How to Fish (渔力全开) - Memory Trainer

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An external Python-based trainer and cheat engine for the Unity Mono game How to Fish (渔力全开).

Powered by pymem, JIT function hooking via Mono runtime interop, and an interactive rich TUI dashboard.

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Features

Hotkey	Feature	Description
F1	Lock Health	Blocks all incoming damage (NPC hits, punches, hazards, fire, poison, starvation) & dissipates elemental gauges. Normal jump physics preserved.
F2	Lock Hunger	Prevents fullness meter from dropping over time or during actions.
F3	Infinite Air Jump	Pure movement patch: allows infinite mid-air jumps / air flight (InGodMode is NOT used; health unaffected).
F4	Unlimited Ammo	Infinite ammunition for all firearms without magazine depletion or forced reloads.
F5	Damage Multiplier	Cycles damage multiplier for firearms, melee weapons, and fists: 1x $\rightarrow$ 2x $\rightarrow$ 5x $\rightarrow$ 10x $\rightarrow$ One-Shot Kill (99999).
F6	Add Money (+1w)	Adds +$10,000 (1w) money with sound effect, UI animation, and multiplayer synchronization on keypress.
F12	Switch Language	Toggles trainer interface language between Chinese (中文) and English (EN).
F10	Safe Exit	Restores all modified code/memory and exits the trainer safely.

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Architecture & How It Works

1. Mono Runtime Interop (howtofish_cheat.mono.bridge):
   • Resolves mono-2.0-bdwgc.dll exports inside How to Fish.exe.
   • Attaches remote threads to the Mono root domain with TLS setup.
   • Dynamically locates loaded assemblies (Assembly-CSharp), classes, methods, and static vtables.
2. JIT Compilation & Memory Scaling (howtofish_cheat.mono.patcher):
   • Lock Health (F1): JIT-patches PlayerVitals.TakeDamage, PlayerVitals.LocalHit, PlayerVitals.DamageFromFullness, PlayerVitals.ApplyNewFire, and PlayerVitals.ApplyNewPoison.
   • Lock Hunger (F2): JIT-patches PlayerVitals.LowerFullness and PlayerVitals.LowerFullnessTick.
   • Infinite Air Jump (F3): Installs a direct call trampoline on PlayerMovement.JumpInput pointing straight to PlayerMovement.Jump, enabling unlimited air jumps without touching health or God Mode.
   • Unlimited Ammo (F4): JIT-patches Weapon.set_Ammo with RET (0xC3) and actively locks magazine capacity to 999 while resetting reload flags.
   • Damage Multiplier (F5): Pure real-time in-memory scaling across PlayerPunching._damage, Melee._sharpnessUpgrades array, Attachments._bulletUpgrades array, and WeaponInfo.ProjectileDamage (1x, 2x, 5x, 10x, One-Shot Kill).
   • Add Money (F6): Directly updates authoritative static <Money>k__BackingField and FishNet SyncVar<int> _money, invokes PlayerUI.SetMoney for floating +$10000 text + HUD animated roll, and calls MoneyManager.MoneySound for audio feedback.
   • Disabling any cheat or exiting cleanly restores original machine code bytes and base values.
3. Interactive Console UI (howtofish_cheat.ui.console):
   • Live status display with connection status, active PID, Mono domain pointer, and real-time cheat states.

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Usage

1. Launch the Trainer

You can launch the trainer either before or after starting the game:

# Using the quick-launch script with uv
uv run python run_trainer.py

# Or as a module with uv
uv run python -m howtofish_cheat

# Build single standalone executable (dist/HowToFishTrainer.exe)
uv run python build.py

# Run unit tests with uv
uv run pytest -v

2. In-Game Controls

• Press F1 to toggle Lock Health.
• Press F2 to toggle Lock Hunger.
• Press F3 to toggle Infinite Air Jump.
• Press F4 to toggle Unlimited Ammo.
• Press F5 to cycle Damage Multiplier (1x $\rightarrow$ 2x $\rightarrow$ 5x $\rightarrow$ 10x $\rightarrow$ One-Shot).
• Press F6 to Add Money (+1w / +$10,000) on press.
• Press F12 to Switch Language (中文 / EN) at any time.
• Press F10 or Ctrl+C to cleanly exit the trainer.

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Technical Documentation

For an in-depth breakdown of the reverse engineering, FishNet network architecture, Mono runtime TLS internals, JIT trampolines, and gotchas, see:

📖 Technical Deep Dive & Architecture Documentation