SDL 2.0
SDL_sensor.h File Reference
#include "SDL_stdinc.h"
#include "SDL_error.h"
#include "begin_code.h"
#include "close_code.h"
+ Include dependency graph for SDL_sensor.h:
+ This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros

#define SDL_STANDARD_GRAVITY   9.80665f
 

Typedefs

typedef struct _SDL_Sensor SDL_Sensor
 
typedef Sint32 SDL_SensorID
 

Enumerations

enum  SDL_SensorType {
  SDL_SENSOR_INVALID = -1 ,
  SDL_SENSOR_UNKNOWN ,
  SDL_SENSOR_ACCEL ,
  SDL_SENSOR_GYRO ,
  SDL_SENSOR_ACCEL_L ,
  SDL_SENSOR_GYRO_L ,
  SDL_SENSOR_ACCEL_R ,
  SDL_SENSOR_GYRO_R
}
 

Functions

void SDL_LockSensors (void)
 
void SDL_UnlockSensors (void)
 
int SDL_NumSensors (void)
 
const char * SDL_SensorGetDeviceName (int device_index)
 
SDL_SensorType SDL_SensorGetDeviceType (int device_index)
 
int SDL_SensorGetDeviceNonPortableType (int device_index)
 
SDL_SensorID SDL_SensorGetDeviceInstanceID (int device_index)
 
SDL_SensorSDL_SensorOpen (int device_index)
 
SDL_SensorSDL_SensorFromInstanceID (SDL_SensorID instance_id)
 
const char * SDL_SensorGetName (SDL_Sensor *sensor)
 
SDL_SensorType SDL_SensorGetType (SDL_Sensor *sensor)
 
int SDL_SensorGetNonPortableType (SDL_Sensor *sensor)
 
SDL_SensorID SDL_SensorGetInstanceID (SDL_Sensor *sensor)
 
int SDL_SensorGetData (SDL_Sensor *sensor, float *data, int num_values)
 
int SDL_SensorGetDataWithTimestamp (SDL_Sensor *sensor, Uint64 *timestamp, float *data, int num_values)
 
void SDL_SensorClose (SDL_Sensor *sensor)
 
void SDL_SensorUpdate (void)
 

Macro Definition Documentation

◆ SDL_STANDARD_GRAVITY

#define SDL_STANDARD_GRAVITY   9.80665f

A constant to represent standard gravity for accelerometer sensors.

The accelerometer returns the current acceleration in SI meters per second squared. This measurement includes the force of gravity, so a device at rest will have an value of SDL_STANDARD_GRAVITY away from the center of the earth, which is a positive Y value.

Definition at line 134 of file SDL_sensor.h.

Typedef Documentation

◆ SDL_Sensor

typedef struct _SDL_Sensor SDL_Sensor

Definition at line 51 of file SDL_sensor.h.

◆ SDL_SensorID

This is a unique ID for a sensor for the time it is connected to the system, and is never reused for the lifetime of the application.

The ID value starts at 0 and increments from there. The value -1 is an invalid ID.

Definition at line 60 of file SDL_sensor.h.

Enumeration Type Documentation

◆ SDL_SensorType

The different sensors defined by SDL.

Additional sensors may be available, using platform dependent semantics.

Here are the additional Android sensors:

https://developer.android.com/reference/android/hardware/SensorEvent.html#values

Accelerometer sensor notes:

The accelerometer returns the current acceleration in SI meters per second squared. This measurement includes the force of gravity, so a device at rest will have an value of SDL_STANDARD_GRAVITY away from the center of the earth, which is a positive Y value.

  • values[0]: Acceleration on the x axis
  • values[1]: Acceleration on the y axis
  • values[2]: Acceleration on the z axis

For phones and tablets held in natural orientation and game controllers held in front of you, the axes are defined as follows:

  • -X ... +X : left ... right
  • -Y ... +Y : bottom ... top
  • -Z ... +Z : farther ... closer

The accelerometer axis data is not changed when the device is rotated.

Gyroscope sensor notes:

The gyroscope returns the current rate of rotation in radians per second. The rotation is positive in the counter-clockwise direction. That is, an observer looking from a positive location on one of the axes would see positive rotation on that axis when it appeared to be rotating counter-clockwise.

  • values[0]: Angular speed around the x axis (pitch)
  • values[1]: Angular speed around the y axis (yaw)
  • values[2]: Angular speed around the z axis (roll)

For phones and tablets held in natural orientation and game controllers held in front of you, the axes are defined as follows:

  • -X ... +X : left ... right
  • -Y ... +Y : bottom ... top
  • -Z ... +Z : farther ... closer

The gyroscope axis data is not changed when the device is rotated.

See also
SDL_GetDisplayOrientation
Enumerator
SDL_SENSOR_INVALID 

Returned for an invalid sensor

SDL_SENSOR_UNKNOWN 

Unknown sensor type

SDL_SENSOR_ACCEL 

Accelerometer

SDL_SENSOR_GYRO 

Gyroscope

SDL_SENSOR_ACCEL_L 

Accelerometer for left Joy-Con controller and Wii nunchuk

SDL_SENSOR_GYRO_L 

Gyroscope for left Joy-Con controller

SDL_SENSOR_ACCEL_R 

Accelerometer for right Joy-Con controller

SDL_SENSOR_GYRO_R 

Gyroscope for right Joy-Con controller

Definition at line 114 of file SDL_sensor.h.

115{
116 SDL_SENSOR_INVALID = -1, /**< Returned for an invalid sensor */
117 SDL_SENSOR_UNKNOWN, /**< Unknown sensor type */
118 SDL_SENSOR_ACCEL, /**< Accelerometer */
119 SDL_SENSOR_GYRO, /**< Gyroscope */
120 SDL_SENSOR_ACCEL_L, /**< Accelerometer for left Joy-Con controller and Wii nunchuk */
121 SDL_SENSOR_GYRO_L, /**< Gyroscope for left Joy-Con controller */
122 SDL_SENSOR_ACCEL_R, /**< Accelerometer for right Joy-Con controller */
123 SDL_SENSOR_GYRO_R /**< Gyroscope for right Joy-Con controller */
SDL_SensorType
Definition SDL_sensor.h:115
@ SDL_SENSOR_GYRO_L
Definition SDL_sensor.h:121
@ SDL_SENSOR_INVALID
Definition SDL_sensor.h:116
@ SDL_SENSOR_GYRO
Definition SDL_sensor.h:119
@ SDL_SENSOR_ACCEL_R
Definition SDL_sensor.h:122
@ SDL_SENSOR_UNKNOWN
Definition SDL_sensor.h:117
@ SDL_SENSOR_ACCEL
Definition SDL_sensor.h:118
@ SDL_SENSOR_ACCEL_L
Definition SDL_sensor.h:120
@ SDL_SENSOR_GYRO_R
Definition SDL_sensor.h:123

Function Documentation

◆ SDL_LockSensors()

void SDL_LockSensors ( void  )
extern

Locking for multi-threaded access to the sensor API

If you are using the sensor API or handling events from multiple threads you should use these locking functions to protect access to the sensors.

In particular, you are guaranteed that the sensor list won't change, so the API functions that take a sensor index will be valid, and sensor events will not be delivered.

Since
This function is available since SDL 2.0.14.

◆ SDL_NumSensors()

int SDL_NumSensors ( void  )
extern

Count the number of sensors attached to the system right now.

Returns
the number of sensors detected.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorClose()

void SDL_SensorClose ( SDL_Sensor sensor)
extern

Close a sensor previously opened with SDL_SensorOpen().

Parameters
sensorThe SDL_Sensor object to close.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorFromInstanceID()

SDL_Sensor * SDL_SensorFromInstanceID ( SDL_SensorID  instance_id)
extern

Return the SDL_Sensor associated with an instance id.

Parameters
instance_idThe sensor from instance id.
Returns
an SDL_Sensor object.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorGetData()

int SDL_SensorGetData ( SDL_Sensor sensor,
float *  data,
int  num_values 
)
extern

Get the current state of an opened sensor.

The number of values and interpretation of the data is sensor dependent.

Parameters
sensorThe SDL_Sensor object to query.
dataA pointer filled with the current sensor state.
num_valuesThe number of values to write to data.
Returns
0 or -1 if an error occurred.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorGetDataWithTimestamp()

int SDL_SensorGetDataWithTimestamp ( SDL_Sensor sensor,
Uint64 timestamp,
float *  data,
int  num_values 
)
extern

Get the current state of an opened sensor with the timestamp of the last update.

The number of values and interpretation of the data is sensor dependent.

Parameters
sensorThe SDL_Sensor object to query.
timestampA pointer filled with the timestamp in microseconds of the current sensor reading if available, or 0 if not.
dataA pointer filled with the current sensor state.
num_valuesThe number of values to write to data.
Returns
0 or -1 if an error occurred.
Since
This function is available since SDL 2.26.0.

◆ SDL_SensorGetDeviceInstanceID()

SDL_SensorID SDL_SensorGetDeviceInstanceID ( int  device_index)
extern

Get the instance ID of a sensor.

Parameters
device_indexThe sensor to get instance id from.
Returns
the sensor instance ID, or -1 if device_index is out of range.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorGetDeviceName()

const char * SDL_SensorGetDeviceName ( int  device_index)
extern

Get the implementation dependent name of a sensor.

Parameters
device_indexThe sensor to obtain name from.
Returns
the sensor name, or NULL if device_index is out of range.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorGetDeviceNonPortableType()

int SDL_SensorGetDeviceNonPortableType ( int  device_index)
extern

Get the platform dependent type of a sensor.

Parameters
device_indexThe sensor to check.
Returns
the sensor platform dependent type, or -1 if device_index is out of range.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorGetDeviceType()

SDL_SensorType SDL_SensorGetDeviceType ( int  device_index)
extern

Get the type of a sensor.

Parameters
device_indexThe sensor to get the type from.
Returns
the SDL_SensorType, or SDL_SENSOR_INVALID if device_index is out of range.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorGetInstanceID()

SDL_SensorID SDL_SensorGetInstanceID ( SDL_Sensor sensor)
extern

Get the instance ID of a sensor.

Parameters
sensorThe SDL_Sensor object to inspect.
Returns
the sensor instance ID, or -1 if sensor is NULL.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorGetName()

const char * SDL_SensorGetName ( SDL_Sensor sensor)
extern

Get the implementation dependent name of a sensor

Parameters
sensorThe SDL_Sensor object.
Returns
the sensor name, or NULL if sensor is NULL.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorGetNonPortableType()

int SDL_SensorGetNonPortableType ( SDL_Sensor sensor)
extern

Get the platform dependent type of a sensor.

Parameters
sensorThe SDL_Sensor object to inspect.
Returns
the sensor platform dependent type, or -1 if sensor is NULL.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorGetType()

SDL_SensorType SDL_SensorGetType ( SDL_Sensor sensor)
extern

Get the type of a sensor.

Parameters
sensorThe SDL_Sensor object to inspect.
Returns
the SDL_SensorType type, or SDL_SENSOR_INVALID if sensor is NULL.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorOpen()

SDL_Sensor * SDL_SensorOpen ( int  device_index)
extern

Open a sensor for use.

Parameters
device_indexThe sensor to open.
Returns
an SDL_Sensor sensor object, or NULL if an error occurred.
Since
This function is available since SDL 2.0.9.

◆ SDL_SensorUpdate()

void SDL_SensorUpdate ( void  )
extern

Update the current state of the open sensors.

This is called automatically by the event loop if sensor events are enabled.

This needs to be called from the thread that initialized the sensor subsystem.

Since
This function is available since SDL 2.0.9.

◆ SDL_UnlockSensors()

void SDL_UnlockSensors ( void  )
extern