gui, logic: add neck displacement feature

With it enabled, user's neck will be treated as separate from the rotation
pivot. Rotating to the left will reposition to the left in addition to the
rotation, and so on.

This feature is subtle but apparently very popular with DCS users.

2 files changed, 111 insertions, 85 deletions

diff --git a/logic/main-settings.hpp b/logic/main-settings.hpp
index 53c5fae1..ea1d93f3 100644
--- a/logic/main-settings.hpp
+++ b/logic/main-settings.hpp
@@ -74,6 +74,7 @@ struct main_settings
     value<bool> use_camera_offset_from_centering;
     value<bool> center_at_startup;
     value<int> center_method;
+    value<int> neck_y, neck_z;
     key_opts key_start_tracking, key_stop_tracking, key_toggle_tracking, key_restart_tracking;
     key_opts key_center, key_toggle, key_zero;
     key_opts key_toggle_press, key_zero_press;
@@ -104,6 +105,8 @@ struct main_settings
         use_camera_offset_from_centering(b, "use-camera-offset-from-centering", false),
         center_at_startup(b, "center-at-startup", true),
         center_method(b, "centering-method", true),
+        neck_y(b, "neck-height", 0),
+        neck_z(b, "neck-depth", 0),
         key_start_tracking(b, "start-tracking"),
         key_stop_tracking(b, "stop-tracking"),
         key_toggle_tracking(b, "toggle-tracking"),
diff --git a/logic/tracker.cpp b/logic/tracker.cpp
index a5892dd0..25e067a7 100644
--- a/logic/tracker.cpp
+++ b/logic/tracker.cpp
@@ -156,8 +156,7 @@ void Tracker::logic()
 
     logger.write_pose(raw); // raw
 
-    if (is_nan(raw))
-        raw = last_raw;
+    bool nanp = is_nan(raw) | is_nan(value);
 
     // TODO split this function, it's too big
 
@@ -171,58 +170,57 @@ void Tracker::logic()
     scaled_rotation.camera = get_camera_offset_matrix(c_div);
     real_rotation.camera = get_camera_offset_matrix(1);
 
-    bool nanp = is_nan(value) || is_nan(scaled_rotation.rotation) || is_nan(real_rotation.rotation);
+    nanp |= is_nan(value) || is_nan(scaled_rotation.rotation) || is_nan(real_rotation.rotation);
 
-    if (!nanp)
+    if (!tracking_started)
     {
-        if (!tracking_started)
-        {
-            using std::fabs;
+        using std::fabs;
 
-            for (int i = 0; i < 6; i++)
-                if (fabs(newpose(i)) != 0)
-                {
-                    tracking_started = true;
-                    break;
-                }
-        }
+        for (int i = 0; i < 6; i++)
+            if (fabs(newpose(i)) != 0)
+            {
+                tracking_started = true;
+                break;
+            }
 
-        if (get(f_center) && tracking_started)
-        {
-            set(f_center, false);
+        tracking_started &= !nanp;
+    }
 
-            if (libs.pFilter)
-                libs.pFilter->center();
+    if (get(f_center) && tracking_started)
+    {
+        set(f_center, false);
 
-            if (libs.pTracker->center())
-            {
-                scaled_rotation.rotation = scaled_rotation.camera.t();
-                real_rotation.rotation = real_rotation.camera.t();
-
-                scaled_rotation.rotation = rmat::eye();
-                real_rotation.rotation = rmat::eye();
-                scaled_rotation.center_roll = rmat::eye();
-                scaled_rotation.center_yaw = rmat::eye();
-                scaled_rotation.center_pitch = rmat::eye();
-            }
-            else
-            {
-                euler::tait_bryan_to_matrices(rmat_to_euler(scaled_rotation.rotation),
-                                              scaled_rotation.center_roll,
-                                              scaled_rotation.center_pitch,
-                                              scaled_rotation.center_yaw);
+        if (libs.pFilter)
+            libs.pFilter->center();
+
+        if (libs.pTracker->center())
+        {
+            scaled_rotation.rotation = scaled_rotation.camera.t();
+            real_rotation.rotation = real_rotation.camera.t();
+
+            scaled_rotation.rotation = rmat::eye();
+            real_rotation.rotation = rmat::eye();
+            scaled_rotation.center_roll = rmat::eye();
+            scaled_rotation.center_yaw = rmat::eye();
+            scaled_rotation.center_pitch = rmat::eye();
+        }
+        else
+        {
+            euler::tait_bryan_to_matrices(rmat_to_euler(scaled_rotation.rotation),
+                                          scaled_rotation.center_roll,
+                                          scaled_rotation.center_pitch,
+                                          scaled_rotation.center_yaw);
 #if 0
-                euler::tait_bryan_to_matrices(rmat_to_euler(real_rotation.rotation),
-                                              real_rotation.center_roll,
-                                              real_rotation.center_pitch,
-                                              real_rotation.center_yaw);
+            euler::tait_bryan_to_matrices(rmat_to_euler(real_rotation.rotation),
+                                          real_rotation.center_roll,
+                                          real_rotation.center_pitch,
+                                          real_rotation.center_yaw);
 #endif
-                real_rotation.rot_center = real_rotation.rotation.t();
-                scaled_rotation.rot_center = scaled_rotation.rotation.t();
-            }
-
-            t_center = euler_t(&value(TX));
+            real_rotation.rot_center = real_rotation.rotation.t();
+            scaled_rotation.rot_center = scaled_rotation.rotation.t();
         }
+
+        t_center = euler_t(&value(TX));
     }
 
     {
@@ -268,20 +266,37 @@ void Tracker::logic()
 
     logger.write_pose(value); // "corrected" - after various transformations to account for camera position
 
-    // whenever something can corrupt its internal state due to nan/inf, elide the call
-    if (is_nan(value))
-    {
-        nanp = true;
-        logger.write_pose(value); // "filtered"
-    }
-    else
+    nanp |= is_nan(value);
+
     {
-        Pose tmp(value);
+        {
+            Pose tmp(value);
 
-        if (libs.pFilter)
-            libs.pFilter->filter(tmp, value);
+            // nan/inf values will corrupt filter internal state
+            if (!nanp && libs.pFilter)
+                libs.pFilter->filter(tmp, value);
+
+            logger.write_pose(value); // "filtered"
+        }
+
+        euler_t neck, rel;
 
-        logger.write_pose(value); // "filtered"
+        {
+            double ny = s.neck_y, nz = -s.neck_z;
+
+            if (ny != 0 || nz != 0)
+            {
+                const rmat R = euler_to_rmat(
+                                   euler_t(value(Yaw)   * d2r,
+                                           value(Pitch) * d2r,
+                                           value(Roll)  * d2r));
+                euler_t xyz(0, ny, nz);
+                t_compensate(R, xyz, xyz, false, false, false);
+                neck(TX) = xyz(TX);
+                neck(TY) = xyz(TY) - ny;
+                neck(TZ) = xyz(TZ) - nz;
+            }
+        }
 
         // CAVEAT rotation only, due to tcomp
         for (int i = 3; i < 6; i++)
@@ -294,38 +309,45 @@ void Tracker::logic()
             for (int i = 0; i < 6; i++)
                 value(i) = 0;
 
-        if (is_nan(value))
-            nanp = true;
-    }
+        const bool reltrans = !get(f_tcomp_disabled);
 
-    if (s.tcomp_p && !get(f_tcomp_disabled))
-    {
-        const double tcomp_c[] =
+        if (s.tcomp_p && reltrans)
         {
-            double(!s.tcomp_disable_src_yaw),
-            double(!s.tcomp_disable_src_pitch),
-            double(!s.tcomp_disable_src_roll),
-        };
-        euler_t value_(value(TX), value(TY), value(TZ));
-        t_compensate(euler_to_rmat(
-                         euler_t(value(Yaw)   * d2r * tcomp_c[0],
-                                 value(Pitch) * d2r * tcomp_c[1],
-                                 value(Roll)  * d2r * tcomp_c[2])),
-                     value_,
-                     value_,
-                     s.tcomp_disable_tx,
-                     s.tcomp_disable_ty,
-                     s.tcomp_disable_tz);
-        if (is_nan(value_))
-            nanp = true;
+            const double tcomp_c[] =
+            {
+                double(!s.tcomp_disable_src_yaw),
+                double(!s.tcomp_disable_src_pitch),
+                double(!s.tcomp_disable_src_roll),
+            };
+            const rmat R = euler_to_rmat(
+                       euler_t(value(Yaw)   * d2r * tcomp_c[0],
+                               value(Pitch) * d2r * tcomp_c[1],
+                               value(Roll)  * d2r * tcomp_c[2]));
+            euler_t ret;
+            t_compensate(R,
+                         euler_t(value(TX), value(TY), value(TZ)),
+                         ret,
+                         s.tcomp_disable_tx,
+                         s.tcomp_disable_ty,
+                         s.tcomp_disable_tz);
+
+            for (int i = 0; i < 3; i++)
+                rel(i) = ret(i) - value(i);
+        }
+
+        // don't t_compensate existing compensated values
         for (int i = 0; i < 3; i++)
-            value(i) = value_(i);
+            value(i) += neck(i) + rel(i);
+
+        nanp |= is_nan(neck) | is_nan(rel) | is_nan(value);
     }
 
     // CAVEAT translation only, due to tcomp
     for (int i = 0; i < 3; i++)
         value(i) = map(value(i), m(i));
 
+    nanp |= is_nan(value);
+
     for (int i = 0; i < 6; i++)
         if (m(i).opts.invert)
             value(i) = -value(i);
@@ -334,17 +356,18 @@ void Tracker::logic()
 
     if (nanp)
     {
-        value = last_mapped;
+        QMutexLocker foo(&mtx);
+
+        value = output_pose;
+        raw = raw_6dof;
 
         // for widget last value display
         for (int i = 0; i < 6; i++)
-            (void) map(value(i), m(i));
+            (void) map(raw_6dof(i), m(i));
     }
 
-    libs.pProtocol->pose(value);
-
-    last_mapped = value;
-    last_raw = raw;
+    if (!nanp)
+        libs.pProtocol->pose(value);
 
     QMutexLocker foo(&mtx);
     output_pose = value;