QTM services. More...

#include <3ds/types.h>

Data Structures
struct	QtmStatusCfgData
	QTM status data (fully enabled/SS3D disabled) in `cfg`. Usually all-zero on N2DSXL. More...

struct	QtmCalibrationData
	QTM calibration data (fully enabled/SS3D disabled) in `cfg`. Usually all-zero on N2DSXL. More...

struct	QtmRawTrackingData
	QTM raw eye tracking data. More...

struct	QtmTrackingData
	QTM processed eye tracking data, suitable for 3D programming. More...

Macros
#define	QTM_STATUS_CFG_BLK_ID 0x180000u
	ID of QTM status data (fully enabled/SS3D disabled) in `cfg`

#define	QTM_CAL_CFG_BLK_ID 0x180001u
	ID of QTM calibration data in `cfg`

Enumerations
enum	QtmStatus { QTM_STATUS_ENABLED = 0 , QTM_STATUS_SS3D_DISABLED = 1 , QTM_STATUS_UNAVAILABLE = 2 }
	QTM enablement status (when cameras not in use by user), set by `qtm:s`. More...

enum	QtmEyeSide { QTM_EYE_LEFT = 0 , QTM_EYE_RIGHT = 1 , QTM_EYE_NUM }
	Left eye or right eye, for QtmTrackingData and QtmRawTrackingData. More...

enum	QtmServiceName { QTM_SERVICE_USER = 0 , QTM_SERVICE_SYSTEM = 1 , QTM_SERVICE_SYSTEM_PROCESS = 2 }
	QTM service name enum, excluding `qtm:c` More...

Functions
bool	qtmCheckServicesRegistered (void)
	Check whether or not QTM services are registered. More...

Result	qtmInit (QtmServiceName serviceName)
	Initializes QTM (except `qtm:c`). More...

void	qtmExit (void)
	Exits QTM.

bool	qtmIsInitialized (void)
	Checks whether or not a `qtm:u`, `qtm:s` or `qtm:sp` session is active.

Handle *	qtmGetSessionHandle (void)
	Returns a pointer to the current `qtm:u` / `qtm:s` / `qtm:sp` session handle.

Result	QTMU_GetRawTrackingDataEx (QtmRawTrackingData *outData, s64 predictionTimePointOrZero)
	Gets the current raw eye tracking data, with an optional prediction made for predictionTimePointOrZero = t+dt, or for the current time point (QTM makes predictions based on gyro data since inner camera runs at 30 FPS). More...

static Result	QTMU_GetRawTrackingData (QtmRawTrackingData *outData)
	Gets the current raw eye tracking data. More...

Result	QTMU_GetTrackingDataEx (QtmTrackingData *outData, s64 predictionTimePointOrZero)
	Gets the current normalized eye tracking data, made suitable for 3D programming with an optional prediction made for predictionTimePointOrZero = t+dt, or for the current time point (QTM makes predictions based on gyro data since inner camera runs at 30 FPS). More...

static Result	QTMU_GetTrackingData (QtmTrackingData *outData)
	Gets the current normalized eye tracking data, made suitable for 3D programming. More...

float	qtmComputeFovX (const QtmTrackingData *data)
	Computes an approximation of the horizontal angular field of view of the camera based on eye tracking data. More...

float	qtmComputeFovY (const QtmTrackingData *data)
	Computes an approximation of the vertical angular field of view of the camera based on eye tracking data. More...

float	qtmComputeInverseAspectRatio (const QtmTrackingData *data)
	Computes a rough approximation of the inverse of the aspect ration of the camera based on eye tracking data. More...

float	qtmComputeHeadTiltAngle (const QtmTrackingData *data)
	Computes the user's head tilt angle, that is, the angle between the line through both eyes and the camera's horizontal axis in camera space. More...

float	qtmEstimateEyeToCameraDistance (const QtmTrackingData *data)
	Estimates the distance between the user's eyes and the camera, based on eye tracking data. More...

Result	QTMU_EnableManualIrLedControl (void)
	Temporarily enables manual control of the IR LED by user, disabling its automatic control. More...

Result	QTMU_DisableManualIrLedControl (void)
	Temporarily disables manual control of the IR LED by user, re-enabling its automatic control. More...

Result	QTMU_SetIrLedStatus (bool on)
	Turns the IR LED on or off during manual control. More...

Result	qtmClearIrLedOverrides (void)
	Attempts to clear IR LED overrides from any of the relevant commands in `qtm:u`, `qtm:s` (and `qtm:c`) commands by calling QTMU_EnableManualIrLedControl followed by QTMU_DisableManualIrLedControl, so that auto IR LED management takes place again. More...

Result	QTMU_IsCurrentAppBlacklisted (bool *outBlacklisted)
	Checks whether or not QTM has been blacklisted, ie. More...

Result	QTMS_SetCenterBarrierPosition (float position)
	Sets the neutral (center) barrier position/offset in calibration, without saving it to `cfg`. More...

Result	QTMS_GetCameraLuminance (float *outLuminanceLux)
	Gets the average ambient luminance as perceived by the inner camera (in lux). More...

Result	QTMS_EnableAutoBarrierControl (void)
	Enables automatic barrier control when in 3D mode with "super stable 3D" enabled. More...

Result	QTMS_DisableAutoBarrierControl (void)
	Temporarily disables automatic barrier control (when in 3D mode with "super stable 3D" enabled). More...

Result	QTMS_SetBarrierPosition (u8 position)
	Temporarily sets the parallax barrier's position (offset in iod/12 units, assuming slit width of 6 units). More...

Result	QTMS_GetCurrentBarrierPosition (u8 *outPosition)
	Gets the current position of the parallax barrier (offset in iod/12 units, slit width of 6 units). More...

Result	QTMS_SetIrLedStatusOverride (bool on)
	Temporarily overrides IR LED state. More...

Result	QTMS_SetCalibrationData (const QtmCalibrationData *cal, bool saveCalToCfg)
	Sets calibration data, taking effect immediately, and optionally saves it to `cfg`. More...

Result	QTMS_GetQtmStatus (QtmStatus *outQtmStatus)
	Gets the current QTM status (enabled/ss3d disabled/unavailable). More...

Result	QTMS_SetQtmStatus (QtmStatus qtmStatus)
	Gets the current QTM status (enabled/ss3d disabled/unavailable). More...

Result	QTMSP_NotifyTopLcdModeChange (u8 newMode)
	Called by GSP's LCD driver to signal 2D<>3D mode change. More...

Result	QTMSP_NotifyTopLcdPowerOn (void)
	Called by GSP's LCD driver during top LCD power-on to signal to QTM that it may power on and/or reconfigure then use the TI TCA6416A expander. More...

Result	QTMSP_IsExpanderInUse (bool *outActive)
	Called by GSP's LCD driver to know whether or not QTM's expander thread is using the TI TCA6416A expander; it is waiting for this to become true/false during LCD power on/power off to proceed. More...

Result	QTMSP_NotifyTopLcdPowerOff (void)
	Called by GSP's LCD driver during top LCD power-on to signal to QTM that it needs to switch the parallax barrier state to a 2D state (all-transparent mask). More...

Detailed Description

QTM services.

QTM is responsible for the following:

tracking and predicting the position of the user's eyes. This is done by using the inner camera sampling at 320x240px at 30 FPS, and by using the gyroscope to predict the position of the eyes between two camera samples (effectively doubling the tracking rate). The API reporting eye tracking data is actually console-agnostic. This concept is most likely covered by patent US9098112B2
automatically managing the IR LED emitter used for eye tracking in low-light conditions
managing the state of the parallax barrier by controlling the positions of the barrier's mask (opaque/transparent state by repeating pattern of 12 units, plus polarity). This is done via a TI TCA6416A I2C->Parallel expander (highlighted in yellow in this teardown photo: https://guide-images.cdn.ifixit.com/igi/IKlW6WTZKKmapYkt.full, with the expected 12 traces being clearly visible near the ribbon cable slot)
updating the barrier position according to eye tracking data relative to an optimal setting stored in calibration data: this is what Nintendo calls "Super Stable 3D" (SS3D); not done when in 2D mode

Head-tracking can be used even if SS3D is disabled.

SS3D works as follows:

compute the raw X and Y pixel coordinates for the eye midpoint: rawX = (leftEyeRawPxCoords.x + rightEyeRawPxCoords.x) / 2 rawY = (leftEyeRawPxCoords.y + rightEyeRawPxCoords.y) / 2
rotate the value around the optical Z-axis using the optimal eye-to-camera angle from calibration data, with a rotation matrix
normalize the X value: xC = (rawX / 320) - 0.5
transform into world space coordinate, using fovX from calibration (convert to radians first). Note that this fovX doesn't take lens distortion into account and is slightly different from the hardcoded angle used in QTMU_GetTrackingData x = xC * tan(fovX/2)
multiply by length of adjacent side (eye-to-camera distance) to get the length of the opposite side. This is the eye horizontal deviation to camera lens in mm, which is then converted to number of iod/12 units: delta = x * optimalDistance / (iod/12)
we then obtain the new target position of the parallax barrier (expressed in iod/12 units, mod iod/12): pos = centerPos + delta
- the value is then rounded to nearest integer. To avoid artifacts, if the rounded value is going to increase, then 0.01 is subtracted, and if it is going to decrease, then 0.01 is added. The value is rounded again to compute the final discrete value written to the expander (barrier position).
- note: all calculation in QTM and otherwise assume interocular distance to be 62mm (the average). Assumedly, if the user's IOD is different, then "optimal distance to screen" effectively changes for that user.

QTM services are not present on O3DS, thus caller must call qtmCheckServicesRegistered to check if the services are registered. Moreover, since QTM functionality might not always be available (due to blacklist or console being N2DSXL), qtm:u users should check Result return values, and qtm:s users can call QTMS_SetQtmStatus to check the actual availability status.

Considering that the eye tracking data reporting API is hardware-agnostic, it is advisable to hardcode neither camera aspect ratio (even if it is 4/3 on real hardware) and resolution nor field-of-view angle.

There is a separate QTM service, qtm:c ("hardware check"), that lets you manipulate parallax barrier pattern directly. It is covered in qtmc.h instead.

Enumeration Type Documentation

◆ QtmEyeSide

enum QtmEyeSide

Left eye or right eye, for QtmTrackingData and QtmRawTrackingData.

Enumerator
QTM_EYE_LEFT	Left eye.
QTM_EYE_RIGHT	Right eye.
QTM_EYE_NUM	Number of eyes.

◆ QtmServiceName

enum QtmServiceName

QTM service name enum, excluding qtm:c

Enumerator

QTM_SERVICE_USER

qtm:u: has eye-tracking commands and IR LED control commands, but for some reason cannot fetch ambiant lux data from the camera's luminosity sensor.

QTM_SERVICE_SYSTEM

qtm:s: has access to all qtm:u commands, plus luminosity sensor, plus manual barrier position setting and calibration adjustment commands.

Automatic barrier control is reenabled on session exit.

QTM_SERVICE_SYSTEM_PROCESS

qtm:sp: has access to all qtm:s (and qtm:u) commands, and merely has a few more commands that GSP uses to notify QTM of 2D<>3D mode switches and power events.

Automatic barrier control is reenabled on session exit. GSP always keeps a qtm:sp sessions open (at least on latest system version), whereas NS opens then immediately closes a qtm:sp sessions only when dealing with a "blacklisted" application (that is, almost never).

◆ QtmStatus

enum QtmStatus

QTM enablement status (when cameras not in use by user), set by qtm:s.

Note: Manual IR LED control, camera lux, and qtm:c commands remain available for use on N3DS and N3DSXL regardless.

Enumerator

QTM_STATUS_ENABLED

QTM is fully enabled.

QTM_STATUS_SS3D_DISABLED

QTM "super stable 3D" feature is disabled. Parallax barrier hardware state is configured to match O3DS.

QTM_STATUS_UNAVAILABLE

QTM is unavailable: either "blacklisted" (usually by NS) for the current title, or console is a N2DSXL.

   In this state, all QTM functionality is disabled. This includes "super-stable 3D"
   (ie. auto barrier adjustment) including `qtm:s` manual barrier position setting functions,
   head tracking, IR LED control and camera luminance reporting (400.0 is returned instead).

Note: qtm:c barrier hardware state setting function (blah) bypasses this state.; Due to an oversight, QTMS_SetQtmStatus allows changing QTM state on N2DSXL. This is not intended to be done, and is in fact never done by official software.

Function Documentation

◆ qtmCheckServicesRegistered()

bool qtmCheckServicesRegistered ( void )

Check whether or not QTM services are registered.

Returns: True on O3DS systems, false on N3DS systems.

◆ qtmClearIrLedOverrides()

Result qtmClearIrLedOverrides ( void )

Attempts to clear IR LED overrides from any of the relevant commands in qtm:u, qtm:s (and qtm:c) commands by calling QTMU_EnableManualIrLedControl followed by QTMU_DisableManualIrLedControl, so that auto IR LED management takes place again.

Returns: The value returned by QTMU_DisableManualIrLedControl.

◆ qtmComputeFovX()

float qtmComputeFovX ( const QtmTrackingData * data )

Computes an approximation of the horizontal angular field of view of the camera based on eye tracking data.

Parameters

data	Eye tracking data, obtained from QTMU_GetTrackingData or QTMU_GetTrackingDataEx.

Returns: Horizontal angular field of view in radians. Corresponds to 64.9 degrees on real hardware.

◆ qtmComputeFovY()

float qtmComputeFovY ( const QtmTrackingData * data )

Computes an approximation of the vertical angular field of view of the camera based on eye tracking data.

Parameters

data	Eye tracking data, obtained from QTMU_GetTrackingData or QTMU_GetTrackingDataEx.

Returns: Vertical angular field of view in radians. Corresponds to 51.0 degrees on real hardware.

◆ qtmComputeHeadTiltAngle()

float qtmComputeHeadTiltAngle ( const QtmTrackingData * data )

Computes the user's head tilt angle, that is, the angle between the line through both eyes and the camera's horizontal axis in camera space.

Parameters

data	Eye tracking data, obtained from QTMU_GetTrackingData or QTMU_GetTrackingDataEx.

Returns: Horizontal head angle relative to camera, in radians.

◆ qtmComputeInverseAspectRatio()

float qtmComputeInverseAspectRatio ( const QtmTrackingData * data )

Computes a rough approximation of the inverse of the aspect ration of the camera based on eye tracking data.

Parameters

data	Eye tracking data, obtained from QTMU_GetTrackingData or QTMU_GetTrackingDataEx.

Returns: Rough approximation of the inverse of the aspect ratio of the camera. Aspect ratio is exactly 0.75 on real hardware.

◆ qtmEstimateEyeToCameraDistance()

float qtmEstimateEyeToCameraDistance ( const QtmTrackingData * data )

Estimates the distance between the user's eyes and the camera, based on eye tracking data.

This may be a little bit inaccurate, as this assumes interocular distance of 62mm (like all 3DS software does), and that both eyes are at the same distance from the screen.

Parameters

data	Eye tracking data, obtained from QTMU_GetTrackingData or QTMU_GetTrackingDataEx.

Returns: Eye-to-camera distance in millimeters.

◆ qtmInit()

Result qtmInit ( QtmServiceName serviceName )

Initializes QTM (except qtm:c).

Excluding qtm:c, QTM has three main services. Only 3 sessions (2 until 9.3.0 sysupdate) for ALL services COMBINED, including qtm:c, can be open at a time. Refer to QtmServiceName enum value descriptions to see which service to choose.

Parameters

serviceName QTM service name enum value (corresponding to qtm:u, qtm:s and qtm:sp respectively).

Note: Result of qtmCheckServicesRegistered should be checked before calling this function.

◆ QTMS_DisableAutoBarrierControl()

Result QTMS_DisableAutoBarrierControl ( void )

Temporarily disables automatic barrier control (when in 3D mode with "super stable 3D" enabled).

Note: This is automatically called upon qtm:s and qtm:sp session exit.

Returns: 0xC8A18009 if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL), otherwise 0 (success).

Note: Due to an oversight, QTMS_SetQtmStatus allows changing QTM state on N2DSXL. This is not intended to be done, and is in fact never done by official software. If that is regardless the case, this function here does nothing.

◆ QTMS_EnableAutoBarrierControl()

Result QTMS_EnableAutoBarrierControl ( void )

Enables automatic barrier control when in 3D mode with "super stable 3D" enabled.

Note: This is automatically called upon qtm:s and qtm:sp session exit.

Returns: 0xC8A18009 if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL), otherwise 0 (success).

Note: Due to an oversight, QTMS_SetQtmStatus allows changing QTM state on N2DSXL. This is not intended to be done, and is in fact never done by official software. If that is regardless the case, this function here does nothing.

◆ QTMS_GetCameraLuminance()

Result QTMS_GetCameraLuminance ( float * outLuminanceLux )

Gets the average ambient luminance as perceived by the inner camera (in lux).

If QTM is unavailable (in particular, QTM is always unavailable on N2DSXL), returns 400.0 instead of the actual luminance.

Parameters

[out] outLuminanceLux Where to write the luminance to. Always 400.0 on N2DSXL.

Note: Camera exposure, and in particular auto-exposure affects the returned luminance value. This must be taken into consideration, because this value can thus surge when user covers the inner camera.

Returns: Always 0 (success).

◆ QTMS_GetCurrentBarrierPosition()

Result QTMS_GetCurrentBarrierPosition ( u8 * outPosition )

Gets the current position of the parallax barrier (offset in iod/12 units, slit width of 6 units).

When "super stable 3D" is disabled, returns 13 instead.

Parameters

[out] outPosition Where to write the barrier's position to.

Returns: 0xC8A18009 if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL), otherwise 0 (success).

Note: When SS3D is disabled, this returns 13 to outPosition . When in 2D mode, the returned position is not updated.; Due to an oversight, QTMS_SetQtmStatus allows changing QTM state on N2DSXL. This is not intended to be done, and is in fact never done by official software. If that is regardless the case, this function here returns 13 to outPosition .

See also: QTMC_SetBarrierPattern

◆ QTMS_GetQtmStatus()

Result QTMS_GetQtmStatus ( QtmStatus * outQtmStatus )

Gets the current QTM status (enabled/ss3d disabled/unavailable).

Parameters

[out] outQtmStatus Where to write the QTM status to.

Returns: Always 0.

◆ QTMS_SetBarrierPosition()

Result QTMS_SetBarrierPosition ( u8 position )

Temporarily sets the parallax barrier's position (offset in iod/12 units, assuming slit width of 6 units).

Does nothing in 2D mode and/or if "super stable 3D" is disabled.

Parameters

position Parallax barrier position (offset in units), must be between 0 and 11 (both included)

Returns: 0xC8A18009 if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL), 0xE0E18002 if position is not in range, otherwise 0 (success).

Note: Due to an oversight, QTMS_SetQtmStatus allows changing QTM state on N2DSXL. This is not intended to be done, and is in fact never done by official software. If that is regardless the case, this function here does nothing.; No effect when the screen is in 2D mode.

See also: QTMC_SetBarrierPattern

◆ QTMS_SetCalibrationData()

Result QTMS_SetCalibrationData	(	const QtmCalibrationData *	cal,
		bool	saveCalToCfg
	)

Sets calibration data, taking effect immediately, and optionally saves it to cfg.

Parameters

cal	Pointer to calibration data.
saveCalToCfg	Whether or not to persist the calibration data in `cfg`.

Returns: 0xC8A18009 if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL), otherwise whatever cfg:s commands return (if used), or 0 (success).

Note: There is no "get" counterpart for this function, and there is no way to see the current calibration data in use unless it has been saved to cfg.; Due to an oversight, QTMS_SetQtmStatus allows changing QTM state on N2DSXL. This is not intended to be done, and is in fact never done by official software. If that is regardless the case, this function here doesn't apply calibrations parameters (they may still be saved, however, even though QTM calibration blocks are always normally 0 on N2DSXL).

◆ QTMS_SetCenterBarrierPosition()

Result QTMS_SetCenterBarrierPosition ( float position )

Sets the neutral (center) barrier position/offset in calibration, without saving it to cfg.

Takes effect immediately. SS3D works by calculating the position of the eye midpoint, rotated by the ideal eye-to-camera angle, expressed in (iod/12 units, iod assumed to be 62mm).

Parameters

position Center barrier position, in terms of iod/12 units modulo iod/12.

Note: This field is floating-point for QTM auto-adjustment purposes, however the actual barrier position in hardware is an integer.; This is the field that System Settings lets you add -1.0 to +1.0 to.; There is no "get" counterpart for this.

Returns: 0xC8A18009 if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL), otherwise 0 (success).

◆ QTMS_SetIrLedStatusOverride()

Result QTMS_SetIrLedStatusOverride ( bool on )

Temporarily overrides IR LED state.

Requires "manual control" from qtm:u to be disabled, and has lower priority than it.

Parameters

on	Whether to turn the IR LED on or off.

Returns: 0xC8A18005 if manual control was enabled or if the operation failed, 0xC8A18008 if camera is in use by user (unless "hardware check" API enabled), or 0xC8A18009 if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL). Otherwise, 0 (success).

◆ QTMS_SetQtmStatus()

Result QTMS_SetQtmStatus ( QtmStatus qtmStatus )

Gets the current QTM status (enabled/ss3d disabled/unavailable).

Also sets or clear the "blacklisted" flag returned by QTMU_IsCurrentAppBlacklisted.

Parameters

qtmStatus QTM status to set. If equal to QTM_STATUS_UNAVAILABLE, sets the "blacklisted" flag, otherwise clears it.

Returns: 0xE0E18002 if enum value is invalid, otherwise 0 (success).

Note: System settings uses this to disable super-stable 3D, and NS to "blacklist" (make QTM unavailable) specific applications.

◆ QTMSP_IsExpanderInUse()

Result QTMSP_IsExpanderInUse ( bool * outActive )

Called by GSP's LCD driver to know whether or not QTM's expander thread is using the TI TCA6416A expander; it is waiting for this to become true/false during LCD power on/power off to proceed.

Always false on N2DSXL.

Parameters

[out] outActive Where to write the "in use" status to.

Returns: Always 0 (success).

◆ QTMSP_NotifyTopLcdModeChange()

Result QTMSP_NotifyTopLcdModeChange ( u8 newMode )

Called by GSP's LCD driver to signal 2D<>3D mode change.

Parameters

newMode 0 for 2D, 1 for 800px 2D (unused for this function, same as 0), 2 for 3D

Returns: Always 0 (success).

◆ QTMSP_NotifyTopLcdPowerOff()

Result QTMSP_NotifyTopLcdPowerOff ( void )

Called by GSP's LCD driver during top LCD power-on to signal to QTM that it needs to switch the parallax barrier state to a 2D state (all-transparent mask).

Causes QTM's expander thread to exit, relinquishing its i2c::QTM session with it.

Returns: Always 0 (success).

◆ QTMSP_NotifyTopLcdPowerOn()

Result QTMSP_NotifyTopLcdPowerOn ( void )

Called by GSP's LCD driver during top LCD power-on to signal to QTM that it may power on and/or reconfigure then use the TI TCA6416A expander.

In the process, QTM re-creates its expander thread.

Returns: Always 0 (success).

◆ QTMU_DisableManualIrLedControl()

Result QTMU_DisableManualIrLedControl ( void )

Temporarily disables manual control of the IR LED by user, re-enabling its automatic control.

If not already done, this also turns off the IR LED.

Returns: Always 0 (success).

◆ QTMU_EnableManualIrLedControl()

Result QTMU_EnableManualIrLedControl ( void )

Temporarily enables manual control of the IR LED by user, disabling its automatic control.

If not already done, this also turns off the IR LED. This setting is cleared when user closes the console's shell.

Returns: Always 0 (success).

◆ QTMU_GetRawTrackingData()

static Result QTMU_GetRawTrackingData ( QtmRawTrackingData * outData )

inlinestatic

Gets the current raw eye tracking data.

Parameters

[out] outData Where to write the raw tracking data to. Cleared to all-zero on failure (instead of being left uninitialized).

Returns: 0xC8A18008 if camera is in use by user, or 0xC8A183EF if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL), Otherwise, 0 (success). Return value should be checked by caller.

Note: Consider using QTMU_GetTrackingData instead.

◆ QTMU_GetRawTrackingDataEx()

Result QTMU_GetRawTrackingDataEx	(	QtmRawTrackingData *	outData,
		s64	predictionTimePointOrZero
	)

Gets the current raw eye tracking data, with an optional prediction made for predictionTimePointOrZero = t+dt, or for the current time point (QTM makes predictions based on gyro data since inner camera runs at 30 FPS).

Parameters

[out]	outData	Where to write the raw tracking data to. Cleared to all-zero on failure (instead of being left uninitialized).
	predictionTimePointOrZero	Either zero, or the time point (in system ticks) for which to make a prediction for. Maximum 1 frame (at 30 FPS) in the past, and up to 5 frames in the future.

Returns: 0xC8A18008 if camera is in use by user, or 0xC8A183EF if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL), Otherwise, 0 (success). Return value should be checked by caller.

Note: Consider using QTMU_GetTrackingDataEx instead.

◆ QTMU_GetTrackingData()

static Result QTMU_GetTrackingData ( QtmTrackingData * outData )

inlinestatic

Gets the current normalized eye tracking data, made suitable for 3D programming.

Parameters

[out] outData Where to write the raw tracking data to. Cleared to all-zero on failure (instead of being left uninitialized).

Returns: 0xC8A18008 if camera is in use by user, or 0xC8A183EF if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL). Otherwise, 0 (success). Return value should be checked by caller.

Note: This can, for example, be used in games to allow the user to control the scene's camera with their own face.

◆ QTMU_GetTrackingDataEx()

Result QTMU_GetTrackingDataEx	(	QtmTrackingData *	outData,
		s64	predictionTimePointOrZero
	)

Gets the current normalized eye tracking data, made suitable for 3D programming with an optional prediction made for predictionTimePointOrZero = t+dt, or for the current time point (QTM makes predictions based on gyro data since inner camera runs at 30 FPS).

Parameters

[out]	outData	Where to write the raw tracking data to. Cleared to all-zero on failure (instead of being left uninitialized).
	predictionTimePointOrZero	Either zero, or the time point (in system ticks) for which to make a prediction for. Maximum 1 frame (at 30 FPS) in the past, and up to 5 frames in the future.

Returns: 0xC8A18008 if camera is in use by user, or 0xC8A183EF if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL). Otherwise, 0 (success). Return value should be checked by caller.

Note: This can, for example, be used in games to allow the user to control the scene's camera with their own face.

◆ QTMU_IsCurrentAppBlacklisted()

Result QTMU_IsCurrentAppBlacklisted ( bool * outBlacklisted )

Checks whether or not QTM has been blacklisted, ie.

that it has been made unavailable. In detail, this means that the last call to QTMS_SetQtmStatus was made with argument QTM_STATUS_UNAVAILABLE, usually by NS. This feature seems to only be used for some internal test titles.

Parameters

[out] outBlacklisted Whether or not QTM is unavailable. Always true on N2DSXL.

Returns: Always 0 (success).

Note: On N2DSXL, even though status is always supposed to be QTM_STATUS_UNAVAILABLE, this function often returns true (because NS doesn't change QTM's status if title isn't blacklisted). Do not rely on this for N2DSXL detection.; Refer to https://www.3dbrew.org/wiki/NS_CFA for a list of title UIDs this is used for.

◆ QTMU_SetIrLedStatus()

Result QTMU_SetIrLedStatus ( bool on )

Turns the IR LED on or off during manual control.

QTMU_EnableManualIrLedControl must have been called.

Parameters

on	Whether to turn the IR LED on or off.

Returns: 0xC8A18005 if manual control was not enabled or if the operation failed, 0xC8A18008 if camera is in use by user, or 0xC8A18009 if QTM is unavailable (in particular, QTM is always unavailable on N2DSXL). Otherwise, 0 (success).

Data Structures

Macros

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ QtmEyeSide

◆ QtmServiceName

◆ QtmStatus

Function Documentation

◆ qtmCheckServicesRegistered()

◆ qtmClearIrLedOverrides()

◆ qtmComputeFovX()

◆ qtmComputeFovY()

◆ qtmComputeHeadTiltAngle()

◆ qtmComputeInverseAspectRatio()

◆ qtmEstimateEyeToCameraDistance()

◆ qtmInit()

◆ QTMS_DisableAutoBarrierControl()

◆ QTMS_EnableAutoBarrierControl()

◆ QTMS_GetCameraLuminance()

◆ QTMS_GetCurrentBarrierPosition()

◆ QTMS_GetQtmStatus()

◆ QTMS_SetBarrierPosition()

◆ QTMS_SetCalibrationData()

◆ QTMS_SetCenterBarrierPosition()

◆ QTMS_SetIrLedStatusOverride()

◆ QTMS_SetQtmStatus()

◆ QTMSP_IsExpanderInUse()

◆ QTMSP_NotifyTopLcdModeChange()

◆ QTMSP_NotifyTopLcdPowerOff()

◆ QTMSP_NotifyTopLcdPowerOn()

◆ QTMU_DisableManualIrLedControl()

◆ QTMU_EnableManualIrLedControl()

◆ QTMU_GetRawTrackingData()

◆ QTMU_GetRawTrackingDataEx()

◆ QTMU_GetTrackingData()

◆ QTMU_GetTrackingDataEx()

◆ QTMU_IsCurrentAppBlacklisted()

◆ QTMU_SetIrLedStatus()