# loading_tip_patcher

Patches the cycle interval of EU4's loading-tip textbox and (when RE
finishes) the loading-screen image cycle. Built because the Clausewitz
engine hardcodes the interval in `eu4.exe` and exposes no define or
GUI knob for it.

## Status

**Skeleton only — not yet functional for end users.** The patch sites
in `eu4.exe` have been narrowed down via static RE (see
[`RE_notes.md`](RE_notes.md)), but the cycle function itself and the
Ironman-bypass functions are still being traced in Ghidra. Once
Ghidra analysis finishes, the placeholder VMA/file-offset constants in
`src/main.cpp` are filled in and the patcher becomes usable.

## What works today

- `config.example.json` shows the config schema (no defaults by design;
  the patcher errors out if `tip_interval_seconds` is missing or `<=0`).
- `src/main.cpp` is a complete Win32 console app skeleton: PID lookup,
  SHA-256, VirtualProtectEx / WriteProcessMemory plumbing, minimal JSON
  reader. Currently applies the **single patch site** at
  VMA `0x141DC1768` (the `8.0` double in the timer-constants table —
  prime suspect for the tip-cycle interval).

## What is missing (Phase 2 RE work)

- The actual cycle function in `eu4.exe` that owns `tip_interval` and
  the (possibly separate) `image_interval` (one vs two timers is still
  undecided).
- The Ironman integrity-check functions (3 sites): hash compute,
  server upload, load-time verify.
- `--revert`, `--status`, `--rescan` (placeholders in main.cpp).
- `state.json` write (currently a TODO).
- Path resolution for `eu4.exe` (currently hardcoded to the Steam
  install path; needs `QueryFullProcessImageNameW`).

## Build

Requires MinGW-w64 GCC 15.2.0 (ships with msys2). The patcher is a
standalone `.exe` with no MSVC runtime dependency.

```bash
cd tools/loading_tip_patcher
make
```

Output: `bin/loading_tip_patcher.exe`.

## Run

```bash
# 1. Edit config.json next to the .exe:
#    cp config.example.json config.json
#    (then set tip_interval_seconds)

# 2. Launch EU4 and start a campaign so eu4.exe is running.

# 3. Apply the patch:
./bin/loading_tip_patcher.exe --apply
```

## Risks (please read)

This tool rewrites bytes in a running Paradox game executable.

- **Ironman / achievements**: Paradox's cloud-save integrity check
  hashes the exe. With a patched exe, ironman saves may fail to load
  on the next session, and the cloud server may refuse to grant
  achievements. The "Ironman + achievements" feature the user
  requested is **separate RE work** in Phase 2 — see
  [`RE_notes.md`](RE_notes.md) for the planned patches.
- **Game updates**: Every Paradox patch changes the binary, which
  moves the timer-constants-table offset. The patcher is designed to
  refuse to run on an unknown SHA-256; run `--rescan` to refresh.
- **Anti-cheat**: Paradox's server-side anti-cheat is out of scope.
  The patcher only touches `eu4.exe`; if Paradox bans the account, that
  is a user-accepted risk.
- **Antivirus false positives**: a tiny standalone .exe that calls
  `OpenProcess` / `WriteProcessMemory` on a known game process is
  exactly the signature AV vendors flag. You may need to add an
  exception.

## Files in this directory

| File                  | Purpose                                                  |
|-----------------------|----------------------------------------------------------|
| `src/main.cpp`        | The patcher source (~290 LoC, plain Win32)              |
| `Makefile`            | MinGW-w64 GCC build                                      |
| `config.example.json` | Sample config (no defaults; user must set interval)      |
| `state.json`          | Per-version patch record — **auto-generated**, do not edit |
| `RE_notes.md`         | Static RE findings + breadcrumbs for the cycle function |
| `README.md`           | This file                                                |