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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/ProwlEngine/Prowl/llms.txt

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Prowl’s entity-component model is the backbone of everything you build. Every interactive thing in a scene — a character, a camera, a light source, a trigger volume — is a GameObject. On its own a GameObject is just a named container with a Transform; the actual behaviour comes from MonoBehaviour components you attach to it. This mirrors the workflow many Unity developers are already familiar with while sitting on a clean .NET 9 foundation.

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EngineObject — the base class

EngineObject is the root of every first-class object in Prowl (both GameObject and MonoBehaviour extend it). It provides:
MemberPurpose
InstanceIDAuto-incrementing integer unique to each live instance
AssetIDGuid used when the object is saved as an asset on disk
FileIDSub-asset index inside an asset file (0 = main asset)
NameHuman-readable display name
IsDestroyedSet to true after DestroyImmediate() / DestroyLater()
// Walk every MonoBehaviour of a given type in the active scene
MySystem?[] systems = EngineObject.FindObjectsOfType<MySystem>();

// Lookup by runtime instance ID (integer)
EngineObject obj = EngineObject.FindObjectByID<EngineObject>(someID);

// Lookup by stable Guid identifier
GameObject go = EngineObject.FindObjectByIdentifier<GameObject>(someGuid);
Comparing an EngineObject to null is safe — the equality operator returns true when the object IsDestroyed, so the pattern if (myRef == null) works even on destroyed objects.

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GameObject

A GameObject is a scene entity that holds a Transform, a flat list of MonoBehaviour components, and an ordered list of child GameObject objects.

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Creating GameObjects

// Empty object — will receive a Transform automatically
GameObject empty = new GameObject("Player");

// Instantiate from a prefab asset reference
AssetRef<Prefab> prefabRef = /* loaded from AssetDatabase */;
GameObject fromPrefab = new GameObject(prefabRef);

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Tags and layers

Tags and layers are string names managed by TagLayerManager. Use CompareTag instead of manually checking indices so renames stay safe: 
go.tag   = "Enemy";
go.layer = "Characters";

if (go.CompareTag("Enemy"))
    Debug.Log("Found an enemy!");

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Enabled state

go.enabled = false;           // disable this object locally
bool active = go.enabledInHierarchy; // false if any ancestor is disabled

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Hierarchy

go.SetParent(parentGO, worldPositionStays: true);
GameObject root = go.parent;                   // null for root objects
List<GameObject> kids = go.children;
IEnumerable<GameObject> deep = go.GetChildrenDeep();

// Find by name or tag
GameObject hero   = GameObject.Find("Hero");
GameObject enemy  = GameObject.FindGameObjectWithTag("Enemy");
GameObject[] mobs = GameObject.FindGameObjectsWithTag("Enemy");

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Component system

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Adding and retrieving components

// Generic, compile-time-safe form
Rigidbody rb   = go.AddComponent<Rigidbody>();
Rigidbody rb2  = go.GetComponent<Rigidbody>();

// Pattern-match style
if (go.TryGetComponent<AudioSource>(out var audio))
    audio.Play();

// All components of a type
foreach (Collider col in go.GetComponents<Collider>())
    col.Enabled = false;

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Hierarchy searches

// Walk up the parent chain
Camera cam = go.GetComponentInParent<Camera>();

// Walk down into children
Light light = go.GetComponentInChildren<Light>(includeSelf: false);

// Collect all renderers in the whole sub-tree
var renderers = go.GetComponentsInChildren<MeshRenderer>();

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Removing components

go.RemoveComponent(existingComp);   // one instance
go.RemoveAll<AudioSource>();        // all of the same type
Removing a component that is required by another component on the same GameObject will fail with an error. Prowl checks [RequireComponent] dependencies before allowing removal.

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Transform

Every GameObject has exactly one Transform that lives alongside the component list. You access it via go.Transform or from inside a MonoBehaviour via the Transform property. 
// World-space read/write
go.Transform.position = new Vector3(0, 1, 0);
go.Transform.rotation = Quaternion.identity;

// Local-space read/write
go.Transform.localPosition = new Vector3(0, 0, 5);
go.Transform.localEulerAngles = new Vector3(0, 90, 0);
go.Transform.localScale = Vector3.one * 2f;

// Convert between spaces
Vector3 world = go.Transform.TransformPoint(localPoint);
Vector3 local = go.Transform.InverseTransformPoint(worldPoint);
The Transform caches world-space matrices using a dirty flag. Write to localPosition, localRotation, or localScale; world values are recomputed on demand.

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Instantiating and destroying GameObjects

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Instantiate

// Clone an existing live object into the current scene
GameObject clone = GameObject.Instantiate(original);

// From a prefab asset
GameObject inst = GameObject.Instantiate(prefabRef);

// With parent
GameObject child = GameObject.Instantiate(original, parentGO);

// With position, rotation, and parent
GameObject placed = GameObject.Instantiate(
    original,
    position: new Vector3(10, 0, 0),
    rotation: Quaternion.identity,
    parent:   null);

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Destroy

// Queued for end-of-frame cleanup — safe to call mid-Update
go.DestroyLater();
This is the standard way to destroy objects during gameplay. Prowl processes the queue via EngineObject.HandleDestroyed() after each update.
Destroying a GameObject automatically:
  • Destroys all child GameObjects recursively
  • Calls OnDisable then OnDestroy on every attached MonoBehaviour that has started

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Prefabs

A Prefab is an EngineObject resource that wraps a root GameObject tree and acts as a reusable template. When a GameObject is created from a Prefab in the editor, it maintains a PrefabLink that records which fields have been deliberately overridden. Applying the link re-copies the prefab data while restoring the per-instance overrides: 
// Read the link on a runtime instance
PrefabLink link = go.PrefabLink;

// Apply prefab data + per-instance overrides
link.Apply();

// Check whether a specific field has been overridden locally
bool overridden = link.HasChange(go, "Name");

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PrefabUtility

// Link an existing GameObject to a prefab
PrefabUtility.LinkToPrefab(go, prefabRef);

// Permanently break the link (makes the object independent)
PrefabUtility.BreakPrefabLink(go);

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Attributes

[RequireComponent]

Automatically adds a dependency when the decorated component is added.
[RequireComponent(typeof(Rigidbody))]
public class PlayerController : MonoBehaviour { }

[AddComponentMenu]

Controls where this component appears in the editor Add Component menu.
[AddComponentMenu("Physics/Custom Mover")]
public class CustomMover : MonoBehaviour { }

[ExecutionOrder]

Sets the order in which Update() and other loop methods run relative to other components.
[ExecutionOrder(-100)]
public class InputSystem : MonoBehaviour { }

[ExecuteAlways]

Allows the component’s lifecycle methods to run in edit mode, not only during play.
[ExecuteAlways]
public class GridSnapper : MonoBehaviour { }

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