diff --git a/src/Cockpit/cockpit.cxx b/src/Cockpit/cockpit.cxx
index 4e7651f7c..0414a0f6a 100644
--- a/src/Cockpit/cockpit.cxx
+++ b/src/Cockpit/cockpit.cxx
@@ -44,6 +44,7 @@
 #include <Main/globals.hxx>
 #include <Main/fg_props.hxx>
 #include <Main/viewmgr.hxx>
+#include <Main/viewer.hxx>
 #include <Scenery/scenery.hxx>
 #include <GUI/gui.h>
 
diff --git a/src/Cockpit/hud.cxx b/src/Cockpit/hud.cxx
index f9b9f3a97..6673184e4 100644
--- a/src/Cockpit/hud.cxx
+++ b/src/Cockpit/hud.cxx
@@ -48,6 +48,7 @@
 #include <Main/globals.hxx>
 #include <Scenery/scenery.hxx>
 #include <Airports/runways.hxx>
+#include <Main/viewer.hxx>
 
 #include "hud.hxx"
 
diff --git a/src/Cockpit/hud_ladr.cxx b/src/Cockpit/hud_ladr.cxx
index e2306b427..38def8d9d 100644
--- a/src/Cockpit/hud_ladr.cxx
+++ b/src/Cockpit/hud_ladr.cxx
@@ -6,7 +6,7 @@
 
 #include "hud.hxx"
 #include "panel.hxx"
-
+#include <Main/viewer.hxx>
 
 // FIXME
 extern float get_roll(void);
diff --git a/src/Cockpit/hud_rwy.cxx b/src/Cockpit/hud_rwy.cxx
index d4b56356b..2bc15bcd1 100644
--- a/src/Cockpit/hud_rwy.cxx
+++ b/src/Cockpit/hud_rwy.cxx
@@ -31,6 +31,7 @@
 #include <Environment/environment.hxx>
 #include <Environment/environment_mgr.hxx>
 #include <ATCDCL/ATCutils.hxx>
+#include <Main/viewer.hxx>
 
 #include <osg/GLU>
 
diff --git a/src/Cockpit/panel.cxx b/src/Cockpit/panel.cxx
index cd68b342a..e2caa87f0 100644
--- a/src/Cockpit/panel.cxx
+++ b/src/Cockpit/panel.cxx
@@ -31,6 +31,8 @@
 #  include <config.h>
 #endif
 
+#include "panel.hxx"
+
 #include <stdio.h>	// sprintf
 #include <string.h>
 #include <iostream>
@@ -55,9 +57,11 @@
 #include <Main/viewmgr.hxx>
 #include <Time/light.hxx>
 #include <GUI/new_gui.hxx>	// FGFontCache
+#include <Main/viewer.hxx>
+#include <Instrumentation/dclgps.hxx>
 
 #include "hud.hxx"
-#include "panel.hxx"
+
 
 #define WIN_X 0
 #define WIN_Y 0
diff --git a/src/Cockpit/panel.hxx b/src/Cockpit/panel.hxx
index 0308967d9..ab4f5264f 100644
--- a/src/Cockpit/panel.hxx
+++ b/src/Cockpit/panel.hxx
@@ -21,21 +21,10 @@
 #ifndef __PANEL_HXX
 #define __PANEL_HXX
 
-#ifndef __cplusplus
-# error This library requires C++
-#endif
-
-
-#ifdef HAVE_CONFIG_H
-#  include <config.h>
-#endif
-
 #include <osg/ref_ptr>
 #include <osg/StateSet>
 #include <osg/Texture2D>
 
-#include <plib/fnt.h>
-
 #include <simgear/compiler.h>
 #include <simgear/props/props.hxx>
 #include <simgear/structure/subsystem_mgr.hxx>
@@ -48,16 +37,11 @@
 #include <map>
 
 #include <Main/fg_props.hxx>
-#include <Instrumentation/dclgps.hxx>
-
-using std::vector;
-using std::map;
-
 
 class FGPanelInstrument;
+class fntFont;
+class DCLGPS;
 
-
-
 ////////////////////////////////////////////////////////////////////////
 // Texture management.
 ////////////////////////////////////////////////////////////////////////
@@ -71,11 +55,11 @@ class FGPanelInstrument;
 class FGTextureManager
 {
 public:
-  static osg::Texture2D* createTexture(const string &relativePath,
+  static osg::Texture2D* createTexture(const std::string &relativePath,
                                        bool staticTexture = true);
-  static void addTexture(const string &relativePath, osg::Texture2D* texture);
+  static void addTexture(const std::string &relativePath, osg::Texture2D* texture);
 private:
-  static map<string,osg::ref_ptr<osg::Texture2D> > _textureMap;
+  static std::map<std::string,osg::ref_ptr<osg::Texture2D> > _textureMap;
 };
 
 
@@ -89,14 +73,14 @@ class FGCroppedTexture
 public:
 
   FGCroppedTexture ();
-  FGCroppedTexture (const string &path,
+  FGCroppedTexture (const std::string &path,
 		  float _minX = 0.0, float _minY = 0.0,
 		  float _maxX = 1.0, float _maxY = 1.0);
   virtual ~FGCroppedTexture ();
 
-  virtual void setPath (const string &path) { _path = path; }
+  virtual void setPath (const std::string &path) { _path = path; }
 
-  virtual const string &getPath () const { return _path; }
+  virtual const std::string &getPath () const { return _path; }
 
   virtual osg::StateSet* getTexture ();
 
@@ -111,7 +95,7 @@ public:
 
 
 private:
-  string _path;
+  std::string _path;
   osg::ref_ptr<osg::StateSet> _texture;
   float _minX, _minY, _maxX, _maxY;
 };
@@ -199,7 +183,7 @@ private:
   mutable int _mouseButton, _mouseX, _mouseY;
   mutable int _mouseDelay;
   mutable FGPanelInstrument * _mouseInstrument;
-  typedef vector<FGPanelInstrument *> instrument_list_type;
+  typedef std::vector<FGPanelInstrument *> instrument_list_type;
   int _width;
   int _height;
   int _view_height;
@@ -273,7 +257,7 @@ public:
   virtual bool doAction (int updown);
 
 private:
-  typedef vector<SGBinding *> binding_list_t;
+  typedef std::vector<SGBinding *> binding_list_t;
 
   int _button;
   int _x;
@@ -356,7 +340,7 @@ public:
 protected:
   int _w, _h;
 
-  typedef vector<FGPanelTransformation *> transformation_list;
+  typedef std::vector<FGPanelTransformation *> transformation_list;
   transformation_list _transformations;
 };
 
@@ -403,7 +387,7 @@ public:
 
 protected:
   int _x, _y, _w, _h;
-  typedef vector<FGPanelAction *> action_list_type;
+  typedef std::vector<FGPanelAction *> action_list_type;
   action_list_type _actions;
 };
 
@@ -430,7 +414,7 @@ public:
   virtual void addTransformation (FGPanelTransformation * transformation);
 
 protected:
-  typedef vector<FGInstrumentLayer *> layer_list;
+  typedef std::vector<FGInstrumentLayer *> layer_list;
   layer_list _layers;
 };
 
@@ -473,7 +457,7 @@ public:
 				// transfer pointer ownership
   virtual void addLayer (FGInstrumentLayer * layer);
 protected:
-  vector<FGInstrumentLayer *> _layers;
+  std::vector<FGInstrumentLayer *> _layers;
 };
 
 
@@ -526,17 +510,17 @@ public:
   class Chunk : public SGConditional
   {
   public:
-    Chunk (const string &text, const string &fmt = "%s");
+    Chunk (const std::string &text, const std::string &fmt = "%s");
     Chunk (ChunkType type, const SGPropertyNode * node,
-	   const string &fmt = "", float mult = 1.0, float offs = 0.0,
+	   const std::string &fmt = "", float mult = 1.0, float offs = 0.0,
            bool truncation = false);
 
     const char * getValue () const;
   private:
     ChunkType _type;
-    string _text;
+    std::string _text;
     SGConstPropertyNode_ptr _node;
-    string _fmt;
+    std::string _fmt;
     float _mult;
     float _offs;
     bool _trunc;
@@ -552,20 +536,20 @@ public:
   virtual void addChunk (Chunk * chunk);
   virtual void setColor (float r, float g, float b);
   virtual void setPointSize (float size);
-  virtual void setFontName ( const string &name );
+  virtual void setFontName ( const std::string &name );
   virtual void setFont (fntFont * font);
 
 private:
 
   void recalc_value () const;
 
-  typedef vector<Chunk *> chunk_list;
+  typedef std::vector<Chunk *> chunk_list;
   chunk_list _chunks;
   float _color[4];
 
   float _pointSize;
-  mutable string _font_name;
-  mutable string _value;
+  mutable std::string _font_name;
+  mutable std::string _value;
   mutable SGTimeStamp _then;
   mutable SGTimeStamp _now;
 };
diff --git a/src/Environment/environment.cxx b/src/Environment/environment.cxx
index a922d834b..a83b7de1a 100644
--- a/src/Environment/environment.cxx
+++ b/src/Environment/environment.cxx
@@ -29,8 +29,6 @@
 
 #include <boost/tuple/tuple.hpp>
 
-#include <plib/sg.h>
-
 #include <simgear/constants.h>
 #include <simgear/debug/logstream.hxx>
 #include <simgear/math/interpolater.hxx>
diff --git a/src/FDM/LaRCsim/LaRCsimIC.hxx b/src/FDM/LaRCsim/LaRCsimIC.hxx
index b6e112153..1d445ca26 100644
--- a/src/FDM/LaRCsim/LaRCsimIC.hxx
+++ b/src/FDM/LaRCsim/LaRCsimIC.hxx
@@ -30,8 +30,6 @@
 INCLUDES
 *******************************************************************************/
 
-#include <plib/sg.h>
-
 #include "ls_constants.h"
 #include "ls_types.h"
 
@@ -43,6 +41,7 @@ CLASS DECLARATION
 #define M_TO_FT 3.2808399
 #define DEFAULT_AGL_ALT 3.758099
 #define DEFAULT_PITCH_ON_GROUND 0.0074002
+#define DEGREES_TO_RADIANS (M_PI / 180.0)
 
 enum lsspeedset { lssetvt, lssetvc, lssetve, lssetmach, lssetuvw, lssetned };
 enum lsaltset { lssetasl, lssetagl };
@@ -71,7 +70,7 @@ public:
   void SetAltitudeAGLFtIC(SCALAR tt);
   
   //"vertical" flight path, recalculate theta
-  inline void SetFlightPathAngleDegIC(SCALAR tt) { SetFlightPathAngleRadIC(tt*SGD_DEGREES_TO_RADIANS); }
+  inline void SetFlightPathAngleDegIC(SCALAR tt) { SetFlightPathAngleRadIC(tt*DEGREES_TO_RADIANS); }
   void SetFlightPathAngleRadIC(SCALAR tt);
   
   //set speed first
@@ -79,26 +78,26 @@ public:
   void SetClimbRateFpsIC(SCALAR tt);
   
   //use currently stored gamma, recalcualte theta
-  inline void SetAlphaDegIC(SCALAR tt)      { alpha=tt*SGD_DEGREES_TO_RADIANS; getTheta(); }
+  inline void SetAlphaDegIC(SCALAR tt)      { alpha=tt*DEGREES_TO_RADIANS; getTheta(); }
   inline void SetAlphaRadIC(SCALAR tt)      { alpha=tt; getTheta(); }
   
   //use currently stored gamma, recalcualte alpha
-  inline void SetPitchAngleDegIC(SCALAR tt) { SetPitchAngleRadIC(tt*SGD_DEGREES_TO_RADIANS); }
+  inline void SetPitchAngleDegIC(SCALAR tt) { SetPitchAngleRadIC(tt*DEGREES_TO_RADIANS); }
          void SetPitchAngleRadIC(SCALAR tt);
 
-  inline void SetBetaDegIC(SCALAR tt)       { beta=tt*SGD_DEGREES_TO_RADIANS; getTheta();}
+  inline void SetBetaDegIC(SCALAR tt)       { beta=tt*DEGREES_TO_RADIANS; getTheta();}
   inline void SetBetaRadIC(SCALAR tt)       { beta=tt; getTheta(); }
   
-  inline void SetRollAngleDegIC(SCALAR tt) { phi=tt*SGD_DEGREES_TO_RADIANS; getTheta(); }
+  inline void SetRollAngleDegIC(SCALAR tt) { phi=tt*DEGREES_TO_RADIANS; getTheta(); }
   inline void SetRollAngleRadIC(SCALAR tt) { phi=tt; getTheta(); }
 
-  inline void SetHeadingDegIC(SCALAR tt)   { psi=tt*SGD_DEGREES_TO_RADIANS; }
+  inline void SetHeadingDegIC(SCALAR tt)   { psi=tt*DEGREES_TO_RADIANS; }
   inline void SetHeadingRadIC(SCALAR tt)   { psi=tt; }
 
-  inline void SetLatitudeGDDegIC(SCALAR tt)  { SetLatitudeGDRadIC(tt*SGD_DEGREES_TO_RADIANS); }
+  inline void SetLatitudeGDDegIC(SCALAR tt)  { SetLatitudeGDRadIC(tt*DEGREES_TO_RADIANS); }
          void SetLatitudeGDRadIC(SCALAR tt);
 
-  inline void SetLongitudeDegIC(SCALAR tt) { longitude=tt*SGD_DEGREES_TO_RADIANS; }
+  inline void SetLongitudeDegIC(SCALAR tt) { longitude=tt*DEGREES_TO_RADIANS; }
   inline void SetLongitudeRadIC(SCALAR tt) { longitude=tt; }
   
   void SetRunwayAltitudeFtIC(SCALAR tt);
@@ -114,32 +113,32 @@ public:
   
   inline SCALAR GetRunwayAltitudeFtIC(void) { return runway_altitude; }
 
-  inline SCALAR GetFlightPathAngleDegIC(void) { return gamma*SGD_RADIANS_TO_DEGREES; }
+  inline SCALAR GetFlightPathAngleDegIC(void) { return gamma*DEGREES_TO_RADIANS; }
   inline SCALAR GetFlightPathAngleRadIC(void) { return gamma; }
 
   inline SCALAR GetClimbRateFpmIC(void) { return hdot*60; }
   inline SCALAR GetClimbRateFpsIC(void) { return hdot; }
 
-  inline SCALAR GetAlphaDegIC(void)      { return alpha*SGD_RADIANS_TO_DEGREES; }
+  inline SCALAR GetAlphaDegIC(void)      { return alpha*DEGREES_TO_RADIANS; }
   inline SCALAR GetAlphaRadIC(void)      { return alpha; }
 
-  inline SCALAR GetPitchAngleDegIC(void) { return theta*SGD_RADIANS_TO_DEGREES; }
+  inline SCALAR GetPitchAngleDegIC(void) { return theta*DEGREES_TO_RADIANS; }
   inline SCALAR GetPitchAngleRadIC(void) { return theta; }
 
 
-  inline SCALAR GetBetaDegIC(void)       { return beta*SGD_RADIANS_TO_DEGREES; }
-  inline SCALAR GetBetaRadIC(void)       { return beta*SGD_RADIANS_TO_DEGREES; }
+  inline SCALAR GetBetaDegIC(void)       { return beta*DEGREES_TO_RADIANS; }
+  inline SCALAR GetBetaRadIC(void)       { return beta*DEGREES_TO_RADIANS; }
 
-  inline SCALAR GetRollAngleDegIC(void) { return phi*SGD_RADIANS_TO_DEGREES; }
+  inline SCALAR GetRollAngleDegIC(void) { return phi*DEGREES_TO_RADIANS; }
   inline SCALAR GetRollAngleRadIC(void) { return phi; }
 
-  inline SCALAR GetHeadingDegIC(void)   { return psi*SGD_RADIANS_TO_DEGREES; }
+  inline SCALAR GetHeadingDegIC(void)   { return psi*DEGREES_TO_RADIANS; }
   inline SCALAR GetHeadingRadIC(void)   { return psi; }
 
-  inline SCALAR GetLatitudeGDDegIC(void)  { return latitude_gd*SGD_RADIANS_TO_DEGREES; }
+  inline SCALAR GetLatitudeGDDegIC(void)  { return latitude_gd*DEGREES_TO_RADIANS; }
   inline SCALAR GetLatitudeGDRadIC(void) { return latitude_gd; }
 
-  inline SCALAR GetLongitudeDegIC(void) { return longitude*SGD_RADIANS_TO_DEGREES; }
+  inline SCALAR GetLongitudeDegIC(void) { return longitude*DEGREES_TO_RADIANS; }
   inline SCALAR GetLongitudeRadIC(void) { return longitude; }
 
   inline SCALAR GetUBodyFpsIC(void) { return vt*cos(alpha)*cos(beta); }
diff --git a/src/Instrumentation/HUD/HUD.cxx b/src/Instrumentation/HUD/HUD.cxx
index 65543dea3..d37f28a3d 100644
--- a/src/Instrumentation/HUD/HUD.cxx
+++ b/src/Instrumentation/HUD/HUD.cxx
@@ -35,6 +35,7 @@
 
 #include <Main/globals.hxx>
 #include <Main/viewmgr.hxx>
+#include <Main/viewer.hxx>
 
 #include "HUD.hxx"
 
diff --git a/src/Instrumentation/gps.cxx b/src/Instrumentation/gps.cxx
index 2d448f575..e2b451467 100644
--- a/src/Instrumentation/gps.cxx
+++ b/src/Instrumentation/gps.cxx
@@ -476,8 +476,9 @@ GPS::updateTTWNode(UpdateContext& ctx, double distance_m, SGPropertyNode_ptr nod
     // increase. Makes most sense when travelling directly towards
     // the waypoint.
     double TTW = 0.0;
-    if (ctx.speed_kt > 0.0 && distance_m > 0.0) {
-        TTW = (distance_m * SG_METER_TO_NM) / (ctx.speed_kt / 3600);
+    double speed_nm_per_second = ctx.speed_kt / 3600;
+    if (speed_nm_per_second > SGLimitsd::min() && distance_m > 0.0) {
+        TTW = (distance_m * SG_METER_TO_NM) / speed_nm_per_second;
     }
     if (TTW < 356400.5) { // That's 99 hours
       unsigned int TTW_seconds = (int) (TTW + 0.5);
diff --git a/src/Instrumentation/mag_compass.cxx b/src/Instrumentation/mag_compass.cxx
index 223c77708..1f57f0791 100644
--- a/src/Instrumentation/mag_compass.cxx
+++ b/src/Instrumentation/mag_compass.cxx
@@ -10,7 +10,6 @@
 #  include <config.h>
 #endif
 
-#include <plib/sg.h>
 #include <simgear/sg_inlines.h>
 
 #include "mag_compass.hxx"
diff --git a/src/Instrumentation/render_area_2d.cxx b/src/Instrumentation/render_area_2d.cxx
index 5a08009a1..c0da87fd7 100644
--- a/src/Instrumentation/render_area_2d.cxx
+++ b/src/Instrumentation/render_area_2d.cxx
@@ -28,11 +28,6 @@
 
 #include "render_area_2d.hxx"
 
-static const float dummy_normals[][3] = {{0.0f, 0.0f, 0.0f},
-                                         {0.0f, 0.0f, 0.0f},
-                                         {0.0f, 0.0f, 0.0f},
-                                         {0.0f, 0.0f, 0.0f}};
-
 RA2DPrimitive::RA2DPrimitive() {
 	invert = false;
 	debug = false;
@@ -184,13 +179,13 @@ void RenderArea2D::oldDrawPixel(int x, int y, bool invert) {
 	//cout << "DP: " << fx1 << ", " << fy1 << " ... " << fx2 << ", " << fy2 << '\n';
 	
 	doSetColor(invert ? _backgroundColor : _pixelColor);
-	sgVec2 corners[4];
-	sgSetVec2(corners[0], fx1, fy1);
-	sgSetVec2(corners[1], fx2, fy1);
-	sgSetVec2(corners[2], fx2, fy2);
-	sgSetVec2(corners[3], fx1, fy2);
-	//cout << "Drawing pixel, x,y is " << x << ", " << y << ", fx is [x1,x2,y1,y2] " << fx1 << ", " << fx2 << ", " << fy1 << ", " << fy2 << '\n';
-	doDrawQuad(&corners[0], dummy_normals);
+	SGVec2f corners[4] = {
+    SGVec2f(fx1, fy1),
+    SGVec2f(fx2, fy1),
+    SGVec2f(fx2, fy2),
+    SGVec2f(fx1, fy2)
+  };
+	doDrawQuad(corners);
 }
 
 void RenderArea2D::DrawLine(int x1, int y1, int x2, int y2) {
@@ -314,12 +309,13 @@ void RenderArea2D::oldDrawQuad(int x1, int y1, int x2, int y2, bool invert) {
 	//cout << "DP: " << fx1 << ", " << fy1 << " ... " << fx2 << ", " << fy2 << '\n';
 	
 	doSetColor(invert ? _backgroundColor : _pixelColor);
-	sgVec2 corners[4];
-	sgSetVec2(corners[0], fx1, fy1);
-	sgSetVec2(corners[1], fx2, fy1);
-	sgSetVec2(corners[2], fx2, fy2);
-	sgSetVec2(corners[3], fx1, fy2);
-	doDrawQuad(&corners[0], dummy_normals);
+	SGVec2f corners[4] = {
+    SGVec2f(fx1, fy1),
+    SGVec2f(fx2, fy1),
+    SGVec2f(fx2, fy2),
+    SGVec2f(fx1, fy2)
+  };
+	doDrawQuad(corners);
 }
 
 void RenderArea2D::DrawBackground() {
@@ -328,12 +324,14 @@ void RenderArea2D::DrawBackground() {
 
 void RenderArea2D::oldDrawBackground() {
 	doSetColor(_backgroundColor);
-	sgVec2 corners[4];
-	sgSetVec2(corners[0], (float)_posx, (float)_posy);
-	sgSetVec2(corners[1], (float)(_posx + _sizex), (float)_posy);
-	sgSetVec2(corners[2], (float)(_posx + _sizex), (float)(_posy + _sizey));
-	sgSetVec2(corners[3], (float)_posx, (float)(_posy + _sizey));
-	doDrawQuad(&corners[0], dummy_normals);
+	SGVec2f corners[4] = {
+    SGVec2f(_posx, _posy),
+    SGVec2f(_posx + _sizex, _posy),
+    SGVec2f(_posx + _sizex, _posy + _sizey),
+    SGVec2f(_posx, _posy + _sizey)
+  };
+  
+	doDrawQuad(corners);
 }
 
 void RenderArea2D::Flush() {
@@ -351,20 +349,23 @@ void RenderArea2D::doSetColor( const float *rgba ) {
   glColor4fv( rgba );
 }
 
-void RenderArea2D::doDrawQuad( const sgVec2 *p, const sgVec3 *normals ) {
+void RenderArea2D::doDrawQuad( const SGVec2f *p) {
   glBegin(GL_QUADS);
-  glNormal3fv( normals[0] ); glVertex2fv( p[0] );
-  glNormal3fv( normals[1] ); glVertex2fv( p[1] );
-  glNormal3fv( normals[2] ); glVertex2fv( p[2] );
-  glNormal3fv( normals[3] ); glVertex2fv( p[3] );
+    glNormal3f(0.0f, 0.0f, 0.0f);
+    glVertex2fv( p[0].data() );
+    glVertex2fv( p[1].data() );
+    glVertex2fv( p[2].data() );
+    glVertex2fv( p[3].data() );
   glEnd();
 }
 
-void RenderArea2D::doDrawQuad( const sgVec2 *p, const sgVec3 *normals, const sgVec4 *color ) {
+void RenderArea2D::doDrawQuad( const SGVec2f *p, const SGVec4f *color ) {
+  
   glBegin(GL_QUADS);
-    glColor4fv( color[0] );glNormal3fv( normals[0] ); glVertex2fv( p[0] );
-    glColor4fv( color[1] );glNormal3fv( normals[1] ); glVertex2fv( p[1] );
-    glColor4fv( color[2] );glNormal3fv( normals[2] ); glVertex2fv( p[2] );
-    glColor4fv( color[3] );glNormal3fv( normals[3] ); glVertex2fv( p[3] );
+    glNormal3f(0.0f, 0.0f, 0.0f);
+    glColor4fv( color[0].data() ); glVertex2fv( p[0].data() );
+    glColor4fv( color[1].data() ); glVertex2fv( p[1].data() );
+    glColor4fv( color[2].data() ); glVertex2fv( p[2].data() );
+    glColor4fv( color[3].data() ); glVertex2fv( p[3].data() );
   glEnd();
 }
diff --git a/src/Instrumentation/render_area_2d.hxx b/src/Instrumentation/render_area_2d.hxx
index 44c5c0db2..646045ea4 100644
--- a/src/Instrumentation/render_area_2d.hxx
+++ b/src/Instrumentation/render_area_2d.hxx
@@ -32,8 +32,8 @@
 #include <osg/State>
 #include <osg/StateSet>
 
-#include <plib/sg.h>
 #include <simgear/compiler.h>
+#include <simgear/math/SGMath.hxx>
 
 #include <vector>
 
@@ -106,8 +106,8 @@ private:
 	
 	// Actual drawing routines copied from Atlas
 	void doSetColor( const float *rgb );
-	void doDrawQuad( const sgVec2 *p, const sgVec3 *normals );
-	void doDrawQuad( const sgVec2 *p, const sgVec3 *normals, const sgVec4 *color );
+	void doDrawQuad( const SGVec2f *p);
+	void doDrawQuad( const SGVec2f *p, const SGVec4f *color );
 	
 	vector<RA2DPrimitive> drawing_list;
 	
diff --git a/src/Main/fg_commands.cxx b/src/Main/fg_commands.cxx
index e92cb0f52..3f36555a0 100644
--- a/src/Main/fg_commands.cxx
+++ b/src/Main/fg_commands.cxx
@@ -47,6 +47,7 @@
 #include "util.hxx"
 #include "viewmgr.hxx"
 #include "main.hxx"
+#include <Main/viewer.hxx>
 
 using std::string;
 using std::ifstream;
diff --git a/src/Main/fg_props.hxx b/src/Main/fg_props.hxx
index 8516c93c9..41772ff35 100644
--- a/src/Main/fg_props.hxx
+++ b/src/Main/fg_props.hxx
@@ -12,7 +12,7 @@
 #include <simgear/math/SGMath.hxx>
 
 #include <Main/globals.hxx>
-
+
 ////////////////////////////////////////////////////////////////////////
 // Property management.
 ////////////////////////////////////////////////////////////////////////
diff --git a/src/Main/main.cxx b/src/Main/main.cxx
index a982888c0..d16cbf4d6 100644
--- a/src/Main/main.cxx
+++ b/src/Main/main.cxx
@@ -63,6 +63,7 @@
 #include <Scenery/tilemgr.hxx>
 #include <Sound/beacon.hxx>
 #include <Sound/morse.hxx>
+#include <Sound/fg_fx.hxx>
 #include <FDM/flight.hxx>
 #include <ATCDCL/ATCmgr.hxx>
 #include <ATCDCL/AIMgr.hxx>
@@ -81,7 +82,7 @@
 #include "fg_init.hxx"
 #include "fg_os.hxx"
 #include "WindowSystemAdapter.hxx"
-
+#include <Main/viewer.hxx>
 
 static double real_delta_time_sec = 0.0;
 double delta_time_sec = 0.0;
@@ -451,13 +452,6 @@ static void fgMainLoop( void ) {
             "Elapsed time is zero ... we're zinging" );
     }
 
-    // Run audio scheduler
-#ifdef ENABLE_AUDIO_SUPPORT
-    if ( globals->get_soundmgr()->is_working() ) {
-        globals->get_soundmgr()->update( delta_time_sec );
-    }
-#endif
-
     globals->get_subsystem_mgr()->update(delta_time_sec);
 
     //
@@ -466,7 +460,6 @@ static void fgMainLoop( void ) {
     //   we may want to move this to its own class at some point
     //
     double visibility_meters = fgGetDouble("/environment/visibility-m");
-    FGViewer *current_view = globals->get_current_view();
 
     globals->get_tile_mgr()->prep_ssg_nodes( visibility_meters );
     // update tile manager for view...
@@ -484,123 +477,10 @@ static void fgMainLoop( void ) {
     // update the view angle as late as possible, but before sound calculations
     globals->get_viewmgr()->update(real_delta_time_sec);
 
+    // Run audio scheduler
 #ifdef ENABLE_AUDIO_SUPPORT
-    if ( globals->get_soundmgr()->is_working() ) {
-        // Right now we make a simplifying assumption that the primary
-        // aircraft is the source of all sounds and that all sounds are
-        // positioned in the aircraft base
-
-        static sgdVec3 last_listener_pos = {0, 0, 0};
-        static sgdVec3 last_model_pos = {0, 0, 0};
-
-        // get the orientation
-        const SGQuatd view_or = current_view->getViewOrientation();
-        SGQuatd surf_or = SGQuatd::fromLonLat(current_view->getPosition());
-        SGQuatd model_or = SGQuatd::fromYawPitchRollDeg(
-            globals->get_aircraft_model()->get3DModel()->getHeadingDeg(),
-            globals->get_aircraft_model()->get3DModel()->getPitchDeg(),
-            globals->get_aircraft_model()->get3DModel()->getRollDeg());
-
-        // get the up and at vector in the aircraft base
-        // (ok, the up vector is a down vector, but the coordinates
-        // are finally calculated in a left hand system and openal
-        // lives in a right hand system. Therefore we need to pass
-        // the down vector to get correct stereo sound.)
-        SGVec3d sgv_up = model_or.rotateBack(
-            surf_or.rotateBack(view_or.rotate(SGVec3d(0, 1, 0))));
-        sgVec3 up;
-        sgSetVec3(up, sgv_up[0], sgv_up[1], sgv_up[2]);
-        SGVec3d sgv_at = model_or.rotateBack(
-        surf_or.rotateBack(view_or.rotate(SGVec3d(0, 0, 1))));
-        sgVec3 at;
-        sgSetVec3(at, sgv_at[0], sgv_at[1], sgv_at[2]);
-
-        // get the location data for the primary FDM (now hardcoded to ac model)...
-        SGGeod geodPos = globals->get_aircraft_model()->get3DModel()->getPosition();
-        SGVec3d model_pos = SGVec3d::fromGeod(geodPos);
-
-        // Calculate speed of listener and model.  This code assumes the
-        // listener is either tracking the model at the same speed or
-        // stationary.
-
-        sgVec3 listener_vel, model_vel;
-        SGVec3d SGV3d_help;
-        sgdVec3 sgdv3_help;
-        sgdVec3 sgdv3_null = {0, 0, 0};
-
-        // the aircraft velocity as reported by the fdm (this will not
-        // vary or be affected by frame rates or timing jitter.)
-        sgVec3 fdm_vel_vec;
-        sgSetVec3( fdm_vel_vec,
-                   vn_fps->getDoubleValue() * SG_FEET_TO_METER,
-                   ve_fps->getDoubleValue() * SG_FEET_TO_METER,
-                   vd_fps->getDoubleValue() * SG_FEET_TO_METER );
-        double fdm_vel = sgLengthVec3(fdm_vel_vec);
-
-        // compute the aircraft velocity vector and scale it to the length
-        // of the fdm velocity vector.  This gives us a vector in the
-        // proper coordinate system, but also with the proper time
-        // invariant magnitude.
-        sgdSubVec3( sgdv3_help,
-                last_model_pos, model_pos.data());
-        sgdAddVec3( last_model_pos, sgdv3_null, model_pos.data());
-        SGV3d_help = model_or.rotateBack(
-        surf_or.rotateBack(SGVec3d(sgdv3_help[0],
-        sgdv3_help[1], sgdv3_help[2])));
-        sgSetVec3( model_vel, SGV3d_help[0], SGV3d_help[1], SGV3d_help[2]);
-
-        float vel = sgLengthVec3(model_vel);
-        if ( fabs(vel) > 0.0001 ) {
-            if ( fabs(fdm_vel / vel) > 0.0001 ) {
-                sgScaleVec3( model_vel, fdm_vel / vel );
-            }
-        }
-
-        // check for moving or stationary listener (view position)
-        sgdSubVec3( sgdv3_help,
-                    last_listener_pos, current_view->get_view_pos().data());
-        sgdAddVec3( last_listener_pos,
-                    sgdv3_null, current_view->get_view_pos().data());
-
-        if ( sgdLengthVec3(sgdv3_help) > 0.2 ) {
-            sgCopyVec3( listener_vel, model_vel );
-        } else {
-            sgSetVec3( listener_vel, 0.0, 0.0, 0.0 );
-        }
-
-        globals->get_soundmgr()->set_listener_vel( listener_vel );
-
-        // set positional offset for sources
-        sgdVec3 dsource_pos_offset;
-        sgdSubVec3( dsource_pos_offset,
-                    current_view->get_view_pos().data(),
-                    model_pos.data() );
-        SGVec3d sgv_dsource_pos_offset = model_or.rotateBack(
-        surf_or.rotateBack(SGVec3d(dsource_pos_offset[0],
-        dsource_pos_offset[1], dsource_pos_offset[2])));
-
-        sgVec3 source_pos_offset;
-        sgSetVec3(source_pos_offset, sgv_dsource_pos_offset[0],
-        sgv_dsource_pos_offset[1], sgv_dsource_pos_offset[2]);
-
-        globals->get_soundmgr()->set_source_pos_all( source_pos_offset );
-
-        float orient[6];
-        for (int i = 0; i < 3; i++) {
-            orient[i] = sgv_at[i];
-            orient[i + 3] = sgv_up[i];
-        }
-        globals->get_soundmgr()->set_listener_orientation( orient );
-
-        // set the velocity
-        // all sources are defined to be in the model
-        globals->get_soundmgr()->set_source_vel_all( model_vel );
-
-        // The listener is always positioned at the origin.
-        sgVec3 listener_pos;
-        sgSetVec3( listener_pos, 0.0, 0.0, 0.0 );
-        globals->get_soundmgr()->set_listener_pos( listener_pos );
-    }
+    FGFX* fx = (FGFX*) globals->get_subsystem("fx");
+    fx->update_fx_late(delta_time_sec);
 #endif
 
     // END Tile Manager udpates
diff --git a/src/Main/options.cxx b/src/Main/options.cxx
index 26054af82..ad17068e6 100644
--- a/src/Main/options.cxx
+++ b/src/Main/options.cxx
@@ -60,7 +60,7 @@
 #include "options.hxx"
 #include "util.hxx"
 #include "viewmgr.hxx"
-
+#include <Main/viewer.hxx>
 
 using std::string;
 using std::sort;
diff --git a/src/Main/renderer.cxx b/src/Main/renderer.cxx
index 7bde729aa..ef3fe6e10 100644
--- a/src/Main/renderer.cxx
+++ b/src/Main/renderer.cxx
@@ -99,6 +99,7 @@
 #include "main.hxx"
 #include "CameraGroup.hxx"
 #include "FGEventHandler.hxx"
+#include <Main/viewer.hxx>
 
 using namespace osg;
 using namespace simgear;
diff --git a/src/Main/viewer.hxx b/src/Main/viewer.hxx
index 50d567439..965e8569a 100644
--- a/src/Main/viewer.hxx
+++ b/src/Main/viewer.hxx
@@ -25,12 +25,7 @@
 
 
 #ifndef _VIEWER_HXX
-#define _VIEWER_HXX
-
-
-#ifndef __cplusplus                                                          
-# error This library requires C++
-#endif                                   
+#define _VIEWER_HXX                                
 
 namespace flightgear
 {
diff --git a/src/Main/viewmgr.cxx b/src/Main/viewmgr.cxx
index 950eace83..596f343ae 100644
--- a/src/Main/viewmgr.cxx
+++ b/src/Main/viewmgr.cxx
@@ -25,14 +25,14 @@
 #  include "config.h"
 #endif
 
+#include "viewmgr.hxx"
+
 #include <string.h>		// strcmp
 
 #include <simgear/compiler.h>
-
 #include <Model/acmodel.hxx>
-
-#include "viewmgr.hxx"
-
+#include <Main/viewer.hxx>
+#include <Main/fg_props.hxx>
 
 // Constructor
 FGViewMgr::FGViewMgr( void ) :
@@ -341,7 +341,71 @@ FGViewMgr::copyToCurrent()
                 get_current_view()->getInternal());
 }
 
+void FGViewMgr::clear()
+{
+  views.clear();
+}
 
+FGViewer*
+FGViewMgr::get_current_view()
+{
+	if ( current < (int)views.size() ) {
+	    return views[current];
+	} else {
+	    return NULL;
+	}
+}
+
+const FGViewer*
+FGViewMgr::get_current_view() const
+{
+	if ( current < (int)views.size() ) {
+	    return views[current];
+	} else {
+	    return NULL;
+	}
+}
+
+
+FGViewer*
+FGViewMgr::get_view( int i )
+{
+	if ( i < 0 ) { i = 0; }
+	if ( i >= (int)views.size() ) { i = views.size() - 1; }
+	return views[i];
+}
+
+const FGViewer*
+FGViewMgr::get_view( int i ) const
+{
+	if ( i < 0 ) { i = 0; }
+	if ( i >= (int)views.size() ) { i = views.size() - 1; }
+	return views[i];
+}
+
+FGViewer*
+FGViewMgr::next_view()
+{
+	setView((current+1 < (int)views.size()) ? (current + 1) : 0);
+	view_number->fireValueChanged();
+	return views[current];
+}
+
+FGViewer*
+FGViewMgr::prev_view()
+{
+	setView((0 < current) ? (current - 1) : (views.size() - 1));
+	view_number->fireValueChanged();
+	return views[current];
+}
+
+void
+FGViewMgr::add_view( FGViewer * v )
+{
+  views.push_back(v);
+  v->init();
+}
+    
 double
 FGViewMgr::getViewHeadingOffset_deg () const
 {
diff --git a/src/Main/viewmgr.hxx b/src/Main/viewmgr.hxx
index ea4470fbb..2955ac845 100644
--- a/src/Main/viewmgr.hxx
+++ b/src/Main/viewmgr.hxx
@@ -28,16 +28,11 @@
 
 #include <simgear/compiler.h>
 #include <simgear/structure/subsystem_mgr.hxx>
+#include <simgear/math/SGMath.hxx>
 
-#ifdef HAVE_CONFIG_H
-#  include <config.h>
-#endif
-
-#include "fg_props.hxx"
-#include "viewer.hxx"
-
-using std::vector;
-
+// forward decls
+class FGViewer;
+typedef SGSharedPtr<FGViewer> FGViewerPtr;
 
 // Define a structure containing view information
 class FGViewMgr : public SGSubsystem
@@ -60,48 +55,21 @@ public:
     // getters
     inline int size() const { return views.size(); }
     inline int get_current() const { return current; }
-    inline FGViewer *get_current_view() {
-	if ( current < (int)views.size() ) {
-	    return views[current];
-	} else {
-	    return NULL;
-	}
-    }
-    inline const FGViewer *get_current_view() const {
-	if ( current < (int)views.size() ) {
-	    return views[current];
-	} else {
-	    return NULL;
-	}
-    }
-    inline FGViewer *get_view( int i ) {
-	if ( i < 0 ) { i = 0; }
-	if ( i >= (int)views.size() ) { i = views.size() - 1; }
-	return views[i];
-    }
-    inline const FGViewer *get_view( int i ) const {
-	if ( i < 0 ) { i = 0; }
-	if ( i >= (int)views.size() ) { i = views.size() - 1; }
-	return views[i];
-    }
-    inline FGViewer *next_view() {
-	setView((current+1 < (int)views.size()) ? (current + 1) : 0);
-	view_number->fireValueChanged();
-	return views[current];
-    }
-    inline FGViewer *prev_view() {
-	setView((0 < current) ? (current - 1) : (views.size() - 1));
-	view_number->fireValueChanged();
-	return views[current];
-    }
-
+    
+    FGViewer *get_current_view();
+    const FGViewer *get_current_view() const;
+    
+    FGViewer *get_view( int i ); 
+    const FGViewer *get_view( int i ) const;
+      
+    FGViewer *next_view();
+    FGViewer *prev_view();
+      
     // setters
-    inline void clear() { views.clear(); }
+    void clear();
     inline void set_view( const int v ) { current = v; }
-    inline void add_view( FGViewer * v ) {
-	views.push_back(v);
-        v->init();
-    }
+    void add_view( FGViewer * v );
+    
     // copies current offset settings to current-view path...
     void copyToCurrent ();
 
@@ -150,7 +118,7 @@ private:
 
     SGPropertyNode_ptr view_number;
     vector<SGPropertyNode_ptr> config_list;
-    typedef vector<SGSharedPtr<FGViewer> > viewer_list;
+    typedef std::vector<FGViewerPtr> viewer_list;
     viewer_list views;
     SGVec3d abs_viewer_position;
 
diff --git a/src/Sound/fg_fx.cxx b/src/Sound/fg_fx.cxx
index caff002e2..50d39479d 100644
--- a/src/Sound/fg_fx.cxx
+++ b/src/Sound/fg_fx.cxx
@@ -29,11 +29,14 @@
 #  include <config.h>
 #endif
 
+#include "fg_fx.hxx"
+
 #include <simgear/debug/logstream.hxx>
 #include <simgear/structure/exception.hxx>
 #include <simgear/misc/sg_path.hxx>
 #include <simgear/props/props.hxx>
 #include <simgear/sound/xmlsound.hxx>
+#include <simgear/sound/soundmgr_openal.hxx>
 
 #include <Main/fg_props.hxx>
 
@@ -41,17 +44,14 @@
 #include <Model/acmodel.hxx>
 #include <Main/viewer.hxx>
 
-#include "fg_fx.hxx"
-
-
 FGFX::FGFX () :
+    last_visitor_pos(SGVec3d::zeros()),
+    last_model_pos(SGVec3d::zeros()),
     last_pause( true ),
     last_volume( 0.0 ),
     _pause( fgGetNode("/sim/sound/pause") ),
     _volume( fgGetNode("/sim/sound/volume") )
 {
-    sgdSetVec3(last_visitor_pos, 0, 0, 0);
-    sgdSetVec3(last_model_pos, 0, 0, 0);
 }
 
 FGFX::~FGFX ()
@@ -137,12 +137,6 @@ FGFX::update (double dt)
         return;
     }
 
-#if 0
-    // moved back to the mainloop to prevent audio problems
-    smgr->update(dt);
-    update_pos_and_orientation(smgr, dt);
-#endif
-
     // command sound manger
     bool pause = _pause->getBoolValue();
     if ( pause != last_pause ) {
@@ -190,6 +184,18 @@ FGFX::update (double dt)
     }
 }
 
+void
+FGFX::update_fx_late(double dt)
+{
+  SGSoundMgr *smgr = globals->get_soundmgr();
+  if (!smgr->is_working()) {
+    return;
+  }
+
+  smgr->update(dt);
+  update_pos_and_orientation(smgr, dt);
+}
+
 /**
  * add a sound sample to the message queue which is played sequentially
  * in order.
@@ -200,7 +206,7 @@ FGFX::play_message( SGSoundSample *_sample )
     _samplequeue.push( _sample );
 }
 void
-FGFX::play_message( const string path, const string fname, double volume )
+FGFX::play_message( const std::string& path, const std::string& fname, double volume )
 {
     if (globals->get_soundmgr()->is_working() == true) {
         SGSoundSample *sample;
@@ -237,87 +243,50 @@ FGFX::update_pos_and_orientation(SGSoundMgr *smgr, double dt)
     // are finally calculated in a left hand system and openal
     // lives in a right hand system. Therefore we need to pass
     // the down vector to get correct stereo sound.)
-    SGVec3d sgv_up, sgv_at;
-    sgVec3 up, at;
-
-    sgv_up
+    SGVec3d sgv_up
       = model_or.rotateBack(surf_or.rotateBack(view_or.rotate(SGVec3d(0,1,0))));
-    sgSetVec3(up, sgv_up[0], sgv_up[1], sgv_up[2]);
-    sgv_at
+    SGVec3d sgv_at
       = model_or.rotateBack(surf_or.rotateBack(view_or.rotate(SGVec3d(0,0,1))));
-    sgSetVec3(at, sgv_at[0], sgv_at[1], sgv_at[2]);
 
     // get the location data for the primary FDM (now hardcoded to ac model)...
     // EMH: to add multiple sound sources this should be replaced
     SGVec3d absolute_view_pos = SGVec3d::fromGeod(model->getPosition());
 
     // calculate speed of visitor and model
-    sgVec3 listener_vel, model_vel;
-    SGVec3d SGV3d_help;
-    sgdVec3 sgdv3_help;
-    sgdVec3 sgdv3_null = {0, 0, 0};
+    SGVec3d moved = last_visitor_pos - observer->get_view_pos();
+    last_visitor_pos = observer->get_view_pos();
+    SGVec3f listener_vel(model_or.rotateBack(surf_or.rotateBack(moved)));
+
+    moved = last_model_pos - absolute_view_pos;
+    last_model_pos = absolute_view_pos;
+    SGVec3f model_vel(model_or.rotateBack(surf_or.rotateBack(moved)));
     
-
-    sgdSubVec3(sgdv3_help,
-                last_visitor_pos, (double *)&observer->get_view_pos());
-    sgdAddVec3(last_visitor_pos,
-                sgdv3_null, (double *)&observer->get_view_pos());
-
-    SGV3d_help = model_or.rotateBack(
-                    surf_or.rotateBack(
-                       SGVec3d(sgdv3_help[0], sgdv3_help[1], sgdv3_help[2])
-                    ));
-    sgSetVec3(listener_vel, SGV3d_help[0], SGV3d_help[1], SGV3d_help[2]);
-
-    sgdSubVec3(sgdv3_help, last_model_pos, absolute_view_pos.data());
-    sgdAddVec3(last_model_pos, sgdv3_null, absolute_view_pos.data());
-
-    SGV3d_help = model_or.rotateBack(
-                    surf_or.rotateBack(
-                       SGVec3d(sgdv3_help[0], sgdv3_help[1], sgdv3_help[2])
-                    ));
-    sgSetVec3( model_vel, SGV3d_help[0], SGV3d_help[1], SGV3d_help[2]);
-
     if (dt > 0) {
-        sgScaleVec3( model_vel, 1 / dt );
-        sgScaleVec3( listener_vel, 1 / dt );
+      model_vel /= dt;
+      listener_vel /= dt;
     }
 
     // checking, if the listener pos has moved suddenly
-    if (sgLengthVec3(listener_vel) > 1000)
-    {
+    if (length(listener_vel) > 1000) {
         // check if the relative speed model vs listener has moved suddenly, too
-        sgVec3 delta_vel;
-        sgSubVec3(delta_vel, listener_vel, model_vel);
-        if (sgLengthVec3(delta_vel) > 1000)
+        SGVec3f delta_vel = listener_vel - model_vel;
+        if (length(delta_vel) > 1000)
             // a sane value
-            sgSetVec3(listener_vel, model_vel[0], model_vel[1], model_vel[2]);
+            smgr->set_listener_vel(model_vel.data());
         else
-            smgr->set_listener_vel(listener_vel);
+            smgr->set_listener_vel(listener_vel.data());
+    } else {
+      smgr->set_listener_vel( listener_vel.data());
     }
-    else
-        smgr->set_listener_vel( listener_vel );
-
+    
     // set positional offset for sources
-    sgdVec3 dsource_pos_offset;
-    sgdSubVec3( dsource_pos_offset,
-                (double*) &observer->get_view_pos(),
-                absolute_view_pos.data() );
-    SGVec3d sgv_dsource_pos_offset;
-    sgv_dsource_pos_offset = model_or.rotateBack(
-                                surf_or.rotateBack(
-                                   SGVec3d(dsource_pos_offset[0],
-                                          dsource_pos_offset[1],
-                                          dsource_pos_offset[2])
+    SGVec3d dsource_pos_offset = observer->get_view_pos() - absolute_view_pos;
+    dsource_pos_offset = model_or.rotateBack(surf_or.rotateBack(
+                                   dsource_pos_offset
                                 ));
-    sgVec3 source_pos_offset;
-    sgSetVec3(source_pos_offset,
-                 sgv_dsource_pos_offset[0],
-                 sgv_dsource_pos_offset[1],
-                 sgv_dsource_pos_offset[2]);
 
-    smgr->set_source_pos_all( source_pos_offset );
-    smgr->set_source_vel_all( model_vel );
+    smgr->set_source_pos_all( SGVec3f(dsource_pos_offset).data() );
+    smgr->set_source_vel_all(model_vel.data() );
 
     float orient[6];
     for (int i = 0; i < 3; i++) {
@@ -327,9 +296,7 @@ FGFX::update_pos_and_orientation(SGSoundMgr *smgr, double dt)
     smgr->set_listener_orientation( orient );
 
     // The listener is always positioned at the origin.
-    sgVec3 listener_pos;
-    sgSetVec3( listener_pos, 0.0, 0.0, 0.0 );
-    smgr->set_listener_pos( listener_pos );
+    smgr->set_listener_pos( SGVec3f::zeros().data() );
 }
 
 // end of fg_fx.cxx
diff --git a/src/Sound/fg_fx.hxx b/src/Sound/fg_fx.hxx
index 864a898bb..1f7138bc1 100644
--- a/src/Sound/fg_fx.hxx
+++ b/src/Sound/fg_fx.hxx
@@ -29,13 +29,12 @@
 #include <queue>
 #include <vector>
 
-#include <simgear/sound/sample_openal.hxx>
 #include <simgear/structure/subsystem_mgr.hxx>
-
-using std::queue;
-using std::vector;
+#include <simgear/math/SGMath.hxx>
 
 class SGXmlSound;
+class SGSoundSample;
+class SGSoundMgr;
 
 /**
  * Generator for FlightGear sound effects.
@@ -72,16 +71,22 @@ public:
      * in order.
      */
     void play_message( SGSoundSample *_sample );
-    void play_message( const string path, const string fname, double volume );
+    void play_message( const std::string& path, const std::string& fname, double volume );
+
+    /**
+     * Explicit late update hook, to avoid problems which occur if done during
+     * normal SGSubsytem updating.
+     */
+    void update_fx_late(double dt);
 
 private:
 
     void update_pos_and_orientation(SGSoundMgr *smgr, double dt);
-    sgdVec3 last_visitor_pos;
-    sgdVec3 last_model_pos;
+    SGVec3d last_visitor_pos;
+    SGVec3d last_model_pos;
 
-    vector<SGXmlSound *> _sound;
-    queue<SGSoundSample *> _samplequeue;
+    std::vector<SGXmlSound *> _sound;
+    std::queue<SGSoundSample *> _samplequeue;
 
     bool last_pause;
     double last_volume;