diff options
Diffstat (limited to 'altoslib/AltosRotation.java')
| -rw-r--r-- | altoslib/AltosRotation.java | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/altoslib/AltosRotation.java b/altoslib/AltosRotation.java index 0de24515..305f932a 100644 --- a/altoslib/AltosRotation.java +++ b/altoslib/AltosRotation.java @@ -21,6 +21,28 @@ package org.altusmetrum.altoslib_12; public class AltosRotation extends AltosQuaternion { private AltosQuaternion rotation; + /* Compute pitch angle from vertical by taking the pad + * orientation vector and rotating it by the current total + * rotation value. That will be a unit vector pointing along + * the airframe axis. The Z value will be the cosine of the + * angle from vertical. + * + * rot = ao_rotation * vertical * ao_rotation° + * rot = ao_rotation * (0,0,0,1) * ao_rotation° + * = ((a.z, a.y, -a.x, a.r) * (a.r, -a.x, -a.y, -a.z)) .z + * + * = (-a.z * -a.z) + (a.y * -a.y) - (-a.x * -a.x) + (a.r * a.r) + * = a.z² - a.y² - a.x² + a.r² + * + * rot = ao_rotation * (0, 0, 0, -1) * ao_rotation° + * = ((-a.z, -a.y, a.x, -a.r) * (a.r, -a.x, -a.y, -a.z)) .z + * + * = (a.z * -a.z) + (-a.y * -a.y) - (a.x * -a.x) + (-a.r * a.r) + * = -a.z² + a.y² + a.x² - a.r² + * + * tilt = acos(rot); /* in radians */ + */ + public double tilt() { double rotz = rotation.z * rotation.z - rotation.y * rotation.y - rotation.x * rotation.x + rotation.r * rotation.r; @@ -28,8 +50,11 @@ public class AltosRotation extends AltosQuaternion { return tilt; } - public void rotate(double dt, double x, double y, double z) { - AltosQuaternion rot = AltosQuaternion.half_euler(x * dt / 2.0, y * dt / 2.0, z * dt / 2.0); + /* Given euler rotations in three axes, perform a combined rotation using + * quaternions + */ + public void rotate(double x, double y, double z) { + AltosQuaternion rot = AltosQuaternion.euler(x, y, z); rotation = rot.multiply(rotation).normalize(); } |