ModAPI(v1) v2.0.9618 - 20260425

The Forest Mod Management Tool — Upgraded Edition

Original: FluffyFish / Philipp Mohrenstecher (Engelskirchen, Germany) Upgrade: zzangae (Republic of Korea)

Overview

ModAPI is a desktop application for managing mods for 5 officially supported games. This upgraded edition includes multi-game support, a fully redesigned Settings tab, Steam path configuration, persistent UI settings, a dynamic font size system, game start validation, Debug/Release build split, and numerous crash fixes verified through in-game testing.

Supported Games

Game	Engine	Version	Steam ID	Executable
The Forest	Unity 5	v1.12 (VR)	242760	`TheForest.exe`
Subnautica	Unity	2025 Patch	264710	`Subnautica.exe`
RAFT	Unity	v1.1.02 (Beta)	648800	`Raft.exe`
Escape The Pacific	Unity 6	v0.67.0.0	655290	`EscapeThePacific.exe`
Green Hell	Unity 2019	v2.9.5	763790	`GH.exe`

The Forest

Item	Value
Engine	Unity 5 (upgraded from Unity 4)
Latest Version	v1.12 (VR)
Last Update	September 11, 2019 — VR support patch; no further major content updates
Executable	`TheForest.exe`
Data Folder	`TheForest_Data/Managed/`
Mods Folder	`mods/TheForest/`
Projects Folder	`projects/TheForest/`
Steam App ID	`242760`
IL2CPP	❌ Mono — fully supported

The Forest was upgraded from Unity 4 to Unity 5, significantly improving visuals and physics. The September 2019 VR patch was the final major update. The game now remains in a stable, finalized state — ideal for modding.

Subnautica

Item	Value
Engine	Unity (integrated codebase, unified with Below Zero in 2022)
Latest Version	2025 Patch (v18810395)
Last Update	August 12, 2025 — bug fixes and performance improvements alongside mobile release
Executable	`Subnautica.exe`
Data Folder	`Subnautica_Data/Managed/`
Mods Folder	`mods/Subnautica/`
Projects Folder	`projects/Subnautica/`
Steam App ID	`264710`
IL2CPP	❌ Mono — supported

Originally built on Unity 5, Subnautica received the 'Living Large' update (v2.0) in late 2022 which merged the engine codebase with Below Zero for improved optimization and stability. Note: the upcoming Subnautica 2 uses Unreal Engine 5.

XML rewritten in v2.0.9610: XGamingRuntime.dll, XblPCSandbox.dll, FMODUnity.dll, Newtonsoft.Json.dll, Unity.InputSystem.dll, Unity.Collections.dll, Unity.Burst.dll added to copyAssembly.

RAFT

Item	Value
Engine	Unity
Latest Version	v1.1.02 (Beta) / v1.09 (Stable)
Last Update	March 2026 — voice chat and multiplayer bug fixes via beta branch
Executable	`Raft.exe`
Data Folder	`Raft_Data/Managed/`
Mods Folder	`mods/Raft/`
Projects Folder	`projects/Raft/`
Steam App ID	`648800`
IL2CPP	❌ Mono — supported
Versions.xml	`1.1.01` (with checksum)

After the official story conclusion in v1.0: The Final Chapter, patches have continued for network code improvements and stability. A beta branch update in March 2026 addressed voice chat and multiplayer issues.

Escape The Pacific

Item	Value
Engine	Unity 6 (migrated from Unity 2021/2022 in late 2025)
Latest Version	v0.67.0.0
Last Update	June 26, 2025 — island distribution rework and engine update; hotfixes ongoing into 2026
Executable	`EscapeThePacific.exe`
Data Folder	`EscapeThePacific_Data/Managed/`
Mods Folder	`mods/EscapeThePacific/`
Projects Folder	`projects/EscapeThePacific/`
IL2CPP	❌ Mono — supported

Completed a major system rebuild and Unity 6 migration in late 2025, enabling more dynamic environments. The game remains in active Early Access development.

XML rewritten in v2.0.9610: extends="GenericUnityGame" removed; includeAssembly set to Assembly-CSharp.dll only — prevents Assembly-CSharp-firstpass.dll inheritance errors.

Green Hell

Item	Value
Engine	Unity 2019
Latest Version	v2.9.5
Last Update	February 4, 2026 — Steam Deck optimization and text readability improvements
Executable	`GH.exe`
Data Folder	`GH_Data/Managed/`
Mods Folder	`mods/GH/`
Projects Folder	`projects/GH/`
Steam App ID	`763790`
IL2CPP	❌ Mono — supported
Versions.xml	`2.9.5` (with checksum)

Developed through Unity 2017 → 2018 → 2019 across its lifecycle. The February 2026 hotfix focused on Steam Deck compatibility and UI readability.

XML rewritten in v2.0.9610: AmplifyBloom.dll, AmplifyColor.dll, AmplifyMotion.dll, com.rlabrecque.steamworks.net.dll, Unity.ProBuilder.dll, Unity.Postprocessing.Runtime.dll added; non-existent DOTweenPro.dll removed.

Architecture

Runtime Split

Component	Target	Runtime	Reason
`ModAPI.exe`	.NET Framework 4.8	Windows .NET 4.8	Desktop application, full modern API
`ModAPI_Shared.dll`	.NET Framework 4.8	Windows .NET 4.8	Shared library
`BaseModLib.dll`	.NET Framework 3.5	Game Mono 2.0	Permanently fixed — PE header must read `v2.0.50727`
Mod DLLs (user)	.NET Framework 4.8	Game Mono 2.0 (patched)	Built with 4.8, PE header patched at Apply time

Debug / Release Build Split

All file validation and assembly processing branches on the build configuration via #if DEBUG / #else.

Location	Debug Build	Release Build
`CheckSteam()`	`File.Exists()` only — dummy files pass	`FileValidator.IsValidSteamExe()` — PE header + min 1 MB
`CheckGamePath()`	`File.Exists()` only — dummy files pass	`FileValidator.IsValidAssemblyDll()` — PE header + CLR metadata + min 64 KB
`ModLib.Create()` — IncludeAssemblies	`File.Copy()` — skip Cecil parsing	Full Mono.Cecil parse + IL modification + `module.Write()`
`ModLib.Create()` — file not found	Log warning, skip and continue	Log error, abort with popup

Debug testing uses create_dummy_Debug_games.ps1 to generate 0-byte placeholder files under bin\Debug\dummy_games\, bin\Debug\dummy_steam\, and bin\Debug\gamefiles\original\. These pass File.Exists() checks and allow full UI workflow testing without a real game installation.

Release builds apply FileValidator (PE header + .NET CLR metadata verification) to reject 0-byte files, text files, and arbitrary binaries. Only valid Windows executables and .NET assemblies pass.

FileValidator — PE Header Verification

ModAPI_Shared\Utils\FileValidator.cs — applied in Release builds only.

Method	Checks	Min Size
`IsValidSteamExe(path)`	MZ signature + PE\0\0 signature	1 MB
`IsValidGameExe(path)`	MZ signature + PE\0\0 signature	512 KB
`IsValidAssemblyDll(path)`	MZ + PE\0\0 + CLR metadata header (data directory #14)	64 KB

PE Header layout checked:
[0x00] 4D 5A          ← "MZ" DOS signature
[0x3C] XX XX XX XX   ← PE header offset (little-endian)
[offset] 50 45 00 00 ← "PE\0\0" signature
[Optional Header → DataDirectory[14]] RVA+Size != 0 ← .NET CLR header present

Assembly Remapping Pipeline

[Mod Developer builds with .NET 4.8]
  → Mod DLL: PE header v4.0.30319, mscorlib 4.0.0.0

[ModAPI Apply — ModProject.cs]
  → AssemblyVersionMap.RemapAllReferences(modModule)
      mscorlib 4.0.0.0 → 2.0.0.0, etc.
  → modModule.RuntimeVersion = "v2.0.50727"
      PE header: v4.0.30319 → v2.0.50727

[Game Mono 2.0]
  → PE header accepted ✅  →  References resolved ✅

Assembly Resolver Fallback

1. gamefiles/original/{GameId}/{AssemblyPath}   ← backup folder
2. {ActualGameInstallPath}/{AssemblyPath}        ← game install folder (fallback)

C# 7.3 Feature Support

Feature	Status	Notes
Pattern matching (`is`, `switch`)	✅	In-game verified
String interpolation (`$""`)	✅	In-game verified
`out` variable inline	✅	In-game verified
`async` / `await`	✅	Via AsyncBridge + System.Threading polyfills
Tuples (`ValueTuple`)	❌ Hard limit	Mono 2.0 `mscorlib` ABI — no workaround

Theme System Detailed Reference

As of v2.0.9613, the theme selection UI has been moved from the Settings tab to a dedicated Themes tab. Adding a new theme requires only one line in the App.xaml.cs dictionary.

Index	ID	File	Palette
0	`classic`	`Dictionary.xaml` only	Original ModAPI texture background
1	`light`	`FluentStylesLight.xaml`	Light tone + blue accent
2	`dark`	`FluentStyles.xaml`	Dark tone + blue accent (default)
3	`diablo`	`FluentStylesDiablo.xaml`	Red + black
4	`nebula`	`FluentStylesNebula.xaml`	Dark space
5	`sunset`	`FluentStylesSunset.xaml`	Bright sunset
6	`ocean`	`FluentStylesOcean.xaml`	Dark ocean
7	`nordic`	`FluentStylesNordic.xaml`	Bright Nordic
8	`citrus`	`FluentStylesCitrus.xaml`	Bright citrus
9	`bloom`	`FluentStylesBloom.xaml`	Bright floral

Theme changes trigger an automatic app restart. (saved to theme.cfg)

Theme	Theme
01. Classic theme	02. Light theme

03. Dark theme	04. Diablo theme

05. Nebula theme	06. Sunset theme

07. Ocean theme	08. Nordic theme

09. Citrus theme	10. Bloom theme

Background Texture

Select an image in the Background Texture card on the Themes tab to apply it as the app-wide background. Supported formats: .png / .jpg / .jpeg, up to 50MB, 4K resolution or below. The image is compressed as JPEG Q75 with a 16-byte magic header and saved as resources\textures\ui_bg\bg.dat (Hidden attribute). SHA-256 hash for integrity verification; tampering triggers automatic reset + warning popup.

When the background is active, UI transparency is processed in two layers: Layer 1 (MergedDictionaries overlay) for {DynamicResource} panels, Layer 2 (WalkStyleBackgrounds) for {StaticResource}-based panels with semi-transparency.

Font Size System

Resource Key	Base	Description
`AppBaseFontSize`	13	Normal text
`AppBaseHeaderFontSize`	16	Headers, panel titles
`AppBaseSmallFontSize`	12	Secondary labels
`AppBaseTinyFontSize`	10	Hint text
`AppBaseLargeFontSize`	20	Large display text

Persistent UI Configuration — `ui.cfg`

Key	Default	Description
`ModListWidth`	`150`	Mods tab list width (px)
`ProjectListWidth`	`150`	Development tab project list width (px)
`AppFontSize`	`13`	Global UI font size (px)
`AlwaysOnTop`	`false`	Window always-on-top
`TexturePath`	(none)	Background texture original filename (display only)
`TextureHash`	(none)	Background texture SHA-256 hash
`TextureActive`	`false`	Background texture activation state
`GamePathReset_{GameId}`	(none)	Game path reset flag
`SteamPathReset`	(none)	Steam path reset flag

File Structure

ModAPI/
├── App.xaml / App.xaml.cs              # ThemeRegistry, ThemeIds, ApplyTheme()
├── ui.cfg                               # Persistent UI settings
├── theme.cfg                            # Current theme
├── Windows/
│   ├── MainWindow.xaml / .cs            # Main UI — 6 tabs, Themes, Settings, Steam path
│   └── SubWindows/
│       ├── SpecifyGamePath.xaml / .cs   # Game path popup (dynamic GameNameLabel)
│       ├── FirstSetup.xaml / .cs        # First-run setup + default initialization
│       └── (14 other SubWindows)
├── Themes/
│   ├── Dictionary.xaml                  # Classic theme
│   ├── FluentStyles.xaml                # Dark theme
│   ├── FluentStylesLight.xaml           # Light theme
│   ├── FluentStylesDiablo.xaml          # Diablo theme
│   ├── FluentStylesNebula.xaml          # Nebula theme
│   ├── FluentStylesSunset.xaml          # Sunset theme
│   ├── FluentStylesOcean.xaml           # Ocean theme
│   ├── FluentStylesNordic.xaml          # Nordic theme
│   ├── FluentStylesCitrus.xaml          # Citrus theme
│   └── FluentStylesBloom.xaml           # Bloom theme
├── Data/
│   ├── Game.cs                          # Assembly patching, null guards, resolver fallback
│   ├── ModLib.cs                        # BaseModLib generation + remapping (#if DEBUG split)
│   ├── Models/
│   │   └── ModProject.cs                # Project create/build/apply + null guards
│   ├── ViewModels/
│   │   ├── ModsViewModel.cs             # FilteredMods, SelectedModItem, SelectedGameFilter
│   │   ├── ModViewModel.cs              # GameId from folder path
│   │   ├── ModProjectsViewModel.cs      # Dispose() for DispatcherTimer
│   │   └── SettingsViewModel.cs         # Default true for UseSteam/AutoUpdate/UpdateVersions
│   └── AssemblyVersionMap.cs            # Mono 2.0 assembly version mapping (20 assemblies)
├── Utils/
│   ├── CustomAssemblyResolver.cs        # Name-based resolver with caching
│   └── MonoHelper.cs                    # Mono.Cecil IL helper utilities
├── resources/
│   ├── langs/                           # 13 language files
│   └── textures/ui_bg/
│       └── bg.dat                       # Compressed & secured background image (runtime-generated)
└── configs/
    ├── games/
    │   ├── TheForest.xml
    │   ├── Subnautica.xml               # Full rewrite v2.0.9610
    │   ├── Raft.xml
    │   ├── EscapeThePacific.xml         # Full rewrite v2.0.9610
    │   ├── GH.xml                       # Full rewrite v2.0.9610
    │   ├── SonsOfTheForest.xml          # IL2CPP — not supported
    │   └── {GameId}/Versions.xml        # Raft, GH, Subnautica, EscapeThePacific
    └── UserConfiguration.xml

ModAPI_Shared/
├── Data/
│   ├── Game.cs                          # Lightweight constructor + ModLibrary init fix
│   └── ModLib.cs                        # #if DEBUG split for Cecil parsing
└── Utils/
    └── FileValidator.cs                 # PE header + CLR metadata validation (Release only)

BaseModLib/
├── BaseModLib.csproj                    # .NET 3.5 + LangVersion 7.3
└── libs/polyfills/
    ├── AsyncBridge.dll
    └── System.Threading.dll

VersionTool/
└── MODAPI_VersionTool.csproj            # Standalone WPF version update tool

bin\Debug\                               # Debug testing only
├── create_dummy_Debug_games.ps1         # Generates dummy game/steam structure
├── dummy_games\{GameId}\               # Dummy game install paths
├── dummy_steam\Steam.exe               # Dummy Steam executable
└── gamefiles\original\{GameId}\        # Dummy backup paths for ModLib

Installation & Setup

Step 1 — Prerequisites

Item	Required
Windows 10 / 11	✅
.NET Framework 4.8	✅ (pre-installed on Windows 11; download for Windows 10)
Steam	Required — must be configured in Settings tab
At least one supported game	Required — must be configured in Settings tab

Step 2 — Install ModAPI

Download the latest release from GitHub
Extract to any folder (e.g. C:\ModAPI\)
Run ModAPI.exe
On first launch the Welcome screen appears — configure preferences and click Continue

Step 3 — Configure Steam Path (Settings Tab)

Go to the Settings tab
Find Steam Installation Path
Click Browse → select Steam.exe
Click Save

Step 4 — Configure Game Paths (Settings Tab)

Click a game card header to expand it
Click Browse → select the game root folder (where the .exe is located)
Click Save

Game	Executable	Example Path
The Forest	`TheForest.exe`	`C:\Steam\steamapps\common\The Forest\`
Subnautica	`Subnautica.exe`	`C:\Steam\steamapps\common\Subnautica\`
RAFT	`Raft.exe`	`C:\Steam\steamapps\common\Raft\`
Escape The Pacific	`EscapeThePacific.exe`	`C:\Steam\steamapps\common\Escape The Pacific\`
Green Hell	`GH.exe`	`C:\Steam\steamapps\common\Green Hell\`

Step 5 — Download Mods (Downloads Tab)

Go to the Downloads tab
Select a game from the game filter
Browse or search for a mod and click Download

Offline: Download .mod files manually from modapi.survivetheforest.net and place them in the corresponding folder:

Game	Folder
The Forest	`mods/TheForest/`
Subnautica	`mods/Subnautica/`
RAFT	`mods/Raft/`
Escape The Pacific	`mods/EscapeThePacific/`
Green Hell	`mods/GH/`

Step 6 — Apply Mods & Start Game (Mods Tab)

Go to the Mods tab
Select a game from Game Filter (Col 0)
Check mods to activate in Mod List (Col 1)
Click Start Game

The following checks run automatically before launch:

#	Check	Failure Popup
1	Steam path configured and valid	SteamNotFound
2	`mods/` folder game matches Settings game path	GameModsMismatch
3	At least one mod selected	NoModSelected
4	No mixed-game mods in selection	MixedGameMods
5	Game path configured and executable exists	GamePathNotSet / GameNotInstalled

Tab Overview

Welcome Tab

First-run setup screen (tab index 0). Configure AutoUpdate, Steam connection, and VersionsData table preferences. On subsequent launches this tab provides community links and release notes.

Mods Tab

Primary mod management workflow — 3-column layout:

Column	Content
Col 0	Game Filter — radio buttons for 5 supported games
Col 1	Mod List — installed mods with version picker and activation checkbox
Col 2	Information — selected mod details, description, version history

Downloads Tab

Browse and download mods from modapi.survivetheforest.net.

Game filter: TheForest / DedicatedServer / VR / Subnautica / RAFT / EscapeThePacific / GH
Category filter: 12 categories (Bugfixes, Balancing, Cheats, …)
Search: by mod name, description, or author
Offline mode: displays folder instructions for all 5 supported games

Development Tab

Mod development workflow — game filter panel (Col 0) covers all 5 supported games.

Create, build, and apply mod projects per game
Language resource management
ModLib generation with 3-step validation (Steam → project → game path)
Safe game switching via lightweight Game constructor (no Verify() call)

Themes Tab

Theme selection and background texture management.

Theme selection: 10 themes (Classic, Light, Dark, Diablo, Nebula, Sunset, Ocean, Nordic, Citrus, Bloom)
Background texture: Select an image as the app-wide background (JPEG compression + security processing)
When background texture is active, theme selection is locked

Settings Tab

Centralized configuration — 4 rows:

Row	Content
0	Language / Font Size / Max Width / Mod List Width / Project List Width
1	Keep VersionsData / Auto Update / Steam Connection / Always On Top
2	Steam Installation Path (TextBox + Browse + Save + Reset)
3	Game Installation Paths — expandable card per game (TextBox + Browse + Save + Reset)

What Changed in v2.0.9618

Version Update Tool (MODAPI_VersionTool)

A standalone WPF tool for updating the version number with a single click.

Location: VersionTool\MODAPI_VersionTool.csproj

Version Tool

Features

Automatically displays the current version (read from App.xaml.cs)
Enter a new version and click Apply Version to update both files simultaneously
Format validation: only X.X.XXXX format accepted

Files Modified

File	Path	Change
`AssemblyInfo.cs`	`ModAPI\Properties\`	`AssemblyVersion`, `AssemblyFileVersion`
`App.xaml.cs`	`ModAPI\`	`public static string Version`

Usage

Run MODAPI_VersionTool.exe
Enter new version (e.g. 2.0.9619)
Click Apply Version
Rebuild the ModAPI solution in Visual Studio

StatusBar Version Display Fixed

VersionLabel.Text now references App.Version instead of the hardcoded Version.Descriptor
Updating the version with VersionTool and rebuilding now reflects immediately in the StatusBar

What Changed in v2.0.9617

Settings Tab — Path Reset Buttons Added

A Reset button has been added to the Steam installation path and each game installation path row.

Steam path row

[TextBox] [Browse] [Save] [Reset]

Game path row (per game)

[TextBox] [Browse] [Save] [Reset]

Reset behavior

Clears the path TextBox immediately
Saves a reset flag to ui.cfg (GamePathReset_{GameId}=1, SteamPathReset=1)
TextBox remains empty after restart
Works around Configuration XML not persisting empty strings

Browse auto-save

Before: required a separate Save button click after Browse
After: automatically saved on file selection — reflected even after switching to the Mods tab

New language key

Key	Value
`Lang.Options.Labels.PathReset`	Reset

What Changed in v2.0.9616

Versions.xml — 4 Games Added / Updated

Game	File Path	BuildID	Notes
Subnautica	`configs/games/Subnautica/Versions.xml`	`20241558`	Newly created
Raft	`configs/games/Raft/Versions.xml`	`22312909`	Checksum updated
EscapeThePacific	`configs/games/EscapeThePacific/Versions.xml`	`19000490`	Newly created
GH	`configs/games/GH/Versions.xml`	`21698250`	Checksum updated

Checksum Composition Rules

The checksum format differs depending on whether Assembly-CSharp-firstpass.dll exists for each game.

Game	firstpass.dll	Checksum Format
GH	✅ Present	`firstpass MD5` + `Assembly-CSharp MD5` concatenated (64 chars)
Subnautica	✅ Present	`firstpass MD5` + `Assembly-CSharp MD5` concatenated (64 chars)
EscapeThePacific	✅ Present	`firstpass MD5` + `Assembly-CSharp MD5` concatenated (64 chars)
Raft	❌ Not present	`Assembly-CSharp MD5` only (32 chars)

Versions.xml Update Procedure on Game Update

Add a new <version> entry without removing existing entries.

Step 1 — Find new BuildID

Get-Content "C:\Program Files (x86)\Steam\steamapps\appmanifest_{AppID}.acf" | Select-String "buildid"

Game	AppID
Subnautica	264710
Raft	648800
EscapeThePacific	655290
GH	815370

Step 2 — Extract new checksum

# Games with firstpass.dll (GH, Subnautica, EscapeThePacific)
Get-FileHash "...\Assembly-CSharp-firstpass.dll" -Algorithm MD5
Get-FileHash "...\Assembly-CSharp.dll" -Algorithm MD5
# → Concatenate both Hash values in order (firstpass first)

# Games without firstpass.dll (Raft)
Get-FileHash "...\Assembly-CSharp.dll" -Algorithm MD5

Step 3 — Add entry to Versions.xml

<version id="{new BuildID}">
    <checksum>{new checksum}</checksum>
</version>

What Changed in v2.0.9615

Settings Tab Game Path Expand Fixed

Card expand height: The window bottom now grows by exactly the height of the input field when expanding a game path card
UpdateWindowHeight() improved: Calls UpdateLayout() before SizeToContent.Height measurement; temporarily sets TextureLayer1 to Collapsed when background texture is active to prevent 4K image original size from affecting height calculation
Inner Grid Row fix: Changed the last Row of the game paths panel inner Grid from Height="*" to Height="Auto" — removes unnecessary bottom whitespace

What Changed in v2.0.9614

Maximize Button Behavior Fixed

Maximize: Uses SystemParameters.WorkArea for manual maximization instead of WindowState.Maximized — fits exactly to the current screen resolution without overlapping the taskbar
Restore: Saves Left, Top, Width, Height, and MaxWidth before maximizing and restores them when the restore button is clicked
MaxWidth handling: Set to ∞ on maximize, restored to saved value on normalize

What Changed in v2.0.9613

New Themes Tab

Tab order is now:

Welcome → Mods → Downloads → Development → Themes → Settings

The theme selection UI has been moved from the Settings tab to a dedicated Themes tab. Icon: Segoe MDL2 Assets  (palette)

Theme Registry (Data-Driven Structure)

Adding a new theme now requires only one line in the App.xaml.cs dictionary. All switch statements have been removed — no code changes needed elsewhere.

// App.xaml.cs
public static readonly Dictionary<string, string> ThemeRegistry = new Dictionary<string, string>
{
    { "classic", null },
    { "light",   "FluentStylesLight.xaml" },
    { "dark",    "FluentStyles.xaml" },
    { "diablo",  "FluentStylesDiablo.xaml" },
    { "nebula",  "FluentStylesNebula.xaml" },
    { "sunset",  "FluentStylesSunset.xaml" },
    { "ocean",   "FluentStylesOcean.xaml" },
    { "nordic",  "FluentStylesNordic.xaml" },
    { "citrus",  "FluentStylesCitrus.xaml" },
    { "bloom",   "FluentStylesBloom.xaml" },
};

public static readonly List<string> ThemeIds = new List<string>(new[]
{
    "classic", "light", "dark", "diablo",
    "nebula", "sunset", "ocean", "nordic", "citrus", "bloom"
});

ThemeSelector ComboBox items are auto-generated from the ThemeIds loop. Language key convention: Lang.Options.Theme.{PascalCase} (e.g. Lang.Options.Theme.Nebula)

Supported Themes

Index	ID	File	Palette
0	`classic`	`Dictionary.xaml` only	Original ModAPI texture background
1	`light`	`FluentStylesLight.xaml`	Light tone + blue accent
2	`dark`	`FluentStyles.xaml`	Dark tone + blue accent (default)
3	`diablo`	`FluentStylesDiablo.xaml`	Red + black
4	`nebula`	`FluentStylesNebula.xaml`	Dark space
5	`sunset`	`FluentStylesSunset.xaml`	Bright sunset
6	`ocean`	`FluentStylesOcean.xaml`	Dark ocean
7	`nordic`	`FluentStylesNordic.xaml`	Bright Nordic
8	`citrus`	`FluentStylesCitrus.xaml`	Bright citrus
9	`bloom`	`FluentStylesBloom.xaml`	Bright floral

Theme changes trigger an automatic app restart. (saved to theme.cfg)

Background Texture Feature

Select an image in the Background Texture card on the Themes tab to apply it as the app-wide background. Works with any theme selected.

Supported input formats: .png / .jpg / .jpeg, up to 50MB, 4K resolution or below

Image processing pipeline

User-selected image (.png / .jpg / .jpeg, max 50MB, 4K or below)
  ↓
JPEG Q75 compression (memory buffer)
  ↓
16-byte magic header inserted
  "MODAPI" + "BG" + version + padding (FF 00 FE 00)
  ↓
Saved as resources\textures\ui_bg\bg.dat (Hidden attribute)
  ↓
SHA-256 hash → stored in ui.cfg as TextureHash

Security layers

Layer	Method	Effect
Magic header	16 bytes prepended before JPEG signature (FF D8 FF)	External viewers cannot recognize the file
Hidden attribute	`FileAttributes.Hidden`	Hidden from Explorer by default
SHA-256 integrity	Hash verified on load	Tampering triggers automatic reset + warning popup

Tampering detection behavior

bg.dat deleted
ui.cfg keys TexturePath, TextureHash, TextureActive reset
TextBox and toggle reset
Lang.Windows.TextureTampered popup displayed

ui.cfg keys

Key	Value	Description
`TexturePath`	Filename (display only)	Original filename shown in TextBox
`TextureHash`	SHA-256 hex	Integrity verification hash
`TextureActive`	`true` / `false`	Activation state

Transparency processing

When the background image is active, UI backgrounds are processed in two layers.

Layer 1 — MergedDictionaries overlay: Panels referencing {DynamicResource FluentBgBrush} etc. are automatically made transparent. Restored with a single Remove() call on deactivation.

Target keys: FluentBgBrush, FluentBgSecondaryBrush, FluentBgTertiaryBrush, FluentSurfaceBrush, FluentCardBrush, FluentTabBarBrush, FluentBorderBrush
Layer 2 — Visual tree walk (WalkStyleBackgrounds): {StaticResource} elements in Fluent themes are unaffected by Layer 1, so the visual tree is traversed directly to apply semi-transparent brushes based on original colors.
```
MakeSemiTransparent(originalBrush, alpha: 100)
// alpha 0=fully transparent, 255=opaque → 100 ≈ 39% opaque
```
Processed: Panel (except Grid), Border, ListBox / ListView

Excluded: Grid (background preserved, children traversed), TabPanel (tab header protection), ButtonBase / ComboBox, Collapsed elements

Restore: Style Setter source → ClearValue(), XAML local value source → restore original brush directly

Tab switching

WPF TabControl lazy-loads tab content, so WalkStyleBackgrounds(this) is re-run at ContextIdle priority on tab change. Already-processed elements are skipped via ContainsKey check.

ThemeSelector lock

When background texture is active, a ThemeSelectorOverlay Border is shown over the theme selector to block interaction.

XAML: ThemeSelectorOverlay Border added above ThemeSelector (IsHitTestVisible=True)
Active: ThemeSelectorOverlay.Visibility = Visible
Inactive: ThemeSelectorOverlay.Visibility = Collapsed
ThemeSelector_SelectionChanged also guarded by _textureActive flag

UI state flow

Image selected (Browse)
  → bg.dat created → toggle unlocked → auto-activate → TextureLayer1 shown
  → SaveAndClearBrushes() → ThemeSelectorOverlay shown

Toggle deactivated
  → RestoreThemeState() → RestoreBrushes() → ThemeSelectorOverlay hidden
  → TextureLayer1 hidden

Clear button
  → bg.dat deleted → toggle locked → TextureLayer1 hidden → brushes restored
  → GC.Collect() (releases 4K image memory)

New language keys

Key	Description
`Lang.Options.Theme.Diablo` ~ `Lang.Options.Theme.Bloom`	7 new theme names
`Lang.Options.Labels.TextureBackground`	Background texture label
`Lang.Options.Labels.TextureEnable`	Enable label
`Lang.Options.Labels.TextureClear`	Clear button
`Lang.Windows.TextureTooLarge`	File size exceeded warning
`Lang.Windows.TextureTampered`	Tampering detected warning

File structure

ModAPI\
├── App.xaml.cs                    # ThemeRegistry, ThemeIds, ApplyTheme()
├── Windows\
│   ├── MainWindow.xaml            # Themes tab, ThemeSelectorOverlay, TextureLayer1
│   └── MainWindow.xaml.cs         # Theme & texture logic
├── Themes\
│   ├── Dictionary.xaml            # Classic theme
│   ├── FluentStyles.xaml          # Dark theme
│   ├── FluentStylesLight.xaml     # Light theme
│   ├── FluentStylesDiablo.xaml    # Diablo theme
│   ├── FluentStylesNebula.xaml    # Nebula theme
│   ├── FluentStylesSunset.xaml    # Sunset theme
│   ├── FluentStylesOcean.xaml     # Ocean theme
│   ├── FluentStylesNordic.xaml    # Nordic theme
│   ├── FluentStylesCitrus.xaml    # Citrus theme
│   └── FluentStylesBloom.xaml     # Bloom theme
└── resources\
    └── textures\
        └── ui_bg\
            └── bg.dat             # Compressed & secured background image (runtime-generated)

Known design constraints

Item	Details
`IsEnabled=false` on ComboBox	Causes `ElementNotEnabledException` crash → `IsHitTestVisible` overlay approach used
Direct `MergedDictionaries` key replacement	Crashes during layout pass → `Add`/`Remove` pattern only
Overwriting Hidden file	`Access Denied` → must reset `FileAttributes.Normal` before writing
`{StaticResource}` backgrounds	Unaffected by Layer 1 → requires WalkStyleBackgrounds (Layer 2)

What Changed in v2.0.9612

Theme Module Separation

New Themes/ folder: Moved Dictionary.xaml, FluentStyles.xaml, FluentStylesLight.xaml, and FluentStylesClassic.xaml to ModAPI\Themes\
App.xaml.cs: ApplyTheme() — Classic theme uses Dictionary.xaml only; Light/Dark/other Fluent themes load corresponding XAML
ModAPI.csproj: Updated theme XAML paths to Themes\ subdirectory; registered FluentStylesClassic.xaml

What Changed in v2.0.9611

Bug Fix

Mod list width not applied after theme switch: Fixed an issue where the Mod list width was not applied after switching between Light/Dark themes and restarting — added ApplyModListWidth(width) call inside InitModListWidth()

What Changed in v2.0.9610

Added

Game XML & Versions Configuration

#	File	Change
1	`GH.xml`	Full rewrite — removed non-existent `DOTweenPro.dll`; added `AmplifyBloom/Color/Motion.dll`, `com.rlabrecque.steamworks.net.dll`, `Unity.ProBuilder.dll`, `Unity.Postprocessing.Runtime.dll`
2	`Subnautica.xml`	Full rewrite — removed `extends="GenericUnityGame"`; added `XGamingRuntime.dll`, `XblPCSandbox.dll`, `FMODUnity.dll`, `Newtonsoft.Json.dll`, `Unity.InputSystem.dll`, `Unity.Collections.dll`, `Unity.Burst.dll`
3	`EscapeThePacific.xml`	Full rewrite — removed `extends="GenericUnityGame"`; `includeAssembly` → `Assembly-CSharp.dll` only
4	`Raft/Versions.xml`	Created — version `1.1.01` with checksum
5	`GH/Versions.xml`	Created — version `2.9.5` with checksum
6	`Subnautica/Versions.xml`	Created — no checksum (updates too frequently)

Critical Bug Fixes

#	Type	Issue	Fix
1	Hang	`extends="GenericUnityGame"` caused `Assembly-CSharp-firstpass.dll` inheritance → `CreateModLibrary` stalled	Removed `extends` from all non-TheForest XML
2	Crash	`ResolutionException: XGamingRuntime.XUserGamertagComponent` during Subnautica apply	Added `XGamingRuntime.dll`, `XblPCSandbox.dll` to `copyAssembly`
3	Crash	Resolver failed on DLLs added to `copyAssembly` after backup created	`Game.cs`: actual install folder added as resolver fallback
4	Crash	`IOException`: `BaseModLib.dll` file-lock between `CreateModLibrary` and `ApplyMods`	Retry loop: max 10 × 500ms read + max 30 × 500ms existence wait
5	Crash	`NullReferenceException` — `typesMap` entry.Value null (game not installed)	Added `if (entry.Value == null) continue`
6	Crash	`NullReferenceException` — lightweight `Game` constructor missing `ModLibrary = new ModLib(this)` → `CreateModLibrary()` crash	Added `ModLibrary = new ModLib(this)` to lightweight constructor
7	Crash	`SwitchDevGame()` — `App.Game.GamePath` empty after lightweight constructor → `CreateModLibrary` crash	Set `App.Game.GamePath = savedPath` after lightweight constructor
8	Wrong Game	`EscapeThePacific` mods classified as TheForest	`ModsViewModel`: `GameId` extracted from folder path
9	Wrong Path	`GetGameFolder()` → `""` → resolves to drive root (e.g. `E:\`)	Null/empty guard at all 6 call sites

Debug / Release Build Split

FileValidator.cs — new file ModAPI_Shared\Utils\FileValidator.cs; registered in ModAPI_Shared.csproj
- IsValidSteamExe() — PE header (MZ + PE\0\0) + minimum 1 MB
- IsValidGameExe() — PE header + minimum 512 KB
- IsValidAssemblyDll() — PE header + .NET CLR metadata header + minimum 64 KB
CheckSteam() — #if DEBUG: File.Exists() only / #else: FileValidator.IsValidSteamExe()
CheckGamePath() — #if DEBUG: File.Exists() only / #else: FileValidator.IsValidAssemblyDll()
ModLib.Create() IncludeAssemblies — #if DEBUG: File.Copy() skip Cecil / #else: full Cecil parse + IL modification
ModLib.Create() file not found — #if DEBUG: log warning, skip / #else: log error, abort

Debug Testing

create_dummy_Debug_games.ps1 — PowerShell script for bin\Debug\; creates 0-byte placeholder files for all 5 games under dummy_games\, dummy_steam\, and gamefiles\original\ — enables full UI workflow testing without real game installation

Settings Tab

Steam path card — integrated into Game Installation Paths card; InitSteamPath(), SteamBrowse_Click(), SteamSave_Click()
Game paths panel — BuildGamePathsPanel() with per-game expandable cards; TextBox uses HorizontalAlignment=Stretch
Expand All / Collapse All button
AlwaysOnTop checkbox (saved to ui.cfg)
Mod/Project List Width sliders — start at minimum 150; saved to ui.cfg
Font Size ComboBox — FHD 10–16, 4K 10–22, 8K 10–28
Checkbox sync — SettingsCheckboxes.DataContext = SettingsVm; AutoUpdate / UseSteam / UpdateVersions now sync correctly
_uiInitialized flag — prevents premature ui.cfg writes during WPF startup

Mods Tab — Start Game Validation

Five-step validation runs on every Start Game click, regardless of mod list state:

Step	Check	Popup
1	Settings tab Steam path valid (`Steam.exe` exists)	SteamNotFound
2	`mods/{GameId}/` folder game matches Settings configured game	GameModsMismatch
3	At least one mod selected	NoModSelected
4	No mixed-game mods in selection	MixedGameMods
5	Game path configured + executable exists	GamePathNotSet / GameNotInstalled

Development Tab — ModLib Validation

Three-step validation on Mod Library Regeneration click:

Step	Check	Popup
1	Settings tab Steam path valid	SteamNotFound
2	At least one project exists	NoProjectWarning
3	`App.Game.GamePath` set	GamePathNotSet

Downloads Tab

Debug string replaced with Lang.Downloads.Status.NoDownloads
Consistent padding for all status messages
Offline manual text updated for 5 supported games; line-break via two TextBlocks

First Setup & Game Path System

FirstSetup.Check() — default true for UseSteam, AutoUpdate, UpdateVersions
FirstSetupDone() — creates mods/ and projects/ folders for all 5 games
SpecifyGamePath — GameNameLabel shows which game; NavigateToSettings() routes to Settings tab

New / Updated Language Keys

Key	English Value
`Lang.Downloads.Status.NoDownloads`	No downloadable files for this mod.
`Lang.Options.Labels.ModListWidth`	Mod List Width
`Lang.Options.Labels.ProjectListWidth`	Project List Width
`Lang.Options.Labels.FontSize`	Font Size
`Lang.Options.Labels.MaxWidth`	Max Width
`Lang.Development.Labels.GameFilter`	Game Filter
`Lang.Options.Labels.SteamPath`	Steam Installation Path
`Lang.Windows.SteamNotFound.Title`	Steam Not Found
`Lang.Windows.SteamNotFound.Text`	Steam is not installed. Please configure Steam in the Settings tab.
`Lang.Windows.GameModsMismatch.Title`	Game Mismatch
`Lang.Windows.GameModsMismatch.Text`	The game in the mods folder does not match the game configured in the Settings tab.
`Lang.Downloads.Offline.Manual2`	(e.g. mods/TheForest, mods/Subnautica, …)

Not Included

Feature	Reason
Auto-update (keep latest version)	Server-side infrastructure not available
Update search	Server-side infrastructure not available

Removed

Item	Reason
`SpecifyGamePath` popup on startup	All paths configured in Settings tab
`SpecifySteamPath` popup on startup	Steam path configured in Settings tab
Login system	Original server no longer operational (removed in v2.0.9400)
`Portable.System.ValueTuple.dll`	Non-functional on Mono 2.0 (removed in v2.0.9586)
`UseSteam` condition on Steam check	Steam is now always validated first on Start Game and Mod Library Regeneration

Planned for Future Releases

#	Feature	Description
1	ModAPI Auto-Update	Automatically download and apply new ModAPI releases
2	ModAPI VersionsData Table Update	Automatically update the game VersionsData table when new game patches are released

What Changed in v2.0.9600

Added

Downloads tab: 5 game filters (TheForest, Subnautica, RAFT, EscapeThePacific, GH)
Welcome tab: added at leftmost position (index 0)
Mods tab: 3-column layout (WrapPanel → vertical list); automatic width adjustment; mod name wrapping
ModsViewModel: game-specific filtering, ResolveGame() for correct Game instance per mod
Game.cs: lightweight constructor new Game(config, true) — identification only, no Verify()
Build: 4 game XML files registered in ModAPI.csproj with CopyToOutputDirectory=Always
Build: warnings cleaned — CS0168, CS0618, CS0252
Game XML: TheForest, Raft, GH DLL lists corrected
Language flags: image sizes standardized across all 13 language badges

Removed

Item	Reason
`extends="GenericUnityGame"` in game XML files	Caused `Assembly-CSharp-firstpass.dll` to be incorrectly inherited — removed from Subnautica, Raft, EscapeThePacific, GH
`WrapPanel` layout in Mods tab	Replaced with 3-column Grid layout (Game Filter / Mod List / Information)

Key Changes by Phase

Phase 1 (v2.0.9200) — .NET 4.8 Migration

All 5 projects migrated from .NET 4.5 → 4.8.

Phase 2 (v2.0.9300) — Build Environment & Fluent Design

ModernWpf 0.9.6, FluentStyles.xaml, UnityEngine stub DLL.

Phase 3 (v2.0.9500) — UI Redesign & Theme System

3-theme system, theme.cfg, window drag fix, hyperlink support.

Phase 4 (v2.0.9400) — Code Cleanup

Login system removed, update mechanism modernized.

Phase 5-1 (v2.0.9552) — Downloads Tab & 13 Languages

Downloads tab, Segoe MDL2 Assets icons, 13-language support.

Phase 5-5 (v2.0.9561) — Assembly Resolution

AssemblyVersionMap.cs, CustomAssemblyResolver.cs, PE header patching.

Phase 5-6B (v2.0.9586) — C# 7.3 & Polyfill

Black screen fixed, ValueTuple removed, C# 7.3 in-game verified.

Phase 6-1 (v2.0.9600) — Multi-Game & Mods Redesign

5 game filters, 3-column Mods tab, lightweight Game constructor, XML registered.

Phase 6-2 (v2.0.9610) — Settings, Safety, Crash Fixes & Debug/Release Split

XML corrected, Steam path, game path safety, Start Game 5-step validation, ModLib 3-step validation, FileValidator PE header verification, #if DEBUG build split, create_dummy_Debug_games.ps1, lightweight constructor ModLibrary fix, SwitchDevGame GamePath fix, 5-game folder creation, crash fixes.

Phase 6-3 (v2.0.9611 ~ v2.0.9618) — Theme System Expansion, Settings Improvements & Tools

Themes tab added, 10 themes + background texture feature, Themes/ folder separation, maximize button fix, game path expand fix, Versions.xml 4-game update, path reset buttons, Browse auto-save, MODAPI_VersionTool.

Version History

v2.0.9618 — 2026-04-25

Added MODAPI_VersionTool (standalone WPF version update tool), StatusBar version display linked to App.Version

v2.0.9617 — 2026-04-24

Added Steam/game path reset buttons in Settings tab, Browse auto-save, reset state preserved via ui.cfg flag

v2.0.9616 — 2026-04-18

Versions.xml created/updated for 4 games (Subnautica, Raft, EscapeThePacific, GH), checksum composition rules established, game update procedure documented

v2.0.9615 — 2026-04-18

Settings tab game path card expand height accuracy fixed, UpdateWindowHeight background texture interference prevention

v2.0.9614 — 2026-04-18

Maximize button WorkArea-based manual maximize, previous size/position save and restore

v2.0.9613 — 2026-04-18

Themes tab added, theme registry data-driven structure, 10 themes supported, background texture feature (compression, security, 2-layer transparency), ThemeSelector lock overlay, 12 new language keys

v2.0.9612 — 2026-04-18

Themes/ folder separation, theme XAML modularization

v2.0.9611 — 2026-04-18

Fixed Mod list width not applied after theme switch

v2.0.9610 — 2026-04-13

Multi-game XML corrected (GH, Subnautica, EscapeThePacific), Versions.xml added, Settings tab redesigned (Steam path, game paths panel, width sliders, font size, checkbox sync), game path null safety (6 sites), startup popups replaced by Settings tab, Mods tab 5-step Start Game validation (Steam always first), Dev tab 3-step ModLib validation, GameModsMismatch popup added, lightweight constructor ModLibrary null fix, SwitchDevGame GamePath fix, FileValidator PE header verification (Release), #if DEBUG build split (CheckSteam / CheckGamePath / ModLib.Create), create_dummy_Debug_games.ps1, persistent ui.cfg, 5-key font system, multiple crash fixes, language keys updated

v2.0.9600 — 2026-04-09

5 game filters, Mods tab 3-column layout, auto width, lightweight Game constructor, ModsViewModel game filtering, 4 XML files registered, build warnings cleaned, Welcome tab, language flags standardized

v2.0.9586 — 2026-03-31

Black screen fixed, polyfill finalized, ValueTuple removed, C# 7.3 verified

v2.0.9561 — 2026-03-06

C# 7.3 support, PE header patching, polyfill pipeline, assembly resolution restored

v2.0.9552 — 2026-02-25

Downloads tab, icon modernization, theme unification, 13-language support

v2.0.9500

Theme system (Classic/Light/Dark), Fluent Design UI, SubWindow system

v2.0.9400

Code cleanup, login removal, legacy modernization

v2.0.9300

Build environment, UnityEngine stub DLL, ModernWpf integration

v2.0.9200

.NET Framework 4.8 migration

v1.x

Original FluffyFish release

Build Requirements

Requirement	Version	Notes
Visual Studio	2022
.NET Framework SDK	4.8	ModAPI projects
.NET Framework SDK	3.5	BaseModLib only
ModernWpf	0.9.6	NuGet
AsyncBridge	0.3.1	NuGet — `libs/polyfills/`
TaskParallelLibrary	1.0.2856	NuGet — `System.Threading.dll` in `libs/polyfills/`

License

GNU General Public License v3.0 — follows the original license.

Name		Name	Last commit message	Last commit date
Latest commit History 121 Commits
.vscode		.vscode
BaseModLib		BaseModLib
Docs		Docs
ModAPI		ModAPI
ModAPI_Installer		ModAPI_Installer
ModAPI_Shared		ModAPI_Shared
Updater		Updater
VersionTool		VersionTool
libs		libs
.gitattributes		.gitattributes
.gitignore		.gitignore
HOWTOCOMPILE.md		HOWTOCOMPILE.md
Ionic.Zip.License.txt		Ionic.Zip.License.txt
LICENSE		LICENSE
ModAPI.License.txt		ModAPI.License.txt
ModAPI.sln		ModAPI.sln
Mono.Cecil.License.txt		Mono.Cecil.License.txt
README.md		README.md
favicon.ico		favicon.ico

Folders and files

Latest commit

History

Repository files navigation

ModAPI(v1) v2.0.9618 - 20260425

Overview

Supported Games

Architecture

Runtime Split

Debug / Release Build Split

FileValidator — PE Header Verification

Assembly Remapping Pipeline

Assembly Resolver Fallback

C# 7.3 Feature Support

Theme System Detailed Reference

Background Texture

Font Size System

Persistent UI Configuration — ui.cfg

File Structure

Installation & Setup

Step 1 — Prerequisites

Step 2 — Install ModAPI

Step 3 — Configure Steam Path (Settings Tab)

Step 4 — Configure Game Paths (Settings Tab)

Step 5 — Download Mods (Downloads Tab)

Step 6 — Apply Mods & Start Game (Mods Tab)

Tab Overview

Welcome Tab

Mods Tab

Downloads Tab

Development Tab

Themes Tab

Settings Tab

What Changed in v2.0.9618

Version Update Tool (MODAPI_VersionTool)

Version Tool

StatusBar Version Display Fixed

What Changed in v2.0.9617

Settings Tab — Path Reset Buttons Added

What Changed in v2.0.9616

Versions.xml — 4 Games Added / Updated

Checksum Composition Rules

Versions.xml Update Procedure on Game Update

What Changed in v2.0.9615

Settings Tab Game Path Expand Fixed

What Changed in v2.0.9614

Maximize Button Behavior Fixed

What Changed in v2.0.9613

New Themes Tab

Theme Registry (Data-Driven Structure)

Supported Themes

Background Texture Feature

What Changed in v2.0.9612

Theme Module Separation

What Changed in v2.0.9611

Bug Fix

What Changed in v2.0.9610

Added

Game XML & Versions Configuration

Critical Bug Fixes

Debug / Release Build Split

Debug Testing

Settings Tab

Mods Tab — Start Game Validation

Development Tab — ModLib Validation

Downloads Tab

First Setup & Game Path System

New / Updated Language Keys

Not Included

Removed

Planned for Future Releases

What Changed in v2.0.9600

Added

Removed

Key Changes by Phase

Phase 1 (v2.0.9200) — .NET 4.8 Migration

Phase 2 (v2.0.9300) — Build Environment & Fluent Design

Phase 3 (v2.0.9500) — UI Redesign & Theme System

Phase 4 (v2.0.9400) — Code Cleanup

Phase 5-1 (v2.0.9552) — Downloads Tab & 13 Languages

Persistent UI Configuration — `ui.cfg`

Packages