tdkpin/tdkpin-rs/RECONSTRUCTION.md

Reconstruction ledger

Source artifacts

The reconstruction was derived from the preserved files under ../original/. The primary program fingerprint is:

a9022f1894e3e6e21fc42e8f6c932f7c549ca77f63aaa0c488bb9d55d9d0174c  TDKPIN.EXE
f1d9ac980c7bfba5dc53eaa9e7cb2c3cd9b82f879ee8962ad40bf863d641bb49  MMTIMER.DLL

The Ghidra recovery covers all 301 named NE exports plus 62 internal function entries. Its raw output and coverage tables remain beside the binary, so later work can be checked against the same evidence rather than against this Rust implementation.

Coverage by subsystem

Subsystem	Rust status	Evidence and boundary
Artwork	Exact	All 34 custom DIB images, three standard bitmaps, icon, and palette derivatives are preserved in assets/original/. The game uses the original 640x460 table, loading, help, ball, wheel, robot, plunger, media, and diamond frames.
Audio	Exact samples	All 16 mono PCM WAV resources are embedded unchanged. Their trigger roles were recovered from resource use and gameplay context.
Help and languages	Exact	Original resource images 1001-1005 are displayed directly.
Playfield collision layout	Recovered	All 109 active type-2 line objects and 40 static active type-1 circles are transcribed from the original 175-object registration table. The registration routine converts its sideways inputs with screen = (y, x - 20) and accumulates explicitly relative objects. Its circle sizes are complete center-contact extents, so the rendered ball radius is not added a second time. Object 174 is omitted because the original overwrites it with the live ball every frame. Moving flippers use equivalent native Rust bodies.
Ball launcher	Recovered	The initial 32-bit fixed-point coordinates decode to (325, 413) in the right shooter lane. Scan code 0x50 compresses the eleven frames in resource 901 while Down is held; the key-release routine activates the ball with the accumulated vertical launch velocity.
Physics arithmetic	Reimplemented	The Win16 fixed-point/timer engine is replaced by deterministic fixed-step floating-point integration. Restitution and impulses are tuned to the recovered table but are not instruction-for-instruction equivalents.
Rules	Partly recovered	Player count, controls, wheel holes, magnetic saves, four-position ball lock, target banks, increasing bumper value, nine-part TDK diamond, permanent double scoring for a completed diamond, KByte media progression, and media extra balls follow the original help and code paths. The claw state machine has now been recovered in readable form, but its raw release-coordinate projection is still being decoded before the Rust behavior can claim parity.
Numeric scoring	Partly inferred	Visible 2000-6000 target values and recovered registration values are preserved. Some bumper, bank-completion, robot, wheel, lock, and media thresholds are best-evidence reconstructions because the decompiler did not recover meaningful names or a clean rule table.
High scores	Compatible import	The original 276-byte table is decoded as ten IWIK-XOR-obfuscated little-endian scores plus ten 22-byte names, sorted, then migrated to portable JSON.
Configuration	Behaviorally compatible	Sound, language, and five detail levels are retained. Storage moves from a local Win16 INI file to the platform user-data directory.
Windows UI shell	Deliberately modernized	Win16 menus, modal dialogs, GDI blitting, and multimedia timers are replaced by an aspect-correct 960x690 native window with keyboard overlays. The visible game and original help remain at 640x460 logical pixels.

Extracted asset inventory

assets/original/ contains 69 files used or preserved by the modern project:

• 40 image files, including all gameplay frames and five localized help pages;
• 16 original WAV resources;
• six decoded dialog descriptions;
• the original icon in ICO and PNG form;
• palette and version metadata;
• the original high-score table and INI configuration sample.

The parent original/assets/ directory remains the lossless extraction record, including raw resource blobs and the extraction manifest. The Rust copy is the decoded, build-ready subset; it does not replace that evidence archive.

Validation levels

• Static coverage: all intended decoded visual/audio resources are preserved; the recovered static collision layout is represented in Rust.
• Build coverage: cargo check, unit tests, and strict Clippy complete on the host. Cross-target checks pass for x86_64-pc-windows-gnu and x86_64-apple-darwin; CI is configured to build and test natively on Linux, macOS, and Windows.
• Runtime coverage: the Linux executable was launched through the real window backend, the attract screen was inspected, a game was started, a ball was launched, collision scoring was observed, and a rendered frame was captured.
• Deterministic mechanics coverage: named launcher, flipper, and all four claw terminal scenarios advance at exact 120 Hz steps, record JSON state/event traces, and can export the logical 640x460 render target at any requested step for visual inspection.
• Semantic boundary: no claim is made that every trajectory or score tick is bit-identical to the 16-bit executable. Remaining numeric inference is listed above instead of being presented as proven parity.

Architecture

• app.rs: screen flow, controls, rendering, audio dispatch, and overlays;
• assets.rs: compile-time original asset embedding;
• game.rs: fixed-step game state, recovered walls, rules, and scoring;
• geometry.rs: segment/circle collision primitives;
• table.rs: source-traceable collision objects recovered from the Win16 table;
• persistence.rs: platform paths, settings, high scores, and legacy import.