From c0b59ca4b2597ff85ab55d9ae903c0ed54182394 Mon Sep 17 00:00:00 2001
From: curt <curt>
Date: Fri, 15 Oct 1999 20:43:02 +0000
Subject: [PATCH] Pan view with mouse both side-to-side and up/down from Norman
 Vine.

---
 src/GUI/gui.cxx    | 934 ++++++++++++++++++++++++++++++++++++++-------
 src/Main/views.cxx |   9 +
 2 files changed, 796 insertions(+), 147 deletions(-)

diff --git a/src/GUI/gui.cxx b/src/GUI/gui.cxx
index 308a32301..42589cdf0 100644
--- a/src/GUI/gui.cxx
+++ b/src/GUI/gui.cxx
@@ -51,10 +51,12 @@
 #include <string.h>
 
 #include <Include/general.hxx>
+#include <Include/fg_constants.h>
 #include <Debug/logstream.hxx>
 #include <Aircraft/aircraft.hxx>
 #include <Airports/simple.hxx>
 #include <Cockpit/panel.hxx>
+#include <Controls/controls.hxx>
 #include <FDM/flight.hxx>
 #include <Main/options.hxx>
 #include <Main/fg_init.hxx>
@@ -64,10 +66,53 @@
 #include <Screen/screen-dump.hxx>
 #include <Time/fg_time.hxx>
 
-#ifdef WIN32
+#if defined( WIN32 ) && !defined( __CYGWIN__ )
 #  include <Screen/win32-printer.h>
 #endif
 
+/*
+ * trackball.h
+ * A virtual trackball implementation
+ * Written by Gavin Bell for Silicon Graphics, November 1988.
+ */
+/*
+ * Pass the x and y coordinates of the last and current positions of
+ * the mouse, scaled so they are from (-1.0 ... 1.0).
+ *
+ * The resulting rotation is returned as a quaternion rotation in the
+ * first paramater.
+ */
+void
+trackball(float q[4], float p1x, float p1y, float p2x, float p2y);
+
+/*
+ * Given two quaternions, add them together to get a third quaternion.
+ * Adding quaternions to get a compound rotation is analagous to adding
+ * translations to get a compound translation.  When incrementally
+ * adding rotations, the first argument here should be the new
+
+  * rotation, the second and third the total rotation (which will be
+ * over-written with the resulting new total rotation).
+ */
+void
+add_quats(float *q1, float *q2, float *dest);
+
+/*
+ * A useful function, builds a rotation matrix in Matrix based on
+ * given quaternion.
+ */
+void
+build_rotmatrix(float m[4][4], float q[4]);
+
+/*
+ * This function computes a quaternion based on an axis (defined by
+ * the given vector) and an angle about which to rotate.  The angle is
+ * expressed in radians.  The result is put into the third argument.
+ */
+void
+axis_to_quat(float a[3], float phi, float q[4]);
+
+
 #include "gui.h"
 
 FG_USING_STD(string);
@@ -76,6 +121,12 @@ FG_USING_STD(string);
 FG_USING_STD(cout);
 #endif
 
+#if defined(WIN32) || defined(__CYGWIN32__)
+#define WIN32_CURSOR_TWEAKS
+#elif (GLUT_API_VERSION >= 4 || GLUT_XLIB_IMPLEMENTATION >= 9)
+#define X_CURSOR_TWEAKS
+#endif
+
 // hack, should come from an include someplace
 extern void fgInitVisuals( void );
 extern void fgReshape( int width, int height );
@@ -113,11 +164,19 @@ char *gui_msg_RESET;  // "RESET"
 
 static char global_dialog_string[256];
 
+// from autopilot.cxx
 extern void NewAltitude( puObject *cb );
 extern void NewHeading( puObject *cb );
 extern void fgAPAdjust( puObject * );
-extern void fgLatLonFormatToggle( puObject *);
 extern void NewTgtAirport( puObject *cb );
+bool fgAPTerrainFollowEnabled( void );
+bool fgAPAltitudeEnabled( void );
+bool fgAPHeadingEnabled( void );
+bool fgAPWayPointEnabled( void );
+bool fgAPAutoThrottleEnabled( void );
+
+// from cockpit.cxx
+extern void fgLatLonFormatToggle( puObject *);
 
 /* --------------------------------------------------------------------
 Mouse stuff
@@ -130,6 +189,35 @@ static int _savedY = 0;
 static int last_buttons = 0 ;
 static int mouse_active = 0;
 static int menu_on = 0;
+static int mouse_joystick_control = 0;
+
+//static time_t mouse_off_time;
+//static int mouse_timed_out;
+
+// to allow returning to previous view
+// on second left click in MOUSE_VIEW mode
+// This has file scope so that it can be reset
+// if the little rodent is moved  NHV
+static  int _mVtoggle;
+
+// we break up the glutGetModifiers return mask
+// once per loop and stash what we need in these
+static int glut_active_shift;
+static int glut_active_ctrl;
+static int glut_active_alt;
+
+static float lastquat[4];
+static float curquat[4];
+static float _quat0[4];
+float quat_mat[4][4];
+
+// uncomment this for view to exactly follow mouse in MOUSE_VIEW mode
+// else smooth out the view panning to .01 radian per frame
+// see view_offset smoothing mechanism in main.cxx
+#define NO_SMOOTH_MOUSE_VIEW
+
+// uncomment following to
+#define RESET_VIEW_ON_LEAVING_MOUSE_VIEW
 
 /* --------------------------------------------------------------------
 Support for mouse as control yoke (david@megginson.com)
@@ -158,167 +246,67 @@ typedef enum {
 } MouseMode;
 
 MouseMode mouse_mode = MOUSE_POINTER;
-static float aileron_sensitivity = 500.0;
-static float elevator_sensitivity = 500.0;
-static float brake_sensitivity = 250.0;
-static float throttle_sensitivity = 250.0;
-static float rudder_sensitivity = 500.0;
-static float trim_sensitivity = 1000.0;
-
-void guiMotionFunc ( int x, int y )
-{
-    if (mouse_mode == MOUSE_POINTER) {
-      puMouse ( x, y ) ;
-      glutPostRedisplay () ;
-    } else {
-      int ww = current_view.get_winWidth();
-      int wh = current_view.get_winHeight();
-
-				// Mouse as yoke
-      if (mouse_mode == MOUSE_YOKE) {
-	if (last_buttons & (1 << GLUT_LEFT_BUTTON)) {
-	  float brake_offset = (_mX - x) / brake_sensitivity;
-	  float throttle_offset = (_mY - y) / throttle_sensitivity;
-	  controls.move_brake(FGControls::ALL_WHEELS, brake_offset);
-	  controls.move_throttle(FGControls::ALL_ENGINES, throttle_offset);
-	} else if (last_buttons & (1 << GLUT_MIDDLE_BUTTON)) {
-	  float rudder_offset = (x - _mX) / rudder_sensitivity;
-	  float trim_offset = (_mY - y) / trim_sensitivity;
-	  controls.move_rudder(rudder_offset);
-	  controls.move_elevator_trim(trim_offset);
-	} else {
-	  float aileron_offset = (x - _mX) / aileron_sensitivity;
-	  float elevator_offset = (_mY - y) / elevator_sensitivity;
-	  controls.move_aileron(aileron_offset);
-	  controls.move_elevator(elevator_offset);
-	}
-
-				// Mouse as view
-      } else {
-	FGView * v = &current_view;
-	double offset = v->get_goal_view_offset();
-	double full = FG_PI * 2.0;
-	offset += (_mX - x) / 500.0;
-	while (offset < 0) {
-	  offset += full;
-	}
-	while (offset > full) {
-	  offset -= full;
-	}
-	v->set_view_offset(offset);
-	v->set_goal_view_offset(offset);
-      }
-
-				// Keep the mouse in the window.
-      if (x < 5 || x > ww-5 || y < 5 || y > wh-5) {
-	_mX = x = ww / 2;
-	_mY = y = wh / 2;
-	glutWarpPointer(x, y);
-      }
-    }
 
-				// Record the new mouse position.
-    _mX = x;
-    _mY = y;
+static double aileron_sensitivity = 1.0/500.0;
+static double elevator_sensitivity = 1.0/500.0;
+static double brake_sensitivity = 1.0/250.0;
+static double throttle_sensitivity = 1.0/250.0;
+static double rudder_sensitivity = 1.0/500.0;
+static double trim_sensitivity = 1.0/1000.0;
+
+static inline void Quat0( void ) {
+    curquat[0] = _quat0[0];
+    curquat[1] = _quat0[1];
+    curquat[2] = _quat0[2];
+    curquat[3] = _quat0[3];
 }
 
-void guiMouseFunc(int button, int updown, int x, int y)
-{
-				// Was the left button pressed?
-    if (updown == GLUT_DOWN && button == GLUT_LEFT_BUTTON) {
-      switch (mouse_mode) {
-      case MOUSE_POINTER:
-	break;
-      case MOUSE_YOKE:
-	break;
-      case MOUSE_VIEW:
-        current_view.set_view_offset( 0.00 );
-        current_view.set_goal_view_offset( 0.00 );
-	break;
-      }
-
-				// Or was it the right button?
-    } else if (updown == GLUT_DOWN && button == GLUT_RIGHT_BUTTON) {
-      switch (mouse_mode) {
-      case MOUSE_POINTER:
-	mouse_mode = MOUSE_YOKE;
-	_savedX = x;
-	_savedY = y;
-	glutSetCursor(GLUT_CURSOR_NONE);
-	FG_LOG( FG_INPUT, FG_INFO, "Mouse in yoke mode" );
-	break;
-      case MOUSE_YOKE:
-	mouse_mode = MOUSE_VIEW;
-	FG_LOG( FG_INPUT, FG_INFO, "Mouse in view mode" );
-	break;
-      case MOUSE_VIEW:
-	mouse_mode = MOUSE_POINTER;
-	_mX = x = _savedX;
-	_mY = y = _savedY;
-	glutWarpPointer(x, y);
-	glutSetCursor(GLUT_CURSOR_INHERIT);
-	FG_LOG( FG_INPUT, FG_INFO, "Mouse in pointer mode" );
-	break;
-      }     
-    }
-
-				// Register the new position (if it
-				// hasn't been registered already).
-    _mX = x;
-    _mY = y;
-
-				// Note which button is pressed.
-    if ( updown == GLUT_DOWN ) {
-        last_buttons |=  ( 1 << button ) ;
-    } else {
-        last_buttons &= ~( 1 << button ) ;
-    }
-
-				// If we're in pointer mode, let PUI
-				// know what's going on.
-    if (mouse_mode == MOUSE_POINTER) {
-	puMouse (button, updown, x,y);
-	glutPostRedisplay ();
-    }
+static inline int left_button( void ) {
+    return( last_buttons & (1 << GLUT_LEFT_BUTTON) );
 }
 
-int guiGetMouseButton(void)
-{
-    return last_buttons;
+static inline int middle_button( void ) {
+    return( last_buttons & (1 << GLUT_MIDDLE_BUTTON) );
 }
 
-void guiGetMouse(int *x, int *y)
-{
-    *x = _mX;
-    *y = _mY;
-};
+static inline int right_button( void ) {
+    return( last_buttons & (1 << GLUT_RIGHT_BUTTON) );
+}
 
 static inline void TurnCursorOn( void )
 {
     mouse_active = ~0;
-#if defined ( WIN32 ) || defined(__CYGWIN32__)
-    glutSetCursor(GLUT_CURSOR_INHERIT);
+#if defined(WIN32_CURSOR_TWEAKS)
+    switch (mouse_mode) {
+        case MOUSE_POINTER:
+            glutSetCursor(GLUT_CURSOR_INHERIT);
+            break;
+        case MOUSE_YOKE:
+            glutSetCursor(GLUT_CURSOR_CROSSHAIR);
+            break;
+        case MOUSE_VIEW:
+            glutSetCursor(GLUT_CURSOR_LEFT_RIGHT);
+            break;
+    }
 #endif
-#if (GLUT_API_VERSION >= 4 || GLUT_XLIB_IMPLEMENTATION >= 9)
-    glutWarpPointer( glutGet((GLenum)GLUT_SCREEN_WIDTH)/2, glutGet((GLenum)GLUT_SCREEN_HEIGHT)/2);
+#if defined(X_CURSOR_TWEAKS)
+    glutWarpPointer( current_view.get_winWidth()/2, current_view.get_winHeight()/2);
 #endif
 }
 
 static inline void TurnCursorOff( void )
 {
     mouse_active = 0;
-#if defined ( WIN32 ) || defined(__CYGWIN32__)
+#if defined(WIN32_CURSOR_TWEAKS)
     glutSetCursor(GLUT_CURSOR_NONE);
-#else  // I guess this is what we want to do ??
-#if (GLUT_API_VERSION >= 4 || GLUT_XLIB_IMPLEMENTATION >= 9)
-    glutWarpPointer( glutGet((GLenum)GLUT_SCREEN_WIDTH), glutGet((GLenum)GLUT_SCREEN_HEIGHT));
-#endif
+#elif defined(X_CURSOR_TWEAKS)
+    glutWarpPointer( current_view.get_winWidth(), current_view.get_winHeight());
 #endif
 }
 
 void maybeToggleMouse( void )
 {
-#ifdef WIN32
+#if defined(WIN32_CURSOR_TWEAKS)
     static int first_time = ~0;
     static int mouse_changed = 0;
 
@@ -328,6 +316,8 @@ void maybeToggleMouse( void )
             TurnCursorOn();
         }
     } else {
+        if( mouse_mode != MOUSE_POINTER )
+            return;
         if( mouse_changed ) {
             mouse_changed = ~mouse_changed;
             if(mouse_active) {
@@ -346,13 +336,318 @@ void BusyCursor( int restore )
     if( restore ) {
         glutSetCursor(cursor);
     } else {
-        cursor = glutGet( (GLenum)GLUT_WINDOW_CURSOR );
-#ifdef WIN32
+        cursor = glutGet( GLUT_WINDOW_CURSOR );
+#if defined(WIN32_CURSOR_TWEAKS)
         TurnCursorOn();
 #endif
         glutSetCursor( GLUT_CURSOR_WAIT );
     }
 }
+
+int guiGetMouseButton(void)
+{
+    return last_buttons;
+}
+
+void guiGetMouse(int *x, int *y)
+{
+    *x = _mX;
+    *y = _mY;
+};
+
+void guiMotionFunc ( int x, int y )
+{
+    int ww, wh, need_warp = 0;
+    float W, H;
+    double offset;
+//  FGTime *t = FGTime::cur_time_params;
+//  if( mouse_timed_out ) {
+//      if( t->get_cur_time() > mouse_off_time ) {
+//          moused_timed_out = 0;
+//          TurnCursorOn();
+//          glutPostRedisplay () ;
+//      }
+//  }
+
+    if (mouse_mode == MOUSE_POINTER) {
+        puMouse ( x, y ) ;
+        glutPostRedisplay () ;
+    } else {
+        if( x == _mX && y == _mY)
+            return;
+        
+        // reset left click MOUSE_VIEW toggle feature
+        _mVtoggle = 0;
+        
+        ww = current_view.get_winWidth();
+        wh = current_view.get_winHeight();
+        
+        switch (mouse_mode) {
+            case MOUSE_YOKE:
+                if( !mouse_joystick_control ) {
+                    mouse_joystick_control = 1;
+                    current_options.set_control_mode( fgOPTIONS::FG_MOUSE );
+                } else {
+                    if ( left_button() ) {
+                        offset = (_mX - x) * brake_sensitivity;
+                        controls.move_brake(FGControls::ALL_WHEELS, offset);
+                        offset = (_mY - y) * throttle_sensitivity;
+                        controls.move_throttle(FGControls::ALL_ENGINES, offset);
+                    } else if ( right_button() ) {
+                        if( !fgAPHeadingEnabled() ) {
+                            offset = (x - _mX) * rudder_sensitivity;
+                            controls.move_rudder(offset);
+                        }
+                        if( !fgAPAltitudeEnabled() ) {
+                            offset = (_mY - y) * trim_sensitivity;
+                            controls.move_elevator_trim(offset);
+                        }
+                    } else {
+                        if( !fgAPHeadingEnabled() ) {
+                            offset = (x - _mX) * aileron_sensitivity;
+                            controls.move_aileron(offset);
+                        }
+                        if( !fgAPAltitudeEnabled() ) {
+                            offset = (_mY - y) * elevator_sensitivity;
+                            controls.move_elevator(offset);
+                        }
+                    }
+                }
+                // Keep the mouse in the window.
+                if (x < 5 || x > ww-5 || y < 5 || y > wh-5) {
+                    x = ww / 2;
+                    y = wh / 2;
+                    need_warp = 1;
+                }
+                break;
+                
+            case MOUSE_VIEW:
+                if( y <= 0 ) {
+#define CONTRAINED_MOUSE_VIEW_Y
+#ifdef CONTRAINED_MOUSE_VIEW_Y
+                    y = 1;
+#else
+                    y = wh-2;
+#endif // CONTRAINED_MOUSE_VIEW_Y
+                    need_warp = 1;
+                } else if( y >= wh-1) {
+#ifdef CONTRAINED_MOUSE_VIEW_Y
+                    y = wh-2;
+#else
+                    y = 1;
+#endif // CONTRAINED_MOUSE_VIEW_Y
+                    need_warp = 1;
+                }
+                // wrap MOUSE_VIEW mode cursor x position
+                if ( x <= 0 ) {
+                    need_warp = 1;
+                    x = ww-2;
+                } else if ( x >= ww-1 ) {
+                    need_warp = 1;
+                    x = 1;
+                }
+                // try to get FG_PI movement in each half of screen
+                // do spherical pan
+                W = ww;
+                H = wh;
+                if( middle_button() ) {
+                    trackball(lastquat,
+                              (2.0f * _mX - W) / W,
+                              0, //(H - 2.0f * y) / H,         // 3
+                              (2.0f * x - W) / W,
+                              0 //(H - 2.0f * _mY) / H       // 1
+                             );
+                    x = _mX;
+                    y = _mY;
+                    need_warp = 1;
+                } else {
+                    trackball(lastquat,
+                              0, //(2.0f * _mX - W) / W,  // 0
+                              (H - 2.0f * y) / H,         // 3
+                              0, //(2.0f * x - W) / W,    // 2
+                              (H - 2.0f * _mY) / H        // 1 
+                             );
+                }
+                add_quats(lastquat, curquat, curquat);
+                build_rotmatrix(quat_mat, curquat);
+                
+                // do horizontal pan
+                // this could be done in above quat
+                // but requires redoing view pipeline
+                offset = current_view.get_goal_view_offset();
+                offset += ((_mX - x) * FG_2PI / W );
+                while (offset < 0.0) {
+                    offset += FG_2PI;
+                }
+                while (offset > FG_2PI) {
+                    offset -= FG_2PI;
+                }
+                current_view.set_goal_view_offset(offset);
+#ifdef NO_SMOOTH_MOUSE_VIEW
+                current_view.set_view_offset(offset);
+#endif
+                break;
+            
+            default:
+                break;
+        }
+    }
+    if( need_warp)
+        glutWarpPointer(x, y);
+    
+    // Record the new mouse position.
+    _mX = x;
+    _mY = y;
+}
+
+
+void guiMouseFunc(int button, int updown, int x, int y)
+{
+    int glutModifiers;
+
+    // private MOUSE_VIEW state variables
+    // to allow alternate left clicks in MOUSE_VIEW mode
+    // to toggle between current offsets and straight ahead
+    // uses _mVtoggle
+    static int _mVx, _mVy, _Vx, _Vy;
+    static float _quat[4];
+    static double _view_offset;
+    
+    // general purpose variables
+    double offset;
+            
+    glutModifiers = glutGetModifiers();
+    glut_active_shift = glutModifiers & GLUT_ACTIVE_SHIFT;
+    glut_active_ctrl  = glutModifiers & GLUT_ACTIVE_CTRL; 
+    glut_active_alt   = glutModifiers & GLUT_ACTIVE_ALT;
+    
+    // Was the left button pressed?
+    if (updown == GLUT_DOWN ) {
+        if( button == GLUT_LEFT_BUTTON)
+        {
+            switch (mouse_mode) {
+                case MOUSE_POINTER:
+                    break;
+                case MOUSE_YOKE:
+                    break;
+                case MOUSE_VIEW:
+                    if(_mVtoggle) {
+                        // resume previous view offsets
+                        _mX = _mVx;
+                        _mY = _mVy;
+                        x = _Vx;
+                        y = _Vy;
+                        curquat[0] = _quat[0];
+                        curquat[1] = _quat[1];
+                        curquat[2] = _quat[2];
+                        curquat[3] = _quat[3];
+                        current_view.set_goal_view_offset(_view_offset);
+#ifdef NO_SMOOTH_MOUSE_VIEW
+                        current_view.set_view_offset(_view_offset);
+#endif
+                    } else {
+                        // center view
+                        _mVx = _mX;
+                        _mVy = _mY;
+                        _Vx = x;
+                        _Vy = y;
+                        _quat[0] = curquat[0];
+                        _quat[1] = curquat[1];
+                        _quat[2] = curquat[2];
+                        _quat[3] = curquat[3];
+                        x = current_view.get_winWidth()/2;
+                        y = current_view.get_winHeight()/2;
+                        Quat0();
+                        _view_offset = current_view.get_goal_view_offset();
+                        current_view.set_goal_view_offset(0.0);
+#ifdef NO_SMOOTH_MOUSE_VIEW
+                        current_view.set_view_offset(0.0);
+#endif
+                    }
+                    glutWarpPointer( x , y);
+                    build_rotmatrix(quat_mat, curquat);
+                    _mVtoggle = ~_mVtoggle;
+                    break;
+            }
+        }else if ( button == GLUT_RIGHT_BUTTON) {
+            switch (mouse_mode) {
+                case MOUSE_POINTER:
+                    mouse_mode = MOUSE_YOKE;
+                    mouse_joystick_control = 0;
+                    _savedX = x;
+                    _savedY = y;
+                    // start with zero point in center of screen
+                    _mX = current_view.get_winWidth()/2;
+                    _mY = current_view.get_winHeight()/2;
+                    
+                    // try to have the MOUSE_YOKE position
+                    // reflect the current stick position
+                    offset = controls.get_aileron();
+                    x = _mX - (int)(offset * aileron_sensitivity);
+                    offset = controls.get_elevator();
+                    y = _mY - (int)(offset * elevator_sensitivity);
+                    
+                    glutSetCursor(GLUT_CURSOR_CROSSHAIR);
+                    FG_LOG( FG_INPUT, FG_INFO, "Mouse in yoke mode" );
+                    break;
+                    
+                case MOUSE_YOKE:
+                    mouse_mode = MOUSE_VIEW;
+                    current_options.set_control_mode( fgOPTIONS::FG_JOYSTICK );
+                    x = current_view.get_winWidth()/2;
+                    y = current_view.get_winHeight()/2;
+                    _mVtoggle = 0;
+                    Quat0();
+                    build_rotmatrix(quat_mat, curquat);
+                    glutSetCursor(GLUT_CURSOR_LEFT_RIGHT);
+                    FG_LOG( FG_INPUT, FG_INFO, "Mouse in view mode" );
+                    break;
+                    
+                case MOUSE_VIEW:
+                    mouse_mode = MOUSE_POINTER;
+                    x = _savedX;
+                    y = _savedY;
+#ifdef RESET_VIEW_ON_LEAVING_MOUSE_VIEW
+                    Quat0();
+                    build_rotmatrix(quat_mat, curquat);
+                    current_view.set_goal_view_offset(0.0);
+#ifdef NO_SMOOTH_MOUSE_VIEW
+                    current_view.set_view_offset(0.0);
+#endif
+#endif      // RESET_VIEW_ON_LEAVING_MOUSE_VIEW
+                    glutSetCursor(GLUT_CURSOR_INHERIT);
+                    
+                    if(!menu_on)
+                        TurnCursorOff();
+                    
+                    FG_LOG( FG_INPUT, FG_INFO, "Mouse in pointer mode" );
+                    break;
+            }     
+            glutWarpPointer( x, y );
+        } // END RIGHT BUTTON
+    } // END UPDOWN == GLUT_DOWN
+    
+    // Note which button is pressed.
+    if ( updown == GLUT_DOWN ) {
+        last_buttons |=  ( 1 << button ) ;
+    } else {
+        last_buttons &= ~( 1 << button ) ;
+    }
+    
+    // If we're in pointer mode, let PUI
+    // know what's going on.
+    if (mouse_mode == MOUSE_POINTER) {
+        puMouse (button, updown, x,y);
+    }
+    
+    // Register the new position (if it
+    // hasn't been registered already).
+    _mX = x;
+    _mY = y;
+    
+    glutPostRedisplay ();
+}
+
 /* ================ General Purpose Functions ================ */
 
 // Intercept the Escape Key
@@ -397,9 +692,10 @@ void guiToggleMenu(void)
     if( menu_on ) {
         // printf("Hiding Menu\n");
         mainMenuBar->hide  ();
-#ifdef WIN32
-        TurnCursorOff();
-#endif // #ifdef WIN32
+#if defined(WIN32_CURSOR_TWEAKS)
+        if( mouse_mode == MOUSE_POINTER )
+            TurnCursorOff();
+#endif // #ifdef WIN32_CURSOR_TWEAKS
     } else {
         // printf("Showing Menu\n");
         mainMenuBar->reveal();
@@ -417,6 +713,8 @@ ____________________________________________________________________*/
 void reInit(puObject *cb)
 {
     BusyCursor(0);
+    Quat0();
+    build_rotmatrix(quat_mat, curquat);
     fgReInitSubsystems();
     BusyCursor(1);
 }
@@ -551,7 +849,7 @@ void helpCb (puObject *)
 
 
 
-#ifdef WIN32
+#if defined( WIN32 ) && !defined( __CYGWIN__)
 // win32 print screen function
 void printScreen ( puObject *obj ) {
     bool show_pu_cursor = false;
@@ -832,7 +1130,7 @@ The menu stuff
 ---------------------------------------------------------------------*/
 char *fileSubmenu               [] = {
     "Exit", /* "Close", "---------", */
-#ifdef WIN32
+#if defined( WIN32 ) && !defined( __CYGWIN__)
     "Print",
 #endif
     "Snap Shot",
@@ -841,7 +1139,7 @@ char *fileSubmenu               [] = {
 };
 puCallback fileSubmenuCb        [] = {
     MayBeGoodBye, /* hideMenuCb, NULL, */
-#ifdef WIN32
+#if defined( WIN32 ) && !defined( __CYGWIN__)
     printScreen, 
 #endif
     /* NULL, notCb, */
@@ -973,6 +1271,11 @@ void guiInit()
         puShowCursor();
         mouse_active = ~mouse_active;
     }
+	
+    // MOUSE_VIEW mode stuff
+    trackball(_quat0, 0.0, 0.0, 0.0, 0.0);  
+    Quat0();
+    build_rotmatrix(quat_mat, curquat);
 
     // Set up our Dialog Boxes
     ConfirmExitDialogInit();
@@ -998,3 +1301,340 @@ void guiInit()
     // Set up menu bar toggle
     menu_on = ~0;
 }
+
+
+
+/*
+ * Trackball code:
+ *
+ * Implementation of a virtual trackball.
+ * Implemented by Gavin Bell, lots of ideas from Thant Tessman and
+ *   the August '88 issue of Siggraph's "Computer Graphics," pp. 121-129.
+ *
+ * Vector manip code:
+ *
+ * Original code from:
+ * David M. Ciemiewicz, Mark Grossman, Henry Moreton, and Paul Haeberli
+ *
+ * Much mucking with by:
+ * Gavin Bell
+ */
+#if defined(_WIN32) && !defined( __CYGWIN32__ )
+#pragma warning (disable:4244)          /* disable bogus conversion warnings */
+#endif
+#include <math.h>
+#include <stdio.h>
+//#include "trackball.h"
+
+/*
+ * This size should really be based on the distance from the center of
+ * rotation to the point on the object underneath the mouse.  That
+ * point would then track the mouse as closely as possible.  This is a
+ * simple example, though, so that is left as an Exercise for the
+ * Programmer.
+ */
+#define TRACKBALLSIZE  (0.8f)
+#define SQRT(x) sqrt(x)
+
+/*
+ * Local function prototypes (not defined in trackball.h)
+ */
+static float tb_project_to_sphere(float, float, float);
+static void normalize_quat(float [4]);
+
+static void
+vzero(float *v)
+{
+    v[0] = 0.0;
+    v[1] = 0.0;
+    v[2] = 0.0;
+}
+
+static void
+vset(float *v, float x, float y, float z)
+{
+    v[0] = x;
+    v[1] = y;
+    v[2] = z;
+}
+
+static void
+vsub(const float *src1, const float *src2, float *dst)
+{
+    dst[0] = src1[0] - src2[0];
+    dst[1] = src1[1] - src2[1];
+    dst[2] = src1[2] - src2[2];
+}
+
+static void
+vcopy(const float *v1, float *v2)
+{
+    register int i;
+    for (i = 0 ; i < 3 ; i++)
+        v2[i] = v1[i];
+}
+
+static void
+vcross(const float *v1, const float *v2, float *cross)
+{
+    float temp[3];
+
+    temp[0] = (v1[1] * v2[2]) - (v1[2] * v2[1]);
+    temp[1] = (v1[2] * v2[0]) - (v1[0] * v2[2]);
+    temp[2] = (v1[0] * v2[1]) - (v1[1] * v2[0]);
+    vcopy(temp, cross);
+}
+
+static float
+vlength(const float *v)
+{
+    float tmp = v[0] * v[0] + v[1] * v[1] + v[2] * v[2];
+    return SQRT(tmp);
+}
+
+static void
+vscale(float *v, float div)
+{
+    v[0] *= div;
+    v[1] *= div;
+    v[2] *= div;
+}
+
+static void
+vnormal(float *v)
+{
+    vscale(v,1.0/vlength(v));
+}
+
+static float
+vdot(const float *v1, const float *v2)
+{
+    return v1[0]*v2[0] + v1[1]*v2[1] + v1[2]*v2[2];
+}
+
+static void
+vadd(const float *src1, const float *src2, float *dst)
+{
+    dst[0] = src1[0] + src2[0];
+    dst[1] = src1[1] + src2[1];
+    dst[2] = src1[2] + src2[2];
+}
+
+/*
+ *  Given an axis and angle, compute quaternion.
+ */
+void
+axis_to_quat(float a[3], float phi, float q[4])
+{
+    double sinphi2, cosphi2;
+    double phi2 = phi/2.0;
+    sinphi2 = sin(phi2);
+    cosphi2 = cos(phi2);
+    vnormal(a);
+    vcopy(a,q);
+    vscale(q,sinphi2);
+    q[3] = cosphi2;
+}
+
+/*
+ * Project an x,y pair onto a sphere of radius r OR a hyperbolic sheet
+ * if we are away from the center of the sphere.
+ */
+static float
+tb_project_to_sphere(float r, float x, float y)
+{
+    float d, t, z, tmp;
+
+    tmp = x*x + y*y;
+    d = SQRT(tmp);
+    if (d < r * 0.70710678118654752440) {    /* Inside sphere */
+        tmp = r*r - d*d;
+        z = SQRT(tmp);
+    } else {           /* On hyperbola */
+        t = r / 1.41421356237309504880;
+        z = t*t / d;
+    }
+    return z;
+}
+
+/*
+ * Quaternions always obey:  a^2 + b^2 + c^2 + d^2 = 1.0
+ * If they don't add up to 1.0, dividing by their magnitued will
+ * renormalize them.
+ *
+ * Note: See the following for more information on quaternions:
+ *
+ * - Shoemake, K., Animating rotation with quaternion curves, Computer
+ *   Graphics 19, No 3 (Proc. SIGGRAPH'85), 245-254, 1985.
+ * - Pletinckx, D., Quaternion calculus as a basic tool in computer
+ *   graphics, The Visual Computer 5, 2-13, 1989.
+ */
+static void
+normalize_quat(float q[4])
+{
+    int i;
+    float mag, tmp;
+
+    tmp = q[0]*q[0] + q[1]*q[1] + q[2]*q[2] + q[3]*q[3];
+    mag = 1.0 / SQRT(tmp);
+    for (i = 0; i < 4; i++)
+        q[i] *= mag;
+}
+
+/*
+ * Ok, simulate a track-ball.  Project the points onto the virtual
+ * trackball, then figure out the axis of rotation, which is the cross
+ * product of P1 P2 and O P1 (O is the center of the ball, 0,0,0)
+ * Note:  This is a deformed trackball-- is a trackball in the center,
+ * but is deformed into a hyperbolic sheet of rotation away from the
+ * center.  This particular function was chosen after trying out
+ * several variations.
+ *
+ * It is assumed that the arguments to this routine are in the range
+ * (-1.0 ... 1.0)
+ */
+void
+trackball(float q[4], float p1x, float p1y, float p2x, float p2y)
+{
+    float a[3]; /* Axis of rotation */
+    float phi;  /* how much to rotate about axis */
+    float p1[3], p2[3], d[3];
+    float t;
+
+    if (p1x == p2x && p1y == p2y) {
+        /* Zero rotation */
+        vzero(q);
+        q[3] = 1.0;
+        return;
+    }
+
+    /*
+     * First, figure out z-coordinates for projection of P1 and P2 to
+     * deformed sphere
+     */
+    vset(p1,p1x,p1y,tb_project_to_sphere(TRACKBALLSIZE,p1x,p1y));
+    vset(p2,p2x,p2y,tb_project_to_sphere(TRACKBALLSIZE,p2x,p2y));
+
+    /*
+     *  Now, we want the cross product of P1 and P2
+     */
+    vcross(p2,p1,a);
+
+    /*
+     *  Figure out how much to rotate around that axis.
+     */
+    vsub(p1,p2,d);
+    t = vlength(d) / (2.0*TRACKBALLSIZE);
+
+    /*
+     * Avoid problems with out-of-control values...
+     */
+    if (t > 1.0) t = 1.0;
+    if (t < -1.0) t = -1.0;
+    phi = 2.0 * asin(t);
+
+    axis_to_quat(a,phi,q);
+}
+
+/*
+ * Given two rotations, e1 and e2, expressed as quaternion rotations,
+ * figure out the equivalent single rotation and stuff it into dest.
+ *
+ * This routine also normalizes the result every RENORMCOUNT times it is
+ * called, to keep error from creeping in.
+ *
+ * NOTE: This routine is written so that q1 or q2 may be the same
+ * as dest (or each other).
+ */
+
+#define RENORMCOUNT 97
+
+void
+add_quats(float q1[4], float q2[4], float dest[4])
+{
+    static int count=0;
+    float t1[4], t2[4], t3[4];
+    float tf[4];
+
+#if 0
+printf("q1 = %f %f %f %f\n", q1[0], q1[1], q1[2], q1[3]);
+printf("q2 = %f %f %f %f\n", q2[0], q2[1], q2[2], q2[3]);
+#endif
+
+    vcopy(q1,t1);
+    vscale(t1,q2[3]);
+
+    vcopy(q2,t2);
+    vscale(t2,q1[3]);
+
+    vcross(q2,q1,t3);
+    vadd(t1,t2,tf);
+    vadd(t3,tf,tf);
+    tf[3] = q1[3] * q2[3] - vdot(q1,q2);
+
+#if 0
+printf("tf = %f %f %f %f\n", tf[0], tf[1], tf[2], tf[3]);
+#endif
+
+    dest[0] = tf[0];
+    dest[1] = tf[1];
+    dest[2] = tf[2];
+    dest[3] = tf[3];
+
+    if (++count > RENORMCOUNT) {
+        count = 0;
+        normalize_quat(dest);
+    }
+}
+
+/*
+ * Build a rotation matrix, given a quaternion rotation.
+ *
+ */
+void
+build_rotmatrix(float m[4][4], float q[4])
+{
+//#define TRANSPOSED_QUAT
+#ifndef TRANSPOSED_QUAT
+    m[0][0] = 1.0 - 2.0 * (q[1] * q[1] + q[2] * q[2]);
+    m[0][1] = 2.0 * (q[0] * q[1] - q[2] * q[3]);
+    m[0][2] = 2.0 * (q[2] * q[0] + q[1] * q[3]);
+    m[0][3] = 0.0;
+
+    m[1][0] = 2.0 * (q[0] * q[1] + q[2] * q[3]);
+    m[1][1]= 1.0 - 2.0 * (q[2] * q[2] + q[0] * q[0]);
+    m[1][2] = 2.0 * (q[1] * q[2] - q[0] * q[3]);
+    m[1][3] = 0.0;
+
+    m[2][0] = 2.0 * (q[2] * q[0] - q[1] * q[3]);
+    m[2][1] = 2.0 * (q[1] * q[2] + q[0] * q[3]);
+    m[2][2] = 1.0 - 2.0 * (q[1] * q[1] + q[0] * q[0]);
+    
+    m[2][3] = 0.0;
+    m[3][0] = 0.0;
+    m[3][1] = 0.0;
+    m[3][2] = 0.0;
+    m[3][3] = 1.0;
+#else //  TRANSPOSED_QUAT
+    m[0][0] = 1.0 - 2.0 * (q[1] * q[1] + q[2] * q[2]);
+    m[0][1] = 2.0 * (q[0] * q[1] + q[2] * q[3]);
+    m[0][2] = 2.0 * (q[2] * q[0] - q[1] * q[3]);
+    m[0][3] = 0.0;
+
+    m[1][0] = 2.0 * (q[0] * q[1] - q[2] * q[3]);
+    m[1][1] = 1.0 - 2.0 * (q[2] * q[2] + q[0] * q[0]);
+    m[1][2] = 2.0 * (q[1] * q[2] + q[0] * q[3]);
+    m[1][3] = 0.0;
+
+    m[2][0] = 2.0 * (q[2] * q[0] + q[1] * q[3]);
+    m[2][1] = 2.0 * (q[1] * q[2] - q[0] * q[3]);
+    m[2][2] = 1.0 - 2.0 * (q[1] * q[1] + q[0] * q[0]);
+    m[2][3] = 0.0;
+    
+    m[3][0] = 0.0;
+    m[3][1] = 0.0;
+    m[3][2] = 0.0;
+    m[3][3] = 1.0;
+#endif // 0
+}
+
diff --git a/src/Main/views.cxx b/src/Main/views.cxx
index 9e1835a22..0bf2c6c15 100644
--- a/src/Main/views.cxx
+++ b/src/Main/views.cxx
@@ -136,6 +136,7 @@ static void print_sgMat4( sgMat4 &in) {
 
 // Update the view parameters
 void FGView::UpdateViewMath( const FGInterface& f ) {
+
     Point3D p;
     sgVec3 v0, minus_z, sgvec, forward;
     sgMat4 VIEWo, TMP;
@@ -251,6 +252,14 @@ void FGView::UpdateViewMath( const FGInterface& f ) {
 
     sgMultMat4( VIEW, VIEW_ROT, TRANS );
 
+//!!!!!!!!!!!!!!!!!!!	
+    // THIS IS THE EXPERIMENTAL VIEWING ANGLE SHIFTER
+    // THE MAJORITY OF THE WORK IS DONE IN GUI.CXX
+    // this in gui.cxx for now just testing
+	extern float quat_mat[4][4];
+	sgPreMultMat4( VIEW, quat_mat);
+// !!!!!!!!!! testing	
+
     sgSetVec3( sgvec, 0.0, 0.0, 1.0 );
     sgXformVec3( forward, sgvec, VIEWo );
     // cout << "forward = " << forward[0] << ","
-- 
2.39.5