per frame and applied to both destinations; _FinishFrame hides the layer window on any frame that did not use it; Hide() override + destructor cover teardown.
• InGameStateMonitor.ahk — seed g_mapHackAlpha := 255; version bump to 0.45.13.299.
• ahk/ConfigManager.ahk — persist [Radar] mapHackAlpha (clamped 20–255).
• ahk/BridgeDispatch.ahk — new SetMapHackAlpha bridge case.
• ahk/WebViewBridge.ahk — mapHackAlpha in the header push.
• ui/index.html — "↳ Wall opacity" slider under Config → Overlay → Map Hack (live oninput, % bubble, activeElement guard on header sync); hidden while the maphack source is "ggpk" (the slider only affects the memory overlay).
• CLAUDE.md / README.md — feature documentation + version sync.

Test plan

• Static verification: brace balance on all edited AHK files; node --check on the extracted inline UI script; <div> balance unchanged vs. HEAD; CRLF preserved in BridgeDispatch.ahk / WebViewBridge.ahk.
• In-game: on a large map with the memory maphack, drag Wall opacity to ~40–60 % — wall outlines become see-through (enemies/ground visible through them) while dots/labels stay crisp.
• In-game: the wall layer stays under the dots and above the game, hides with the map/radar, and HUD + loot-label exclusion zones stay clear.
• In-game: no perf regression (one extra full-window BitBlt per frame only while alpha < 255; at 255 the old path runs unchanged).

Notes for the reviewer

• Colour-key windows cannot do per-pixel alpha, so this is deliberately per-layer: the whole wall window blends at one alpha. Both map layers ride it (wall borders + unexplored wash) because they share the composite scroll cache and both are "map paint over the game".
• The below-radar z-order is re-asserted on the same cadence as the base topmost heal (SetWindowPos insertAfter=radar); inserting after a topmost window keeps the layer in the topmost band.

🤖 Generated with Claude Code

https://claude.ai/code/session_013UCQfY5KTNcmggpfapfciC

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Generated by Claude Code