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Merge "allow rotation-vector to have 4 components" into gingerbread

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This commit is contained in:
Mathias Agopian
2010-11-30 15:38:38 -08:00
committed by Android (Google) Code Review
parent 91abcb624a 7badd2c402
commit 186b68b744
3 changed files with 50 additions and 20 deletions
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48
core/java/android/hardware/SensorEvent.java
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@@ -220,25 +220,47 @@ public class SensorEvent {
* </p>
*
* <h4>{@link android.hardware.Sensor#TYPE_GRAVITY Sensor.TYPE_GRAVITY}:</h4>
* A three dimensional vector indicating the direction and magnitude of gravity. Units
* are m/s^2. The coordinate system is the same as is used by the acceleration sensor.
* <p>A three dimensional vector indicating the direction and magnitude of gravity. Units
* are m/s^2. The coordinate system is the same as is used by the acceleration sensor.</p>
* <p><b>Note:</b> When the device is at rest, the output of the gravity sensor should be identical
* to that of the accelerometer.</p>
*
* <h4>{@link android.hardware.Sensor#TYPE_LINEAR_ACCELERATION Sensor.TYPE_LINEAR_ACCELERATION}:</h4>
* A three dimensional vector indicating acceleration along each device axis, not including
* gravity. All values have units of m/s^2. The coordinate system is the same as is used by the
* acceleration sensor.
* acceleration sensor.
* <p>The output of the accelerometer, gravity and linear-acceleration sensors must obey the
* following relation:</p>
* <p><ul>acceleration = gravity + linear-acceleration</ul></p>
*
* <h4>{@link android.hardware.Sensor#TYPE_ROTATION_VECTOR Sensor.TYPE_ROTATION_VECTOR}:</h4>
* The rotation vector represents the orientation of the device as a combination of an angle
* and an axis, in which the device has rotated through an angle theta around an axis
* &lt;x, y, z>. The three elements of the rotation vector are
* &lt;x*sin(theta/2), y*sin(theta/2), z*sin(theta/2)>, such that the magnitude of the rotation
* vector is equal to sin(theta/2), and the direction of the rotation vector is equal to the
* direction of the axis of rotation. The three elements of the rotation vector are equal to
* the last three components of a unit quaternion
* &lt;cos(theta/2), x*sin(theta/2), y*sin(theta/2), z*sin(theta/2)>. Elements of the rotation
* vector are unitless. The x,y, and z axis are defined in the same way as the acceleration
* sensor.
* <p>The rotation vector represents the orientation of the device as a combination of an <i>angle</i>
* and an <i>axis</i>, in which the device has rotated through an angle &#952 around an axis
* &lt;x, y, z>.</p>
* <p>The three elements of the rotation vector are
* &lt;x*sin(&#952/2), y*sin(&#952/2), z*sin(&#952/2)>, such that the magnitude of the rotation
* vector is equal to sin(&#952/2), and the direction of the rotation vector is equal to the
* direction of the axis of rotation.</p>
* </p>The three elements of the rotation vector are equal to
* the last three components of a <b>unit</b> quaternion
* &lt;cos(&#952/2), x*sin(&#952/2), y*sin(&#952/2), z*sin(&#952/2)>.</p>
* <p>Elements of the rotation vector are unitless.
* The x,y, and z axis are defined in the same way as the acceleration
* sensor.</p>
* <ul>
* <p>
* values[0]: x*sin(&#952/2)
* </p>
* <p>
* values[1]: y*sin(&#952/2)
* </p>
* <p>
* values[2]: z*sin(&#952/2)
* </p>
* <p>
* values[3]: cos(&#952/2) <i>(optional: only if value.length = 4)</i>
* </p>
* </ul>
*
* <h4>{@link android.hardware.Sensor#TYPE_ORIENTATION
* Sensor.TYPE_ORIENTATION}:</h4> All values are angles in degrees.

21
core/java/android/hardware/SensorManager.java
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@@ -1938,13 +1938,18 @@ public class SensorManager
* @param R an array of floats in which to store the rotation matrix
*/
public static void getRotationMatrixFromVector(float[] R, float[] rotationVector) {
float q0 = (float)Math.sqrt(1 - rotationVector[0]*rotationVector[0] -
rotationVector[1]*rotationVector[1] -
rotationVector[2]*rotationVector[2]);
float q0;
float q1 = rotationVector[0];
float q2 = rotationVector[1];
float q3 = rotationVector[2];
if (rotationVector.length == 4) {
q0 = rotationVector[3];
} else {
q0 = (float)Math.sqrt(1 - q1*q1 - q2*q2 - q3*q3);
}
float sq_q1 = 2 * q1 * q1;
float sq_q2 = 2 * q2 * q2;
float sq_q3 = 2 * q3 * q3;
@@ -1995,10 +2000,12 @@ public class SensorManager
* @param Q an array of floats in which to store the computed quaternion
*/
public static void getQuaternionFromVector(float[] Q, float[] rv) {
float w = (float)Math.sqrt(1 - rv[0]*rv[0] - rv[1]*rv[1] - rv[2]*rv[2]);
//In this case, the w component of the quaternion is known to be a positive number
Q[0] = w;
if (rv.length == 4) {
Q[0] = rv[3];
} else {
//In this case, the w component of the quaternion is known to be a positive number
Q[0] = (float)Math.sqrt(1 - rv[0]*rv[0] - rv[1]*rv[1] - rv[2]*rv[2]);
}
Q[1] = rv[0];
Q[2] = rv[1];
Q[3] = rv[2];

1
services/sensorservice/RotationVectorSensor.cpp
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@@ -125,6 +125,7 @@ bool RotationVectorSensor::process(sensors_event_t* outEvent,
outEvent->data[0] = qx;
outEvent->data[1] = qy;
outEvent->data[2] = qz;
outEvent->data[3] = qw;
outEvent->sensor = '_rov';
outEvent->type = SENSOR_TYPE_ROTATION_VECTOR;
return true;