Package org.lwjgl.openxr

Class FBDisplayRefreshRate

java.lang.Object

org.lwjgl.openxr.FBDisplayRefreshRate

public class FBDisplayRefreshRate
extends Object

The XR_FB_display_refresh_rate extension.

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:

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

• An application to identify what display refresh rates the session supports and the current display refresh rate.
• An application to request a display refresh rate to indicate its preference to the runtime.
• An application to receive notification of changes to the display refresh rate which are delivered via events.

In order to enable the functionality of this extension, the application must pass the name of the extension into CreateInstance via the XrInstanceCreateInfo::enabledExtensionNames parameter as indicated in the extension section.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	XR_ERROR_DISPLAY_REFRESH_RATE_UNSUPPORTED_FB	Extends XrResult.
static final String	XR_FB_DISPLAY_REFRESH_RATE_EXTENSION_NAME	The extension name.
static final int	XR_FB_display_refresh_rate_SPEC_VERSION	The extension specification version.
static final int	XR_TYPE_EVENT_DATA_DISPLAY_REFRESH_RATE_CHANGED_FB	Extends XrStructureType.

Method Summary

Modifier and Type	Method	Description
static int	nxrEnumerateDisplayRefreshRatesFB(XrSession session, int displayRefreshRateCapacityInput, long displayRefreshRateCountOutput, long displayRefreshRates)	Unsafe version of: EnumerateDisplayRefreshRatesFB
static int	nxrGetDisplayRefreshRateFB(XrSession session, long displayRefreshRate)	Unsafe version of: GetDisplayRefreshRateFB
static int	xrEnumerateDisplayRefreshRatesFB(XrSession session, IntBuffer displayRefreshRateCountOutput, @Nullable FloatBuffer displayRefreshRates)	Enumerates display refresh rates.
static int	xrGetDisplayRefreshRateFB(XrSession session, FloatBuffer displayRefreshRate)	Get the current display refresh rate.
static int	xrRequestDisplayRefreshRateFB(XrSession session, float displayRefreshRate)	Request a display refresh rate.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

XR_FB_display_refresh_rate_SPEC_VERSION

public static final int XR_FB_display_refresh_rate_SPEC_VERSION

The extension specification version.

See Also:

• Constant Field Values

XR_FB_DISPLAY_REFRESH_RATE_EXTENSION_NAME

public static final String XR_FB_DISPLAY_REFRESH_RATE_EXTENSION_NAME

The extension name.

See Also:

• Constant Field Values

XR_TYPE_EVENT_DATA_DISPLAY_REFRESH_RATE_CHANGED_FB

public static final int XR_TYPE_EVENT_DATA_DISPLAY_REFRESH_RATE_CHANGED_FB

Extends XrStructureType.

See Also:

• Constant Field Values

XR_ERROR_DISPLAY_REFRESH_RATE_UNSUPPORTED_FB

public static final int XR_ERROR_DISPLAY_REFRESH_RATE_UNSUPPORTED_FB

Extends XrResult.

See Also:

• Constant Field Values

Method Details

nxrEnumerateDisplayRefreshRatesFB

public static int nxrEnumerateDisplayRefreshRatesFB(XrSession session,
 int displayRefreshRateCapacityInput,
 long displayRefreshRateCountOutput,
 long displayRefreshRates)

Unsafe version of: EnumerateDisplayRefreshRatesFB

Parameters:

displayRefreshRateCapacityInput - the capacity of the displayRefreshRates, or 0 to retrieve the required capacity.

xrEnumerateDisplayRefreshRatesFB

public static int xrEnumerateDisplayRefreshRatesFB(XrSession session,
 IntBuffer displayRefreshRateCountOutput,
 @Nullable FloatBuffer displayRefreshRates)

Enumerates display refresh rates.

C Specification

The EnumerateDisplayRefreshRatesFB function is defined as:

 XrResult xrEnumerateDisplayRefreshRatesFB(
     XrSession                                   session,
     uint32_t                                    displayRefreshRateCapacityInput,
     uint32_t*                                   displayRefreshRateCountOutput,
     float*                                      displayRefreshRates);

Description

EnumerateDisplayRefreshRatesFB enumerates the display refresh rates supported by the current session. Display refresh rates must be in order from lowest to highest supported display refresh rates. Runtimes must always return identical buffer contents from this enumeration for the lifetime of the session.

Valid Usage (Implicit)

• The XR_FB_display_refresh_rate extension must be enabled prior to calling EnumerateDisplayRefreshRatesFB
• session must be a valid XrSession handle
• displayRefreshRateCountOutput must be a pointer to a uint32_t value
• If displayRefreshRateCapacityInput is not 0, displayRefreshRates must be a pointer to an array of displayRefreshRateCapacityInput float values

Return Codes

On success, this command returns

• SUCCESS
• SESSION_LOSS_PENDING

On failure, this command returns

• ERROR_FUNCTION_UNSUPPORTED
• ERROR_VALIDATION_FAILURE
• ERROR_RUNTIME_FAILURE
• ERROR_HANDLE_INVALID
• ERROR_INSTANCE_LOST
• ERROR_SESSION_LOST
• ERROR_SIZE_INSUFFICIENT

See Also

GetDisplayRefreshRateFB, RequestDisplayRefreshRateFB

Parameters:

session - the session that enumerates the supported display refresh rates.

displayRefreshRateCountOutput - a pointer to the count of float displayRefreshRates written, or a pointer to the required capacity in the case that displayRefreshRateCapacityInput is insufficient.

displayRefreshRates - a pointer to an array of float display refresh rates, but can be NULL if displayRefreshRateCapacityInput is 0.

nxrGetDisplayRefreshRateFB

public static int nxrGetDisplayRefreshRateFB(XrSession session,
 long displayRefreshRate)

Unsafe version of: GetDisplayRefreshRateFB

xrGetDisplayRefreshRateFB

public static int xrGetDisplayRefreshRateFB(XrSession session,
 FloatBuffer displayRefreshRate)

Get the current display refresh rate.

C Specification

The GetDisplayRefreshRateFB function is defined as:

 XrResult xrGetDisplayRefreshRateFB(
     XrSession                                   session,
     float*                                      displayRefreshRate);

Description

GetDisplayRefreshRateFB retrieves the current display refresh rate.

Valid Usage (Implicit)

• The XR_FB_display_refresh_rate extension must be enabled prior to calling GetDisplayRefreshRateFB
• session must be a valid XrSession handle
• displayRefreshRate must be a pointer to a float value

Return Codes

On success, this command returns

• SUCCESS
• SESSION_LOSS_PENDING

On failure, this command returns

• ERROR_FUNCTION_UNSUPPORTED
• ERROR_VALIDATION_FAILURE
• ERROR_RUNTIME_FAILURE
• ERROR_HANDLE_INVALID
• ERROR_INSTANCE_LOST
• ERROR_SESSION_LOST

See Also

EnumerateDisplayRefreshRatesFB, RequestDisplayRefreshRateFB

Parameters:

session - the XrSession to query.

displayRefreshRate - a pointer to a float into which the current display refresh rate will be placed.

xrRequestDisplayRefreshRateFB

public static int xrRequestDisplayRefreshRateFB(XrSession session,
 float displayRefreshRate)

Request a display refresh rate.

C Specification

The RequestDisplayRefreshRateFB function is defined as:

 XrResult xrRequestDisplayRefreshRateFB(
     XrSession                                   session,
     float                                       displayRefreshRate);

Description

RequestDisplayRefreshRateFB provides a mechanism for an application to request the system to dynamically change the display refresh rate to the application preferred value. The runtime must return ERROR_DISPLAY_REFRESH_RATE_UNSUPPORTED_FB if displayRefreshRate is not either 0.0f or one of the values enumerated by EnumerateDisplayRefreshRatesFB. A display refresh rate of 0.0f indicates the application has no preference.

Note that this is only a request and does not guarantee the system will switch to the requested display refresh rate.

Valid Usage (Implicit)

• The XR_FB_display_refresh_rate extension must be enabled prior to calling RequestDisplayRefreshRateFB
• session must be a valid XrSession handle

Return Codes

On success, this command returns

• SUCCESS
• SESSION_LOSS_PENDING

On failure, this command returns

• ERROR_FUNCTION_UNSUPPORTED
• ERROR_VALIDATION_FAILURE
• ERROR_RUNTIME_FAILURE
• ERROR_HANDLE_INVALID
• ERROR_INSTANCE_LOST
• ERROR_SESSION_LOST
• ERROR_FEATURE_UNSUPPORTED
• ERROR_DISPLAY_REFRESH_RATE_UNSUPPORTED_FB

See Also

EnumerateDisplayRefreshRatesFB, GetDisplayRefreshRateFB

Parameters:

session - a valid XrSession handle.

displayRefreshRate - 0.0f or a supported display refresh rate. Supported display refresh rates are indicated by EnumerateDisplayRefreshRatesFB.