World/Udon Bugs & Feature Requests

Gravity and Kinematic flags on VRCObjectSync components don't sync correctly right now and also cannot be set correctly while holding the pickup. To set gravity or kinematic flags, VRChat added two new methods for us: https://udonsharp.docs.vrchat.com/vrchat-api/#vrcobjectsync (they are supposed to behave like a synced variable) There are two bugs related to this: ~ Bug 1: ~ All you need is to create a pickup that has no gravity and then toggle the gravity flag on the VRCObjectSync component with an external button after claiming ownership. Then you let different people in the world pick up the pickup and drop it (to show their own local state). In my tests, this resulted in a pickup where the gravity flag is wildly different on each client and only syncs occasionally or not at all. They would see the pickup drop on my end, but when they pick it up it has no gravity for them. ~ Bug 2: ~ All you need is to create a pickup that has no gravity and then toggle the gravity flag on the VRCObjectSync component in OnPickupUseDown() . In my tests, this resulted in a pickup where the gravity stays enabled after the first OnPickupUseDown() and I am unable to turn gravity off again. To check gravity, the pickup is dropped. You can also just test it out here: Right setup: Bug 1 / Left setup: Bug 2 https://vrchat.com/home/world/wrld_9cefd5ec-4492-43c5-8cd3-05036c494556 Additional note: Since we only got a setter and not a getter method, we are left in the dark here when it comes to analyzing the problem. Reading out the local rigidbody state doesn't give us access to the real synced state. A getter method should be added.

While local strings allow storing from range \u0000 to \uffff , any synced strings are forcefully encoded with UTF-16, making any characters within range \ud7fff to \udfff be truncated to \ufffd . It seems like internal serializer or deserializer is treating all strings as UTF-16 encoded texts, no matter what their purpose is. I do know strings require terminators like \0 to be memory safe, or for some other features like support for emojis via utilizing surrogate pairs, but in raw memory side, string can be treated just like other containers, and I'm utilizing for maximum productivity and memory&network efficiency. (For example, treating each character as 2 bytes, or even go further, 4 hexadecimal numbers) I see this becomes important, due to VRChat's network bandwidth limitations and Udon's performance compared to normal C# codes. Just like gameboy-era old games did, I need to squeeze out all the possible bytes to make the code both performance and network-efficient. Maybe treat string just like byte[] when serialized? or maybe adding a special attributes like NonEncoded to the string variable so that the variable is treated just like another data container?

I have encountered a problem related to Unity's DSP chain and Udon. I am planning to create an audio focused world, where I need to implement a custom DSP algorithm on audio that can respond to player behavior/controls in real-time. In the native Unity Mono framework, I can insert custom effects into the audio DSP chain by implementing the OnAudioFilterRead method in MonoBehaviour (see https://docs.unity3d.com/ScriptReference/MonoBehaviour.OnAudioFilterRead.html ). In the UdonSharp documentation, I found that there is a method stub for OnAudioFilterRead in Unity events (see https://udonsharp.docs.vrchat.com/events/ ), so I should be able to implement it. However, it does not work in my Unity setup. I also saw a post on Canny mentioning that a component called OnAudioFilterReadProxy should be automatically added to the object if OnAudioFilterRead is implemented (See: https://vrchat.canny.io/udon/p/order-of-onaudiofilterreadproxy ), but this is not happening on my end. Any idea what could be going wrong with my script or configuration? Or it is a bug? My test code is like the following: using UdonSharp; using UnityEngine; using VRC.SDKBase; using VRC.Udon; public class SimpleSineGenerator : UdonSharpBehaviour { [SerializeField, Range(0, 1)] private float amplitude = 0.5f; [SerializeField] private float frequency = 261.62f; private double phase = 0; private double sampleRate = 48000; public void Update() { // verify that the script is running transform.Rotate(Vector3.up, 90f * Time.deltaTime); } public void OnAudioFilterRead(float[] data, int channels) { // DSP code double phaseIncrement = 2 * Mathf.PI * frequency / sampleRate; for (int i = 0; i < data.Length; i += channels) { phase += phaseIncrement; if (phase > 2 * Mathf.PI) { phase -= 2 * Mathf.PI; } float value = amplitude * Mathf.Sin((float)phase); for (int j = 0; j < channels; j++) { data[i + j] = value; } } } }

Udon's OnVideoPause and OnVideoPlay are not called. Using several multi-function video players provided by volunteers, I attached the following script to the same object as VRC Unity Video Player or VRC AVPro Video Player and tried to play/pause/resume/stop/loop the video player. OnVideoEnd, OnVideoError, OnVideoLoop, OnVideoStart, and OnVideoReady are called, but OnVideoPause and OnVideoPlay are not. ----------------------------------------------------- using UdonSharp; using UnityEngine; using VRC.SDK3.Components.Video ; public class VideoPlayerDebugLoger : UdonSharpBehaviour { public override void OnVideoEnd() { Debug.Log("---------------- Video Ended"); } public override void OnVideoError(VideoError videoError) { Debug.Log("---------------- Video Error: " + videoError); } public override void OnVideoLoop() { Debug.Log("---------------- Video Loop"); } public override void OnVideoPause() { Debug.Log("---------------- Video Paused"); } public override void OnVideoPlay() { Debug.Log("---------------- Video Played"); } public override void OnVideoReady() { Debug.Log("---------------- Video Ready"); } public override void OnVideoStart() { Debug.Log("---------------- Video Started"); } }

Converting an enum to an int in a method call which takes a DataToken as argument crashes at runtime with error Cannot retrieve heap variable of type 'Int32' as type 'DataToken' . Converting it beforehand does not crash. For example, this crashes: DataList dataList = new DataList(); AnEnum anEnumState = AnEnum.AState; dataList.Add((int)anEnumState); Whereas this doesn't crash: DataList dataList = new DataList(); AnEnum anEnumState = AnEnum.AState; int anEnumStateInt = (int)anEnumState; dataList.Add(anEnumStateInt);

VRChat Version: VRChat Build 1664, SDK 3.8.2 It occurred at least in the current version. I don't remember when it started occurring. Description of the bug: If the local player loses ownership of an object to which VRCObjectSync and VRCPickup are attached, the position of it may temporarily revert to the position it was in when the local player acquired ownership. This occurs when ownership is transferred when VRCObjectSync is active and not when it is sleeping. It also does not occur without VRCPickup. The position moves from OnOwnershipTransferred to the next OnDeserialization. Steps to reproduce (how did you encounter the bug?): Move an object to which VRCObjectSync and VRCPickup are attached. Pass its ownership to a remote player while VRCObjectSync is active. Any extra files? (output logs, screenshots): I have confirmed this with the Udon below. The log of the run is also attached. https://gist.github.com/llaser/321a9fc3f63c66f3623615b2383a873e

Reproduction: Add a private readonly int _fade = Shader.PropertyToID("_fade"); to your c# program and then compile it to udonasm using the included u# compiler. Edit: The same also happens with private int _fade = VRCShader.PropertyToID("fade"); . Expected Behaviour: The compilation fails, with the error message, that Shader.PropertyToID is not exposed to udon. When using VRCShader.PropertyToID instead of Shader.PropertyToID the _fade variable should be initialized with the return value of the VRCShader.PropertyToID call or there should be an error saying that readonly isn't supported. Actual Behaviour: The compilation succeeds. When looking at the UdonASM, then I can see that the _fade variable is only ever read from.

Currently, "Continuous" mode syncing syncs 100% of the time. However, in many cases, there are idle periods in which continuous syncing isn't needed, followed by periods in which smooth syncing is necessary. The VRC Object Sync component does this exact behaviour, going to zero bandwidth usage when not moving, and having the ability to do this for UdonBehaviour variables would be very useful. This is particularly the case when the UdonBehaviour is attached to an Object Synced object; right now, this results in greatly increasing bandwidth usage as the Object Sync data is no longer able to go to sleep.

My vehicles relied on OnOwnershipTransferred() running before OnPlayerLeft() to turn the engines off when a player left the game while piloting. The way it worked was: If the master takes ownership while Occupied=true (set false in OnPlayerLeft()) they would know to turn the engine off This used to be reliable, but now it seems to be random (Only working sometimes), I can find a workaround, but I think this should be consistant, one way or the other. Suggested fix: Ownership of all a player's objects should be transferred either before or after the OnPlayerLeft() event is run. I prefer before, because it lets me know what they were doing when they left. Additionally, me using OnPlayerLeft() in the first place was a workaround for OnStationExited() not firing when a player leaves while in a station. canny here: https://feedback.vrchat.com/bug-reports/p/772-vrcstations-onremoteplayerexitstation-does-not-fire-if-the-seated-player-lea WORLD FOR TESTING: wrld_c98d4f48-afb4-4f80-ac86-3f746bc0dcae

It appears that there is a threshold that must be met when scrolling the content of a world space ScrollView which is not adjusted based on the size of the scroll view. This makes it impossible to scroll sufficiently small ScrollViews (if there are no scrollbars). In Client Sim, there is no such threshold. In-Game example: https://i.imgur.com/yQ6Fj0c.mp4 Editor example: https://i.imgur.com/Ry1QZk6.mp4