#591: night-time rendering issues, avoid negative color values

[flightgear.git] / src / Autopilot / digitalfilter.cxx

diff --git a/src/Autopilot/digitalfilter.cxx b/src/Autopilot/digitalfilter.cxx
index bdd39397a51b6dc97410e52a65188589ced08b1c..6f83b01e1f6ea48d2b134f1748a572c1033445e2 100644 (file)
--- a/src/Autopilot/digitalfilter.cxx
+++ b/src/Autopilot/digitalfilter.cxx
@@ -25,6 +25,11 @@
 #include "functor.hxx"
 #include <deque>
 
+using std::map;
+using std::string;
+using std::endl;
+using std::cout;
+
 namespace FGXMLAutopilot {
 
 /* --------------------------------------------------------------------------------- */
@@ -136,7 +141,7 @@ bool GainFilterImplementation::configure( const std::string & nodeName, SGProper
 
 double ReciprocalFilterImplementation::compute(  double dt, double input )
 {
-  if( input >= -SGLimitsd::min() || input <= SGLimitsd::min() )
+  if( input >= -SGLimitsd::min() && input <= SGLimitsd::min() )
     return SGLimitsd::max();
 
   return _gainInput.get_value() / input;
@@ -265,9 +270,14 @@ void ExponentialFilterImplementation::initialize( double output )
 double ExponentialFilterImplementation::compute(  double dt, double input )
 {
   input = GainFilterImplementation::compute( dt, input );
+  double tf = _TfInput.get_value();
 
   double output_0;
-  double alpha = 1 / ((_TfInput.get_value()/dt) + 1);
+
+  // avoid negative filter times 
+  // and div by zero if -tf == dt
+
+  double alpha = tf > 0.0 ? 1 / ((tf/dt) + 1) : 1.0;
  
   if(_isSecondOrder) {
     output_0 = alpha * alpha * input + 
@@ -303,7 +313,8 @@ bool ExponentialFilterImplementation::configure( const std::string & nodeName, S
 /* --------------------------------------------------------------------------------- */
 
 DigitalFilter::DigitalFilter() :
-    AnalogComponent()
+    AnalogComponent(),
+    _initializeTo(INITIALIZE_INPUT)
 {
 }
 
@@ -335,6 +346,20 @@ bool DigitalFilter::configure(const string& nodeName, SGPropertyNode_ptr configN
     return true;
   }
 
+  if( nodeName == "initialize-to" ) {
+    string s( configNode->getStringValue() );
+    if( s == "input" ) {
+      _initializeTo = INITIALIZE_INPUT;
+    } else if( s == "output" ) {
+      _initializeTo = INITIALIZE_OUTPUT;
+    } else if( s == "none" ) {
+      _initializeTo = INITIALIZE_NONE;
+    } else {
+      SG_LOG( SG_AUTOPILOT, SG_WARN, "unhandled initialize-to value '" << s << "' ignored" );
+    }
+    return true;
+  }
+
   SG_LOG( SG_AUTOPILOT, SG_BULK, "DigitalFilter::configure(" << nodeName << ") [unhandled]" << endl );
   return false; // not handled by us, let the base class try
 }
@@ -344,8 +369,22 @@ void DigitalFilter::update( bool firstTime, double dt)
   if( _implementation == NULL ) return;
 
   if( firstTime ) {
-    SG_LOG(SG_AUTOPILOT,SG_DEBUG, "First time initialization of " << get_name() << " to " << _valueInput.get_value() );
-    _implementation->initialize( _valueInput.get_value() );
+    switch( _initializeTo ) {
+
+      case INITIALIZE_INPUT:
+        SG_LOG(SG_AUTOPILOT,SG_DEBUG, "First time initialization of " << get_name() << " to " << _valueInput.get_value() );
+        _implementation->initialize( _valueInput.get_value() );
+        break;
+
+      case INITIALIZE_OUTPUT:
+        SG_LOG(SG_AUTOPILOT,SG_DEBUG, "First time initialization of " << get_name() << " to " << get_output_value() );
+        _implementation->initialize( get_output_value() );
+        break;
+
+      default:
+        SG_LOG(SG_AUTOPILOT,SG_DEBUG, "First time initialization of " << get_name() << " to (uninitialized)" );
+        break;
+    }
   }
 
   double input = _valueInput.get_value() - _referenceInput.get_value();