ScalerCore

A scaling library for R.E.P.O. modders. Handles the hard parts of scaling game objects -- physics, audio, animation, colliders, NavMesh, multiplayer sync -- so you don't have to.

If you're building a mod that changes the size of things (shrink rays, growth potions, whatever), ScalerCore gives you a clean API and takes care of the edge cases.

This is a library, not a standalone mod. End users don't need to interact with it directly. If you're a player, you probably got here because a mod like ShrinkerGun: COMPRESSOR depends on it.

For modders building size-changing mechanics. If you're looking for a shrink ray, check out ShrinkerGun: COMPRESSOR which is built on ScalerCore.

Installation

Reference ScalerCore.dll in your project. Add a hard dependency in your plugin:

[BepInDependency("Vippy.ScalerCore", BepInDependency.DependencyFlags.HardDependency)]

ScalerCore automatically attaches ScaleController components to all enemies, players, valuables, items, carts, and doors at runtime via Harmony patches. You don't need to add them yourself.

Quick Start

using ScalerCore;

// Shrink with default options (40% scale)
ScaleManager.Apply(targetGameObject);

// Shrink with custom options
var opts = ScaleOptions.Default;
opts.Factor = 0.5f;
opts.Duration = 60f;
ScaleManager.Apply(targetGameObject, opts);

// Restore with animation
ScaleManager.Restore(targetGameObject);

// Restore instantly (for bonk/damage reactions)
ScaleManager.RestoreImmediate(targetGameObject);

// Check state
bool tiny = ScaleManager.IsScaled(targetGameObject);

ScaleManager.Apply is host-authoritative. The host calls it, and RPCs propagate to all clients automatically. Late-joining players receive the current state on connect.

How It Works

ScalerCore attaches a ScaleController (a MonoBehaviourPunCallbacks) to every enemy, player, valuable, item, and door. On the first scale operation, the controller:

1. Resolves a handler via ScaleHandlerRegistry based on what the object is
2. Applies the target scale with a smooth animation (back-out easing for players, linear interpolation for objects)
3. Adjusts physics (mass, grab force, collider radius), audio pitch, and NavMesh speed
4. Syncs state to all clients via Photon RPCs
5. Force-applies the target scale every LateUpdate to fight game code that resets localScale

Built-in handlers cover enemies, players, valuables, items, carts, and doors.

Custom Handlers

Implement IScaleHandler and register it with a predicate:

using ScalerCore;
using ScalerCore.Handlers;

public class MyBossHandler : IScaleHandler
{
    public void Setup(ScaleController ctrl)
    {
        // Cache components, set ScaleTarget if the visual root
        // is different from the physics root
    }

    public void OnScale(ScaleController ctrl)
    {
        // Called when the object is scaled down
    }

    public void OnRestore(ScaleController ctrl, bool isBonk)
    {
        // Called when restored. isBonk = true means instant (damage),
        // false means animated (timer/gun toggle)
    }

    public void OnUpdate(ScaleController ctrl)    { }
    public void OnLateUpdate(ScaleController ctrl) { }
    public void OnDestroy(ScaleController ctrl)    { }
}

Register it at plugin startup. Use priority > 0 to override built-in handlers:

ScaleHandlerRegistry.Register(
    new MyBossHandler(),
    go => go.GetComponentInParent<EnemyParent>()?.name.Contains("MyBoss") == true,
    priority: 10
);

The registry resolves handlers by checking predicates in descending priority order. First match wins.

API Reference

ScaleManager (static)

ScaleController (MonoBehaviourPunCallbacks)

Attached automatically to game objects. Key public members:

IScaleHandler

public interface IScaleHandler
{
    void Setup(ScaleController ctrl);
    void OnScale(ScaleController ctrl);
    void OnRestore(ScaleController ctrl, bool isBonk);
    void OnUpdate(ScaleController ctrl);
    void OnLateUpdate(ScaleController ctrl);
    void OnDestroy(ScaleController ctrl);
}

ScaleHandlerRegistry (static)

ScaleOptions

Each Apply() call takes a ScaleOptions struct. Use ScaleOptions.Default as a starting point and override what you need.

ScaleTargets

Flags enum for filtering what Apply() affects:

var opts = ScaleOptions.Default;
opts.AllowedTargets = ScaleTargets.Enemies | ScaleTargets.Valuables;
ScaleManager.Apply(target, opts); // skips players and items

Configuration

ScalerCore is a pure library with no user-facing config. All scaling behavior (factor, speed, duration, etc.) is controlled per-call via ScaleOptions -- consuming mods expose whatever settings make sense for them.

What ScalerCore Handles

For enemies:

• Visual mesh + physics rigidbody scaled separately (EnemyParent is never scaled)
• NavMesh agent speed and radius
• Grab force reduced to zero (instantly grabbable when shrunken)
• Follow force scaled so grabbed enemies don't fight back
• Damage output reduced
• Knockback force reduced
• Bonk restore on taking damage (with immunity window)

For players:

• Camera offset, crouch/crawl positions, vision targets
• Collision capsules (stand, crouch, stand-check)
• Grab strength, range, throw strength
• Movement speed
• FOV adjustment
• Voice chat pitch
• Footstep sound pitch
• Animation speed
• Enlarged pupils (big cute eyes)
• Pause menu avatar scaled to match
• Near clip plane adjusted

For valuables:

• Mass scaled and clamped
• Extraction zone detection box scaled
• Brief indestructibility after shrinking (prevents fall damage from collider resize)
• Value-drop detection triggers bonk restore
• ForceGrabPoint disabled to prevent grab oscillation

For items:

• Effect fields auto-scaled (explosion size, orb radius, damage)
• Inventory system compatibility (yields during equip/unequip)
• ForceGrabPoint handling

For non-pocketable items (carts, cart cannon, cart laser, tracker):

• Become pocketable while shrunken (press inventory key to stash)
• Shrunken players can't pocket shrunken items — if you get shrunk while holding one, it drops
• Restoring removes the equip ability so full-size items stay on the ground

For all types:

• Audio pitch shifted on all Sound objects
• Smooth scale animation with force-apply in LateUpdate
• Multiplayer sync via Photon RPCs
• Late-join state sync
• Automatic cleanup on level change

Known Issues

• Loom (Shadow) arms don't scale proportionally when shrunken (IK solver conflict — cosmetic only, attack distance still scales)
• Some untested enemy types may float or clip into the ground while shrunken

Dependencies

• BepInEx 5 (5.4.2100+)

Reference Implementation

ShrinkerGun: COMPRESSOR is a shrink ray gun built on ScalerCore. Shows how to build ScaleOptions, call Apply, and handle per-target-type durations.