udev and SDL Sensor and Touchpad

libretro-common/include/libretro.h

@@ -7313,14 +7313,75 @@ struct retro_device_power
 };
 enum retro_sensor_selector
 {
+
+   /**
+    * Returns the device's acceleration along its local X axis minus the effect of gravity, in m/s^2.
+    *
+    * Positive values mean that the device is accelerating to the right.
+    * assuming the user is looking at it head-on.
+    */
    RETRO_SENSOR_ACCELEROMETER_X,
+
+   /**
+    * Returns the device's acceleration along its local Y axis minus the effect of gravity, in m/s^2.
+    *
+    * Positive values mean that the device is accelerating upwards,
+    * assuming the user is looking at it head-on.
+    */
    RETRO_SENSOR_ACCELEROMETER_Y,
+
+   /**
+    * Returns the the device's acceleration along its local Z axis minus the effect of gravity, in m/s^2.
+    *
+    * Positive values indicate forward acceleration towards the user,
+    * assuming the user is looking at the device head-on.
+    */
    RETRO_SENSOR_ACCELEROMETER_Z,
+
+   /**
+    * Returns the angular velocity of the device around its local X axis, in radians per second.
+    *
+    * Positive values indicate counter-clockwise rotation.
+    *
+    * @note A radian is about 57 degrees, and a full 360-degree rotation is 2*pi radians.
+    * @see https://developer.android.com/reference/android/hardware/SensorEvent#sensor.type_gyroscope
+    * for guidance on using this value to derive a device's orientation.
+    */
    RETRO_SENSOR_GYROSCOPE_X,
+
+   /**
+    * Returns the angular velocity of the device around its local Z axis, in radians per second.
+    *
+    * Positive values indicate counter-clockwise rotation.
+    *
+    * @note A radian is about 57 degrees, and a full 360-degree rotation is 2*pi radians.
+    * @see https://developer.android.com/reference/android/hardware/SensorEvent#sensor.type_gyroscope
+    * for guidance on using this value to derive a device's orientation.
+    */
    RETRO_SENSOR_GYROSCOPE_Y,
+
+   /**
+    * Returns the angular velocity of the device around its local Z axis, in radians per second.
+    *
+    * Positive values indicate counter-clockwise rotation.
+    *
+    * @note A radian is about 57 degrees, and a full 360-degree rotation is 2*pi radians.
+    * @see https://developer.android.com/reference/android/hardware/SensorEvent#sensor.type_gyroscope
+    * for guidance on using this value to derive a device's orientation.
+    */
    RETRO_SENSOR_GYROSCOPE_Z,
+
+   /**
+    * Returns the ambient illuminance (light intensity) of the device's environment, in lux.
+    *
+    * @see https://en.wikipedia.org/wiki/Lux for a table of common lux values.
+    */
    RETRO_SENSOR_ILLUMINANCE,
+
+
    RETRO_SENSOR_MAX,
+
+   /** Dummy value to ensure sizeof(enum retro_hw_context_type) == sizeof(int). Do not use. */
    RETRO_SENSOR_SELECTOR_DUMMY=INT_MAX
 };
 /** @} */