Eye Tracked Foveated Rendering (ETFR) utilizes the gaze direction to render full resolution where you are looking at (the foveal region), and low pixel density in the periphery taking advantage of lower peripheral acuity in human vision. The technique reduces the amount of pixels rendered more than when using Fixed Foveated Rendering which leads to better GPU savings.

Eye Tracked Foveated Rendering is the next evolution of FFR (Fixed Foveated Rendering), which renders at full resolution in the center of the screen (in the foveal region), and low resolution in the periphery. This provides substantial GPU savings for Meta Quest applications.

In the case of ETFR, the foveal region is moved around to match where you’re looking using eye tracking. Because the low resolution region is hidden in your peripheral vision at all time, more aggressive foveation maps can be used resulting in more GPU saving.

Before you begin with ETFR, make sure to use the latest version of the Meta Quest Pro operating system and the Meta XR Core SDK. Here are the requirements to enable ETFR for your application:

To get started with ETFR, set up the Unity project with the following settings:

Enabling the feature at runtime is done using the API provided by the Meta XR Core SDK scripts. You’ll need to check if the feature is supported first before enabling it:

if (OVRManager.eyeTrackedFoveatedRenderingSupported)
{
    OVRManager.eyeTrackedFoveatedRenderingEnabled = true;
}

In the case that Eye Tracking was disabled by the user or the Eye Tracking permission was declined, ETFR will not be enabled. You can validate whether or ETFR is enabled by:

if (OVRManager.eyeTrackedFoveatedRenderingEnabled)
{
    // Enable features with the extra GPU savings!
}

By default, the foveation level is off and you won’t see any difference until you switch to a higher level. You can do that at runtime similarly to FFR by:

OVRManager.foveatedRenderingLevel = OVRManager.FoveatedRenderingLevel.Medium;

Optionally, you can enable Dynamic Foveated Rendering (automatically switching foveated rendering level based on the current GPU load) by:

OVRManager.useDynamicFoveatedRendering = true;

The very first time a user opens an app with ETFR, the system will display a permission prompt requesting the user to accept the Eye Tracking permission. The Meta XR Core SDK will handle the underlying eye tracking permission (Android Manifest changes, permission request dialog, etc.). So you don’t need to add specific code in your application to handle permission requests.

The following section offers several best practices to integrate ETFR in your application.

There are a few things to keep in mind when integrating ETFR in your application. The first one is that the feature is only available on Meta Quest Pro. If your application is shipping for Meta Quest 2, you’ll need to make sure to enable the feature only if the device supports it.

It’s also possible that users disable Eye Tracking from the system settings or don’t accept the permission request for Eye Tracking. In those cases, ETFR will not be turned on when calling OVRManager.eyeTrackedFoveatedRenderingEnabled = true;

Finally, it’s a good idea to have an option in your application’s settings so that users can turn it on and off depending on their preference.

Because of that, it is important to understand that whatever you decide to do with the extra performance you get from ETFR might need to be turned off depending on some of those factors.

ETFR on average has higher GPU savings compared to FFR across all levels by using a more aggressive foveation map as shown below. Devs can choose between performance savings and visual quality by selecting a foveation level that best fits their application’s content, along with other surface parameters like MSAA and eye texture scale factor.

One of the recommended ways to use the extra GPU performance from ETFR is to increase eye textures size for crisper and shaper images. Here’s an example of the GPU render time for FFR / ETFR rendered at both default and increased eye texture size for one of our test application:

As an example, if this application were using FFR-3, we could switch to ETFR-2 and use an increased eye texture resolution with MSAA2 for a sharper image at around the same GPU time cost.

The GPU saving you’ll get from ETFR will depend on your application’s content, so make sure to profile your application at different foveation levels and render target size, in order to determine which combination works the best for you.

We also recommend turning on dynamic foveated rendering so that the foveation level is adjusted automatically based on the current GPU rendering load. The maximum foveation level that can be used is specified by foveated rendering level. You should make sure to fully test the rendering quality (e.g. not too much foveation artifact in the peripheral vision) at the maximum foveation level before enabling this option.