Added Michael Johnson's audio patches for testing.

Also did a few tweaks to avoid numerical problems when starting at a place
with no (or bogus) scenery.

diff --git a/Main/GLUTmain.cxx b/Main/GLUTmain.cxx
index 4de2b3ad0edc4a00451a582dfe60e02f3dd82684..562753a99f91b2051f92527271678ac91e7f1176 100644 (file)
--- a/Main/GLUTmain.cxx
+++ b/Main/GLUTmain.cxx
@@ -21,6 +21,7 @@
 // $Id$
 // (Log is kept at end of this file)
 
+#define MICHAEL_JOHNSON_EXPERIMENTAL_ENGINE_AUDIO
 
 #ifdef HAVE_CONFIG_H
 #  include <config.h>
@@ -572,10 +573,64 @@ static void fgMainLoop( void ) {
     // Run audio scheduler
 #ifdef ENABLE_AUDIO_SUPPORT
     if ( current_options.get_sound() && audio_sched->working() ) {
-       double param = controls.get_throttle( 0 ) * 2.0 + 1.0;
 
-       pitch_envelope.setStep  ( 0, 0.01, param );
-       volume_envelope.setStep ( 0, 0.01, param );
+#   ifdef MICHAEL_JOHNSON_EXPERIMENTAL_ENGINE_AUDIO
+
+       // note: all these factors are relative to the sample.  our
+       // sample format should really contain a conversion factor so
+       // that we can get prop speed right for arbitrary samples.
+       // Note that for normal-size props, there is a point at which
+       // the prop tips approach the speed of sound; that is a pretty
+       // strong limit to how fast the prop can go.
+
+       // multiplication factor is prime pitch control; add some log
+       // component for verisimilitude
+
+       double pitch = log((controls.get_throttle(0) * 14.0) + 1.0);
+       //fprintf(stderr, "pitch1: %f ", pitch);
+       if (controls.get_throttle(0) > 0.0 || f->v_rel_wind > 40.0) {
+           //fprintf(stderr, "rel_wind: %f ", f->v_rel_wind);
+           // only add relative wind and AoA if prop is moving
+           // or we're really flying at idle throttle
+           if (pitch < 5.4) {  // this needs tuning
+               // prop tips not breaking sound barrier
+               pitch += log(f->v_rel_wind + 0.8)/2;
+           } else {
+               // prop tips breaking sound barrier
+               pitch += log(f->v_rel_wind + 0.8)/10;
+           }
+           //fprintf(stderr, "pitch2: %f ", pitch);
+           //fprintf(stderr, "AoA: %f ", FG_Gamma_vert_rad);
+
+           // Angle of Attack next... -x^3(e^x) is my best guess Just
+           // need to calculate some reasonable scaling factor and
+           // then clamp it on the positive aoa (neg adj) side
+           double aoa = FG_Gamma_vert_rad * 2.2;
+           double aoa_adj = pow(-aoa, 3) * pow(M_E, aoa);
+           if (aoa_adj < -0.8) aoa_adj = -0.8;
+           pitch += aoa_adj;
+           //fprintf(stderr, "pitch3: %f ", pitch);
+
+           // don't run at absurdly slow rates -- not realistic
+           // and sounds bad to boot.  :-)
+           if (pitch < 0.8) pitch = 0.8;
+       }
+       //fprintf(stderr, "pitch4: %f\n", pitch);
+
+       double volume = controls.get_throttle(0) * 1.15 + 0.3 +
+           log(f->v_rel_wind + 1.0)/14.0;
+       // fprintf(stderr, "volume: %f\n", volume);
+
+       pitch_envelope.setStep  ( 0, 0.01, pitch );
+       volume_envelope.setStep ( 0, 0.01, volume );
+
+#   else
+
+       double param = controls.get_throttle( 0 ) * 2.0 + 1.0;
+       pitch_envelope.setStep  ( 0, 0.01, param );
+       volume_envelope.setStep ( 0, 0.01, param );
+
+#   endif // experimental throttle patch
 
        audio_sched -> update();
     }
@@ -891,6 +946,11 @@ int main( int argc, char **argv ) {
 
 
 // $Log$
+// Revision 1.66  1998/11/11 00:24:00  curt
+// Added Michael Johnson's audio patches for testing.
+// Also did a few tweaks to avoid numerical problems when starting at a place
+// with no (or bogus) scenery.
+//
 // Revision 1.65  1998/11/09 23:39:22  curt
 // Tweaks for the instrument panel.
 //

diff --git a/Main/fg_init.cxx b/Main/fg_init.cxx
index 7d4f2f2054eecfc2ae796aac81cde9ead04d4a50..e9c09066994e290164b3ca463dcb3313b9c38aa0 100644 (file)
--- a/Main/fg_init.cxx
+++ b/Main/fg_init.cxx
@@ -212,8 +212,12 @@ int fgInitSubsystems( void )
     abs_view_pos = fgGeodToCart(geod_pos);
 
     // Calculate ground elevation at starting point
+    FG_LOG( FG_GENERAL, FG_DEBUG, 
+           "Altitude before update " << scenery.cur_elev );
     scenery.cur_elev = 
        fgTileMgrCurElev( FG_Longitude, FG_Latitude, abs_view_pos );
+    FG_LOG( FG_GENERAL, FG_DEBUG, 
+           "Altitude after update " << scenery.cur_elev );
     FG_Runway_altitude = scenery.cur_elev * METER_TO_FEET;
 
     // Reset our altitude if we are below ground
@@ -377,6 +381,11 @@ int fgInitSubsystems( void )
 
 
 // $Log$
+// Revision 1.49  1998/11/11 00:24:02  curt
+// Added Michael Johnson's audio patches for testing.
+// Also did a few tweaks to avoid numerical problems when starting at a place
+// with no (or bogus) scenery.
+//
 // Revision 1.48  1998/11/07 19:07:10  curt
 // Enable release builds using the --without-logging option to the configure
 // script.  Also a couple log message cleanups, plus some C to C++ comment