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Merge "Bug fix and documentation clarification" into mnc-dev

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This commit is contained in:
Peng Xu
2015-05-28 18:57:45 +00:00
committed by Android (Google) Code Review
parent e0e8570d59 ca09d8cf8c
commit 08ecf676e6
2 changed files with 36 additions and 27 deletions
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4
core/java/android/hardware/SensorEvent.java
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@@ -312,7 +312,7 @@ public class SensorEvent {
* </p>
*
* <p>
* values[2]: Roll, rotation around the x-axis (-90 to 90)
* values[2]: Roll, rotation around the y-axis (-90 to 90)
* increasing as the device moves clockwise.
* </p>
* </ul>
@@ -325,6 +325,8 @@ public class SensorEvent {
*
* <p>
* <b>Note:</b> This sensor type exists for legacy reasons, please use
* {@link android.hardware.Sensor#TYPE_ROTATION_VECTOR
* rotation vector sensor type} and
* {@link android.hardware.SensorManager#getRotationMatrix
* getRotationMatrix()} in conjunction with
* {@link android.hardware.SensorManager#remapCoordinateSystem

59
core/java/android/hardware/SensorManager.java
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@@ -967,8 +967,9 @@ public abstract class SensorManager {
* TYPE_MAGNETIC_FIELD}.
*
* @return <code>true</code> on success, <code>false</code> on failure (for
* instance, if the device is in free fall). On failure the output
* matrices are not modified.
* instance, if the device is in free fall). Free fall is defined as
* condition when the magnitude of the gravity is less than 1/10 of
* the nominal value. On failure the output matrices are not modified.
*
* @see #getInclination(float[])
* @see #getOrientation(float[], float[])
@@ -981,6 +982,15 @@ public abstract class SensorManager {
float Ax = gravity[0];
float Ay = gravity[1];
float Az = gravity[2];
final float normsqA = (Ax*Ax + Ay*Ay + Az*Az);
final float g = 9.81f;
final float freeFallGravitySquared = 0.01f * g * g;
if (normsqA < freeFallGravitySquared) {
// gravity less than 10% of normal value
return false;
}
final float Ex = geomagnetic[0];
final float Ey = geomagnetic[1];
final float Ez = geomagnetic[2];
@@ -988,6 +998,7 @@ public abstract class SensorManager {
float Hy = Ez*Ax - Ex*Az;
float Hz = Ex*Ay - Ey*Ax;
final float normH = (float)Math.sqrt(Hx*Hx + Hy*Hy + Hz*Hz);
if (normH < 0.1f) {
// device is close to free fall (or in space?), or close to
// magnetic north pole. Typical values are > 100.
@@ -1117,12 +1128,12 @@ public abstract class SensorManager {
* returned by {@link #getRotationMatrix}.
*
* @param X
* defines on which world axis and direction the X axis of the device
* is mapped.
* defines the axis of the new cooridinate system that coincide with the X axis of the
* original coordinate system.
*
* @param Y
* defines on which world axis and direction the Y axis of the device
* is mapped.
* defines the axis of the new cooridinate system that coincide with the Y axis of the
* original coordinate system.
*
* @param outR
* the transformed rotation matrix. inR and outR should not be the same
@@ -1219,27 +1230,18 @@ public abstract class SensorManager {
* <p>
* When it returns, the array values is filled with the result:
* <ul>
* <li>values[0]: <i>azimuth</i>, rotation around the Z axis.</li>
* <li>values[1]: <i>pitch</i>, rotation around the X axis.</li>
* <li>values[0]: <i>azimuth</i>, rotation around the -Z axis,
* i.e. the opposite direction of Z axis.</li>
* <li>values[1]: <i>pitch</i>, rotation around the -X axis,
* i.e the opposite direction of X axis.</li>
* <li>values[2]: <i>roll</i>, rotation around the Y axis.</li>
* </ul>
* <p>The reference coordinate-system used is different from the world
* coordinate-system defined for the rotation matrix:</p>
* <ul>
* <li>X is defined as the vector product <b>Y.Z</b> (It is tangential to
* the ground at the device's current location and roughly points West).</li>
* <li>Y is tangential to the ground at the device's current location and
* points towards the magnetic North Pole.</li>
* <li>Z points towards the center of the Earth and is perpendicular to the ground.</li>
* </ul>
*
* <p>
* <center><img src="../../../images/axis_globe_inverted.png"
* alt="Inverted world coordinate-system diagram." border="0" /></center>
* </p>
* <p>
* Applying these three intrinsic rotations in azimuth, pitch and roll order transforms
* identity matrix to the rotation matrix given in input R.
* All three angles above are in <b>radians</b> and <b>positive</b> in the
* <b>counter-clockwise</b> direction.
* <b>counter-clockwise</b> direction. Range of output is: azimuth from -&pi; to &pi;,
* pitch from -&pi;/2 to &pi;/2 and roll from -&pi; to &pi;.
*
* @param R
* rotation matrix see {@link #getRotationMatrix}.
@@ -1275,6 +1277,7 @@ public abstract class SensorManager {
values[1] = (float)Math.asin(-R[9]);
values[2] = (float)Math.atan2(-R[8], R[10]);
}
return values;
}
@@ -1314,9 +1317,9 @@ public abstract class SensorManager {
/** Helper function to compute the angle change between two rotation matrices.
* Given a current rotation matrix (R) and a previous rotation matrix
* (prevR) computes the rotation around the z,x, and y axes which
* (prevR) computes the intrinsic rotation around the z, x, and y axes which
* transforms prevR to R.
* outputs a 3 element vector containing the z,x, and y angle
* outputs a 3 element vector containing the z, x, and y angle
* change at indexes 0, 1, and 2 respectively.
* <p> Each input matrix is either as a 3x3 or 4x4 row-major matrix
* depending on the length of the passed array:
@@ -1333,9 +1336,13 @@ public abstract class SensorManager {
* | R[ 8] R[ 9] R[10] R[11] |
* \ R[12] R[13] R[14] R[15] /
*</pre>
*
* See {@link #getOrientation} for more detailed definition of the output.
*
* @param R current rotation matrix
* @param prevR previous rotation matrix
* @param angleChange an an array of floats (z, x, and y) in which the angle change is stored
* @param angleChange an an array of floats (z, x, and y) in which the angle change
* (in radians) is stored
*/
public static void getAngleChange( float[] angleChange, float[] R, float[] prevR) {