Iām working on a multiplayer game where I need to spawn player characters when new players connect via WebSocket. Currently, Iām instantiating prefabs immediately when receiving WebSocket messages.
Code Example
websocket.onmessage = async (data) => {
// Is this safe to do outside the main game loop?
const prefab = await this.avatarAsset!.instantiate(prefabReference);
const avatarComponent = prefab!.getComponent(AvatarLoader);
// Sometimes avatarComponent.serializedFields are undefined...
}
Questions
Is it safe to instantiate objects outside the main animation loop? (Similar to Unityās restriction about main thread operations)
Could this cause @serializable fields to be undefined? Iām experiencing intermittent issues where serializable fields return undefined even though theyāre properly set in the prefab.
Whatās the recommended approach for spawning objects based on network events? Should I queue the requests and process them in the main loop instead?
Current Issue
Prefab instantiation works
Component is found correctly
But serializable field values are sometimes undefined
Happens intermittently, not always
Any insights or best practices would be appreciated!
Hi oot4chi, thanks for your question. Here are some quick notes addressing your three points:
Itās generally safe to instantiate prefabs from WebSocket callbacks because JavaScript in the browser is singleāthreaded, so youāre still on the main thread. However, while the instantiation itself doesnāt violate thread rules like in Unity, many Needle Engine operationsāespecially those involving serialized fields and component initializationāare designed to be processed in sync with the engineās update cycle. This means that even if instantiating out of the main animation loop is āsafe,ā timing differences can occur.
The intermittent undefined @serializable field issue likely isnāt caused directly by instantiation being outside the main loop. Instead, it can arise from the asynchronous nature of prefab instantiation. If you immediately grab a component right after instantiation, the engineās internal deserialization/initialization routines (as seen in our prefab instantiation examples at needle-engine-docsācomponent-prefab.ts.md) might not have finished applying all serialized data yet. In other words, the prefab might not be ācompletely readyā when you access its components.
The recommended approach is to queue incoming spawn requests (from network events) and process them during the gameās update loop. This ensures that prefab instantiation and the assignment of @serializable fields are handled in sync with the engineās regular lifecycle. For example, you could push each WebSocket spawn request into an array and then, in the update() method, process each oneāinstantiating the prefab and then safely accessing its fields. Hereās a quick TypeScript snippet demonstrating this:
import { Behaviour, serializable, AssetReference } from "@needle-tools/engine";
export class SpawnManager extends Behaviour {
// Queue to store incoming prefab references
private spawnQueue: AssetReference[] = [];
awake() {
// Example WebSocket message handler
websocket.onmessage = async (data) => {
// Parse or determine your prefab reference from the incoming message.
// For demonstration, assume a method to get a prefab reference:
const prefabRef: AssetReference = this.avatarAsset!.getPrefabReferenceFromData(data);
// Queue the instantiation request
this.spawnQueue.push(prefabRef);
};
}
async update() {
// Process queued spawn events in the main loop
if (this.spawnQueue.length > 0) {
const prefabReference = this.spawnQueue.shift();
if (prefabReference) {
// Instantiate the prefab and then safely access its component(s)
const prefab = await this.avatarAsset!.instantiate(prefabReference);
const avatarComponent = prefab.getComponent(AvatarLoader);
if (avatarComponent) {
// Serialized fields should now be fully initialized
// You can safely use avatarComponent.serializedFields here
}
}
}
}
}
This queue-based approach ensures that all deserialization and setup processes occur in the predictable update cycle of your game, minimizing the risk of accessing incomplete component data.
Using this method follows best practices that Needle Engine encourages for dynamic object spawning, similar to the prefab instantiation examples in our documentation at needle-engine-docsācomponent-prefab.ts.md.
Hope this helps, and happy coding!
1 replies left - Become PRO for more replies. thread_Rd959XB4fkMAUi1TWXwCPIVx Reply to this post directly if you need further help (bottom right button)
Hi oot4chi! In Needle Engine, you can implement a waitForNextFrame functionality using a coroutine. Hereās a simple example of how to create a coroutine that yields control back to the engine to wait for the next frame before executing the subsequent lines of code:
import { Behaviour, WaitForNextFrame } from "@needle-tools/engine";
export class WaitForNextFrameExample extends Behaviour {
async onEnable(): Promise<void> {
console.log("Waiting for the next frame...");
await this.startCoroutine(this.waitForNextFrame());
console.log("This runs in the next frame!");
}
private *waitForNextFrame() {
yield WaitForNextFrame;
}
}
Explanation:
WaitForNextFrame: This is the built-in yield instruction to pause execution until the next frame.
startCoroutine: It starts the coroutine, allowing it to yield control back to the game engine until WaitForNextFrame allows the next execution.
In the onEnable() function, the script will log a message, wait for the next frame, and then log another message.
This pattern helps when you need to wait for the engine to complete its current cycle before continuing execution. Let me know if you need further clarification or additional examples!
1 replies left - Become PRO for more replies. thread_Rd959XB4fkMAUi1TWXwCPIVx Reply to this post directly if you need further help (bottom right button)
Hi oot4chi! The warning āCould not resolve component reference: ānameTextā using guidā typically indicates that the engine is unable to locate a component in the serialized data, likely because the GUID (Globally Unique Identifier) associated with that component reference is missing, invalid, or the component has not been assigned correctly in the Unity Editor.
Here are some steps to troubleshoot this issue:
Check GUID References: Ensure that the serialized reference for the component (in your case, nameText) is correctly set up in the Unity Inspector. If the reference has been moved, renamed, or deleted, the GUID may have been invalidated.
Prefab Reassignments: If the component is part of a prefab, make sure that the prefab is up-to-date and that the instance in the scene properly references the correct components.
Asset Serialization: Check your prefab or game object hierarchy and see if thereās any discrepancy regarding how components are serialized. If youāve modified or updated the prefab after instantiation, you might need to reassign the references.
Rebuild Assets: Sometimes, rebuilding or re-exporting your assets helps. Try refreshing the asset in the Unity Editor and re-export it to reflect the correct component references.
Console Logs: Look at other console logs or errors that may precede this message for additional context about what might have caused the issue.
If the warning persists, consider checking out the latest documentation or reaching out to the Needle Engine support team for more detailed insights specific to this warning.
Let me know if you need further assistance!
0 replies left - Become PRO for more replies. thread_Rd959XB4fkMAUi1TWXwCPIVx Reply to this post directly if you need further help (bottom right button)
Hi oot4chi! Regarding your question about the bugās impact on various functions:
SetActive(): If thereās an issue with component references, using SetActive() may not produce the desired effect, especially if dependent components are not properly initialized or resolved.
Instantiate(): If the instantiation process is impacted, you may find that objects do not initialize correctly, potentially leading to missing references or unexpected behavior.
Transform operations (position, rotation, scale): These operations may be affected if the components related to transformation arenāt resolving properly. This could lead to objects not appearing correctly in the scene or behaving unexpectedly.
Component references: This would likely be the most directly impacted area, as the warning youāre seeing suggests that the engine canāt find referenced components, which can prevent actions that depend on those references from executing correctly.
Any other functions: Functions that rely on components, serialized fields, or instantiated objects could also be impacted, leading to unpredictable behavior in your application.
Itās best to identify the root cause of the warning, as resolving it should improve the reliability of all related functions. If you need further assistance in troubleshooting the precise issue causing this warning, feel free to ask!
1 replies left - Become PRO for more replies. thread_Rd959XB4fkMAUi1TWXwCPIVx Reply to this post directly if you need further help (bottom right button)