Functions
varjo_Bool	varjo_IsAvailable ()
	Checks whether Varjo system is available. More...

const char *	varjo_GetVersionString ()
	Gets the short version of the runtime. More...

const uint64_t	varjo_GetVersion ()
	Gets the version number of the runtime. More...

struct varjo_Session *	varjo_SessionInit (void)
	Initializes a Varjo client session. More...

void	varjo_SessionShutDown (struct varjo_Session *session)
	Shuts down a session and releases all the resources internally allocated by Varjo session. More...

void	varjo_SessionSetPriority (struct varjo_Session *session, int32_t priority)
	Sets session overlay priority. More...

varjo_Nanoseconds	varjo_GetCurrentTime (struct varjo_Session *session)
	Gets the current time in a format that Varjo API uses. More...

varjo_Nanoseconds	varjo_ConvertToUnixTime (struct varjo_Session *session, varjo_Nanoseconds varjoTime)
	Calculates Real Time Clock value (i.e. More...

struct varjo_FrameInfo *	varjo_CreateFrameInfo (struct varjo_Session *session)
	Creates a frame info with initial values. More...

void	varjo_FreeFrameInfo (struct varjo_FrameInfo *frameInfo)
	Frees an allocated frame info. More...

void	varjo_SetCenteredProjection (struct varjo_Session *session, varjo_Bool enabled)
	Forces the provided projection matrices to be centered. More...

int32_t	varjo_GetViewCount (struct varjo_Session *session)
	Gets numbers of views. More...

struct varjo_AlignedView	varjo_GetAlignedView (double *projectionMatrix)
	Gets an aligned view from a projection matrix. More...

void	varjo_WaitSync (struct varjo_Session session, struct varjo_FrameInfo frameInfo)
	Called at the start of a frame. More...

varjo_Nanoseconds	varjo_FrameGetDisplayTime (struct varjo_Session *session)
	Gets the time when the frame is scheduled to be displayed. More...

struct varjo_Matrix	varjo_FrameGetPose (struct varjo_Session *session, varjo_PoseType type)
	Gets a pose for the current frame. More...

struct varjo_Matrix	varjo_GetTrackingToLocalTransform (struct varjo_Session *session)
	Transform from tracking space to local client space. More...

struct varjo_Matrix	varjo_GetRelativePoseTransform (struct varjo_Session *session, varjo_PoseType src, varjo_PoseType dest)
	Gets a relative transformation from source pose to destination pose. More...

struct varjo_Matrix	varjo_ApplyTransform (struct varjo_Session session, struct varjo_Matrix m1, struct varjo_Matrix *m2)
	Applies transform using post multiplication. More...

void	varjo_ResetPose (struct varjo_Session *session, varjo_Bool position, varjo_RotationReset rotation)
	Resets pose tracking origin. More...

struct varjo_ViewDescription	varjo_GetViewDescription (struct varjo_Session *session, int32_t viewIndex)
	Gets the display information for a given view. More...

struct varjo_Mesh2Df *	varjo_CreateOcclusionMesh (struct varjo_Session *session, int32_t viewIndex, varjo_WindingOrder windingOrder)
	Creates the occlusion mesh for a given view index. More...

void	varjo_FreeOcclusionMesh (struct varjo_Mesh2Df *mesh)
	Frees the memory allocated by varjo_CreateOcclusionMesh. More...

varjo_Error	varjo_GetError (struct varjo_Session *session)
	Gets the latest error code. More...

const char *	varjo_GetErrorDesc (varjo_Error error)
	Gets error description for the specified error code. More...

void	varjo_GazeInit (struct varjo_Session *session)
	Initializes the gaze tracking system. More...

void	varjo_GazeInitWithParameters (struct varjo_Session session, struct varjo_GazeParameters parameters, int32_t parameterCount)
	Initializes the gaze tracking system with provided parameters. More...

varjo_Bool	varjo_IsGazeAllowed (struct varjo_Session *session)
	Is gaze allowed to be used? More...

void	varjo_RequestGazeCalibration (struct varjo_Session *session)
	Requests a HMD gaze calibration. More...

void	varjo_RequestGazeCalibrationWithParameters (struct varjo_Session session, struct varjo_GazeCalibrationParameters parameters, int32_t parameterCount)
	Requests a HMD gaze calibration with provided parameters. More...

void	varjo_CancelGazeCalibration (struct varjo_Session *session)
	Cancels currently active gaze calibration routine, if any, and resets gaze tracker to default state. More...

struct varjo_Gaze	varjo_GetGaze (struct varjo_Session *session)
	Gets the current state of the user gaze. More...

varjo_Bool	varjo_GetGazeData (struct varjo_Session session, struct varjo_Gaze gaze, struct varjo_EyeMeasurements *eyeMeasurements)
	Gets the current state of the user gaze. More...

int32_t	varjo_GetGazeArray (struct varjo_Session session, struct varjo_Gaze array, int32_t maxSize)
	Gets gaze measurements since last query. More...

int32_t	varjo_GetGazeDataArray (struct varjo_Session session, struct varjo_Gaze gazeArray, struct varjo_EyeMeasurements *eyeMeasurementsArray, int32_t maxSize)
	Gets gaze measurements since last query. More...

void	varjo_SyncProperties (struct varjo_Session *session)
	Updates and synchronizes system properties with the system state. More...

int32_t	varjo_GetPropertyCount (struct varjo_Session *session)
	Gets the number of system properties. More...

varjo_PropertyKey	varjo_GetPropertyKey (struct varjo_Session *session, int32_t index)
	Gets a property key for a property index. More...

const char *	varjo_GetPropertyName (struct varjo_Session *session, varjo_PropertyKey propertyKey)
	Gets the name of the property key. More...

varjo_Bool	varjo_HasProperty (struct varjo_Session *session, varjo_PropertyKey propertyKey)
	Checks if the key has value in the properties. More...

varjo_Bool	varjo_GetPropertyBool (struct varjo_Session *session, varjo_PropertyKey propertyKey)
	Gets a boolean value of a property. More...

double	varjo_GetPropertyDouble (struct varjo_Session *session, varjo_PropertyKey propertyKey)
	Gets a floating point value of a property. More...

int32_t	varjo_GetPropertyInt (struct varjo_Session *session, varjo_PropertyKey propertyKey)
	Gets an integer value of a property. More...

void	varjo_GetPropertyString (struct varjo_Session session, varjo_PropertyKey propertyKey, char buffer, uint32_t maxSize)
	Gets a string value of a property. More...

uint32_t	varjo_GetPropertyStringSize (struct varjo_Session *session, varjo_PropertyKey propertyKey)
	Gets the size of a buffer that is big enough to hold the property, including the null terminator. More...

struct varjo_SwapChainLimits	varjo_GetSwapChainLimits (struct varjo_Session *session)
	Gets swap chain limits. More...

void	varjo_GetSupportedTextureFormats (struct varjo_Session session, varjo_RenderAPI renderApi, int32_t formatCount, varjo_TextureFormat *formats)
	Gets supported texture formats in the order of most preferred to least preferred. More...

struct varjo_Event *	varjo_AllocateEvent ()
	Allocates an event. More...

void	varjo_FreeEvent (struct varjo_Event *event)
	Free an event. More...

varjo_Bool	varjo_PollEvent (struct varjo_Session session, struct varjo_Event evt)
	Polls events. More...

void	varjo_GetTextureSize (struct varjo_Session session, varjo_TextureSize_Type type, int32_t viewIndex, int32_t width, int32_t *height)
	Gets texture size for specific varjo_TextureSize_type and view index. More...

void	varjo_D3D12UpdateVariableRateShadingTexture (struct varjo_Session session, struct ID3D12GraphicsCommandList commandList, struct ID3D12Resource texture, struct varjo_VariableRateShadingConfig config)
	Creates variable rate shading texture. More...

void	varjo_D3D11UpdateVariableRateShadingTexture (struct varjo_Session session, struct ID3D11Device device, struct ID3D11Texture2D texture, struct varjo_VariableRateShadingConfig config, struct varjo_ShadingRateTable *shadingRateTable)
	Updates variable rate shading texture. More...

void	varjo_GLUpdateVariableRateShadingTexture (struct varjo_Session session, unsigned int texture, int width, int height, struct varjo_VariableRateShadingConfig config, struct varjo_ShadingRateTable *shadingRateTable)
	Updates variable rate shading texture. More...

varjo_Bool	varjo_GetRenderingGaze (struct varjo_Session session, struct varjo_Gaze gaze)
	Returns gaze which can be used for foveated rendering or to generate variable rate shading texture. More...

struct varjo_FovTangents	varjo_GetFoveatedFovTangents (struct varjo_Session session, int32_t indexView, struct varjo_Gaze gaze, struct varjo_FoveatedFovTangents_Hints *hints)
	Returns foveated view tangents for a given index and gaze vector. More...

struct varjo_FovTangents	varjo_GetFovTangents (struct varjo_Session *session, int32_t viewIndex)
	Returns tangents for a given view index. More...

void	varjo_SetInterPupillaryDistanceParameters (struct varjo_Session session, struct varjo_InterPupillaryDistanceParameters parameters, int32_t parameterCount)
	Sets interpupillary distance (IPD) parameters for HMD. More...

Function Documentation

◆ varjo_AllocateEvent()

struct varjo_Event* varjo_AllocateEvent ( )

Allocates an event.

Helper function if you don't want to do the allocation by yourself.

Returns: Allocated event.

◆ varjo_ApplyTransform()

struct varjo_Matrix varjo_ApplyTransform	(	struct varjo_Session *	session,
		struct varjo_Matrix *	m1,
		struct varjo_Matrix *	m2
	)

Applies transform using post multiplication.

Parameters

session	Varjo session handle.
m1	First transform.
m2	Second transform.

Returns: Second transformation applied to the first one.

◆ varjo_CancelGazeCalibration()

void varjo_CancelGazeCalibration ( struct varjo_Session * session )

Cancels currently active gaze calibration routine, if any, and resets gaze tracker to default state.

After this function has been called, any active gaze calibration user interface will be closed. Last successful gaze calibration, if any, will be reset. Gaze tracker will continue without calibration and may still estimate gaze using "Best estimation without calibration" depending on foveated rendering calibration mode currently selected in Varjo Base.

Parameters

session Varjo session handle.

◆ varjo_ConvertToUnixTime()

varjo_Nanoseconds varjo_ConvertToUnixTime	(	struct varjo_Session *	session,
		varjo_Nanoseconds	varjoTime
	)

Calculates Real Time Clock value (i.e.

time-of-day) for the given monotonic Varjo Time value.

Conversion is done by running synchronization of Varjo clock with operating system's time-of-day clock. Note, conversion will fail if requested for a time value preceding the Varjo system launch or if the input value is too old vs current Varjo time. Please check Varjo documentation for more information. When conversion fails, the error varjo_Error_InvalidParameter is set and 0 is returned.

Parameters

session	Varjo session handle.
varjoTime	nanoseconds value of the Varjo Time (e.g. from varjo_GetCurrentTime or varjo_Gaze::captureTime).

Returns: Nanoseconds since the Unix Epoch corresponding to the given Varjo Time, or 0 in case of failure.

◆ varjo_CreateFrameInfo()

struct varjo_FrameInfo* varjo_CreateFrameInfo ( struct varjo_Session * session )

Creates a frame info with initial values.

Allocates enough data to hold all of the views.

Use varjo_FreeFrameInfo to free the allocated memory.

Parameters

session Varjo session handle.

Returns: Frame info.

◆ varjo_CreateOcclusionMesh()

struct varjo_Mesh2Df* varjo_CreateOcclusionMesh	(	struct varjo_Session *	session,
		int32_t	viewIndex,
		varjo_WindingOrder	windingOrder
	)

Creates the occlusion mesh for a given view index.

Due to lens distortion some display pixels are not visible in the optical path so the application can stencil out pixels to reduce shading workload and improve performance.

Mesh data is a triangle list where each triplet of vertices forms a triangle.

Use varjo_FreeOcclusionMesh to free the created mesh.

Parameters

session	Varjo session handle.
viewIndex	View number to get the occlusion mesh for. Must be in range [0, varjo_GetViewCount - 1].
windingOrder	Winding order of the triangles

Returns: Occlusion mesh, null if the viewIndex invalid.

◆ varjo_D3D11UpdateVariableRateShadingTexture()

void varjo_D3D11UpdateVariableRateShadingTexture	(	struct varjo_Session *	session,
		struct ID3D11Device *	device,
		struct ID3D11Texture2D *	texture,
		struct varjo_VariableRateShadingConfig *	config,
		struct varjo_ShadingRateTable *	shadingRateTable
	)

Updates variable rate shading texture.

This function will add execution of compute shader which will calculate best possible VRS map based on flags. Function should be executed as late as possible to get most recent gaze. Function should be called as many times as there are views: 4 or 2.

See also: varjo_VariableRateShadingConfig for details.

Parameters

session	Varjo session handle.
device	D3D11 device.
texture	Texture which will be used as VRS map. Format must be R8 UINT.
config	Configuration flags.
shadingRateTable	Array that specifies which shading rate matches which integer value. This is very similar to shading rate table in NV_D3D11_VIEWPORT_SHADING_RATE_DESC_V1.

◆ varjo_D3D12UpdateVariableRateShadingTexture()

void varjo_D3D12UpdateVariableRateShadingTexture	(	struct varjo_Session *	session,
		struct ID3D12GraphicsCommandList *	commandList,
		struct ID3D12Resource *	texture,
		struct varjo_VariableRateShadingConfig *	config
	)

Creates variable rate shading texture.

This function will add execution of compute shader which will calculate best possible VRS map based on flags. Command list should be executed as late as possible to get most recent gaze. Function should be called as many times as there are views: 4 or 2.

Texture has to be in D3D12_RESOURCE_STATE_UNORDERED_ACCESS state.

See also: varjo_VariableRateShadingConfig for details.

Parameters

session	Varjo session handle.
commandList	D3D12 command list.
texture	Texture which will be used as VRS map. Format must be R8 UINT.
config	Configuration flags.

◆ varjo_FrameGetDisplayTime()

varjo_Nanoseconds varjo_FrameGetDisplayTime ( struct varjo_Session * session )

Gets the time when the frame is scheduled to be displayed.

This time refers to the average perceived moment of when the image is shown.

The display time is updated in varjo_WaitSync and is guaranteed to remain constant for the duration of the frame.

This is a helper function for when you don't have access to varjo_FrameInfo.

Parameters

session Varjo session handle.

Returns: Nanoseconds since epoch.

◆ varjo_FrameGetPose()

struct varjo_Matrix varjo_FrameGetPose	(	struct varjo_Session *	session,
		varjo_PoseType	type
	)

Gets a pose for the current frame.

If it's called before varjo_WaitSync() is complete, it will return new pose. Following calls to varjo_FrameGetPose() will return the same matrix. varjo_WaitSync() will also derive it's matrices from that pose. If varjo_FrameGetPose() is called after varjo_WaitSync() it will derive matrices from that pose.

Parameters

session	Varjo session handle.
type	Type of the pose.

Returns: The pose matrix.

◆ varjo_FreeEvent()

void varjo_FreeEvent ( struct varjo_Event * event )

Free an event.

Must be allocated with varjo_AllocateEvent.

Parameters

event Event to free.

◆ varjo_FreeFrameInfo()

void varjo_FreeFrameInfo ( struct varjo_FrameInfo * frameInfo )

Frees an allocated frame info.

Parameters

frameInfo Frame info to free.

◆ varjo_FreeOcclusionMesh()

void varjo_FreeOcclusionMesh ( struct varjo_Mesh2Df * mesh )

Frees the memory allocated by varjo_CreateOcclusionMesh.

Parameters

mesh	Occlusion mesh to free.

◆ varjo_GazeInit()

void varjo_GazeInit ( struct varjo_Session * session )

Initializes the gaze tracking system.

Parameters

session Varjo session handle.

◆ varjo_GazeInitWithParameters()

void varjo_GazeInitWithParameters	(	struct varjo_Session *	session,
		struct varjo_GazeParameters *	parameters,
		int32_t	parameterCount
	)

Initializes the gaze tracking system with provided parameters.

If parameter is not supported by currently connected headset, this function will set varjo_Error_GazeUnsupportedParameter error.

Parameters

session	Varjo session handle.
parameters	Gaze key-value parameters.
parameterCount	Number of parameters provided.

◆ varjo_GetAlignedView()

struct varjo_AlignedView varjo_GetAlignedView ( double * projectionMatrix )

Gets an aligned view from a projection matrix.

Note: the projection matrix from varjo_FrameInfo might not always be axis aligned.

Parameters

projectionMatrix Projection matrix.

Returns: Aligned view.

◆ varjo_GetCurrentTime()

varjo_Nanoseconds varjo_GetCurrentTime ( struct varjo_Session * session )

Gets the current time in a format that Varjo API uses.

This is a realtime monotonic counter since system-specific starting point and is not affected by time-of-day setting.

Parameters

session Varjo session handle.

Returns: Nanoseconds since epoch.

◆ varjo_GetError()

varjo_Error varjo_GetError ( struct varjo_Session * session )

Gets the latest error code.

You should check for errors at least once a frame.

Error status will be cleared after this function.

Use varjo_GetErrorDesc to get more detailed error description.

Returns: Error code if there was an error, varjo_NoError if there wasn't.

◆ varjo_GetErrorDesc()

const char* varjo_GetErrorDesc ( varjo_Error error )

Gets error description for the specified error code.

Returns: Error description string.

◆ varjo_GetFoveatedFovTangents()

struct varjo_FovTangents varjo_GetFoveatedFovTangents	(	struct varjo_Session *	session,
		int32_t	indexView,
		struct varjo_Gaze *	gaze,
		struct varjo_FoveatedFovTangents_Hints *	hints
	)

Returns foveated view tangents for a given index and gaze vector.

varjo_Error_GazeInvalid error will be set if the provided gaze is not valid.

Parameters

session	Varjo session handle
indexView	View index in range [0, varjo_GetViewCount() - 1].
gaze	A valid gaze, returned by varjo_GetRenderingGaze().
hints	A non-null pointer to a varjo_FoveatedFovTangents_Hints struct.

Returns: Foveated tangents for the given view.

See also: varjo_FovTangents

◆ varjo_GetFovTangents()

struct varjo_FovTangents varjo_GetFovTangents	(	struct varjo_Session *	session,
		int32_t	viewIndex
	)

Returns tangents for a given view index.

Parameters

session	Varjo session handle
viewIndex	View index in range [0, varjo_GetViewCount() - 1].

Returns: Tangents for the given view.

See also: varjo_FovTangents

◆ varjo_GetGaze()

struct varjo_Gaze varjo_GetGaze ( struct varjo_Session * session )

Gets the current state of the user gaze.

Gaze system must have been previously initialized by calling varjo_GazeInit or varjo_GazeInitWithParameters.

Parameters

session Varjo session handle.

Returns: Current state of the user gaze.

◆ varjo_GetGazeArray()

int32_t varjo_GetGazeArray	(	struct varjo_Session *	session,
		struct varjo_Gaze *	array,
		int32_t	maxSize
	)

Gets gaze measurements since last query.

Gaze system must have been previously initialized by calling varjo_GazeInit or varjo_GazeInitWithParameters.

Parameters

session	Varjo session handle.
array	Array of varjo_Gaze structures
maxSize	Number of elements in array

Returns: Number of items written to array

◆ varjo_GetGazeData()

varjo_Bool varjo_GetGazeData	(	struct varjo_Session *	session,
		struct varjo_Gaze *	gaze,
		struct varjo_EyeMeasurements *	eyeMeasurements
	)

Gets the current state of the user gaze.

Gaze system must have been previously initialized by calling varjo_GazeInit or varjo_GazeInitWithParameters.

Parameters

session	Varjo session handle.
gaze	Optional pointer to varjo_Gaze data structure. Can be NULL.
eyeMeasurements	Optional pointer to varjo_EyeMeasurements data structure. Can be NULL.

Returns: varjo_True if operation completed successfully and given data structures were filled with data, varjo_False otherwise.

◆ varjo_GetGazeDataArray()

int32_t varjo_GetGazeDataArray	(	struct varjo_Session *	session,
		struct varjo_Gaze *	gazeArray,
		struct varjo_EyeMeasurements *	eyeMeasurementsArray,
		int32_t	maxSize
	)

Gets gaze measurements since last query.

Gaze system must have been previously initialized by calling varjo_GazeInit or varjo_GazeInitWithParameters.

Note: Even if either gazeArray or eyeMeasurementsArray is NULL, items are drained from the queue. So if you need both data in your application, call this function only from one place and provide both arrays.

Parameters

session	Varjo session handle.
gazeArray	Optional array of varjo_Gaze structures. Can be NULL.
eyeMeasurementsArray	Optional array of varjo_EyeMeasurements structures. Can be NULL.
maxSize	Number of elements in the arrays. Both arrays must be at least "maxSize" long, if not NULL.

Returns: Number of items written to arrays

◆ varjo_GetPropertyBool()

varjo_Bool varjo_GetPropertyBool	(	struct varjo_Session *	session,
		varjo_PropertyKey	propertyKey
	)

Gets a boolean value of a property.

Parameters

session	Varjo session handle.
propertyKey	The property key.

Returns: Value of a boolean property if exists, false if the property does not exist. Undefined if the key type is not a boolean.

◆ varjo_GetPropertyCount()

int32_t varjo_GetPropertyCount ( struct varjo_Session * session )

Gets the number of system properties.

Parameters

session Varjo session handle.

Returns: Number of system properties.

◆ varjo_GetPropertyDouble()

double varjo_GetPropertyDouble	(	struct varjo_Session *	session,
		varjo_PropertyKey	propertyKey
	)

Gets a floating point value of a property.

Parameters

session	Varjo session handle.
propertyKey	The property key.

Returns: Value of a floating point property if exists, 0.0 if the property does not exist. Undefined if the key type is not a float.

◆ varjo_GetPropertyInt()

int32_t varjo_GetPropertyInt	(	struct varjo_Session *	session,
		varjo_PropertyKey	propertyKey
	)

Gets an integer value of a property.

Parameters

session	Varjo session handle.
propertyKey	The property key.

Returns: Value of an integer property if exists, 0 if the property does not exist. Undefined if the key type is not an integer.

◆ varjo_GetPropertyKey()

varjo_PropertyKey varjo_GetPropertyKey	(	struct varjo_Session *	session,
		int32_t	index
	)

Gets a property key for a property index.

Parameters

session	Varjo session handle.
index	Zero-based index.

Returns: Key at index location in the properties. 0 if the key index is out of bounds.

◆ varjo_GetPropertyName()

const char* varjo_GetPropertyName	(	struct varjo_Session *	session,
		varjo_PropertyKey	propertyKey
	)

Gets the name of the property key.

Parameters

session	Varjo session handle.
propertyKey	The property key.

Returns: Name of the property key.

◆ varjo_GetPropertyString()

void varjo_GetPropertyString	(	struct varjo_Session *	session,
		varjo_PropertyKey	propertyKey,
		char *	buffer,
		uint32_t	maxSize
	)

Gets a string value of a property.

A null-terminated string will be returned to the given buffer. The string will not be copied if the size is smaller than the length of the property string + 1 (null terminator), i.e. truncation will not happen.

Parameters

session	Varjo session handle.
propertyKey	The property key.
buffer	Pointer to a char buffer.
maxSize	Size of the given char buffer.

◆ varjo_GetPropertyStringSize()

uint32_t varjo_GetPropertyStringSize	(	struct varjo_Session *	session,
		varjo_PropertyKey	propertyKey
	)

Gets the size of a buffer that is big enough to hold the property, including the null terminator.

Parameters

session	Varjo session handle.
propertyKey	The property key.

Returns: Size of a buffer that is big enough to hold the string. If the string is empty, the return value will be 1 (for the null terminator), and 0 if the property key does not exist or is not of a string type.

◆ varjo_GetRelativePoseTransform()

struct varjo_Matrix varjo_GetRelativePoseTransform	(	struct varjo_Session *	session,
		varjo_PoseType	src,
		varjo_PoseType	dest
	)

Gets a relative transformation from source pose to destination pose.

Parameters

session	Varjo session handle.
src	Source pose.
dest	Destination pose.

Returns: Relative transformation from source pose to destination pose.

◆ varjo_GetRenderingGaze()

varjo_Bool varjo_GetRenderingGaze	(	struct varjo_Session *	session,
		struct varjo_Gaze *	gaze
	)

Returns gaze which can be used for foveated rendering or to generate variable rate shading texture.

It may not be the same as the one returned by varjo_GetGaze(). For example, it handles eye blinks and doesn't return invalid gaze in those cases.

varjo_Error_NullPointer error will be set if the gaze pointer is null.

Parameters

session	Varjo session handle.
gaze	A pointer to valid varjo_Gaze.

Returns: True if there is a valid gaze, otherwise false.

◆ varjo_GetSupportedTextureFormats()

void varjo_GetSupportedTextureFormats	(	struct varjo_Session *	session,
		varjo_RenderAPI	renderApi,
		int32_t *	formatCount,
		varjo_TextureFormat *	formats
	)

Gets supported texture formats in the order of most preferred to least preferred.

To allocate memory for the formats output buffer, you should first call this function by passing null formats and query the count for the formats.

Parameters

session	Varjo session handle.
renderApi	Rendering API being used.
formatCount	Output pointer for the format count. Cannot be null.
formats	Output pointer for the formats. Can be null.

◆ varjo_GetSwapChainLimits()

struct varjo_SwapChainLimits varjo_GetSwapChainLimits ( struct varjo_Session * session )

Gets swap chain limits.

Parameters

session Varjo session handle.

Returns: Swap chain limits.

◆ varjo_GetTextureSize()

void varjo_GetTextureSize	(	struct varjo_Session *	session,
		varjo_TextureSize_Type	type,
		int32_t	viewIndex,
		int32_t *	width,
		int32_t *	height
	)

Gets texture size for specific varjo_TextureSize_type and view index.

Check varjo_TextureSize_Type description for details about different varjo_TextureSize_type.

Parameters

session	Varjo session handle.
type	Requeste texture size type.
viewIndex	View index.
width	A pointer to an int which will contain width (cannot be null).
height	A pointer to an int which will contain height (cannot be null).

◆ varjo_GetTrackingToLocalTransform()

struct varjo_Matrix varjo_GetTrackingToLocalTransform ( struct varjo_Session * session )

Transform from tracking space to local client space.

Client space may differ from tracking space if: client has explicitly called varjo_ResetPose or by implicit change of tracking origin for all clients. Client should use varjo_GetTrackingToLocalTransform() in order to sync tracking space poses (e.g. controller poses) with client local space poses.

Parameters

session Varjo session handle.

Returns: The pose offset matrix.

◆ varjo_GetVersion()

const uint64_t varjo_GetVersion ( )

Gets the version number of the runtime.

Use VARJO_MAKE_VERSION macro to create a version that can be then used to test against the returned version number.

Note that VarjoLib version is stored in VARJO_VERSION define.

eg. VARJO_MAKE_VERSION(0, 7, 0, 0) >= varjo_GetVersion()

Returns: Installed Varjo runtime version number.

◆ varjo_GetVersionString()

const char* varjo_GetVersionString ( )

Gets the short version of the runtime.

Eg. "0.7.0.0".

Returns: Installed Varjo runtime version string.

◆ varjo_GetViewCount()

int32_t varjo_GetViewCount ( struct varjo_Session * session )

Gets numbers of views.

Parameters

session Varjo session handle.

◆ varjo_GetViewDescription()

struct varjo_ViewDescription varjo_GetViewDescription	(	struct varjo_Session *	session,
		int32_t	viewIndex
	)

Gets the display information for a given view.

Use this to retrieve information about which display or eye the given view belongs to.

varjo_ViewDescription also contains the recommended render texture dimensions. Use varjo_GetTextureSize to query sizes for various different purposes (for example, best quality rendering).

Parameters

session	Varjo session handle.
viewIndex	View number to get the display information for. Must be in range [0, varjo_GetViewCount - 1].

Returns: View description.

◆ varjo_GLUpdateVariableRateShadingTexture()

void varjo_GLUpdateVariableRateShadingTexture	(	struct varjo_Session *	session,
		unsigned int	texture,
		int	width,
		int	height,
		struct varjo_VariableRateShadingConfig *	config,
		struct varjo_ShadingRateTable *	shadingRateTable
	)

Updates variable rate shading texture.

This function will add execution of compute shader which will calculate best possible VRS map based on flags. Function should be executed as late as possible to get most recent gaze. Function should be called as many times as there are views: 4 or 2.

See also: varjo_VariableRateShadingConfig for details.

Parameters

session	Varjo session handle.
texture	OpenGL texture (GLuint) which will be used as VRS map. Format must be GL_R8UI.
width	Texture width.
height	Texture height.
config	Configuration flags.
shadingRateTable	Array that specifies which shading rate matches which integer value. This is very similar to shading rate palette in glShadingRateImagePaletteNV.

◆ varjo_HasProperty()

varjo_Bool varjo_HasProperty	(	struct varjo_Session *	session,
		varjo_PropertyKey	propertyKey
	)

Checks if the key has value in the properties.

Parameters

session	Varjo session handle.
propertyKey	The property key.

Returns: 1 if the property key has a value, 0 if the value doesn't exist.

◆ varjo_IsAvailable()

varjo_Bool varjo_IsAvailable ( )

Checks whether Varjo system is available.

If varjo_IsAvailable() returns false, it is guaranteed that the session cannot be initialized. If this returns true, application may try initiating a new session.

This call executes fast and can be called per frame unlike varjo_SessionInit.

Returns: 0 if Varjo system is not available, 1 if it is available.

◆ varjo_IsGazeAllowed()

varjo_Bool varjo_IsGazeAllowed ( struct varjo_Session * session )

Is gaze allowed to be used?

User can disallow gaze tracking completely.

Parameters

session Varjo session handle.

Returns: varjo_True if gaze is allowed to be used, varjo_False otherwise.

◆ varjo_PollEvent()

varjo_Bool varjo_PollEvent	(	struct varjo_Session *	session,
		struct varjo_Event *	evt
	)

Polls events.

Holds the latest 100 events in the queue. If the queue size exceeds that, starts dropping events starting from the oldest. Make sure to call often enough (eg. once per frame) if you don't want to miss an event.

Use this in a loop to go through all of the queued events.

Parameters

session	Varjo session handle.
evt	Event to receive data to.

Returns: varjo_True if there was an event, varjo_False if all events have been processed.

◆ varjo_RequestGazeCalibration()

void varjo_RequestGazeCalibration ( struct varjo_Session * session )

Requests a HMD gaze calibration.

This attempts to trigger the gaze calibration sequence if the user has allowed gaze tracking from Varjo settings and Varjo system is in a state where it can bring up the calibration UI.

Parameters

session Varjo session handle.

◆ varjo_RequestGazeCalibrationWithParameters()

void varjo_RequestGazeCalibrationWithParameters	(	struct varjo_Session *	session,
		struct varjo_GazeCalibrationParameters *	parameters,
		int32_t	parameterCount
	)

Requests a HMD gaze calibration with provided parameters.

This attempts to trigger the gaze calibration sequence if the user has allowed gaze tracking from Varjo settings and Varjo system is in a state where it can bring up the calibration UI.

Parameters

session	Varjo session handle.
parameters	Gaze calibration key-value parameters.
parameterCount	Number of parameters provided.

◆ varjo_ResetPose()

void varjo_ResetPose	(	struct varjo_Session *	session,
		varjo_Bool	position,
		varjo_RotationReset	rotation
	)

Resets pose tracking origin.

This will reset the tracking origin to the current transform of the user. rotation parameter can be used to reset only some components of the transform.

Parameters

session	Varjo session handle.
position	Reset position
rotation	Rotation reset type

◆ varjo_SessionInit()

struct varjo_Session* varjo_SessionInit ( void )

Initializes a Varjo client session.

varjo_SessionInit initializes a new Varjo session and returns an opaque pointer handle representing the session which should be passed to all Varjo API calls that are related to this session. When done, the session needs to be cleaned up by calling varjo_SessionShutDown.

There can be multiple simultaneous sessions, but generally applications don't need more than one. Single session can be shared between different threads.

Returns: Pointer handle to Varjo session.

◆ varjo_SessionSetPriority()

void varjo_SessionSetPriority	(	struct varjo_Session *	session,
		int32_t	priority
	)

Sets session overlay priority.

All sessions are grouped based on this value. Only one session from a group is displayed. Higher priority sessions are overlaid on top of lower priority one's.

Parameters

session	Varjo session handle.
priority	Varjo session priority. Negative values allowed. Zero on SessionInit by default.

◆ varjo_SessionShutDown()

void varjo_SessionShutDown ( struct varjo_Session * session )

Shuts down a session and releases all the resources internally allocated by Varjo session.

Session pointer will become invalid after calling this function.

Access to session must be externally synchronized.

Parameters

session Varjo session handle.

◆ varjo_SetCenteredProjection()

void varjo_SetCenteredProjection	(	struct varjo_Session *	session,
		varjo_Bool	enabled
	)

Forces the provided projection matrices to be centered.

This may result in suboptimal resolution.

Parameters

session	Varjo session handle.
enabled	True, if the matrices need to be centered. False if off-center projection is ok.

◆ varjo_SetInterPupillaryDistanceParameters()

void varjo_SetInterPupillaryDistanceParameters	(	struct varjo_Session *	session,
		struct varjo_InterPupillaryDistanceParameters *	parameters,
		int32_t	parameterCount
	)

Sets interpupillary distance (IPD) parameters for HMD.

varjo_Error_InvalidParameter error will be set if parsing the provided parameters fails.

Parameters

session	Varjo session handle.
parameters	IPD key-value parameters.
parameterCount	Number of parameters provided.

◆ varjo_SyncProperties()

void varjo_SyncProperties ( struct varjo_Session * session )

Updates and synchronizes system properties with the system state.

Parameters

session Varjo session handle.

◆ varjo_WaitSync()

void varjo_WaitSync	(	struct varjo_Session *	session,
		struct varjo_FrameInfo *	frameInfo
	)

Called at the start of a frame.

Obtains required metadata for the frame and blocks until optimal time to start rendering so that the application can use the latest possible pose data. In some cases, compositor may block the call for longer duration. (e.g. if it has something else to display.)

varjo_WaitSync() and varjo_FrameGetPose() will always derive matrixes from the same pose. So it's safe to call varjo_FrameGetPose() before varjo_WaitSync() is complete.

Parameters

session	Varjo session handle.
frameInfo	Output pointer for frame info.

Functions

Function Documentation

◆ varjo_AllocateEvent()

◆ varjo_ApplyTransform()

◆ varjo_CancelGazeCalibration()

◆ varjo_ConvertToUnixTime()

◆ varjo_CreateFrameInfo()

◆ varjo_CreateOcclusionMesh()

◆ varjo_D3D11UpdateVariableRateShadingTexture()

◆ varjo_D3D12UpdateVariableRateShadingTexture()

◆ varjo_FrameGetDisplayTime()

◆ varjo_FrameGetPose()

◆ varjo_FreeEvent()

◆ varjo_FreeFrameInfo()

◆ varjo_FreeOcclusionMesh()

◆ varjo_GazeInit()

◆ varjo_GazeInitWithParameters()

◆ varjo_GetAlignedView()

◆ varjo_GetCurrentTime()

◆ varjo_GetError()

◆ varjo_GetErrorDesc()

◆ varjo_GetFoveatedFovTangents()

◆ varjo_GetFovTangents()

◆ varjo_GetGaze()

◆ varjo_GetGazeArray()

◆ varjo_GetGazeData()

◆ varjo_GetGazeDataArray()

◆ varjo_GetPropertyBool()

◆ varjo_GetPropertyCount()

◆ varjo_GetPropertyDouble()

◆ varjo_GetPropertyInt()

◆ varjo_GetPropertyKey()

◆ varjo_GetPropertyName()

◆ varjo_GetPropertyString()

◆ varjo_GetPropertyStringSize()

◆ varjo_GetRelativePoseTransform()

◆ varjo_GetRenderingGaze()

◆ varjo_GetSupportedTextureFormats()

◆ varjo_GetSwapChainLimits()

◆ varjo_GetTextureSize()

◆ varjo_GetTrackingToLocalTransform()

◆ varjo_GetVersion()

◆ varjo_GetVersionString()

◆ varjo_GetViewCount()

◆ varjo_GetViewDescription()

◆ varjo_GLUpdateVariableRateShadingTexture()

◆ varjo_HasProperty()

◆ varjo_IsAvailable()

◆ varjo_IsGazeAllowed()

◆ varjo_PollEvent()

◆ varjo_RequestGazeCalibration()

◆ varjo_RequestGazeCalibrationWithParameters()

◆ varjo_ResetPose()

◆ varjo_SessionInit()

◆ varjo_SessionSetPriority()

◆ varjo_SessionShutDown()

◆ varjo_SetCenteredProjection()

◆ varjo_SetInterPupillaryDistanceParameters()

◆ varjo_SyncProperties()

◆ varjo_WaitSync()