SDL 3.0
SDL_sensor.h File Reference
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Macros

#define SDL_STANDARD_GRAVITY   9.80665f
 

Typedefs

typedef struct SDL_Sensor SDL_Sensor
 
typedef Uint32 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

SDL_SensorIDSDL_GetSensors (int *count)
 
const char * SDL_GetSensorNameForID (SDL_SensorID instance_id)
 
SDL_SensorType SDL_GetSensorTypeForID (SDL_SensorID instance_id)
 
int SDL_GetSensorNonPortableTypeForID (SDL_SensorID instance_id)
 
SDL_SensorSDL_OpenSensor (SDL_SensorID instance_id)
 
SDL_SensorSDL_GetSensorFromID (SDL_SensorID instance_id)
 
SDL_PropertiesID SDL_GetSensorProperties (SDL_Sensor *sensor)
 
const char * SDL_GetSensorName (SDL_Sensor *sensor)
 
SDL_SensorType SDL_GetSensorType (SDL_Sensor *sensor)
 
int SDL_GetSensorNonPortableType (SDL_Sensor *sensor)
 
SDL_SensorID SDL_GetSensorID (SDL_Sensor *sensor)
 
bool SDL_GetSensorData (SDL_Sensor *sensor, float *data, int num_values)
 
void SDL_CloseSensor (SDL_Sensor *sensor)
 
void SDL_UpdateSensors (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.

Since
This macro is available since SDL 3.1.3.

Definition at line 74 of file SDL_sensor.h.

Typedef Documentation

◆ SDL_Sensor

typedef struct SDL_Sensor SDL_Sensor

CategorySensor

SDL sensor management.

In order to use these functions, SDL_Init() must have been called with the SDL_INIT_SENSOR flag. This causes SDL to scan the system for sensors, and load appropriate drivers. The opaque structure used to identify an opened SDL sensor.

Since
This struct is available since SDL 3.1.3.

Definition at line 52 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 value 0 is an invalid ID.

Since
This datatype is available since SDL 3.1.3.

Definition at line 62 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.

Since
This enum is available since SDL 3.1.3.
See also
SDL_GetCurrentDisplayOrientation
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 130 of file SDL_sensor.h.

131{
132 SDL_SENSOR_INVALID = -1, /**< Returned for an invalid sensor */
133 SDL_SENSOR_UNKNOWN, /**< Unknown sensor type */
134 SDL_SENSOR_ACCEL, /**< Accelerometer */
135 SDL_SENSOR_GYRO, /**< Gyroscope */
136 SDL_SENSOR_ACCEL_L, /**< Accelerometer for left Joy-Con controller and Wii nunchuk */
137 SDL_SENSOR_GYRO_L, /**< Gyroscope for left Joy-Con controller */
138 SDL_SENSOR_ACCEL_R, /**< Accelerometer for right Joy-Con controller */
139 SDL_SENSOR_GYRO_R /**< Gyroscope for right Joy-Con controller */
SDL_SensorType
Definition SDL_sensor.h:131
@ SDL_SENSOR_GYRO_L
Definition SDL_sensor.h:137
@ SDL_SENSOR_INVALID
Definition SDL_sensor.h:132
@ SDL_SENSOR_GYRO
Definition SDL_sensor.h:135
@ SDL_SENSOR_ACCEL_R
Definition SDL_sensor.h:138
@ SDL_SENSOR_UNKNOWN
Definition SDL_sensor.h:133
@ SDL_SENSOR_ACCEL
Definition SDL_sensor.h:134
@ SDL_SENSOR_ACCEL_L
Definition SDL_sensor.h:136
@ SDL_SENSOR_GYRO_R
Definition SDL_sensor.h:139

Function Documentation

◆ SDL_CloseSensor()

void SDL_CloseSensor ( SDL_Sensor sensor)
extern

Close a sensor previously opened with SDL_OpenSensor().

Parameters
sensorthe SDL_Sensor object to close.
Since
This function is available since SDL 3.1.3.

◆ SDL_GetSensorData()

bool SDL_GetSensorData ( 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
true on success or false on failure; call SDL_GetError() for more information.
Since
This function is available since SDL 3.1.3.

◆ SDL_GetSensorFromID()

SDL_Sensor * SDL_GetSensorFromID ( SDL_SensorID  instance_id)
extern

Return the SDL_Sensor associated with an instance ID.

Parameters
instance_idthe sensor instance ID.
Returns
an SDL_Sensor object or NULL on failure; call SDL_GetError() for more information.
Since
This function is available since SDL 3.1.3.

◆ SDL_GetSensorID()

SDL_SensorID SDL_GetSensorID ( SDL_Sensor sensor)
extern

Get the instance ID of a sensor.

Parameters
sensorthe SDL_Sensor object to inspect.
Returns
the sensor instance ID, or 0 on failure; call SDL_GetError() for more information.
Since
This function is available since SDL 3.1.3.

◆ SDL_GetSensorName()

const char * SDL_GetSensorName ( SDL_Sensor sensor)
extern

Get the implementation dependent name of a sensor.

Parameters
sensorthe SDL_Sensor object.
Returns
the sensor name or NULL on failure; call SDL_GetError() for more information.
Since
This function is available since SDL 3.1.3.

◆ SDL_GetSensorNameForID()

const char * SDL_GetSensorNameForID ( SDL_SensorID  instance_id)
extern

Get the implementation dependent name of a sensor.

This can be called before any sensors are opened.

Parameters
instance_idthe sensor instance ID.
Returns
the sensor name, or NULL if instance_id is not valid.
Since
This function is available since SDL 3.1.3.

◆ SDL_GetSensorNonPortableType()

int SDL_GetSensorNonPortableType ( 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 3.1.3.

◆ SDL_GetSensorNonPortableTypeForID()

int SDL_GetSensorNonPortableTypeForID ( SDL_SensorID  instance_id)
extern

Get the platform dependent type of a sensor.

This can be called before any sensors are opened.

Parameters
instance_idthe sensor instance ID.
Returns
the sensor platform dependent type, or -1 if instance_id is not valid.
Since
This function is available since SDL 3.1.3.

◆ SDL_GetSensorProperties()

SDL_PropertiesID SDL_GetSensorProperties ( SDL_Sensor sensor)
extern

Get the properties associated with a sensor.

Parameters
sensorthe SDL_Sensor object.
Returns
a valid property ID on success or 0 on failure; call SDL_GetError() for more information.
Since
This function is available since SDL 3.1.3.

◆ SDL_GetSensors()

SDL_SensorID * SDL_GetSensors ( int *  count)
extern

Get a list of currently connected sensors.

Parameters
counta pointer filled in with the number of sensors returned, may be NULL.
Returns
a 0 terminated array of sensor instance IDs or NULL on failure; call SDL_GetError() for more information. This should be freed with SDL_free() when it is no longer needed.
Since
This function is available since SDL 3.1.3.

◆ SDL_GetSensorType()

SDL_SensorType SDL_GetSensorType ( 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 3.1.3.

◆ SDL_GetSensorTypeForID()

SDL_SensorType SDL_GetSensorTypeForID ( SDL_SensorID  instance_id)
extern

Get the type of a sensor.

This can be called before any sensors are opened.

Parameters
instance_idthe sensor instance ID.
Returns
the SDL_SensorType, or SDL_SENSOR_INVALID if instance_id is not valid.
Since
This function is available since SDL 3.1.3.

◆ SDL_OpenSensor()

SDL_Sensor * SDL_OpenSensor ( SDL_SensorID  instance_id)
extern

Open a sensor for use.

Parameters
instance_idthe sensor instance ID.
Returns
an SDL_Sensor object or NULL on failure; call SDL_GetError() for more information.
Since
This function is available since SDL 3.1.3.

◆ SDL_UpdateSensors()

void SDL_UpdateSensors ( 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 3.1.3.