# Unigine::Plugins::VrpnTrackerDevice Class (CPP)

**Header:** #include <plugins/Unigine/VrpnClient/UnigineVrpnClient.h>


A class for the [VRPN Plugin](../../../../code/plugins/vrpn/index_cpp.md) that allows receiving data about position, orientation, velocity and acceleration of tracked objects from 3D tracking sensors.


### See Also


- Article on [VRPN Plugin](../../../../code/plugins/vrpn/index_cpp.md)
- UnigineScript samples:

  -
  -


## VrpnTrackerDevice Class

### Members

## int getNumSensors () const

Returns the current total number of sensors.
### Return value

Current total number of sensors.
---

## VrpnTrackerDevice ( const char * name )

Constructor.
### Arguments

- *const char ** **name** - Path to the device in the format *device_name@server_address*.

## void setAccelerationCallback ( const char * name )

Sets the world script callback function that receives data about acceleration of tracked objects.
### Arguments

- *const char ** **name** - Callback function name.

### Examples


```cpp
VrpnTrackerDevice vrpn_tracker;

int init() {
	vrpn_tracker = new VrpnTrackerDevice("device_name@server_addr");
	vrpn_tracker.setAccelerationCallback("acceleration_callback");

	return 1;
}

int shutdown() {
	delete vrpn_tracker;
	return 1;
}

int update() {
	vrpn_tracker.update();
	return 1;
}
// a callback function
void acceleration_callback(int sensor,vec3 acceleration,quat orientation,float ifps) {
	log.message("Device sensor %d: acceleration %s, orientation %s, ifps %f\n",sensor,acceleration,orientation,ifps);
}

```


## const char * getAccelerationCallback ( )

Returns a name of the world script callback function that receives data about acceleration of tracked objects. The callback function should be defined in the world script and receive **4** arguments:


1. Sensor number (*int*)
2. Linear acceleration (*vec3* for the float precision version, or *dvec3* for the double precision version)
3. Acceleration of orientation change (an analog of angular acceleration; *quat*)
4. Acceleration measurement time (*float* for the float precision version, or *double* for the double precision version)


```cpp
// float precision
void callback_func(int sensor,vec3 acceleration,quat acceleration_orientation,float ifps) {
	// function logic
}
// double precision
void callback_func(int sensor,dvec3 acceleration,quat acceleration_orientation,double ifps) {
	// function logic
}

```


### Return value

Callback function name.
## void setTransformCallback ( const char * name )

Sets the world script callback function that receives data about position and orientation of tracked objects.
### Arguments

- *const char ** **name** - Callback function name.

### Examples


```cpp
VrpnTrackerDevice vrpn_tracker;

int init() {
	vrpn_tracker = new VrpnTrackerDevice("device_name@server_addr");
	vrpn_tracker.setTransformCallback("transform_callback");

	return 1;
}

int shutdown() {
	delete vrpn_tracker;
	return 1;
}

int update() {
	vrpn_tracker.update();
	return 1;
}
// a callback function
void transform_callback(int sensor,vec3 position,quat orientation) {
	log.message("Device sensor %d: position %s, orientation %s\n",sensor,position,orientation);
}

```


## const char * getTransformCallback ( )


Returns a name of the world script callback function that receives data about position and orientation of tracked objects. The callback function should be defined in the world script and receive **3** arguments:


1. Sensor number (*int*)
2. Position (*vec3* for the float precision version, or *dvec3* for the double precision version)
3. Orientation (*quat*)


```cpp
// float precision
void callback_func(int sensor,vec3 acceleration,quat acceleration_orientation,float ifps) {
	// function logic
}
// double precision
void callback_func(int sensor,dvec3 acceleration,quat acceleration_orientation,double ifps) {
	// function logic
}

```


### Return value

Callback function name.
## void setVelocityCallback ( const char * name )

Sets the world script callback function that receives data about velocity of tracked objects.
### Arguments

- *const char ** **name** - Callback function name.

### Examples


```cpp
VrpnTrackerDevice vrpn_tracker;

int init() {
	vrpn_tracker = new VrpnTrackerDevice("device_name@server_addr");
	vrpn_tracker.setVelocityCallback("velocity_callback");

	return 1;
}

int shutdown() {
	delete vrpn_tracker;
	return 1;
}

int update() {
	vrpn_tracker.update();
	return 1;
}

// a callback function
void velocity_callback(int sensor,vec3 velocity,quat orientation,float velocity_ifps) {
	log.message("Device sensor %d: velocity %s, orientation %s, ifps %f\n",sensor,velocity,orientation,ifps);
}

```


## const char * getVelocityCallback ( )


Returns a name of the world script callback function that receives data about velocity of tracked objects. The callback function should be defined in the world script and receive **4** arguments:


1. Sensor number (*int*)
2. Linear velocity (*vec3* for the float precision version, or *dvec3* for the double precision version)
3. Velocity of orientation change (an analog of angular velocity; *quat*)
4. Velocity measurement time (*float* for the float precision version, or *double* for the double precision version)


```cpp
// float precision
void callback_func(int sensor,vec3 velocity,quat velocity_orientation,float ifps) {
	// function logic
}
// double precision
void callback_func(int sensor,dvec3 velocity,quat velocity_orientation,double ifps) {
	// function logic
}

```


### Return value

Callback function name.
## void update ( )


Updates the internal state of the device and receives input data.


> **Notice:** This function should be called each frame.


## Math:: Vec3 getSensorPosition ( int num ) const

Returns the specified sensor position.
### Arguments

- *int* **num** - Sensor index number in range [0; [NUM_SENSORS](#getNumSensors_int) - 1 ].

### Return value

Sensor position.
## Math:: quat getSensorRotation ( int num ) const

Returns the specified sensor rotation.
### Arguments

- *int* **num** - Sensor index number in range [0; [NUM_SENSORS](#getNumSensors_int) - 1 ].

### Return value

Sensor rotation.
## Math:: Vec3 getSensorVelocity ( int num ) const

Returns the current sensor velocity (m/s2).
### Arguments

- *int* **num** - Sensor index number in range [0; [NUM_SENSORS](#getNumSensors_int) - 1 ].

### Return value

Sensor velocity, in units per second.
## Math:: quat getSensorVelocityOrientation ( int num ) const

Returns the orientation of the specified sensor after the [delta time](#getSensorVelocityIFps_int_scalar).
### Arguments

- *int* **num** - Sensor index number in range [0; [NUM_SENSORS](#getNumSensors_int) - 1 ].

### Return value

Orientation of the sensor velocity.
## Math::Scalar getSensorVelocityIFps ( int num ) const

Returns the delta time (in seconds) for the sensor velocity.
### Arguments

- *int* **num** - Sensor index number in range [0; [NUM_SENSORS](#getNumSensors_int) - 1 ].

### Return value

Delta time (in seconds).
## Math:: Vec3 getSensorAcceleration ( int num ) const

Returns the current sensor acceleration (m/s2).
### Arguments

- *int* **num** - Sensor index number in range [0; [NUM_SENSORS](#getNumSensors_int) - 1 ].

### Return value

Sensor acceleration.
## Math:: quat getSensorAccelerationOrientation ( int num ) const

Returns the orientation of the specified sensor after the [delta time](#getSensorAccelerationIFps_int_scalar).
### Arguments

- *int* **num** - Sensor index number in range [0; [NUM_SENSORS](#getNumSensors_int) - 1 ].

### Return value

Orientation of the sensor acceleration.
## Math::Scalar getSensorAccelerationIFps ( int num ) const

Returns delta time (in seconds) for the sensor acceleration.
### Arguments

- *int* **num** - Sensor index number in range [0; [NUM_SENSORS](#getNumSensors_int) - 1 ].

### Return value

Delta time (in seconds).