X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=Cockpit%2Fhud.c;h=590fda67ca5f25d3805034810aa89de899e41726;hb=50c0f6c9e628b9e1ff6bfecfa4ce04084beaccb7;hp=dce3cb5730046423b72cc8c732ce6c1f4114fdb6;hpb=0bb3c2969a80b026b33b5852386c489a05773b3b;p=flightgear.git

diff --git a/Cockpit/hud.c b/Cockpit/hud.c
index dce3cb573..590fda67c 100644
--- a/Cockpit/hud.c
+++ b/Cockpit/hud.c
@@ -38,13 +38,14 @@
 
 #include "hud.h"
 
-#include <Aircraft/aircraft.h>
 #include <Include/fg_constants.h>
+#include <Aircraft/aircraft.h>
 #include <Main/fg_debug.h>
 #include <Math/fg_random.h>
 #include <Math/mat3.h>
 #include <Math/polar.h>
 #include <Scenery/scenery.h>
+// #include <Scenery/mesh.h>   /* not used any more :-) */
 #include <Time/fg_timer.h>
 #include <Weather/weather.h>
 
@@ -53,7 +54,68 @@
 #define drawOneLine(x1,y1,x2,y2)  glBegin(GL_LINES);  \
    glVertex2f ((x1),(y1)); glVertex2f ((x2),(y2)); glEnd();
    
-/* textString - Bitmap font string */
+
+// The following routines obtain information concerntin the aircraft's
+// current state and return it to calling instrument display routines.
+// They should eventually be member functions of the aircraft.
+//
+
+double get_speed( void )
+{
+	fgFLIGHT *f;
+
+	f = current_aircraft.flight;
+	return( FG_V_equiv_kts );    // Make an explicit function call.
+}
+
+double get_aoa( void )
+{
+	fgFLIGHT *f;
+              
+	f = current_aircraft.flight;
+	return( FG_Gamma_vert_rad * RAD_TO_DEG );
+}
+
+double get_roll( void )
+{
+	fgFLIGHT *f;
+              
+	f = current_aircraft.flight;
+	return( FG_Phi );
+}
+
+double get_pitch( void )
+{
+	fgFLIGHT *f;
+              
+	f = current_aircraft.flight;
+	return( FG_Theta );
+}
+
+double get_heading( void )
+{
+	fgFLIGHT *f;
+
+	f = current_aircraft.flight;
+	return( FG_Psi*RAD_TO_DEG );
+}
+
+double get_altitude( void )
+{
+	fgFLIGHT *f;
+	// double rough_elev;
+
+	f = current_aircraft.flight;
+	// rough_elev = mesh_altitude(FG_Longitude * RAD_TO_ARCSEC,
+	//		                   FG_Latitude  * RAD_TO_ARCSEC);
+
+	return( FG_Altitude * FEET_TO_METER /* -rough_elev */ );
+}
+
+//
+// The following code deals with painting the "instrument" on the display
+//
+   /* textString - Bitmap font string */
 
 static void textString(int x, int y, char *msg, void *font)
 {
@@ -65,313 +127,404 @@ static void textString(int x, int y, char *msg, void *font)
 }
 
 /* strokeString - Stroke font string */
-/* static void strokeString(int x, int y, char *msg, void *font) */
-/* { */
-/* 	glPushMatrix(); */
-/* 	glTranslatef(x, y, 0); */
-/* 	glScalef(.04, .04, .04); */
-/* 	while (*msg) { */
-/* 		glutStrokeCharacter(font, *msg); */
-/* 		msg++; */
-/* 	} */
-/* 	glPopMatrix(); */
-/* } */
+/*
+static void strokeString(int x, int y, char *msg, void *font)
+{
+	glPushMatrix();
+	glTranslatef(x, y, 0);
+	glScalef(.04, .04, .04);
+	while (*msg) {
+		glutStrokeCharacter(font, *msg);
+		msg++;
+	}
+	glPopMatrix();
+}
+*/
 
 /*
 
 	Draws a measuring scale anywhere on the HUD
-		
-	
+
+
 	Needs: HUD_scale struct
 
 */
-static void drawscale( int type, int sub_type, int min_value, int orientation, int scr_pos, \
-		int scr_min, int scr_max, double total_amount, int min_div, int max_div, \
-		double cur_value )
+static void drawscale( HUD_scale * pscale )
 {
-    double vmin, vmax;
-    int marker_x, marker_y;
-    int mid_scr;
-    // int scale_min, scale_max;
-    register i;
-    double factor;
-    char TextScale[80];
-    int condition;
-
-    vmin = cur_value-total_amount/2;
-    vmax = cur_value+total_amount/2;
-    
-    mid_scr = scr_min+(scr_max-scr_min)/2;
-    
-    if( type == VERTICAL )     // Vertical scale
+  double vmin, vmax;
+  int marker_x;
+  int marker_y;
+  int mid_scr;
+  register i;
+  double factor;
+  char TextScale[80];
+  int condition;
+  double cur_value = (*(pscale->load_value))();
+
+  vmin = cur_value - pscale->maximum_value / 2;
+  vmax = cur_value + pscale->maximum_value / 2;
+
+  mid_scr = pscale->scr_min+(pscale->scr_max-pscale->scr_min)/2;
+
+  if( pscale->type == VERTICAL )     // Vertical scale
     {
-        if( orientation == LEFT )
-            marker_x = scr_pos-6;
-        else if( orientation == RIGHT )
-            marker_x = scr_pos;
-        drawOneLine( scr_pos, scr_min, scr_pos, scr_max );
-        if( orientation == LEFT )
+    if( pscale->orientation == LEFT )
+      marker_x = pscale->scr_pos-6;
+    else
+      if( pscale->orientation == RIGHT )
+        marker_x = pscale->scr_pos;
+    drawOneLine( pscale->scr_pos,
+                 pscale->scr_min,
+                 pscale->scr_pos,
+                 pscale->scr_max );
+    if( pscale->orientation == LEFT )
+      {
+      drawOneLine( pscale->scr_pos-3,
+                   pscale->scr_min,
+                   pscale->scr_pos,
+                   pscale->scr_min );
+
+      drawOneLine( pscale->scr_pos-3,
+                   pscale->scr_max,
+                   pscale->scr_pos,
+                   pscale->scr_max );
+
+      drawOneLine( pscale->scr_pos,
+                   mid_scr,
+                   pscale->scr_pos+6,
+                   mid_scr );
+
+      }
+    else
+      if( pscale->orientation == RIGHT )
         {
-            drawOneLine( scr_pos-3, scr_min, scr_pos, scr_min );
-            drawOneLine( scr_pos-3, scr_max, scr_pos, scr_max );
-            drawOneLine( scr_pos, mid_scr, scr_pos+6, mid_scr );
-        } else if( orientation == RIGHT )
-        {
-            drawOneLine( scr_pos, scr_min, scr_pos+3, scr_min );
-            drawOneLine( scr_pos, scr_max, scr_pos+3, scr_max );
-            drawOneLine( scr_pos, mid_scr, scr_pos-6, mid_scr );
+        drawOneLine( pscale->scr_pos,
+                     pscale->scr_min,
+                     pscale->scr_pos+3,
+                     pscale->scr_min );
+
+        drawOneLine( pscale->scr_pos,
+                     pscale->scr_max,
+                     pscale->scr_pos+3,
+                     pscale->scr_max );
+
+        drawOneLine( pscale->scr_pos,
+                     mid_scr,
+                     pscale->scr_pos-6,
+                     mid_scr );
         }
 
-        factor = (scr_max-scr_min)/total_amount;
+    factor = (pscale->scr_max - pscale->scr_min)/pscale->maximum_value;
 
-        for( i=vmin; i<=vmax; i+=1 )
+    for( i=vmin; i<=vmax; i+=1 )
+      {
+      if( pscale->sub_type == LIMIT )
+        condition = i>= pscale->minimum_value;
+      else
+        if( pscale->sub_type == NOLIMIT )
+          condition = 1;
+
+      if( condition )
         {
-        	if( sub_type == LIMIT )
-        		condition = i>= min_value;
-        	else if( sub_type == NOLIMIT )
-        		condition = 1;
-        		
-            if( condition )
+        marker_y = pscale->scr_min+(i-vmin)*factor;
+        if( i%pscale->div_min==0 )
+          if( pscale->orientation == LEFT )
             {
-                marker_y = scr_min+(i-vmin)*factor;
-                if( i%min_div==0 )
-                    if( orientation == LEFT )
-                    {
-                    	drawOneLine( marker_x+3, marker_y, marker_x+6, marker_y );
-                    }
-                    else if( orientation == RIGHT )
-                    {
-                    	drawOneLine( marker_x, marker_y, marker_x+3, marker_y );
-                    }
-                if( i%max_div==0 )
+            drawOneLine( marker_x+3, marker_y, marker_x+6, marker_y );
+            }
+          else
+            if( pscale->orientation == RIGHT )
+              {
+              drawOneLine( marker_x, marker_y, marker_x+3, marker_y );
+              }
+            if( i%pscale->div_max==0 )
+              {
+              drawOneLine( marker_x, marker_y, marker_x+6, marker_y );
+              sprintf( TextScale, "%d", i );
+              if( pscale->orientation == LEFT )
                 {
-                	drawOneLine( marker_x, marker_y, marker_x+6, marker_y );
-                    sprintf( TextScale, "%d", i );
-                    if( orientation == LEFT )
-                    {
-                    	textString( marker_x-8*strlen(TextScale)-2, marker_y-4, TextScale, GLUT_BITMAP_8_BY_13 );
-                    }
-                    else if( orientation == RIGHT )
-                    {
-                    	textString( marker_x+10, marker_y-4, TextScale, GLUT_BITMAP_8_BY_13 );
-                    }
+                textString( marker_x-8*strlen(TextScale)-2, marker_y-4,
+                            TextScale, GLUT_BITMAP_8_BY_13 );
                 }
-            }
-        }
+              else
+                if( pscale->orientation == RIGHT )
+                  {
+                  textString( marker_x+10, marker_y-4,
+                              TextScale, GLUT_BITMAP_8_BY_13 );
+                  }
+              }
+         }
+      } // End for range of i from vmin to vmax
     }
-    if( type == HORIZONTAL )     // Horizontal scale
+  if( pscale->type == HORIZONTAL )     // Horizontal scale
     {
-        if( orientation == TOP )
-            marker_y = scr_pos;
-        else if( orientation == BOTTOM )
-            marker_y = scr_pos-6;
-        drawOneLine( scr_min, scr_pos, scr_max, scr_pos );
-        if( orientation == TOP )
+    if( pscale->orientation == TOP )
+      marker_y = pscale->scr_pos;
+    else
+      if( pscale->orientation == BOTTOM )
+        marker_y = pscale->scr_pos-6;
+    drawOneLine( pscale->scr_min,
+                 pscale->scr_pos,
+                 pscale->scr_max,
+                 pscale->scr_pos );
+    if( pscale->orientation == TOP )
+      {
+      drawOneLine( pscale->scr_min,
+                   pscale->scr_pos,
+                   pscale->scr_min,
+                   pscale->scr_pos-3 );
+
+      drawOneLine( pscale->scr_max,
+                   pscale->scr_pos,
+                   pscale->scr_max,
+                   pscale->scr_pos-3 );
+
+      drawOneLine( mid_scr,
+                   pscale->scr_pos,
+                   mid_scr,
+                   pscale->scr_pos-6 );
+
+      }
+    else
+      if( pscale->orientation == BOTTOM )
         {
-        	drawOneLine( scr_min, scr_pos, scr_min, scr_pos-3 );
-            drawOneLine( scr_max, scr_pos, scr_max, scr_pos-3 );
-            drawOneLine( mid_scr, scr_pos, mid_scr, scr_pos-6 );
-        } else if( orientation == BOTTOM )
-        {
-        	drawOneLine( scr_min, scr_pos, scr_min, scr_pos+3 );
-            drawOneLine( scr_max, scr_pos, scr_max, scr_pos+3 );
-            drawOneLine( mid_scr, scr_pos, mid_scr, scr_pos+6 );
+        drawOneLine( pscale->scr_min,
+                     pscale->scr_pos,
+                     pscale->scr_min,
+                     pscale->scr_pos+3 );
+
+        drawOneLine( pscale->scr_max,
+                     pscale->scr_pos,
+                     pscale->scr_max,
+                     pscale->scr_pos+3 );
+
+        drawOneLine( mid_scr,
+                     pscale->scr_pos,
+                     mid_scr,
+                     pscale->scr_pos+6 );
         }
 
-        factor = (scr_max-scr_min)/total_amount;
+    factor = (pscale->scr_max - pscale->scr_min)/pscale->maximum_value;
 
-        for( i=vmin; i<=vmax; i+=1 )
+    for( i=vmin; i<=vmax; i+=1 )
+      {
+      if( pscale->sub_type == LIMIT )
+        condition = i>= pscale->minimum_value;
+      else
+        if( pscale->sub_type == NOLIMIT )
+          condition = 1;
+
+      if( condition )
         {
-        	if( sub_type == LIMIT )
-        		condition = i>= min_value;
-        	else if( sub_type == NOLIMIT )
-        		condition = 1;
-        		
-            if( condition )
+        marker_x = pscale->scr_min+(i-vmin)*factor;
+        if( i%pscale->div_min==0 )
+          if( pscale->orientation == TOP )
+            {
+            drawOneLine( marker_x, marker_y, marker_x, marker_y+3 );
+            }
+          else
+            if( pscale->orientation == BOTTOM )
+              {
+              drawOneLine( marker_x, marker_y+3, marker_x, marker_y+6 );
+              }
+          if( i%pscale->div_max==0 )
             {
-                marker_x = scr_min+(i-vmin)*factor;
-                if( i%min_div==0 )
-                    if( orientation == TOP )
-                    {
-                    	drawOneLine( marker_x, marker_y, marker_x, marker_y+3 );
-                   	}
-                    else if( orientation == BOTTOM )
-                    {
-                    	drawOneLine( marker_x, marker_y+3, marker_x, marker_y+6 );
-                    }
-                if( i%max_div==0 )
+            sprintf( TextScale, "%d", i );
+            if( pscale->orientation == TOP )
+              {
+              drawOneLine( marker_x, marker_y, marker_x, marker_y+6 );
+              textString ( marker_x-4*strlen(TextScale), marker_y+14,
+                           TextScale, GLUT_BITMAP_8_BY_13 );
+              }
+            else
+              if( pscale->orientation == BOTTOM )
                 {
-                    sprintf( TextScale, "%d", i );
-                    if( orientation == TOP )
-                    {
-                    	drawOneLine( marker_x, marker_y, marker_x, marker_y+6 );
-                    	textString( marker_x-4*strlen(TextScale), marker_y+14, TextScale, GLUT_BITMAP_8_BY_13 );
-                    }
-                    else if( orientation == BOTTOM )
-                    {
-                    	drawOneLine( marker_x, marker_y, marker_x, marker_y+6 );
-                    	textString( marker_x+10, marker_y-4, TextScale, GLUT_BITMAP_8_BY_13 );
-                    }
+                drawOneLine( marker_x, marker_y, marker_x, marker_y+6 );
+                textString ( marker_x+10, marker_y-4,
+                             TextScale, GLUT_BITMAP_8_BY_13 );
                 }
             }
         }
+      }
     }
 
-}              
+}
 
 /*
 
 	Draws a climb ladder in the center of the HUD
-		
-	
-	Needs: HUD_ladder struct
 
 */
-static void drawladder( struct HUD_ladder ladder )
+
+static void drawladder( HUD_ladder *ladder )
 {
-    double vmin, vmax;
-    double roll_value, pitch_value;
-    /* double cos_roll, sin_roll; */
-    int marker_x, marker_y;
-    int mid_scr;
-    int scr_min, scr_max;
-    int x_ini, x_end;
-    int y_ini, y_end;
-    int new_x_ini, new_x_end;
-    int new_y_ini, new_y_end;
-    register i;
-    double factor;
-    char TextLadder[80];
-    int condition;
-
-	roll_value = (*ladder.load_roll)();
-	pitch_value = (*ladder.load_pitch)()*RAD_TO_DEG;
-	
-    vmin = pitch_value-ladder.width_units/2;
-    vmax = pitch_value+ladder.width_units/2;
-    
-    scr_min = ladder.y_pos-(ladder.scr_height/2);
-    scr_max = scr_min+ladder.scr_height;
+  double vmin, vmax;
+  double roll_value, pitch_value;
+  int marker_x, marker_y;
+#ifdef DEBUGHUD
+  int mid_scr;
+#endif
+  int scr_min, scr_max;
+  int x_ini, x_end;
+  int y_ini, y_end;
+  int new_x_ini, new_x_end;
+  int new_y_ini, new_y_end;
+  register i;
+  double factor;
+  char TextLadder[80];
+  int condition;
+
+  roll_value = (*ladder->load_roll)();
+  pitch_value = (*ladder->load_pitch)()*RAD_TO_DEG;
+
+  vmin = pitch_value - ladder->width_units/2;
+  vmax = pitch_value + ladder->width_units/2;
     
-    mid_scr = scr_min+(scr_max-scr_min)/2;
+  scr_min = ladder->y_pos - (ladder->scr_height/2);
+  scr_max = scr_min       + ladder->scr_height;
 
-	marker_x = ladder.x_pos-ladder.scr_width/2;
-	
-    factor = (scr_max-scr_min)/ladder.width_units;
+#ifdef DEBUGHUD
+  mid_scr = scr_min       + (scr_max-scr_min)/2;
+#endif
 
-    for( i=vmin; i<=vmax; i+=1 )
+  marker_x = ladder->x_pos - ladder->scr_width/2;
+
+  factor = (scr_max-scr_min)/ladder->width_units;
+
+  for( i=vmin; i<=vmax; i+=1 )
     {
-    	condition = 1;
-        if( condition )
+    condition = 1;
+    if( condition )
+      {
+      marker_y = scr_min+(i-vmin)*factor;
+      if( i%ladder->div_units==0 )
         {
-            marker_y = scr_min+(i-vmin)*factor;
-            if( i%ladder.div_units==0 )
+        sprintf( TextLadder, "%d", i );
+        if( ladder->scr_hole == 0 )
+          {
+          if( i )
+            x_ini = ladder->x_pos - ladder->scr_width/2;
+          else
+            x_ini = ladder->x_pos - ladder->scr_width/2 - 10;
+          y_ini = marker_y;
+          x_end = ladder->x_pos + ladder->scr_width/2;
+          y_end = marker_y;
+          new_x_ini = ladder->x_pos +                             \
+                      (x_ini - ladder->x_pos) * cos(roll_value) - \
+                      (y_ini - ladder->y_pos) * sin(roll_value);
+          new_y_ini = ladder->y_pos +                             \
+                      (x_ini - ladder->x_pos) * sin(roll_value) + \
+                      (y_ini - ladder->y_pos) * cos(roll_value);
+          new_x_end = ladder->x_pos +                             \
+                      (x_end - ladder->x_pos) * cos(roll_value) - \
+                      (y_end - ladder->y_pos) * sin(roll_value);
+          new_y_end = ladder->y_pos +                             \
+                      (x_end - ladder->x_pos) * sin(roll_value) + \
+                      (y_end - ladder->y_pos) * cos(roll_value);
+
+          if( i >= 0 )
             {
-            	sprintf( TextLadder, "%d", i );
-            	if( ladder.scr_hole == 0 )
-            	{
-            		if( i != 0 )
-               			x_ini = ladder.x_pos-ladder.scr_width/2;
-               		else
-               			x_ini = ladder.x_pos-ladder.scr_width/2-10;
-               		y_ini = marker_y;
-               		x_end = ladder.x_pos+ladder.scr_width/2;
-               		y_end = marker_y;
-           			new_x_ini = ladder.x_pos+(x_ini-ladder.x_pos)*cos(roll_value)-\
-           				(y_ini-ladder.y_pos)*sin(roll_value);
-           			new_y_ini = ladder.y_pos+(x_ini-ladder.x_pos)*sin(roll_value)+\
-           				(y_ini-ladder.y_pos)*cos(roll_value);
-           			new_x_end = ladder.x_pos+(x_end-ladder.x_pos)*cos(roll_value)-\
-           				(y_end-ladder.y_pos)*sin(roll_value);
-           			new_y_end = ladder.y_pos+(x_end-ladder.x_pos)*sin(roll_value)+\
-           				(y_end-ladder.y_pos)*cos(roll_value);
-   
-   					if( i >= 0 )
-   					{
-            			drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
-            		}
-            		else
-            		{
-            			glEnable(GL_LINE_STIPPLE);
-            			glLineStipple( 1, 0x00FF );
-            			drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
-            			glDisable(GL_LINE_STIPPLE);
-            		}
-                	textString( new_x_ini-8*strlen(TextLadder)-8, new_y_ini-4, TextLadder, GLUT_BITMAP_8_BY_13 );
-                	textString( new_x_end+10, new_y_end-4, TextLadder, GLUT_BITMAP_8_BY_13 );
-            	}
-            	else
-            	{
-            		if( i != 0 )
-               			x_ini = ladder.x_pos-ladder.scr_width/2;
-               		else
-               			x_ini = ladder.x_pos-ladder.scr_width/2-10;
-               		y_ini = marker_y;
-               		x_end = ladder.x_pos-ladder.scr_width/2+ladder.scr_hole/2;
-               		y_end = marker_y;
-           			new_x_ini = ladder.x_pos+(x_ini-ladder.x_pos)*cos(roll_value)-\
-           				(y_ini-ladder.y_pos)*sin(roll_value);
-           			new_y_ini = ladder.y_pos+(x_ini-ladder.x_pos)*sin(roll_value)+\
-           				(y_ini-ladder.y_pos)*cos(roll_value);
-           			new_x_end = ladder.x_pos+(x_end-ladder.x_pos)*cos(roll_value)-\
-           				(y_end-ladder.y_pos)*sin(roll_value);
-           			new_y_end = ladder.y_pos+(x_end-ladder.x_pos)*sin(roll_value)+\
-           				(y_end-ladder.y_pos)*cos(roll_value);
-            
-            		if( i >= 0 )
-            		{
-            			drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
-            		}
-            		else
-            		{
-            			glEnable(GL_LINE_STIPPLE);
-            			glLineStipple( 1, 0x00FF );
-            			drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
-            			glDisable(GL_LINE_STIPPLE);
-            		}
-            		textString( new_x_ini-8*strlen(TextLadder)-8, new_y_ini-4, TextLadder, GLUT_BITMAP_8_BY_13 );
-            		
-            		x_ini = ladder.x_pos+ladder.scr_width/2-ladder.scr_hole/2;
-               		y_ini = marker_y;
-               		if( i != 0 )
-               			x_end = ladder.x_pos+ladder.scr_width/2;
-               		else
-               			x_end = ladder.x_pos+ladder.scr_width/2+10;
-               		y_end = marker_y;
-           			new_x_ini = ladder.x_pos+(x_ini-ladder.x_pos)*cos(roll_value)-\
-           				(y_ini-ladder.y_pos)*sin(roll_value);
-           			new_y_ini = ladder.y_pos+(x_ini-ladder.x_pos)*sin(roll_value)+\
-           				(y_ini-ladder.y_pos)*cos(roll_value);
-           			new_x_end = ladder.x_pos+(x_end-ladder.x_pos)*cos(roll_value)-\
-           				(y_end-ladder.y_pos)*sin(roll_value);
-           			new_y_end = ladder.y_pos+(x_end-ladder.x_pos)*sin(roll_value)+\
-           				(y_end-ladder.y_pos)*cos(roll_value);
-            
-            		if( i >= 0 )
-            		{
-            			drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
-            		}
-            		else
-            		{
-            			glEnable(GL_LINE_STIPPLE);
-            			glLineStipple( 1, 0x00FF );
-            			drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
-            			glDisable(GL_LINE_STIPPLE);
-            		}
-            		textString( new_x_end+10, new_y_end-4, TextLadder, GLUT_BITMAP_8_BY_13 );
-            	}
+            drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
+            }
+          else
+            {
+            glEnable(GL_LINE_STIPPLE);
+            glLineStipple( 1, 0x00FF );
+            drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
+            glDisable(GL_LINE_STIPPLE);
+            }
+          textString( new_x_ini -  8 * strlen(TextLadder) - 8,
+                      new_y_ini -  4,
+                      TextLadder, GLUT_BITMAP_8_BY_13 );
+          textString( new_x_end + 10,
+                      new_y_end -  4,
+                      TextLadder, GLUT_BITMAP_8_BY_13 );
+          }
+        else
+          {
+          if( i != 0 )
+            x_ini = ladder->x_pos - ladder->scr_width/2;
+          else
+            x_ini = ladder->x_pos - ladder->scr_width/2 - 10;
+          y_ini = marker_y;
+          x_end = ladder->x_pos - ladder->scr_width/2 + ladder->scr_hole/2;
+          y_end = marker_y;
+          new_x_ini = ladder->x_pos+                             \
+                      (x_ini - ladder->x_pos) * cos(roll_value) -\
+                      (y_ini - ladder->y_pos) * sin(roll_value);
+          new_y_ini = ladder->y_pos+                             \
+                      (x_ini - ladder->x_pos) * sin(roll_value) +\
+                      (y_ini - ladder->y_pos) * cos(roll_value);
+          new_x_end = ladder->x_pos+                             \
+                      (x_end - ladder->x_pos) * cos(roll_value) -\
+                      (y_end - ladder->y_pos) * sin(roll_value);
+          new_y_end = ladder->y_pos+                             \
+                      (x_end - ladder->x_pos) * sin(roll_value) +\
+                      (y_end - ladder->y_pos) * cos(roll_value);
+
+          if( i >= 0 )
+            {
+            drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
+            }
+          else
+            {
+            glEnable(GL_LINE_STIPPLE);
+            glLineStipple( 1, 0x00FF );
+            drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
+            glDisable(GL_LINE_STIPPLE);
             }
-            /* if( i%max_div==0 )
+          textString( new_x_ini - 8 * strlen(TextLadder) - 8,
+                      new_y_ini - 4,
+                      TextLadder, GLUT_BITMAP_8_BY_13 );
+
+          x_ini = ladder->x_pos + ladder->scr_width/2 - ladder->scr_hole/2;
+          y_ini = marker_y;
+          if( i != 0 )
+            x_end = ladder->x_pos + ladder->scr_width/2;
+          else
+            x_end = ladder->x_pos + ladder->scr_width/2 + 10;
+          y_end = marker_y;
+          new_x_ini = ladder->x_pos +                        \
+                      (x_ini-ladder->x_pos)*cos(roll_value) -\
+                      (y_ini-ladder->y_pos)*sin(roll_value);
+          new_y_ini = ladder->y_pos +                        \
+                      (x_ini-ladder->x_pos)*sin(roll_value) +\
+                      (y_ini-ladder->y_pos)*cos(roll_value);
+          new_x_end = ladder->x_pos +                        \
+                      (x_end-ladder->x_pos)*cos(roll_value) -\
+           				 (y_end-ladder->y_pos)*sin(roll_value);
+          new_y_end = ladder->y_pos +                        \
+                      (x_end-ladder->x_pos)*sin(roll_value) +\
+                      (y_end-ladder->y_pos)*cos(roll_value);
+
+          if( i >= 0 )
+            {
+            drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
+            }
+          else
+            {
+            glEnable(GL_LINE_STIPPLE);
+            glLineStipple( 1, 0x00FF );
+            drawOneLine( new_x_ini, new_y_ini, new_x_end, new_y_end );
+            glDisable(GL_LINE_STIPPLE);
+            }
+          textString( new_x_end+10, new_y_end-4,
+                      TextLadder, GLUT_BITMAP_8_BY_13 );
+          }
+        }
+            /* if( i%pscale->div_max==0 )
             {
             	drawOneLine( marker_x, marker_y, marker_x+6, marker_y );
                 sprintf( TextScale, "%d", i );
-                if( orientation == LEFT )
+                if( pscale->orientation == LEFT )
                 {
-                	textString( marker_x-8*strlen(TextScale)-2, marker_y-4, TextScale, GLUT_BITMAP_8_BY_13 );
+                	textString( marker_x-8*strlen(TextScale)-2, marker_y-4,
+                              TextScale, GLUT_BITMAP_8_BY_13 );
                 }
-                else if( orientation == RIGHT )
+                else if( pscale->orientation == RIGHT )
                 {
-                	textString( marker_x+10, marker_y-4, TextScale, GLUT_BITMAP_8_BY_13 );
+                	textString( marker_x+10, marker_y-4,
+                              TextScale, GLUT_BITMAP_8_BY_13 );
                 }
             } */
         }
@@ -379,49 +532,45 @@ static void drawladder( struct HUD_ladder ladder )
 
 }
 
-/*
+//
+//	Draws an artificial horizon line in the center of the HUD
+//	(with or without a center hole)
+//
+//	Needs: x_center, y_center, length, hole
+//
 
-	Draws an artificial horizon line in the center of the HUD
-		(with or without a center hole)
-	
-	Needs: x_center, y_center, length, hole
-
-*/
-static void drawhorizon( struct HUD_horizon horizon )
+static void drawhorizon( HUD_horizon *horizon )
 {
-	int x_inc1, y_inc1;
-	int x_inc2, y_inc2;
-	/* struct fgFLIGHT *f; */
-	double sin_bank, cos_bank;
-	double bank_angle;
-              
-	/* f = &current_aircraft.flight; */
-	
-	bank_angle = (*horizon.load_value)();
+  int x_inc1, y_inc1;
+  int x_inc2, y_inc2;
+//	struct fgFLIGHT *f = &current_aircraft.flight;
+  double sin_bank, cos_bank;
+  double bank_angle;
+
+  bank_angle = (*horizon->load_value)();
 
 	// sin_bank = sin( FG_2PI-FG_Phi );
 	// cos_bank = cos( FG_2PI-FG_Phi );
-	sin_bank = sin(FG_2PI-bank_angle);
-	cos_bank = cos(FG_2PI-bank_angle);
-	x_inc1 = (int)(horizon.scr_width*cos_bank);
-	y_inc1 = (int)(horizon.scr_width*sin_bank);
-	x_inc2 = (int)(horizon.scr_hole*cos_bank);
-	y_inc2 = (int)(horizon.scr_hole*sin_bank);
-	
-	if( horizon.scr_hole == 0 )
-	{
-		drawOneLine( horizon.x_pos-x_inc1, horizon.y_pos-y_inc1, \
-						horizon.x_pos+x_inc1, horizon.y_pos+y_inc1 );
-	}
-	else
-	{
-		drawOneLine( horizon.x_pos-x_inc1, horizon.y_pos-y_inc1, \
-						horizon.x_pos-x_inc2, horizon.y_pos-y_inc2 );
-		drawOneLine( horizon.x_pos+x_inc2, horizon.y_pos+y_inc2, \
-						horizon.x_pos+x_inc1, horizon.y_pos+y_inc1 );
-	}	
+  sin_bank = sin(FG_2PI-bank_angle);
+  cos_bank = cos(FG_2PI-bank_angle);
+  x_inc1 = (int)(horizon->scr_width * cos_bank);
+  y_inc1 = (int)(horizon->scr_width * sin_bank);
+  x_inc2 = (int)(horizon->scr_hole  * cos_bank);
+  y_inc2 = (int)(horizon->scr_hole  * sin_bank);
+
+  if( horizon->scr_hole == 0 )
+    {
+    drawOneLine( horizon->x_pos - x_inc1, horizon->y_pos - y_inc1, \
+                 horizon->x_pos + x_inc1, horizon->y_pos + y_inc1 );
+    }
+  else
+    {
+    drawOneLine( horizon->x_pos - x_inc1, horizon->y_pos - y_inc1, \
+                 horizon->x_pos - x_inc2, horizon->y_pos - y_inc2 );
+    drawOneLine( horizon->x_pos + x_inc2, horizon->y_pos + y_inc2, \
+                 horizon->x_pos + x_inc1, horizon->y_pos + y_inc1 );
+    }
 }
-
 /*
 
 	Draws a representation of the control surfaces in their current state
@@ -430,446 +579,476 @@ static void drawhorizon( struct HUD_horizon horizon )
 	Needs: struct HUD_control_surfaces
 
 */
-static void drawcontrolsurfaces( struct HUD_control_surfaces ctrl_surf )
+static void drawControlSurfaces( HUD_control_surfaces *ctrl_surf )
 {
 	int x_ini, y_ini;
 	int x_end, y_end;
 	/* int x_1, y_1; */
 	/* int x_2, y_2; */
-	struct fgCONTROLS *c;
-	
-	x_ini = ctrl_surf.x_pos;
-	y_ini = ctrl_surf.y_pos;
-	x_end = x_ini+150;
-	y_end = y_ini+60;
-	
+	fgCONTROLS *c;
+
+	x_ini = ctrl_surf->x_pos;
+	y_ini = ctrl_surf->y_pos;
+	x_end = x_ini + 150;
+	y_end = y_ini + 60;
+
 	drawOneLine( x_ini, y_ini, x_end, y_ini );
 	drawOneLine( x_ini, y_ini, x_ini, y_end );
 	drawOneLine( x_ini, y_end, x_end, y_end );
 	drawOneLine( x_end, y_end, x_end, y_ini );
-	drawOneLine( x_ini+30, y_ini, x_ini+30, y_end );
-	drawOneLine( x_ini+30, y_ini+30, x_ini+90, y_ini+30 );
-	drawOneLine( x_ini+90, y_ini, x_ini+90, y_end );
-	drawOneLine( x_ini+120, y_ini, x_ini+120, y_end );
-              
-	c = &current_aircraft.controls;
-	
+	drawOneLine( x_ini + 30, y_ini, x_ini + 30, y_end );
+	drawOneLine( x_ini + 30, y_ini + 30, x_ini + 90, y_ini + 30 );
+	drawOneLine( x_ini + 90, y_ini, x_ini + 90, y_end );
+	drawOneLine( x_ini + 120, y_ini, x_ini + 120, y_end );
+
+	c = current_aircraft.controls;
+
 	/* Draw elevator diagram */
-	textString( x_ini+1, y_end-11, "E", GLUT_BITMAP_8_BY_13 );	
-	drawOneLine( x_ini+15, y_ini+5, x_ini+15, y_ini+55 );
-	drawOneLine( x_ini+14, y_ini+30, x_ini+16, y_ini+30 );
+	textString( x_ini + 1, y_end-11, "E", GLUT_BITMAP_8_BY_13 );
+	drawOneLine( x_ini + 15, y_ini + 5, x_ini + 15, y_ini + 55 );
+	drawOneLine( x_ini + 14, y_ini + 30, x_ini + 16, y_ini + 30 );
 	if( FG_Elevator <= -0.01 || FG_Elevator >= 0.01 )
 	{
-		drawOneLine( x_ini+10, y_ini+5+(int)(((FG_Elevator+1.0)/2)*50.0), \
-				x_ini+20, y_ini+5+(int)(((FG_Elevator+1.0)/2)*50.0) );
+		drawOneLine( x_ini + 10, y_ini + 5 + (int)(((FG_Elevator + 1.0)/2)*50.0), \
+				x_ini + 20, y_ini + 5 + (int)(((FG_Elevator + 1.0)/2)*50.0) );
 	}
 	else
 	{
-		drawOneLine( x_ini+7, y_ini+5+(int)(((FG_Elevator+1.0)/2)*50.0), \
-				x_ini+23, y_ini+5+(int)(((FG_Elevator+1.0)/2)*50.0) );
+		drawOneLine( x_ini + 7, y_ini + 5 + (int)(((FG_Elevator + 1.0)/2)*50.0), \
+				x_ini + 23, y_ini + 5 + (int)(((FG_Elevator + 1.0)/2)*50.0) );
 	}
-	
+
 	/* Draw aileron diagram */
-	textString( x_ini+30+1, y_end-11, "A", GLUT_BITMAP_8_BY_13 );	
-	drawOneLine( x_ini+35, y_end-15, x_ini+85, y_end-15 );
-	drawOneLine( x_ini+60, y_end-14, x_ini+60, y_end-16 );
+	textString( x_ini + 30 + 1, y_end-11, "A", GLUT_BITMAP_8_BY_13 );
+	drawOneLine( x_ini + 35, y_end-15, x_ini + 85, y_end-15 );
+	drawOneLine( x_ini + 60, y_end-14, x_ini + 60, y_end-16 );
 	if( FG_Aileron <= -0.01 || FG_Aileron >= 0.01 )
 	{
-		drawOneLine( x_ini+35+(int)(((FG_Aileron+1.0)/2)*50.0), y_end-20, \
-				x_ini+35+(int)(((FG_Aileron+1.0)/2)*50.0), y_end-10 );
+		drawOneLine( x_ini + 35 + (int)(((FG_Aileron + 1.0)/2)*50.0), y_end-20, \
+				x_ini + 35 + (int)(((FG_Aileron + 1.0)/2)*50.0), y_end-10 );
 	}
 	else
 	{
-		drawOneLine( x_ini+35+(int)(((FG_Aileron+1.0)/2)*50.0), y_end-25, \
-				x_ini+35+(int)(((FG_Aileron+1.0)/2)*50.0), y_end-5 );
+		drawOneLine( x_ini + 35 + (int)(((FG_Aileron + 1.0)/2)*50.0), y_end-25, \
+				x_ini + 35 + (int)(((FG_Aileron + 1.0)/2)*50.0), y_end-5 );
 	}
-	
+
 	/* Draw rudder diagram */
-	textString( x_ini+30+1, y_ini+21, "R", GLUT_BITMAP_8_BY_13 );	
-	drawOneLine( x_ini+35, y_ini+15, x_ini+85, y_ini+15 );
-	drawOneLine( x_ini+60, y_ini+14, x_ini+60, y_ini+16 );
+	textString( x_ini + 30 + 1, y_ini + 21, "R", GLUT_BITMAP_8_BY_13 );
+	drawOneLine( x_ini + 35, y_ini + 15, x_ini + 85, y_ini + 15 );
+	drawOneLine( x_ini + 60, y_ini + 14, x_ini + 60, y_ini + 16 );
 	if( FG_Rudder <= -0.01 || FG_Rudder >= 0.01 )
 	{
-		drawOneLine( x_ini+35+(int)(((FG_Rudder+1.0)/2)*50.0), y_ini+20, \
-				x_ini+35+(int)(((FG_Rudder+1.0)/2)*50.0), y_ini+10 );
+		drawOneLine( x_ini + 35 + (int)(((FG_Rudder + 1.0)/2)*50.0), y_ini + 20, \
+				x_ini + 35 + (int)(((FG_Rudder + 1.0)/2)*50.0), y_ini + 10 );
 	}
 	else
 	{
-		drawOneLine( x_ini+35+(int)(((FG_Rudder+1.0)/2)*50.0), y_ini+25, \
-				x_ini+35+(int)(((FG_Rudder+1.0)/2)*50.0), y_ini+5 );
+		drawOneLine( x_ini + 35 + (int)(((FG_Rudder + 1.0)/2)*50.0), y_ini + 25, \
+				x_ini + 35 + (int)(((FG_Rudder + 1.0)/2)*50.0), y_ini + 5 );
 	}
 	
 	
 	/* Draw throttle diagram */
-	textString( x_ini+90+1, y_end-11, "T", GLUT_BITMAP_8_BY_13 );	
-	textString( x_ini+90+1, y_end-21, "r", GLUT_BITMAP_8_BY_13 );	
-	drawOneLine( x_ini+105, y_ini+5, x_ini+105, y_ini+55 );
-	drawOneLine( x_ini+100, y_ini+5+(int)(FG_Throttle[0]*50.0), \
-			x_ini+110, y_ini+5+(int)(FG_Throttle[0]*50.0) );
+	textString( x_ini + 90 + 1, y_end-11, "T", GLUT_BITMAP_8_BY_13 );	
+	textString( x_ini + 90 + 1, y_end-21, "r", GLUT_BITMAP_8_BY_13 );	
+	drawOneLine( x_ini + 105, y_ini + 5, x_ini + 105, y_ini + 55 );
+	drawOneLine( x_ini + 100, y_ini + 5 + (int)(FG_Throttle[0]*50.0), \
+			x_ini + 110, y_ini + 5 + (int)(FG_Throttle[0]*50.0) );
 	
 	
 	/* Draw elevator trim diagram */
-	textString( x_ini+121, y_end-11, "T", GLUT_BITMAP_8_BY_13 );	
-	textString( x_ini+121, y_end-22, "m", GLUT_BITMAP_8_BY_13 );	
-	drawOneLine( x_ini+135, y_ini+5, x_ini+135, y_ini+55 );
-	drawOneLine( x_ini+134, y_ini+30, x_ini+136, y_ini+30 );
+	textString( x_ini + 121, y_end-11, "T", GLUT_BITMAP_8_BY_13 );	
+	textString( x_ini + 121, y_end-22, "m", GLUT_BITMAP_8_BY_13 );	
+	drawOneLine( x_ini + 135, y_ini + 5, x_ini + 135, y_ini + 55 );
+	drawOneLine( x_ini + 134, y_ini + 30, x_ini + 136, y_ini + 30 );
 	if( FG_Elev_Trim <= -0.01 || FG_Elev_Trim >= 0.01 )
 	{
-		drawOneLine( x_ini+130, y_ini+5+(int)(((FG_Elev_Trim+1)/2)*50.0), \
-				x_ini+140, y_ini+5+(int)(((FG_Elev_Trim+1.0)/2)*50.0) );
+		drawOneLine( x_ini + 130, y_ini + 5 + (int)(((FG_Elev_Trim + 1)/2)*50.0), \
+				x_ini + 140, y_ini + 5 + (int)(((FG_Elev_Trim + 1.0)/2)*50.0) );
 	}
 	else
 	{
-		drawOneLine( x_ini+127, y_ini+5+(int)(((FG_Elev_Trim+1.0)/2)*50.0), \
-				x_ini+143, y_ini+5+(int)(((FG_Elev_Trim+1.0)/2)*50.0) );
+		drawOneLine( x_ini + 127, y_ini + 5 + (int)(((FG_Elev_Trim + 1.0)/2)*50.0), \
+				x_ini + 143, y_ini + 5 + (int)(((FG_Elev_Trim + 1.0)/2)*50.0) );
 	}
 	
 }
 
-/*
-
-	Draws a label anywhere in the HUD
-	
-	Needs: HUD_label struct
+//
+// Draws a label anywhere in the HUD
+//
+//
 
-*/	
-static void drawlabel( struct HUD_label label )
+static void drawlabel( HUD_label *label )
 {
-	char buffer[80];
-	char string[80];
-	int posincr;
-	int lenstr;
-	
-	if( label.pre_str != NULL && label.post_str != NULL )
-		sprintf( buffer, "%s%s%s", label.pre_str, label.format, label.post_str );
-	else if( label.pre_str == NULL && label.post_str != NULL )
-		sprintf( buffer, "%s%s", label.format, label.post_str );
-	else if( label.pre_str != NULL && label.post_str == NULL )
-		sprintf( buffer, "%s%s", label.pre_str, label.format );
+  char buffer[80];
+  char string[80];
+  int posincr;
+  int lenstr;
+
+  if( !label ) { // Eliminate the possible, but absurd case.
+    return;
+    }
+
+  if( label->pre_str != NULL) {
+    if( label->post_str != NULL ) {
+      sprintf( buffer, "%s%s%s", label->pre_str,  \
+                                 label->format,   \
+                                 label->post_str );
+      }
+    else {
+      sprintf( buffer, "%s%s",   label->pre_str, \
+                                 label->format );
+      }
+    }
+  else {
+    if( label->post_str != NULL ) {
+      sprintf( buffer, "%s%s",   label->format,  \
+                                 label->post_str );
+      }
+    } // else do nothing if both pre and post strings are nulls. Interesting.
+
 
-	sprintf( string, buffer, (*label.load_value)() );
+  sprintf( string, buffer, (*label->load_value)() );
 
 	fgPrintf( FG_COCKPIT, FG_DEBUG,  buffer );
 	fgPrintf( FG_COCKPIT, FG_DEBUG,  "\n" );
 	fgPrintf( FG_COCKPIT, FG_DEBUG, string );
 	fgPrintf( FG_COCKPIT, FG_DEBUG, "\n" );
 
-	lenstr = strlen( string );
-	if( label.justify == LEFT_JUST )
-		posincr = -lenstr*8;
-	else if( label.justify == CENTER_JUST )
-		posincr = -lenstr*4;
-	else if( label.justify == RIGHT_JUST )
-		posincr = 0;
-	
-	if( label.size == SMALL )
-		textString( label.x_pos+posincr, label.y_pos, string, GLUT_BITMAP_8_BY_13);
-	else if( label.size == LARGE )
-		textString( label.x_pos+posincr, label.y_pos, string, GLUT_BITMAP_9_BY_15);
-	
-}
-
-double get_speed( void )
-{
-	struct fgFLIGHT *f;
-              
-	f = &current_aircraft.flight;
-	return( FG_V_equiv_kts );
-}
+  lenstr = strlen( string );
+  if( label->justify == LEFT_JUST ) {
+   posincr = -lenstr*8;
+   }
+  else {
+    if( label->justify == CENTER_JUST ) {
+      posincr = -lenstr*4;
+      }
+    else {
+      if( label->justify == RIGHT_JUST ) {
+        posincr = 0;
+        }
+      }
+    }
 
-double get_aoa( void )
-{
-	struct fgFLIGHT *f;
-              
-	f = &current_aircraft.flight;
-	return( FG_Gamma_vert_rad*RAD_TO_DEG );
+  if( label->size == SMALL ) {
+    textString( label->x_pos + posincr, label->y_pos,
+                string, GLUT_BITMAP_8_BY_13);
+    }
+  else  {
+    if( label->size == LARGE ) {
+      textString( label->x_pos + posincr, label->y_pos,
+                  string, GLUT_BITMAP_9_BY_15);
+      }
+    }
 }
-
-double get_roll( void )
+// The following routines concern HUD object/component object construction
+//
+
+// fgHUDInit
+//
+// Constructs a HUD object and then adds in instruments. At the present
+// the instruments are hard coded into the routine. Ultimately these need
+// to be defined by the aircraft's instrumentation records so that the
+// display for a Piper Cub doesn't show the speed range of a North American
+// mustange and the engine readouts of a B36!
+//
+Hptr fgHUDInit( fgAIRCRAFT *current_aircraft )
 {
-	struct fgFLIGHT *f;
-              
-	f = &current_aircraft.flight;
-	return( FG_Phi );
+  Hptr hud;
+
+  hud = (Hptr)calloc(sizeof( HUD),1);
+  if( hud == NULL )
+    return( NULL );
+
+  hud->code = 1;
+  hud->status = 0;
+
+  // For now lets just hardcode the hud here .
+  // In the future, hud information has to come from the same place
+  // aircraft information came from.
+
+  fgHUDAddHorizon( hud, 590, 50, 40, 20, get_roll );
+  fgHUDAddScale  ( hud, VERTICAL, NOLIMIT, 220, 100, 280, 5, 10,
+                   LEFT, LEFT, 0, 100, get_speed );
+  fgHUDAddScale  ( hud, VERTICAL, NOLIMIT, 440, 100, 280, 1, 5,
+                   RIGHT, RIGHT, -400, 25, get_aoa );
+  fgHUDAddScale  ( hud, HORIZONTAL, NOLIMIT, 280, 220, 440, 5, 10,
+                   TOP, TOP, 0, 50, get_heading );
+  fgHUDAddLabel  ( hud, 180, 85, SMALL, NOBLINK,
+                   RIGHT_JUST, NULL, " Kts", "%5.0f", get_speed );
+  fgHUDAddLabel  ( hud, 180, 73, SMALL, NOBLINK,
+                   RIGHT_JUST, NULL, " m", "%5.0f", get_altitude );
+  fgHUDAddLadder ( hud, 330, 190, 90, 180, 70, 10,
+                   NONE, 45, get_roll, get_pitch );
+  // fgHUDAddControlSurfaces( hud, 10, 10, get_heading );
+
+  return( hud );
 }
 
-double get_pitch( void )
-{
-	struct fgFLIGHT *f;
-              
-	f = &current_aircraft.flight;
-	return( FG_Theta );
-}
+// add_instrument
+//
+// This is a stand in for linked list code that will get replaced later
+// by some more elegant list handling code.
 
-double get_heading( void )
+void add_instrument( Hptr hud, HIptr pinstrument )
 {
-	struct fgFLIGHT *f;
-              
-	f = &current_aircraft.flight;
-	return( FG_Psi*RAD_TO_DEG );
+  if( !hud || !pinstrument ) {
+    return;
+    }
+  pinstrument->next = hud->instruments;
+  hud->instruments = pinstrument;
 }
 
-double get_altitude( void )
+// fgHUDAddHorizon
+//
+// Constructs a HUD_horizon "object" and installs it into the hud instrument
+// list.
+
+Hptr fgHUDAddHorizon( Hptr hud,     \
+                      int x_pos,    \
+                      int y_pos,    \
+                      int length,   \
+                      int hole_len, \
+                      double (*load_value)() )
 {
-	struct fgFLIGHT *f;
-	/* double rough_elev; */
-              
-	f = &current_aircraft.flight;
-	/* rough_elev = mesh_altitude(FG_Longitude * RAD_TO_ARCSEC,
-			                   FG_Latitude  * RAD_TO_ARCSEC); */
-                                                   
-	return( FG_Altitude * FEET_TO_METER /* -rough_elev */ );
-}
+  HUD_horizon *phorizon;
+  HUD_instr   *pinstrument;
 
-void add_instrument( Hptr hud, HIptr instrument )
-{
-	HIptr instruments;
-	
-	instruments = hud->instruments;
-	// while( ++instruments
-}
+  if( !hud ) {
+    return NULL;
+    }
+                                       // construct the parent object
+	pinstrument = (HIptr)calloc(sizeof(HUD_instr),1);
+	if( pinstrument == NULL ) {
+		return( NULL );
+    }
+	pinstrument->type    = HUDhorizon;  //  ARTIFICIAL_HORIZON;
 
-Hptr fgHUDInit( struct fgAIRCRAFT current_aircraft, int color )
-{
-	Hptr hud;
-	
-	hud = (Hptr)calloc(sizeof(struct HUD),1);
-	if( hud == NULL )
+                                      // Construct the horizon
+	phorizon = (HUD_horizon *) calloc( sizeof(HUD_horizon),1);
+	if( phorizon == NULL )   {
 		return( NULL );
-		
-	hud->code = 1;		/* It will be aircraft dependent */
-	hud->status = 0;
-	
-	// For now lets just hardcode a hud here .
-	// In the future, hud information has to come from the same place 
-	// aircraft information came
-	
-	fgHUDAddHorizon( hud, 590, 50, 40, 20, get_roll );
-	fgHUDAddScale( hud, VERTICAL, 220, 100, 280, 5, 10, LEFT, LEFT, 0, 100, get_speed );
-	fgHUDAddScale( hud, VERTICAL, 440, 100, 280, 1, 5, RIGHT, RIGHT, -400, 25, get_aoa );
-	fgHUDAddScale( hud, HORIZONTAL, 280, 220, 440, 5, 10, TOP, TOP, 0, 50, get_heading );
-	fgHUDAddLabel( hud, 180, 85, SMALL, NOBLINK, RIGHT_JUST, NULL, " Kts", "%5.0f", get_speed );
-	fgHUDAddLabel( hud, 180, 73, SMALL, NOBLINK, RIGHT_JUST, NULL, " m", "%5.0f", get_altitude );
-	fgHUDAddLadder( hud, 330, 190, 90, 180, 70, 10, NONE, 45, get_roll, get_pitch );
-	fgHUDAddControlSurfaces( hud, 10, 10, get_heading );
-	
-	return( hud );
+    }
+
+  phorizon->x_pos      = x_pos;
+  phorizon->y_pos      = y_pos;
+  phorizon->scr_width  = length;
+  phorizon->scr_hole   = hole_len;
+  phorizon->load_value = load_value;
+                                      //  Install the horizon in the parent.
+  pinstrument->instr   = phorizon;
+                                      //  Install the instrument into hud.
+  add_instrument( hud, pinstrument);
+
+  return( hud );
 }
 
-Hptr fgHUDAddHorizon( Hptr hud, int x_pos, int y_pos, int length, \
-						int hole_len, double (*load_value)() )
+// fgHUDAddScale
+//
+// Constructs a HUD_scale "object" and installs it into the hud instrument
+// list.
+
+Hptr fgHUDAddScale( Hptr hud,        \
+                    int type,        \
+                    int sub_type,    \
+                    int scr_pos,     \
+                    int scr_min,     \
+                    int scr_max,     \
+                    int div_min,     \
+                    int div_max,     \
+                    int orientation, \
+                    int with_min,    \
+                    int min_value,   \
+                    int width_units, \
+                    double (*load_value)() )
 {
-	struct HUD_horizon *horizon;
-	struct HUD_instr *instrument;
-	HIptr tmp_first, tmp_next;
-	
-	tmp_first = hud->instruments;
-	if( tmp_first != NULL )
-		tmp_next = tmp_first->next;
-	else
-		tmp_next = NULL;
-	
-	instrument = (HIptr)calloc(sizeof(struct HUD_instr),1);
-	if( instrument == NULL )
-		return( NULL );
-		
-	horizon = (struct HUD_horizon *)calloc(sizeof(struct HUD_horizon),1);
-	if( horizon == NULL )
-		return( NULL );
-	
-	instrument->type = ARTIFICIAL_HORIZON;
-	instrument->instr.horizon = *horizon;
-	instrument->instr.horizon.x_pos = x_pos;
-	instrument->instr.horizon.y_pos = y_pos;
-	instrument->instr.horizon.scr_width = length;
-	instrument->instr.horizon.scr_hole = hole_len;
-	instrument->instr.horizon.load_value = load_value;
-	instrument->next = tmp_first;
+  HUD_scale *pscale;
+  HUD_instr *pinstrument;
 
-	hud->instruments = instrument;
+  if( !hud ) {
+    return NULL;
+    }
 
-	return( hud );
-}
+	pinstrument = (HIptr)calloc(sizeof(HUD_instr),1);
+	if( pinstrument == NULL ) {
+     return( NULL );
+     }
 
-Hptr fgHUDAddScale( Hptr hud, int type, int scr_pos, int scr_min, int scr_max, int div_min, int div_max, \
-					int orientation, int with_min, int min_value, int width_units, double (*load_value)() )
-{
-	struct HUD_scale *scale;
-	struct HUD_instr *instrument;
-	HIptr tmp_first, tmp_next;
-	
-	tmp_first = hud->instruments;
-	if( tmp_first != NULL )
-		tmp_next = tmp_first->next;
-	else
-		tmp_next = NULL;
-	
-	instrument = (HIptr)calloc(sizeof(struct HUD_instr),1);
-	if( instrument == NULL )
-		return( NULL );
-		
-	scale = (struct HUD_scale *)calloc(sizeof(struct HUD_scale),1);
-	if( scale == NULL )
-		return( NULL );
-	
-	instrument->type = SCALE;
-	instrument->instr.scale = *scale;
-	instrument->instr.scale.type = type;
-	instrument->instr.scale.scr_pos = scr_pos;
-	instrument->instr.scale.scr_min = scr_min;
-	instrument->instr.scale.scr_max = scr_max;
-	instrument->instr.scale.div_min = div_min;
-	instrument->instr.scale.div_max = div_max;
-	instrument->instr.scale.orientation = orientation;
-	instrument->instr.scale.with_minimum = with_min;
-	instrument->instr.scale.minimum_value = min_value;
-	instrument->instr.scale.width_units = width_units;
-	instrument->instr.scale.load_value = load_value;
-	instrument->next = tmp_first;
-
-	hud->instruments = instrument;
+  pinstrument->type = SCALE;
 
-	return( hud );
+  pscale = ( HUD_scale *)calloc(sizeof(HUD_scale),1);
+  if( pscale == NULL )   {
+     return( NULL );
+    }
+  pscale->type          = type;
+  pscale->type          = sub_type;
+  pscale->scr_pos       = scr_pos;
+  pscale->scr_min       = scr_min;
+  pscale->scr_max       = scr_max;
+  pscale->div_min       = div_min;
+  pscale->div_max       = div_max;
+  pscale->orientation   = orientation;
+  pscale->with_minimum  = with_min;
+  pscale->minimum_value = min_value;
+  pscale->width_units   = width_units;
+  pscale->load_value    = load_value;
+                                     // Install the scale
+  pinstrument->instr = pscale;
+                                      //  Install the instrument into hud.
+  add_instrument( hud, pinstrument);
+
+  return( hud );
 }
 
-Hptr fgHUDAddLabel( Hptr hud, int x_pos, int y_pos, int size, int blink, int justify, \
-					char *pre_str, char *post_str, char *format, double (*load_value)() )
+// fgHUDAddLabel
+//
+// Constructs a HUD_Label object and installs it into the hud instrument
+// list.
+Hptr fgHUDAddLabel( Hptr hud,       \
+                    int x_pos,      \
+                    int y_pos,      \
+                    int size,       \
+                    int blink,      \
+                    int justify,    \
+					          char *pre_str,  \
+                    char *post_str, \
+                    char *format,   \
+                    double (*load_value)() )
 {
-	struct HUD_label *label;
-	struct HUD_instr *instrument;
-	HIptr tmp_first, tmp_next;
-	
-	tmp_first = hud->instruments;
-	if( tmp_first != NULL )
-		tmp_next = tmp_first->next;
-	else
-		tmp_next = NULL;
-	
-	instrument = (HIptr)calloc(sizeof(struct HUD_instr),1);
-	if( instrument == NULL )
-		return( NULL );
-		
-	label = (struct HUD_label *)calloc(sizeof(struct HUD_label),1);
-	if( label == NULL )
-		return( NULL );
-	
-	instrument->type = LABEL;
-	instrument->instr.label = *label;
-	instrument->instr.label.x_pos = x_pos;
-	instrument->instr.label.y_pos = y_pos;
-	instrument->instr.label.size = size;
-	instrument->instr.label.blink = blink;
-	instrument->instr.label.justify = justify;
-	instrument->instr.label.pre_str = pre_str;
-	instrument->instr.label.post_str = post_str;
-	instrument->instr.label.format = format;
-	instrument->instr.label.load_value = load_value;
-	instrument->next = tmp_first;
-
-	hud->instruments = instrument;
+	HUD_label *plabel;
+	HUD_instr *pinstrument;
 
-	return( hud );
-}
+  if( !hud ) {
+    return NULL;
+    }
 
-Hptr fgHUDAddLadder( Hptr hud, int x_pos, int y_pos, int scr_width, int scr_height, \
-					int hole_len, int div_units, int label_pos, int width_units, \
-					double (*load_roll)(), double (*load_pitch)() )
-{
-	struct HUD_ladder *ladder;
-	struct HUD_instr *instrument;
-	HIptr tmp_first, tmp_next;
-	
-	tmp_first = hud->instruments;
-	if( tmp_first != NULL )
-		tmp_next = tmp_first->next;
-	else
-		tmp_next = NULL;
-	
-	instrument = (HIptr)calloc(sizeof(struct HUD_instr),1);
-	if( instrument == NULL )
-		return( NULL );
-		
-	ladder = (struct HUD_ladder *)calloc(sizeof(struct HUD_ladder),1);
-	if( ladder == NULL )
-		return( NULL );
+	pinstrument = (HIptr)calloc(sizeof(HUD_instr),1);
+	if( pinstrument == NULL ) {
+    return NULL;
+    }
+	pinstrument->type = LABEL;
+
+	plabel = (HUD_label *)calloc(sizeof(HUD_label),1);
+	if( plabel == NULL ){
+    return NULL;
+    }
 
-	instrument->type = LADDER;
-	instrument->instr.ladder = *ladder;
-	instrument->instr.ladder.type = 0;	// Not used.
-	instrument->instr.ladder.x_pos = x_pos;
-	instrument->instr.ladder.y_pos = y_pos;
-	instrument->instr.ladder.scr_width = scr_width;
-	instrument->instr.ladder.scr_height = scr_height;
-	instrument->instr.ladder.scr_hole = hole_len;
-	instrument->instr.ladder.div_units = div_units;
-	instrument->instr.ladder.label_position = label_pos;
-	instrument->instr.ladder.width_units = width_units;
-	instrument->instr.ladder.load_roll = load_roll;
-	instrument->instr.ladder.load_pitch = load_pitch;
-	instrument->next = tmp_first;
-
-	hud->instruments = instrument;
+  plabel->x_pos      = x_pos;
+  plabel->y_pos      = y_pos;
+  plabel->size       = size;
+  plabel->blink      = blink;
+  plabel->justify    = justify;
+  plabel->pre_str    = pre_str;
+  plabel->post_str   = post_str;
+  plabel->format     = format;
+  plabel->load_value = load_value;
+                                      // Install the label
+	pinstrument->instr = plabel;
+                                      //  Install the instrument into hud.
+  add_instrument( hud, pinstrument);
 
 	return( hud );
 }
 
-Hptr fgHUDAddControlSurfaces( Hptr hud, int x_pos, int y_pos, double (*load_value)() )
+// fgHUDAddLadder
+//
+// Contains code that constructs a ladder "object" and installs it as
+// a hud instrument in the hud instrument list.
+//
+Hptr fgHUDAddLadder( Hptr hud,        \
+                     int x_pos,       \
+                     int y_pos,       \
+                     int scr_width,   \
+                     int scr_height,  \
+					           int hole_len,    \
+                     int div_units,   \
+                     int label_pos,   \
+                     int width_units, \
+					           double (*load_roll)(),
+                     double (*load_pitch)() )
 {
-	struct HUD_control_surfaces *ctrl_surf;
-	struct HUD_instr *instrument;
-	HIptr tmp_first, tmp_next;
-	
-	tmp_first = hud->instruments;
-	if( tmp_first != NULL )
-		tmp_next = tmp_first->next;
-	else
-		tmp_next = NULL;
-	
-	instrument = (HIptr)calloc(sizeof(struct HUD_instr),1);
-	if( instrument == NULL )
-		return( NULL );
-		
-	ctrl_surf = (struct HUD_control_surfaces *)calloc(sizeof(struct HUD_control_surfaces),1);
-	if( ctrl_surf == NULL )
+	HUD_ladder *pladder;
+	HUD_instr  *pinstrument;
+
+  if( !hud ) {
+    return NULL;
+    }
+
+	pinstrument = (HIptr)calloc(sizeof(HUD_instr),1);
+	if( pinstrument == NULL )
 		return( NULL );
-	
-	instrument->type = CONTROL_SURFACES;
-	instrument->instr.control_surfaces = *ctrl_surf;
-	instrument->instr.control_surfaces.x_pos = x_pos;
-	instrument->instr.control_surfaces.y_pos = y_pos;
-	instrument->instr.horizon.load_value = load_value;
-	instrument->next = tmp_first;
 
-	hud->instruments = instrument;
+	pinstrument->type = LADDER;
 
-	return( hud );
+	pladder = (HUD_ladder *)calloc(sizeof(HUD_ladder),1);
+	if( pladder == NULL )
+		return( NULL );
+
+  pladder->type           = 0; // Not used.
+  pladder->x_pos          = x_pos;
+  pladder->y_pos          = y_pos;
+  pladder->scr_width      = scr_width;
+  pladder->scr_height     = scr_height;
+  pladder->scr_hole       = hole_len;
+  pladder->div_units      = div_units;
+  pladder->label_position = label_pos;
+  pladder->width_units    = width_units;
+  pladder->load_roll      = load_roll;
+  pladder->load_pitch     = load_pitch;
+
+  pinstrument->instr      = pladder;
+                                      //  Install the instrument into hud.
+  add_instrument( hud, pinstrument);
+	return hud;
 }
 
 /*
-Hptr fgHUDAddMovingHorizon( Hptr hud, int x_pos, int y_pos, int length, int hole_len, \
-						int color )
+Hptr fgHUDAddMovingHorizon(  Hptr hud,     \
+                             int x_pos,    \
+                             int y_pos,    \
+                             int length,   \
+                             int hole_len, \
+                             int color )
 {
 
 }
 
-Hptr fgHUDAddCircularLadder( Hptr hud, int scr_min, int scr_max, int div_min, int div_max, \
-						int max_value )
+Hptr fgHUDAddCircularLadder( Hptr hud,    \
+                             int scr_min, \
+                             int scr_max, \
+                             int div_min, \
+                             int div_max, \
+                             int max_value )
 {
 
 }
 
-Hptr fgHUDAddNumDisp( Hptr hud, int x_pos, int y_pos, int size, int color, int blink, \
-						char *pre_str, char *post_str )
+Hptr fgHUDAddNumDisp( Hptr hud,           \
+                      int x_pos,          \
+                      int y_pos,          \
+                      int size,           \
+                      int color,          \
+                      int blink,          \
+						          char *pre_str,      \
+                      char *post_str )
 {
 
 }
 */
 
+// fgUpdateHUD
+//
+// Performs a once around the list of calls to instruments installed in
+// the HUD object with requests for redraw. Kinda. It will when this is
+// all C++.
+//
+
 void fgUpdateHUD( Hptr hud )
 {
-	HIptr hud_instr;
-	union HUD_instr_data instr_data;
-              
+	HIptr phud_instr;
+
 	glMatrixMode(GL_PROJECTION);
 	glPushMatrix();
 
@@ -878,76 +1057,67 @@ void fgUpdateHUD( Hptr hud )
 	glMatrixMode(GL_MODELVIEW);
 	glPushMatrix();
 	glLoadIdentity();
-         
+
 	glColor3f(1.0, 1.0, 1.0);
 	glIndexi(7);
-              
+
 	glDisable(GL_DEPTH_TEST);
 	glDisable(GL_LIGHTING);
-                  
+
 	glLineWidth(1);
 	glColor3f (0.1, 0.9, 0.1);
-                      
-    fgPrintf( FG_COCKPIT, FG_DEBUG,  "HUD Code %d  Status %d\n", 
-	      hud->code, hud->status ); 
-    hud_instr = hud->instruments;
-	while( hud_instr != NULL )
-	{
-		instr_data = hud_instr->instr;
-		fgPrintf( FG_COCKPIT, FG_DEBUG, 
-			  "Instr Type %d   SubType %d  Orient %d\n", 
-			  hud_instr->type, hud_instr->sub_type, hud_instr->orientation );
-		if( hud_instr->type == ARTIFICIAL_HORIZON )
-		{
-			drawhorizon( instr_data.horizon );
-		  	/* drawhorizon( instr_data.horizon.x_pos, instr_data.horizon.y_pos, \
-    				instr_data.horizon.scr_width, instr_data.horizon.scr_hole ); */
-    	}
-    	else if( hud_instr->type == SCALE )
-    	{
-    		drawscale( instr_data.scale.type, instr_data.scale.with_minimum, \
-    				instr_data.scale.minimum_value, instr_data.scale.orientation, \
-    				instr_data.scale.scr_pos, instr_data.scale.scr_min, \
-    				instr_data.scale.scr_max, instr_data.scale.width_units, \
-    				instr_data.scale.div_min, instr_data.scale.div_max, \
-					(*instr_data.scale.load_value)() );     				
-    	}
-    	else if( hud_instr->type == CONTROL_SURFACES )
-    	{
-    		drawcontrolsurfaces( instr_data.control_surfaces );
-    	}
-    	else if( hud_instr->type == LABEL )
-    	{
-    		drawlabel( instr_data.label );
-    		/* drawlabel( instr_data.label.x_pos, instr_data.label.y_pos, instr_data.label.size, \
-    				instr_data.label.blink, instr_data.label.pre_str, instr_data.label.post_str, \
-    				instr_data.label.format, (*instr_data.label.load_value)() ); */
-    	}
-    	else if( hud_instr->type == LADDER )
-    	{
-    		drawladder( instr_data.ladder );
-    	}
-    	hud_instr = hud_instr->next;
+
+  fgPrintf( FG_COCKPIT, FG_DEBUG,
+            "HUD Code %d  Status %d\n",
+            hud->code, hud->status );
+
+  phud_instr = hud->instruments;
+  while( phud_instr ) 	{
+    switch (phud_instr->type){
+		  case HUDhorizon:                  // ARTIFICIAL HORIZON
+        drawhorizon( (pHUDhorizon)phud_instr );
+    	  break;
+
+    	case HUDscale:                  // Need to simplify this call.
+        drawscale (  (pHUDscale)  phud_instr  );
+        break;
+
+      case HUDlabel:
+        drawlabel (  (pHUDlabel)  phud_instr  );
+        break;
+
+    	case HUDladder:
+    		drawladder(  (pHUDladder) phud_instr  );
+        break;
+
+      case HUDcontrols:
+        drawControlSurfaces( (pHUDControlSurface) phud_instr );
+      default:; // Ignore anything you don't know about.
+      }
+   	phud_instr = phud_instr->next;
     }
-    
-    
+
 	glEnable(GL_DEPTH_TEST);
 	glEnable(GL_LIGHTING);
 	glMatrixMode(GL_PROJECTION);
 	glPopMatrix();
 	glMatrixMode(GL_MODELVIEW);
 	glPopMatrix();
-                
+
 }
 
 
 /* $Log$
-/* Revision 1.10  1998/02/03 23:20:14  curt
-/* Lots of little tweaks to fix various consistency problems discovered by
-/* Solaris' CC.  Fixed a bug in fg_debug.c with how the fgPrintf() wrapper
-/* passed arguments along to the real printf().  Also incorporated HUD changes
-/* by Michele America.
+/* Revision 1.11  1998/02/07 15:29:34  curt
+/* Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss
+/* <chotchkiss@namg.us.anritsu.com>
 /*
+ * Revision 1.10  1998/02/03 23:20:14  curt
+ * Lots of little tweaks to fix various consistency problems discovered by
+ * Solaris' CC.  Fixed a bug in fg_debug.c with how the fgPrintf() wrapper
+ * passed arguments along to the real printf().  Also incorporated HUD changes
+ * by Michele America.
+ *
  * Revision 1.9  1998/01/31 00:43:04  curt
  * Added MetroWorks patches from Carmen Volpe.
  *