From 22de2508aade107b021e50889b6cfa69af3bfcea Mon Sep 17 00:00:00 2001
From: mfranz <mfranz>
Date: Sat, 28 Jul 2007 08:08:22 +0000
Subject: [PATCH] - set filter dt only once - make throttle more responsive
 (again)

---
 src/FDM/UFO.cxx | 19 +++++++++++--------
 src/FDM/UFO.hxx |  9 +++++++--
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/src/FDM/UFO.cxx b/src/FDM/UFO.cxx
index ab4652b09..a62ab40e1 100644
--- a/src/FDM/UFO.cxx
+++ b/src/FDM/UFO.cxx
@@ -35,9 +35,11 @@
 
 #include "UFO.hxx"
 
+double FGUFO::lowpass::_dt;
+
 
 FGUFO::FGUFO( double dt ) :
-    Throttle(new lowpass(fgGetDouble("/controls/damping/throttle", 0.3))),
+    Throttle(new lowpass(fgGetDouble("/controls/damping/throttle", 0.1))),
     Aileron(new lowpass(fgGetDouble("/controls/damping/aileron", 0.65))),
     Elevator(new lowpass(fgGetDouble("/controls/damping/elevator", 0.65))),
     Rudder(new lowpass(fgGetDouble("/controls/damping/rudder", 0.05))),
@@ -76,6 +78,7 @@ void FGUFO::update( double dt ) {
     if (is_suspended())
         return;
 
+    lowpass::set_delta(dt);
     double time_step = dt;
 
     // read the throttle
@@ -86,16 +89,16 @@ void FGUFO::update( double dt ) {
     if (brake_left > 0.5 || brake_right > 0.5)
         throttle = -throttle;
 
-    throttle = Throttle->filter(dt, throttle);
+    throttle = Throttle->filter(throttle);
 
     // read and lowpass-filter the state of the control surfaces
-    double aileron = Aileron->filter(dt, globals->get_controls()->get_aileron());
-    double elevator = Elevator->filter(dt, globals->get_controls()->get_elevator());
-    double rudder = Rudder->filter(dt, globals->get_controls()->get_rudder());
+    double aileron = Aileron->filter(globals->get_controls()->get_aileron());
+    double elevator = Elevator->filter(globals->get_controls()->get_elevator());
+    double rudder = Rudder->filter(globals->get_controls()->get_rudder());
 
-    aileron += Aileron_Trim->filter(dt, globals->get_controls()->get_aileron_trim());
-    elevator += Elevator_Trim->filter(dt, globals->get_controls()->get_elevator_trim());
-    rudder += Rudder_Trim->filter(dt, globals->get_controls()->get_rudder_trim());
+    aileron += Aileron_Trim->filter(globals->get_controls()->get_aileron_trim());
+    elevator += Elevator_Trim->filter(globals->get_controls()->get_elevator_trim());
+    rudder += Rudder_Trim->filter(globals->get_controls()->get_rudder_trim());
 
     double velocity = throttle * Speed_Max->getDoubleValue(); // meters/sec
 
diff --git a/src/FDM/UFO.hxx b/src/FDM/UFO.hxx
index b680fd953..38266e3c4 100644
--- a/src/FDM/UFO.hxx
+++ b/src/FDM/UFO.hxx
@@ -28,18 +28,23 @@
 
 
 class FGUFO: public FGInterface {
+private:
+
     class lowpass {
+    private:
+        static double _dt;
         double _coeff;
         double _last;
         bool _initialized;
     public:
         lowpass(double coeff) : _coeff(coeff), _initialized(false) {}
-        double filter(double dt, double value) {
+        static inline void set_delta(double dt) { _dt = dt; }
+        double filter(double value) {
             if (!_initialized) {
                 _initialized = true;
                 return _last = value;
             }
-            double c = dt / (_coeff + dt);
+            double c = _dt / (_coeff + _dt);
             return _last = value * c + _last * (1.0 - c);
         }
     };
-- 
2.39.5