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SDL_sensor.h File Reference
#include "SDL_stdinc.h"
#include "SDL_error.h"
#include "begin_code.h"
#include "close_code.h"

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 }
 

Functions

DECLSPEC void SDLCALL SDL_LockSensors (void)
 
DECLSPEC void SDLCALL SDL_UnlockSensors (void)
 
DECLSPEC int SDLCALL SDL_NumSensors (void)
 Count the number of sensors attached to the system right now.
 
DECLSPEC const char *SDLCALL SDL_SensorGetDeviceName (int device_index)
 Get the implementation dependent name of a sensor. More...
 
DECLSPEC SDL_SensorType SDLCALL SDL_SensorGetDeviceType (int device_index)
 Get the type of a sensor. More...
 
DECLSPEC int SDLCALL SDL_SensorGetDeviceNonPortableType (int device_index)
 Get the platform dependent type of a sensor. More...
 
DECLSPEC SDL_SensorID SDLCALL SDL_SensorGetDeviceInstanceID (int device_index)
 Get the instance ID of a sensor. More...
 
DECLSPEC SDL_Sensor *SDLCALL SDL_SensorOpen (int device_index)
 Open a sensor for use. More...
 
DECLSPEC SDL_Sensor *SDLCALL SDL_SensorFromInstanceID (SDL_SensorID instance_id)
 
DECLSPEC const char *SDLCALL SDL_SensorGetName (SDL_Sensor *sensor)
 Get the implementation dependent name of a sensor. More...
 
DECLSPEC SDL_SensorType SDLCALL SDL_SensorGetType (SDL_Sensor *sensor)
 Get the type of a sensor. More...
 
DECLSPEC int SDLCALL SDL_SensorGetNonPortableType (SDL_Sensor *sensor)
 Get the platform dependent type of a sensor. More...
 
DECLSPEC SDL_SensorID SDLCALL SDL_SensorGetInstanceID (SDL_Sensor *sensor)
 Get the instance ID of a sensor. More...
 
DECLSPEC int SDLCALL SDL_SensorGetData (SDL_Sensor *sensor, float *data, int num_values)
 
DECLSPEC void SDLCALL SDL_SensorClose (SDL_Sensor *sensor)
 
DECLSPEC void SDLCALL SDL_SensorUpdate (void)
 

Detailed Description

Include file for SDL sensor event handling

Macro Definition Documentation

◆ SDL_STANDARD_GRAVITY

#define SDL_STANDARD_GRAVITY   9.80665f

Accelerometer sensor

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.

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

For phones held in portrait mode 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 axis data is not changed when the phone is rotated.

See also
SDL_GetDisplayOrientation()

Typedef Documentation

◆ SDL_SensorID

typedef Sint32 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.

Enumeration Type Documentation

◆ SDL_SensorType

Enumerator
SDL_SENSOR_INVALID 

Returned for an invalid sensor

SDL_SENSOR_UNKNOWN 

Unknown sensor type

SDL_SENSOR_ACCEL 

Accelerometer

SDL_SENSOR_GYRO 

Gyroscope

Function Documentation

◆ SDL_LockSensors()

DECLSPEC void SDLCALL SDL_LockSensors ( void  )

Gyroscope sensor

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 held in portrait mode 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 axis data is not changed when the phone or controller is rotated.

See also
SDL_GetDisplayOrientation() 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.

◆ SDL_SensorClose()

DECLSPEC void SDLCALL SDL_SensorClose ( SDL_Sensor *  sensor)

Close a sensor previously opened with SDL_SensorOpen()

◆ SDL_SensorFromInstanceID()

DECLSPEC SDL_Sensor* SDLCALL SDL_SensorFromInstanceID ( SDL_SensorID  instance_id)

Return the SDL_Sensor associated with an instance id.

◆ SDL_SensorGetData()

DECLSPEC int SDLCALL SDL_SensorGetData ( SDL_Sensor *  sensor,
float *  data,
int  num_values 
)

Get the current state of an opened sensor.

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

Parameters
sensorThe sensor 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.

◆ SDL_SensorGetDeviceInstanceID()

DECLSPEC SDL_SensorID SDLCALL SDL_SensorGetDeviceInstanceID ( int  device_index)

Get the instance ID of a sensor.

This can be called before any sensors are opened.

Returns
The sensor instance ID, or -1 if device_index is out of range.

◆ SDL_SensorGetDeviceName()

DECLSPEC const char* SDLCALL SDL_SensorGetDeviceName ( int  device_index)

Get the implementation dependent name of a sensor.

This can be called before any sensors are opened.

Returns
The sensor name, or NULL if device_index is out of range.

◆ SDL_SensorGetDeviceNonPortableType()

DECLSPEC int SDLCALL SDL_SensorGetDeviceNonPortableType ( int  device_index)

Get the platform dependent type of a sensor.

This can be called before any sensors are opened.

Returns
The sensor platform dependent type, or -1 if device_index is out of range.

◆ SDL_SensorGetDeviceType()

DECLSPEC SDL_SensorType SDLCALL SDL_SensorGetDeviceType ( int  device_index)

Get the type of a sensor.

This can be called before any sensors are opened.

Returns
The sensor type, or SDL_SENSOR_INVALID if device_index is out of range.

◆ SDL_SensorGetInstanceID()

DECLSPEC SDL_SensorID SDLCALL SDL_SensorGetInstanceID ( SDL_Sensor *  sensor)

Get the instance ID of a sensor.

This can be called before any sensors are opened.

Returns
The sensor instance ID, or -1 if the sensor is NULL.

◆ SDL_SensorGetName()

DECLSPEC const char* SDLCALL SDL_SensorGetName ( SDL_Sensor *  sensor)

Get the implementation dependent name of a sensor.

Returns
The sensor name, or NULL if the sensor is NULL.

◆ SDL_SensorGetNonPortableType()

DECLSPEC int SDLCALL SDL_SensorGetNonPortableType ( SDL_Sensor *  sensor)

Get the platform dependent type of a sensor.

This can be called before any sensors are opened.

Returns
The sensor platform dependent type, or -1 if the sensor is NULL.

◆ SDL_SensorGetType()

DECLSPEC SDL_SensorType SDLCALL SDL_SensorGetType ( SDL_Sensor *  sensor)

Get the type of a sensor.

This can be called before any sensors are opened.

Returns
The sensor type, or SDL_SENSOR_INVALID if the sensor is NULL.

◆ SDL_SensorOpen()

DECLSPEC SDL_Sensor* SDLCALL SDL_SensorOpen ( int  device_index)

Open a sensor for use.

The index passed as an argument refers to the N'th sensor on the system.

Returns
A sensor identifier, or NULL if an error occurred.

◆ SDL_SensorUpdate()

DECLSPEC void SDLCALL SDL_SensorUpdate ( void  )

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.