Use the SRP foveation API

Configure the scriptable render pipeline (SRP) foveation method in the OpenXR settings, then set the foveation level at runtime.

The SRP foveation API works on every platform that supports foveated rendering, so you can share code across device types. Configuring the setting on its own has no effect: you must also set the foveation level at runtime, because Unity sets that level to 0 by default.

Prerequisites

Before you begin, make sure your project meets the conditions in Foveated rendering requirements reference.

Configure the SRP foveation method

To configure foveated rendering with the SRP foveation API in Unity 6 or later:

  1. Open the Project Settings window.
  2. Under XR Plug-in Management, select the OpenXR settings.
  3. Select the tab for the platform you want to configure.
  4. In the list of OpenXR Feature Groups, select All Features.
  5. Under OpenXR Feature Groups, enable the Foveated Rendering feature.
  6. Under OpenXR Feature Groups, select the gear icon next to the Foveated Rendering feature.
  7. Set the Foveated Rendering Method option to the SRP foveation option. Unity names this option Foveated rendering (SRP API) on Android, and SRP Foveation on other platforms.

Settings to enable foveated rendering with the SRP foveation API
SRP foveation API settings.

After you apply these settings, the SRP foveation API is available in your project. Next, set the foveation level at runtime.

Set the foveation level

To specify the amount of the foveation effect, assign a value between 0 and 1 to the XRDisplaySubsystem.foveatedRenderingLevel property. The default value of 0 disables foveation, and 1 is the maximum level. Different device types can interpret this value in the way that best suits their platform-specific APIs.

Meta Quest devices, for example, have discrete foveation levels. If you assign 0.5 to foveatedRenderingLevel, the provider plug-in sets the device's Medium level.

To use gaze-based foveated rendering, set XRDisplaySubsystem.foveatedRenderingFlags to FoveatedRenderingFlags.GazeAllowed.

The device uses fixed foveated rendering in any of the following cases:

  • You don't set this flag.
  • The device doesn't support gaze-based foveated rendering.
  • The user denies or revokes eye-tracking permission.

To set either of these properties, you must first get a reference to the active XRDisplaySubsystem from the Unity SubsystemManager. Unity supports multiple subsystems of the same type, and returns a list when you get the subsystems of a given type. Ordinarily, only one XRDisplaySubsystem exists. Use the single entry in the list that SubsystemManager.GetSubsystems returns.

The following code example sets foveated rendering to the maximum level and enables gaze-based foveation, after getting the instance of the active XRDisplaySubsystem:

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.XR;

namespace UnityEngine.XR.OpenXR.CodeSamples.Editor.Tests
{
    // Requires Unity 6.0.0 or newer.
    public class FoveationStarter : MonoBehaviour
    {
        List<XRDisplaySubsystem> xrDisplays = new List<XRDisplaySubsystem>();

        void Start()
        {
            SubsystemManager.GetSubsystems(xrDisplays);
            if (xrDisplays.Count == 1)
            {
                xrDisplays[0].foveatedRenderingLevel = 1.0f; // Full strength
                xrDisplays[0].foveatedRenderingFlags =
                    XRDisplaySubsystem.FoveatedRenderingFlags.GazeAllowed;
            }
        }
    }
}
Note

This code example relies on methods available in Unity 6 or later. It doesn't compile in earlier versions.

Skip the fragment density map on the final passes

When your project uses post-processing, the Universal Render Pipeline (URP) renders two lightweight full-screen passes at the end of each frame. UberPost applies effects such as bloom and tone mapping, and FinalBlit copies the result to the eye textures. Foveating these passes saves little GPU time, and on Meta Quest it costs more than it saves.

In Unity 6.7 and later, Unity does the following for you:

  • On Meta Quest, Unity doesn't attach a fragment density map to either pass when you enable post-processing and disable multisample antialiasing (MSAA), reducing GPU frame time.
  • On every platform, Unity foveates FinalBlit only when it can't foveate the intermediate passes, for example when your project uses dynamic resolution.

Unity applies the Meta Quest behavior when your project uses the Meta Quest build target or build profile. It doesn't apply to any other build target by default, including Android XR, Android, and the standalone build targets. If you build for a Meta Quest device through the Android build target, set FoveatedRenderingFeature.skipFDMForFinalPassesSRP to true to get the same result:

using UnityEngine;
using UnityEngine.XR.OpenXR;
using UnityEngine.XR.OpenXR.Features;

public class SkipFdmFinalPassesEnabler : MonoBehaviour
{
    void Start()
    {
        // Unity sets this automatically when you use the Meta Quest build target or build profile.
        var foveatedRendering = OpenXRSettings.Instance.GetFeature<FoveatedRenderingFeature>();
        foveatedRendering.skipFDMForFinalPassesSRP = true;
    }
}

This property applies only to the SRP foveation API. It has no effect if your project uses the legacy foveation API or quad views, and no effect in Unity versions earlier than 6.7.

Additional resources