first cut at turnon scripts for EasyTimer v2

[fw/altos] / altoslib / AltosRotation.java

diff --git a/altoslib/AltosRotation.java b/altoslib/AltosRotation.java
index 411ecbdfae7edd530fc4fd7e1c684499f053b65f..85e213b25f5a0ef0700c3151b6723ee8ff34b925 100644 (file)
--- a/altoslib/AltosRotation.java
+++ b/altoslib/AltosRotation.java
@@ -3,7 +3,8 @@
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -15,11 +16,33 @@
  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  */
 
-package org.altusmetrum.altoslib_11;
+package org.altusmetrum.altoslib_14;
 
-public class AltosRotation {
+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;
 
@@ -27,8 +50,39 @@ public class AltosRotation {
                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);
+       /* Compute azimuth angle from a reference line pointing out the side
+        * of the airframe
+        *
+        * rot = ao_rotation * x_axis * ao_rotation°
+        * rot = ao_rotation * (0,1,0,0) * ao_rotation°
+        *     = (-a.x, a.r, a.z, -a.y) * (a.r, -a.x, -a.y, -a.z) . x
+        *     = (-a.x * -a.x) + (a.r * a.r) + (a.z * -a.z) - (-a.y * -a.y)
+        *     = a.x² + a.r² - a.z² - a.y²
+        *
+        *     = (-a.x, a.r, a.z, -a.y) * (a.r, -a.x, -a.y, -a.z) . y
+        *     = (-a.x * -a.y) - (a.r * -a.z) + (a.z * a.r) + (-a.y * -a.x)
+        *     = a.x * a.y + a.r * a.z + a.z * a.r + a.y * a.x
+        *
+        * The X value will be the cosine of the rotation. The Y value will be the
+        * sine of the rotation; use the sign of that to figure out which direction from
+        * zero we've headed
+        */
+
+       public double azimuth() {
+               double rotx = rotation.x * rotation.x + rotation.r * rotation.r - rotation.z * rotation.z - rotation.y * rotation.y;
+               double roty = rotation.x * rotation.y + rotation.r * rotation.z + rotation.z * rotation.r + rotation.y * rotation.x;
+
+               double az = Math.acos(rotx) * 180.0 / Math.PI;
+               if (roty < 0)
+                       return -az;
+               return az;
+       }
+
+       /* 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();
        }
 
@@ -43,8 +97,12 @@ public class AltosRotation {
                             double z,
                             int pad_orientation) {
                AltosQuaternion orient = AltosQuaternion.vector(x, y, z).normalize();
-               double sky = pad_orientation == 0 ? 1 : -1;
+               double sky = (pad_orientation & 1) == 0 ? 1 : -1;
                AltosQuaternion up = new AltosQuaternion(0, 0, 0, sky);
                rotation = up.vectors_to_rotation(orient);
        }
+
+       public AltosRotation() {
+               rotation = new AltosQuaternion();
+       }
 }