Browser Input Process

Unity Render Streaming supports user input from the browser, making it possible to replicate operating Unity in the browser.

Input devices

Browser input is supported for the following devices. Multiple devices can be used simultaneously.

• Mouse
• Keyboard
• Touch
• Gamepad

The browser sends byte sequences, and Unity uses the New Input System.

Data Format

Mouse Events

index	value	size
0	0	1
1	position x	2
3	position y	2
5	button	1

Keyboard Events

index	value	size
0	1	1
1	key code	1

Touch Events

The data size for touch events varies depending on the number of detected fingers. The length value of the first byte corresponds to the number of detected fingers.

index	value	size
0	2	1
1	phase	1
2	length	1
3	position x	2
5	position y	2
7	force	4

Gamepad Events

There are four types of gamepad events. Each type has a different data format.

event name	value
button down	0
button up	1
button pressed	2
axis	3

For button down 、 button up 、 button pressed:

index	value	size
0	5	1
1	event type	1
2	button index	1
3	value	8

For axis:

index	value	size
0	5	1
1	event type	1
2	button index	1
3	axis x	8
11	axis y	8

Multi-user

The RemoteInputReceiver class can be used to control inputs from multiple users. Call RemoteInputReceiver.Create to create a RemoteInput instance. Next the message from the RTCDataChannelis passed to the RemoteInput.ProcessInput method.

// Create a RemoteInput instance
RemoteInput input = RemoteInputReceiver.Create();
channel.OnMessage = bytes => input.ProcessInput(bytes);

Get the input device from the RemoteInput instance and reference the device value to control the input. Below is an example of using keyboard input.

// Get the keyboard device, process on w key press
Keyboard keyboard = input.RemoteKeyboard;
if(keyboard.wKey.isPressed)
{
   // ... 
}

Using Unity UI

If you use UnityUI, press Replace with InputSystemUIInputModule in the StandaloneInputModule that is attached to the same object as the EventSystem component.

You can control the UnityUI placed on the game scene from browser.

Workaround for using UnityUI on RunInBackground

If use UnityUI in the background, follow the steps below.

1. Update com.unity.inputsystem to 1.1.0-preview.2 on PackageManager.

2. In Project Setting > Player > Other Setting, check Allow 'unsafe' code.

3. Replace EventSystem in the Scene with the following component.

using UnityEngine.EventSystems;
using UnityEngine.InputSystem;
using UnityEngine.InputSystem.LowLevel;

public class CustomEventSystem : EventSystem
{
    protected override void Awake()
    {
        base.Awake();
        unsafe
        {
            InputSystem.onDeviceCommand += InputSystemOnDeviceCommand;
        }
    }

    private static unsafe long? InputSystemOnDeviceCommand(InputDevice device, InputDeviceCommand* command)
    {
        if (command->type != QueryCanRunInBackground.Type)
        {
            // return null is skip this evaluation
            return null;
        }

        ((QueryCanRunInBackground*)command)->canRunInBackground = true;
        return InputDeviceCommand.GenericSuccess;
    }

    protected override void OnApplicationFocus(bool hasFocus)
    {
        //Do not change focus flag on eventsystem
    }
}

4. (Optional) For UnityEditor, Open Window > Analysis > Input Debugger and turn on Lock Input to Game View in Options.