altos/telefireone-v2.0: Remove build of ao_product.h from Makefile

[fw/altos] / altoslib / AltosRotation.java

diff --git a/altoslib/AltosRotation.java b/altoslib/AltosRotation.java
index 1235d86b90e57a1c0da9d3923b2c16db0cd09d0f..54b3b1f939a46d1d12fff739fe8b658994afd035 100644 (file)
--- a/altoslib/AltosRotation.java
+++ b/altoslib/AltosRotation.java
@@ -16,11 +16,33 @@
  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  */
 
-package org.altusmetrum.altoslib_11;
+package org.altusmetrum.altoslib_13;
 
 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();
        }