X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FMain%2Fviewmgr.cxx;h=cb2dfa0531045664b6a76f52b82fba9d2236d072;hb=18d1593c42c2df60d7fb44ace722ca3e8a7fd82c;hp=e9170f0fac47153bdc5a3a71d0a5c173f50dfba8;hpb=cf6022e43937bc19dc97885fb8248e67e69b6ad8;p=flightgear.git

diff --git a/src/Main/viewmgr.cxx b/src/Main/viewmgr.cxx
index e9170f0fa..cb2dfa053 100644
--- a/src/Main/viewmgr.cxx
+++ b/src/Main/viewmgr.cxx
@@ -1,8 +1,9 @@
 // viewmgr.cxx -- class for managing all the views in the flightgear world.
 //
 // Written by Curtis Olson, started October 2000.
+//   partially rewritten by Jim Wilson March 2002
 //
-// Copyright (C) 2000  Curtis L. Olson  - curt@flightgear.org
+// Copyright (C) 2000  Curtis L. Olson  - http://www.flightgear.org/~curt
 //
 // This program is free software; you can redistribute it and/or
 // modify it under the terms of the GNU General Public License as
@@ -16,19 +17,687 @@
 //
 // You should have received a copy of the GNU General Public License
 // along with this program; if not, write to the Free Software
-// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 //
 // $Id$
 
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
+
+#include <string.h>		// strcmp
+
+#include <plib/sg.h>
+
+#include <simgear/compiler.h>
+
+#include <Model/acmodel.hxx>
 
 #include "viewmgr.hxx"
 
 
 // Constructor
-FGViewMgr::FGViewMgr( void ) {
+FGViewMgr::FGViewMgr( void ) :
+  axis_long(0),
+  axis_lat(0),
+  view_number(fgGetNode("/sim/current-view/view-number", true)),
+  config_list(fgGetNode("/sim", true)->getChildren("view")),
+  current(0)
+{
 }
 
-
 // Destructor
 FGViewMgr::~FGViewMgr( void ) {
 }
+
+void
+FGViewMgr::init ()
+{
+  double aspect_ratio_multiplier
+      = fgGetDouble("/sim/current-view/aspect-ratio-multiplier");
+
+  for (unsigned int i = 0; i < config_list.size(); i++) {
+    SGPropertyNode *n = config_list[i];
+
+    // find out if this is an internal view (e.g. in cockpit, low near plane)
+    bool internal = n->getBoolValue("internal", false);
+
+    // FIXME:
+    // this is assumed to be an aircraft model...we will need to read
+    // model-from-type as well.
+
+    // find out if this is a model we are looking from...
+    bool from_model = n->getBoolValue("config/from-model");
+    int from_model_index = n->getIntValue("config/from-model-idx");
+
+    double x_offset_m = n->getDoubleValue("config/x-offset-m");
+    double y_offset_m = n->getDoubleValue("config/y-offset-m");
+    double z_offset_m = n->getDoubleValue("config/z-offset-m");
+
+    double heading_offset_deg = n->getDoubleValue("config/heading-offset-deg");
+    n->setDoubleValue("config/heading-offset-deg", heading_offset_deg);
+    double pitch_offset_deg = n->getDoubleValue("config/pitch-offset-deg");
+    n->setDoubleValue("config/pitch-offset-deg", pitch_offset_deg);
+    double roll_offset_deg = n->getDoubleValue("config/roll-offset-deg");
+    n->setDoubleValue("config/roll-offset-deg", roll_offset_deg);
+
+    double fov_deg = n->getDoubleValue("config/default-field-of-view-deg");
+    double near_m = n->getDoubleValue("config/ground-level-nearplane-m");
+
+    // supporting two types "lookat" = 1 and "lookfrom" = 0
+    const char *type = n->getStringValue("type");
+    if (!strcmp(type, "lookat")) {
+
+      bool at_model = n->getBoolValue("config/at-model");
+      int at_model_index = n->getIntValue("config/at-model-idx");
+
+      double damp_roll = n->getDoubleValue("config/at-model-roll-damping");
+      double damp_pitch = n->getDoubleValue("config/at-model-pitch-damping");
+      double damp_heading = n->getDoubleValue("config/at-model-heading-damping");
+
+      double target_x_offset_m = n->getDoubleValue("config/target-x-offset-m");
+      double target_y_offset_m = n->getDoubleValue("config/target-y-offset-m");
+      double target_z_offset_m = n->getDoubleValue("config/target-z-offset-m");
+
+      add_view(new FGViewer ( FG_LOOKAT, from_model, from_model_index,
+                              at_model, at_model_index,
+                              damp_roll, damp_pitch, damp_heading,
+                              x_offset_m, y_offset_m,z_offset_m,
+                              heading_offset_deg, pitch_offset_deg,
+                              roll_offset_deg, fov_deg, aspect_ratio_multiplier,
+                              target_x_offset_m, target_y_offset_m,
+                              target_z_offset_m, near_m, internal ));
+    } else {
+      add_view(new FGViewer ( FG_LOOKFROM, from_model, from_model_index,
+                              false, 0, 0.0, 0.0, 0.0,
+                              x_offset_m, y_offset_m, z_offset_m,
+                              heading_offset_deg, pitch_offset_deg,
+                              roll_offset_deg, fov_deg, aspect_ratio_multiplier,
+                              0, 0, 0, near_m, internal ));
+    }
+  }
+
+  copyToCurrent();
+}
+
+void
+FGViewMgr::reinit ()
+{
+  // reset offsets and fov to configuration defaults
+  for (unsigned int i = 0; i < config_list.size(); i++) {
+    SGPropertyNode *n = config_list[i];
+    setView(i);
+
+    fgSetDouble("/sim/current-view/x-offset-m",
+        n->getDoubleValue("config/x-offset-m"));
+    fgSetDouble("/sim/current-view/y-offset-m",
+        n->getDoubleValue("config/y-offset-m"));
+    fgSetDouble("/sim/current-view/z-offset-m",
+        n->getDoubleValue("config/z-offset-m"));
+    fgSetDouble("/sim/current-view/pitch-offset-deg",
+        n->getDoubleValue("config/pitch-offset-deg"));
+    fgSetDouble("/sim/current-view/heading-offset-deg",
+        n->getDoubleValue("config/heading-offset-deg"));
+    fgSetDouble("/sim/current-view/roll-offset-deg",
+        n->getDoubleValue("config/roll-offset-deg"));
+
+    double fov_deg = n->getDoubleValue("config/default-field-of-view-deg");
+    if (fov_deg < 10.0)
+      fov_deg = 55.0;
+    fgSetDouble("/sim/current-view/field-of-view", fov_deg);
+
+    // target offsets for lookat mode only...
+    fgSetDouble("/sim/current-view/target-x-offset-deg",
+        n->getDoubleValue("config/target-x-offset-m"));
+    fgSetDouble("/sim/current-view/target-y-offset-deg",
+        n->getDoubleValue("config/target-y-offset-m"));
+    fgSetDouble("/sim/current-view/target-z-offset-deg",
+        n->getDoubleValue("config/target-z-offset-m"));
+  }
+  setView(0);
+}
+
+typedef double (FGViewMgr::*double_getter)() const;
+
+void
+FGViewMgr::bind ()
+{
+  // these are bound to the current view properties
+  fgTie("/sim/current-view/heading-offset-deg", this,
+	&FGViewMgr::getViewHeadingOffset_deg,
+        &FGViewMgr::setViewHeadingOffset_deg);
+  fgSetArchivable("/sim/current-view/heading-offset-deg");
+  fgTie("/sim/current-view/goal-heading-offset-deg", this,
+	&FGViewMgr::getViewGoalHeadingOffset_deg,
+        &FGViewMgr::setViewGoalHeadingOffset_deg);
+  fgSetArchivable("/sim/current-view/goal-heading-offset-deg");
+  fgTie("/sim/current-view/pitch-offset-deg", this,
+	&FGViewMgr::getViewPitchOffset_deg,
+        &FGViewMgr::setViewPitchOffset_deg);
+  fgSetArchivable("/sim/current-view/pitch-offset-deg");
+  fgTie("/sim/current-view/goal-pitch-offset-deg", this,
+	&FGViewMgr::getGoalViewPitchOffset_deg,
+        &FGViewMgr::setGoalViewPitchOffset_deg);
+  fgSetArchivable("/sim/current-view/goal-pitch-offset-deg");
+  fgTie("/sim/current-view/roll-offset-deg", this,
+	&FGViewMgr::getViewRollOffset_deg,
+        &FGViewMgr::setViewRollOffset_deg);
+  fgSetArchivable("/sim/current-view/roll-offset-deg");
+  fgTie("/sim/current-view/goal-roll-offset-deg", this,
+	&FGViewMgr::getGoalViewRollOffset_deg,
+        &FGViewMgr::setGoalViewRollOffset_deg);
+  fgSetArchivable("/sim/current-view/goal-roll-offset-deg");
+
+  fgTie("/sim/current-view/view-number", this,
+                      &FGViewMgr::getView, &FGViewMgr::setView);
+  fgSetArchivable("/sim/current-view/view-number", FALSE);
+
+  fgTie("/sim/current-view/axes/long", this,
+	(double_getter)0, &FGViewMgr::setViewAxisLong);
+  fgSetArchivable("/sim/current-view/axes/long");
+
+  fgTie("/sim/current-view/axes/lat", this,
+	(double_getter)0, &FGViewMgr::setViewAxisLat);
+  fgSetArchivable("/sim/current-view/axes/lat");
+
+  fgTie("/sim/current-view/field-of-view", this,
+	&FGViewMgr::getFOV_deg, &FGViewMgr::setFOV_deg);
+  fgSetArchivable("/sim/current-view/field-of-view");
+
+  fgTie("/sim/current-view/aspect-ratio-multiplier", this,
+	&FGViewMgr::getARM_deg, &FGViewMgr::setARM_deg);
+  fgSetArchivable("/sim/current-view/field-of-view");
+
+  fgTie("/sim/current-view/ground-level-nearplane-m", this,
+	&FGViewMgr::getNear_m, &FGViewMgr::setNear_m);
+  fgSetArchivable("/sim/current-view/ground-level-nearplane-m");
+
+  SGPropertyNode *n = fgGetNode("/sim/current-view", true);
+  n->tie("viewer-x-m", SGRawValuePointer<double>(&abs_viewer_position[0]));
+  n->tie("viewer-y-m", SGRawValuePointer<double>(&abs_viewer_position[1]));
+  n->tie("viewer-z-m", SGRawValuePointer<double>(&abs_viewer_position[2]));
+}
+
+void
+FGViewMgr::unbind ()
+{
+  // FIXME:
+  // need to redo these bindings to the new locations (move to viewer?)
+  fgUntie("/sim/current-view/heading-offset-deg");
+  fgUntie("/sim/current-view/goal-heading-offset-deg");
+  fgUntie("/sim/current-view/pitch-offset-deg");
+  fgUntie("/sim/current-view/goal-pitch-offset-deg");
+  fgUntie("/sim/current-view/field-of-view");
+  fgUntie("/sim/current-view/aspect-ratio-multiplier");
+  fgUntie("/sim/current-view/view-number");
+  fgUntie("/sim/current-view/axes/long");
+  fgUntie("/sim/current-view/axes/lat");
+  fgUntie("/sim/current-view/ground-level-nearplane-m");
+  fgUntie("/sim/current-view/viewer-x-m");
+  fgUntie("/sim/current-view/viewer-y-m");
+  fgUntie("/sim/current-view/viewer-z-m");
+}
+
+void
+FGViewMgr::update (double dt)
+{
+  FGViewer * view = get_current_view();
+  if (view == 0)
+    return;
+
+  FGViewer *loop_view = (FGViewer *)get_view(current);
+  SGPropertyNode *n = config_list[current];
+  double lon_deg, lat_deg, alt_ft, roll_deg, pitch_deg, heading_deg;
+
+  // Set up view location and orientation
+
+  if (!n->getBoolValue("config/from-model")) {
+    lon_deg = fgGetDouble(n->getStringValue("config/eye-lon-deg-path"));
+    lat_deg = fgGetDouble(n->getStringValue("config/eye-lat-deg-path"));
+    alt_ft = fgGetDouble(n->getStringValue("config/eye-alt-ft-path"));
+    roll_deg = fgGetDouble(n->getStringValue("config/eye-roll-deg-path"));
+    pitch_deg = fgGetDouble(n->getStringValue("config/eye-pitch-deg-path"));
+    heading_deg = fgGetDouble(n->getStringValue("config/eye-heading-deg-path"));
+
+    loop_view->setPosition(lon_deg, lat_deg, alt_ft);
+    loop_view->setOrientation(roll_deg, pitch_deg, heading_deg);
+  } else {
+    // force recalc in viewer
+    loop_view->set_dirty();
+  }
+
+  // if lookat (type 1) then get target data...
+  if (loop_view->getType() == FG_LOOKAT) {
+    if (!n->getBoolValue("config/from-model")) {
+      lon_deg = fgGetDouble(n->getStringValue("config/target-lon-deg-path"));
+      lat_deg = fgGetDouble(n->getStringValue("config/target-lat-deg-path"));
+      alt_ft = fgGetDouble(n->getStringValue("config/target-alt-ft-path"));
+      roll_deg = fgGetDouble(n->getStringValue("config/target-roll-deg-path"));
+      pitch_deg = fgGetDouble(n->getStringValue("config/target-pitch-deg-path"));
+      heading_deg = fgGetDouble(n->getStringValue("config/target-heading-deg-path"));
+
+      loop_view->setTargetPosition(lon_deg, lat_deg, alt_ft);
+      loop_view->setTargetOrientation(roll_deg, pitch_deg, heading_deg);
+    } else {
+      loop_view->set_dirty();
+    }
+  }
+
+  setViewXOffset_m(fgGetDouble("/sim/current-view/x-offset-m"));
+  setViewYOffset_m(fgGetDouble("/sim/current-view/y-offset-m"));
+  setViewZOffset_m(fgGetDouble("/sim/current-view/z-offset-m"));
+
+  setViewTargetXOffset_m(fgGetDouble("/sim/current-view/target-x-offset-m"));
+  setViewTargetYOffset_m(fgGetDouble("/sim/current-view/target-y-offset-m"));
+  setViewTargetZOffset_m(fgGetDouble("/sim/current-view/target-z-offset-m"));
+
+  // Update the current view
+  do_axes();
+  view->update(dt);
+  abs_viewer_position = loop_view->getViewPosition();
+}
+
+void
+FGViewMgr::copyToCurrent()
+{
+    SGPropertyNode *n = config_list[current];
+    fgSetString("/sim/current-view/name", n->getStringValue("name"));
+    fgSetString("/sim/current-view/type", n->getStringValue("type"));
+
+    // copy certain view config data for default values
+    fgSetDouble("/sim/current-view/config/heading-offset-deg",
+                n->getDoubleValue("config/default-heading-offset-deg"));
+    fgSetDouble("/sim/current-view/config/pitch-offset-deg",
+                n->getDoubleValue("config/pitch-offset-deg"));
+    fgSetDouble("/sim/current-view/config/roll-offset-deg",
+                n->getDoubleValue("config/roll-offset-deg"));
+    fgSetDouble("/sim/current-view/config/default-field-of-view-deg",
+                n->getDoubleValue("config/default-field-of-view-deg"));
+    fgSetBool("/sim/current-view/config/from-model",
+                n->getBoolValue("config/from-model"));
+
+    // copy view data
+    fgSetDouble("/sim/current-view/x-offset-m", getViewXOffset_m());
+    fgSetDouble("/sim/current-view/y-offset-m", getViewYOffset_m());
+    fgSetDouble("/sim/current-view/z-offset-m", getViewZOffset_m());
+
+    fgSetDouble("/sim/current-view/goal-heading-offset-deg",
+                get_current_view()->getGoalHeadingOffset_deg());
+    fgSetDouble("/sim/current-view/goal-pitch-offset-deg",
+                get_current_view()->getGoalPitchOffset_deg());
+    fgSetDouble("/sim/current-view/goal-roll-offset-deg",
+                get_current_view()->getRollOffset_deg());
+    fgSetDouble("/sim/current-view/heading-offset-deg",
+                get_current_view()->getHeadingOffset_deg());
+    fgSetDouble("/sim/current-view/pitch-offset-deg",
+                get_current_view()->getPitchOffset_deg());
+    fgSetDouble("/sim/current-view/roll-offset-deg",
+                get_current_view()->getRollOffset_deg());
+    fgSetDouble("/sim/current-view/target-x-offset-m",
+                get_current_view()->getTargetXOffset_m());
+    fgSetDouble("/sim/current-view/target-y-offset-m",
+                get_current_view()->getTargetYOffset_m());
+    fgSetDouble("/sim/current-view/target-z-offset-m",
+                get_current_view()->getTargetZOffset_m());
+    fgSetBool("/sim/current-view/internal",
+                get_current_view()->getInternal());
+}
+
+
+double
+FGViewMgr::getViewHeadingOffset_deg () const
+{
+  const FGViewer * view = get_current_view();
+  return (view == 0 ? 0 : view->getHeadingOffset_deg());
+}
+
+void
+FGViewMgr::setViewHeadingOffset_deg (double offset)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0) {
+    view->setGoalHeadingOffset_deg(offset);
+    view->setHeadingOffset_deg(offset);
+  }
+}
+
+double
+FGViewMgr::getViewGoalHeadingOffset_deg () const
+{
+  const FGViewer * view = get_current_view();
+  return (view == 0 ? 0 : view->getGoalHeadingOffset_deg());
+}
+
+void
+FGViewMgr::setViewGoalHeadingOffset_deg (double offset)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0)
+    view->setGoalHeadingOffset_deg(offset);
+}
+
+double
+FGViewMgr::getViewPitchOffset_deg () const
+{
+  const FGViewer * view = get_current_view();
+  return (view == 0 ? 0 : view->getPitchOffset_deg());
+}
+
+void
+FGViewMgr::setViewPitchOffset_deg (double tilt)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0) {
+    view->setGoalPitchOffset_deg(tilt);
+    view->setPitchOffset_deg(tilt);
+  }
+}
+
+double
+FGViewMgr::getGoalViewPitchOffset_deg () const
+{
+  const FGViewer * view = get_current_view();
+  return (view == 0 ? 0 : view->getGoalPitchOffset_deg());
+}
+
+void
+FGViewMgr::setGoalViewPitchOffset_deg (double tilt)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0)
+    view->setGoalPitchOffset_deg(tilt);
+}
+
+double
+FGViewMgr::getViewRollOffset_deg () const
+{
+  const FGViewer * view = get_current_view();
+  return (view == 0 ? 0 : view->getRollOffset_deg());
+}
+
+void
+FGViewMgr::setViewRollOffset_deg (double tilt)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0) {
+    view->setGoalRollOffset_deg(tilt);
+    view->setRollOffset_deg(tilt);
+  }
+}
+
+double
+FGViewMgr::getGoalViewRollOffset_deg () const
+{
+  const FGViewer * view = get_current_view();
+  return (view == 0 ? 0 : view->getGoalRollOffset_deg());
+}
+
+void
+FGViewMgr::setGoalViewRollOffset_deg (double tilt)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0)
+    view->setGoalRollOffset_deg(tilt);
+}
+
+double
+FGViewMgr::getViewXOffset_m () const
+{
+  const FGViewer * view = get_current_view();
+  if (view != 0) {
+    return ((FGViewer *)view)->getXOffset_m();
+  } else {
+    return 0;
+  }
+}
+
+void
+FGViewMgr::setViewXOffset_m (double x)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0) {
+    view->setXOffset_m(x);
+  }
+}
+
+double
+FGViewMgr::getViewYOffset_m () const
+{
+  const FGViewer * view = get_current_view();
+  if (view != 0) {
+    return ((FGViewer *)view)->getYOffset_m();
+  } else {
+    return 0;
+  }
+}
+
+void
+FGViewMgr::setViewYOffset_m (double y)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0) {
+    view->setYOffset_m(y);
+  }
+}
+
+double
+FGViewMgr::getViewZOffset_m () const
+{
+  const FGViewer * view = get_current_view();
+  if (view != 0) {
+    return ((FGViewer *)view)->getZOffset_m();
+  } else {
+    return 0;
+  }
+}
+
+void
+FGViewMgr::setViewZOffset_m (double z)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0) {
+    view->setZOffset_m(z);
+  }
+}
+
+double
+FGViewMgr::getViewTargetXOffset_m () const
+{
+  const FGViewer * view = get_current_view();
+  if (view != 0) {
+    return ((FGViewer *)view)->getTargetXOffset_m();
+  } else {
+    return 0;
+  }
+}
+
+void
+FGViewMgr::setViewTargetXOffset_m (double x)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0) {
+    view->setTargetXOffset_m(x);
+  }
+}
+
+double
+FGViewMgr::getViewTargetYOffset_m () const
+{
+  const FGViewer * view = get_current_view();
+  if (view != 0) {
+    return ((FGViewer *)view)->getTargetYOffset_m();
+  } else {
+    return 0;
+  }
+}
+
+void
+FGViewMgr::setViewTargetYOffset_m (double y)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0) {
+    view->setTargetYOffset_m(y);
+  }
+}
+
+double
+FGViewMgr::getViewTargetZOffset_m () const
+{
+  const FGViewer * view = get_current_view();
+  if (view != 0) {
+    return ((FGViewer *)view)->getTargetZOffset_m();
+  } else {
+    return 0;
+  }
+}
+
+void
+FGViewMgr::setViewTargetZOffset_m (double z)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0) {
+    view->setTargetZOffset_m(z);
+  }
+}
+
+int
+FGViewMgr::getView () const
+{
+  return ( current );
+}
+
+void
+FGViewMgr::setView (int newview)
+{
+  // negative numbers -> set view with node index -newview
+  if (newview < 0) {
+    for (int i = 0; i < (int)config_list.size(); i++) {
+      int index = -config_list[i]->getIndex();
+      if (index == newview)
+        newview = i;
+    }
+    if (newview < 0)
+      return;
+  }
+
+  // if newview number too low wrap to last view...
+  if (newview < 0)
+    newview = (int)views.size() - 1;
+
+  // if newview number to high wrap to zero...
+  if (newview >= (int)views.size())
+    newview = 0;
+
+  // set new view
+  set_view(newview);
+  // copy in view data
+  copyToCurrent();
+
+  // Copy the fdm's position into the SGLocation which is shared with
+  // some views ...
+  globals->get_aircraft_model()->update(0);
+  // Do the update ...
+  update(0);
+}
+
+
+double
+FGViewMgr::getFOV_deg () const
+{
+  const FGViewer * view = get_current_view();
+  return (view == 0 ? 0 : view->get_fov());
+}
+
+void
+FGViewMgr::setFOV_deg (double fov)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0)
+    view->set_fov(fov);
+}
+
+double
+FGViewMgr::getARM_deg () const
+{
+  const FGViewer * view = get_current_view();
+  return (view == 0 ? 0 : view->get_aspect_ratio_multiplier());
+}
+
+void
+FGViewMgr::setARM_deg (double aspect_ratio_multiplier)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0)
+    view->set_aspect_ratio_multiplier(aspect_ratio_multiplier);
+}
+
+double
+FGViewMgr::getNear_m () const
+{
+  const FGViewer * view = get_current_view();
+  return (view == 0 ? 0.5f : view->getNear_m());
+}
+
+void
+FGViewMgr::setNear_m (double near_m)
+{
+  FGViewer * view = get_current_view();
+  if (view != 0)
+    view->setNear_m(near_m);
+}
+
+void
+FGViewMgr::setViewAxisLong (double axis)
+{
+  axis_long = axis;
+}
+
+void
+FGViewMgr::setViewAxisLat (double axis)
+{
+  axis_lat = axis;
+}
+
+void
+FGViewMgr::do_axes ()
+{
+				// Take no action when hat is centered
+  if ( ( axis_long <  0.01 ) &&
+       ( axis_long > -0.01 ) &&
+       ( axis_lat  <  0.01 ) &&
+       ( axis_lat  > -0.01 )
+     )
+    return;
+
+  double viewDir = 999;
+
+  /* Do all the quick and easy cases */
+  if (axis_long < 0) {		// Longitudinal axis forward
+    if (axis_lat == axis_long)
+      viewDir = fgGetDouble("/sim/view/config/front-left-direction-deg");
+    else if (axis_lat == - axis_long)
+      viewDir = fgGetDouble("/sim/view/config/front-right-direction-deg");
+    else if (axis_lat == 0)
+      viewDir = fgGetDouble("/sim/view/config/front-direction-deg");
+  } else if (axis_long > 0) {	// Longitudinal axis backward
+    if (axis_lat == - axis_long)
+      viewDir = fgGetDouble("/sim/view/config/back-left-direction-deg");
+    else if (axis_lat == axis_long)
+      viewDir = fgGetDouble("/sim/view/config/back-right-direction-deg");
+    else if (axis_lat == 0)
+      viewDir = fgGetDouble("/sim/view/config/back-direction-deg");
+  } else if (axis_long == 0) {	// Longitudinal axis neutral
+    if (axis_lat < 0)
+      viewDir = fgGetDouble("/sim/view/config/left-direction-deg");
+    else if (axis_lat > 0)
+      viewDir = fgGetDouble("/sim/view/config/right-direction-deg");
+    else return; /* And assertion failure maybe? */
+  }
+
+				// Do all the difficult cases
+  if ( viewDir > 900 )
+    viewDir = SGD_RADIANS_TO_DEGREES * atan2 ( -axis_lat, -axis_long );
+  if ( viewDir < -1 ) viewDir += 360;
+
+  get_current_view()->setGoalHeadingOffset_deg(viewDir);
+}