Day/Night Cycle

Adds a continuous day and night cycle to How to Fish. The sun moves across the sky, and fog, ambient light and sun color follow the time of day — dawn, day, dusk, night, and back around.

The clock is derived from the FishNet server tick, so everyone in a co-op lobby sees the same time without a single extra network message.

Install

With a mod manager (r2modman / Thunderstore Mod Manager): click Install. Nothing else to do.

Manually:

1. Install BepInEx 5.4.23+ (win x64 Mono build) into the game folder, next to How to Fish.exe.
2. Launch the game once and close it, to generate BepInEx/plugins and BepInEx/config.
3. Copy the BepInEx folder from this zip over the one in the game folder.
4. Launch the game.

Features

• Continuous cycle. Sun rotation, fog color and density, ambient intensity and reflection intensity all interpolate through dawn, day, dusk and night.
• Synced in co-op. Time comes from the FishNet server tick, so it cannot drift between players, and someone joining mid-session lands on the correct time on their first frame.
• Zero network cost. No broadcasts, no serializers, no handshake.
• A night that actually looks like night. The game's skybox ships with an unauthored night gradient (a burnt-orange horizon that reads as a permanent sunset). The mod replaces those two colors, and keeps the real sunrise/sunset band where it belongs.
• Configurable. Cycle length, starting time, night sun intensity, moonlight color, night fog color and density.
• Underwater fog untouched. Diving still looks the way the game intended.
• Works offline. Falls back to a local clock in single player or when no server is running.
• Open to other mods. Exposes a public DayNightAPI with TimeOfDay, DaylightFactor and NightFell / DayBroke events.

Config

Written to BepInEx/config/com.zpaulin.howtofish.daynight.cfg on the first run.

Commands

Typed into the game's own debug console. Output goes to the BepInEx console.

/dn                 status
/dn on | off
/dn day | night | dawn | dusk
/dn time 0.75       or  /dn time 18:30
/dn length 600
/dn freeze
/dn resync

Time commands shift only your own client, on purpose, for testing. Use /dn resync to return to the lobby clock.

Co-op notes

Every player needs the mod, with matching DayLengthSeconds and StartTimeOfDay. The defaults match, so this only matters if you edit the config — mismatched values mean players see different skies.

For mod authors

[BepInPlugin("com.example.mymod", "My Mod", "1.0.0")]
[BepInDependency("com.zpaulin.howtofish.daynight")]
public class MyPlugin : BaseUnityPlugin
{
    private void Awake()
    {
        DayNightAPI.NightFell += day => SpawnWave(day);
        DayNightAPI.DayBroke  += day => EndWave();
    }
}

Surface: TimeOfDay, Phase, DayNumber, DaylightFactor, IsNight, IsRunning, IsNetworkSynced, Clock(), SetTimeOfDay(), and the PhaseChanged / NightFell / DayBroke events. Use DaylightFactor (0..1, continuous, twilight included) to scale difficulty smoothly instead of flipping at a threshold.

Credits

Thanks to the BepInEx and HarmonyX teams for the tooling, and to the How to Fish devs for leaving the code readable and unobfuscated.