Using RefreshRate in Your App

On platforms which support dynamically adjusting the display refresh rate, application developers may request a specific display refresh rate in order to improve the overall user experience, examples include:

1. A video application may choose a display refresh rate which better matches the video content playback rate in order to achieve smoother video frames.

2. An application which can support a higher frame rate may choose to render at the higher rate to improve the overall perceptual quality, for example, lower latency and less flicker.

This extension allows:

1. An application to identify what display refrhttps://dl.vive.com/SDK/openxr/unity/xrpluginmaesh rates the session supports and the current display refresh rate.

2. An application to request a display refresh rate to indicate its preference to the runtime.

Step 1. Check your VIVE OpenXR Plugin version

In Window > Package Manager, make sure your VIVE OpenXR Plugin 2.0.0 or newer.

Step 2. Enable the RefreshRate feature

In Edit > Project Settings > XR Plug-in Management > OpenXR, enable the XR FB Display Refresh Rate feature.

Step 3. Create a script and attach it onto any GameObject in the scene.

In the script, first add a using namespace.

using VIVE.OpenXR;

1) To Get current Refresh Rate:

{
    float value;
    if (XR_FB_display_refresh_rate.GetDisplayRefreshRate(out value) == XrResult.XR_SUCCESS)
    {
        Debug.Log("GetDisplayRefreshRate = " + value);
    }    
}

2) To Request a specific Refresh Rate:

{
    XR_FB_display_refresh_rate.RequestDisplayRefreshRate(90.0f);
}

3) Check the capacity of the display Refresh Rates of the Device:

{
    UInt32 count;
    float[] values = new float[2];
    XrResult result = XR_FB_display_refresh_rate.EnumerateDisplayRefreshRates(displayRefreshRateCapacityInput : 0, displayRefreshRateCountOutput:out count, displayRefreshRates: out values[0]);
    if (result == XrResult.XR_SUCCESS)
    {
        Debug.Log("EnumerateDisplayRefreshRates = " + count);
        Array.Resize(ref values, (int)count);
        result = XR_FB_display_refresh_rate.EnumerateDisplayRefreshRates(displayRefreshRateCapacityInput: count, displayRefreshRateCountOutput: out count, displayRefreshRates: out values[0]);
        if (result == XrResult.XR_SUCCESS)
        {
            for (int i = 0; i < count; i++)
            {
                Debug.Log("EnumerateDisplayRefreshRates index " + i + " RefreshRates = " + values[i]);
            }
        }
    }
}