From 88c2b7a833cc478035247fd72814d1d74ea0dc24 Mon Sep 17 00:00:00 2001
From: Erik Hofman <erik@ehofman.com>
Date: Wed, 30 Sep 2020 15:39:30 +0200
Subject: [PATCH] Make LaRCsim work again when UIUC is dissabled. Unfortunately
 only the c172 seems to be stable. The Navion and Cherokee fail to trim at the
 runway.

---
 src/FDM/LaRCsim/LaRCsim.cxx |  9 +++++++--
 src/FDM/LaRCsim/ls_model.c  |  2 ++
 src/FDM/LaRCsim/ls_step.c   | 12 ++++++++----
 src/FDM/LaRCsim/uiuc_aero.c |  3 +++
 4 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/FDM/LaRCsim/LaRCsim.cxx b/src/FDM/LaRCsim/LaRCsim.cxx
index deba568ab..512fa397e 100644
--- a/src/FDM/LaRCsim/LaRCsim.cxx
+++ b/src/FDM/LaRCsim/LaRCsim.cxx
@@ -34,9 +34,11 @@
 
 #include <Aircraft/controls.hxx>
 #include <FDM/flight.hxx>
-#include <FDM/UIUCModel/uiuc_aircraft.h>
 #include <Main/fg_props.hxx>
 #include <Model/acmodel.hxx>
+#if ENABLE_UIUC_MODEL
+# include <FDM/UIUCModel/uiuc_aircraft.h>
+#endif
 
 #include "ls_cockpit.h"
 #include "ls_generic.h"
@@ -317,6 +319,7 @@ void FGLaRCsim::update( double dt ) {
     fgSetDouble("/engines/engine/running", 1);
 
     // if flying uiuc, set some properties and over-ride some previous ones
+#if ENABLE_UIUC_MODEL
     if ( !strcmp(aero->getStringValue(), "uiuc")) {
 
       // surface positions and other general properties
@@ -408,7 +411,6 @@ void FGLaRCsim::update( double dt ) {
       }
     }
 
-
     // add Gamma_horiz_deg to properties, mss 021213
     if (use_gamma_horiz_on_speed) {
       if (V_rel_wind > gamma_horiz_on_speed) {
@@ -421,6 +423,7 @@ void FGLaRCsim::update( double dt ) {
     else {
       fgSetDouble("/orientation/gamma-horiz-deg",  fgGetDouble("/orientation/heading-deg"));
     }
+#endif // ENABLE_UIUC_MODEL
     ls_update(multiloop);
 
     // printf("%d FG_Altitude = %.2f\n", i, FG_Altitude * 0.3048);
@@ -757,6 +760,7 @@ bool FGLaRCsim::copy_from_LaRCsim() {
     _set_Climb_Rate( -1 * V_down );
     // cout << "climb rate = " << -V_down * 60 << endl;
 
+#if ENABLE_UIUC_MODEL
     if ( !strcmp(aero->getStringValue(), "uiuc") ) {
         if (pilot_elev_no) {
             globals->get_controls()->set_elevator(Long_control);
@@ -777,6 +781,7 @@ bool FGLaRCsim::copy_from_LaRCsim() {
             //          controls.set_throttle(0,Throttle_pct);
         }
     }
+#endif
 
     return true;
 }
diff --git a/src/FDM/LaRCsim/ls_model.c b/src/FDM/LaRCsim/ls_model.c
index 912f54e57..7446a5770 100644
--- a/src/FDM/LaRCsim/ls_model.c
+++ b/src/FDM/LaRCsim/ls_model.c
@@ -204,6 +204,7 @@ void ls_model( SCALAR dt, int Initialize ) {
       basic_gear( dt, Initialize );
       break;
     case UIUC:
+#if ENABLE_UIUC_MODEL
       inertias( dt, Initialize );
       subsystems( dt, Initialize );
       // During initialization period, re-initialize velocities
@@ -216,6 +217,7 @@ void ls_model( SCALAR dt, int Initialize ) {
       uiuc_gear_2_wrapper( dt, Initialize );
       uiuc_network_send_2_wrapper();
       uiuc_record_2_wrapper(dt);
+#endif
       break;
     }
 }
diff --git a/src/FDM/LaRCsim/ls_step.c b/src/FDM/LaRCsim/ls_step.c
index cbfd36cf5..b836ac54b 100644
--- a/src/FDM/LaRCsim/ls_step.c
+++ b/src/FDM/LaRCsim/ls_step.c
@@ -297,8 +297,6 @@ Initial Flight Gear revision.
 
 --------------------------------------------------------------------------*/
 
-#include "FDM/UIUCModel/uiuc_wrapper.h"
-
 #include "ls_types.h"
 #include "ls_constants.h"
 #include "ls_generic.h"
@@ -315,6 +313,9 @@ Initial Flight Gear revision.
 extern Model current_model;        /* defined in ls_model.c */
 extern SCALAR Simtime;                /* defined in ls_main.c */
 
+#if ENABLE_UIUC_MODEL
+# include "FDM/UIUCModel/uiuc_wrapper.h"
+
 void uiuc_init_vars() {
     static int init = 0;
 
@@ -325,7 +326,7 @@ void uiuc_init_vars() {
 
     uiuc_initial_init();
 }
-
+#endif
 
 void ls_step( SCALAR dt, int Initialize ) {
         static        int        inited = 0;
@@ -366,10 +367,11 @@ void ls_step( SCALAR dt, int Initialize ) {
 
 /* Initialize quaternions and transformation matrix from Euler angles */
         // Initialize UIUC aircraft model
+#if ENABLE_UIUC_MODEL
         if (current_model == UIUC) {
           uiuc_init_2_wrapper();
         }
-
+#endif
             e_0 = cos(Psi*0.5)*cos(Theta*0.5)*cos(Phi*0.5) 
                 + sin(Psi*0.5)*sin(Theta*0.5)*sin(Phi*0.5);
             e_1 = cos(Psi*0.5)*cos(Theta*0.5)*sin(Phi*0.5) 
@@ -388,11 +390,13 @@ void ls_step( SCALAR dt, int Initialize ) {
             T_local_to_body_32 = 2*(e_2*e_3 - e_0*e_1);
             T_local_to_body_33 = e_0*e_0 - e_1*e_1 - e_2*e_2 + e_3*e_3;
 
+#ifdef ENABLE_UIUC_MODEL
             // Initialize local velocities (V_north, V_east, V_down)
             // based on transformation matrix calculated above
             if (current_model == UIUC) {
               uiuc_local_vel_init();
             }
+#endif
 
 /*        Calculate local gravitation acceleration        */
 
diff --git a/src/FDM/LaRCsim/uiuc_aero.c b/src/FDM/LaRCsim/uiuc_aero.c
index 57a9bc7c8..925f4ae79 100644
--- a/src/FDM/LaRCsim/uiuc_aero.c
+++ b/src/FDM/LaRCsim/uiuc_aero.c
@@ -53,6 +53,7 @@
 
 --------------------------------------------------------------------------*/
 
+#if ENABLE_UIUC_MODEL
 
 #include <math.h>
 #include "ls_types.h"
@@ -121,3 +122,5 @@ void uiuc_network_send_2_wrapper()
 {
   uiuc_network_send_routine();
 }
+
+#endif // ENABLE_UIUC_MODEL