frinky-engine

Prefabs & Entity References

Prefabs

Prefabs store reusable entity hierarchies as .fprefab JSON files.

Workflow

1. Create — right-click an entity in the hierarchy and select “Create Prefab” (Ctrl+Shift+M), or use PrefabSerializer.CreateFromEntity()
2. Instantiate — drag a .fprefab from the asset browser into the viewport or hierarchy
3. Override — modify properties on a prefab instance; changes are tracked as overrides against the prefab source
4. Update — changes to the source .fprefab propagate to all instances (overridden properties are preserved)

Prefab Operations

Operation	Shortcut	Description
Apply Prefab	Ctrl+Alt+P	Push instance overrides back to the source .fprefab
Revert Prefab	Ctrl+Alt+R	Discard instance overrides and match the source
Make Unique	Ctrl+Shift+U	Save a new .fprefab from this instance
Unpack	Ctrl+Alt+K	Break the prefab link, turning the instance into regular entities

Runtime Instantiation

Spawn prefabs from scripts using Scene.Instantiate():

using FrinkyEngine.Core.ECS;
using FrinkyEngine.Core.Assets;

public class SpawnerComponent : Component
{
    [AssetFilter(AssetType.Prefab)]
    public AssetReference ProjectilePrefab { get; set; }

    public override void Update(float dt)
    {
        if (Input.IsMouseButtonPressed(0))
        {
            // Spawn at a position and rotation
            var entity = Entity.Scene.Instantiate(
                ProjectilePrefab,
                Transform.WorldPosition,
                Transform.WorldRotation);

            // Or spawn with just a path
            // var entity = Entity.Scene.Instantiate("Prefabs/Bullet.fprefab");

            // Optionally parent to another transform
            // var entity = Entity.Scene.Instantiate(ProjectilePrefab, parent: someTransform);
        }
    }
}

All overloads accept an optional parent parameter. Entity references within the prefab are automatically remapped to the new instance.

Internals

Prefabs use stable IDs to track entities across edits and support nested hierarchies. When a prefab is instantiated, entity IDs are remapped so each instance gets unique IDs while maintaining internal cross-references.

Entity References

EntityReference is a struct for linking one entity to another. It stores the target entity’s GUID and resolves at runtime.

Usage

using FrinkyEngine.Core.ECS;

public class MyComponent : Component
{
    public EntityReference Target { get; set; }

    public override void Update(float dt)
    {
        var entity = Target.Resolve(Scene);
        if (entity != null)
        {
            // Use the referenced entity
            var targetPos = entity.Transform.WorldPosition;
        }
    }
}

Serialization

• Serialized as a GUID string in scene/prefab JSON
• Automatically resolved at runtime via Scene.FindEntityById()

Remapping

Entity references are automatically remapped in these scenarios:

• Duplication — when duplicating entities, references between co-duplicated entities point to the new copies
• Prefab instantiation — references between entities within the same prefab are remapped to the new instance’s entities

References to entities outside the duplicated/instantiated group remain unchanged.

Inspector Assignment

Drag an entity from the hierarchy panel onto an EntityReference field in the inspector to assign it. The inspector shows the referenced entity’s name or “None” if unassigned.

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