From ca13c2194348fc703b3a9f3f573aeac7e04e9da7 Mon Sep 17 00:00:00 2001
From: Klaus Basan <klaus.basan@klausbasan.de>
Date: Sun, 21 Jan 2018 19:38:57 +0100
Subject: [PATCH] Ref T231, utility functions

* corrected altitude also considering CG
* 0 if CG is NULL
---
 src/blackmisc/aviation/aircraftsituation.cpp    | 10 ++++++----
 src/blackmisc/aviation/aircraftsituation.h      |  2 +-
 src/blackmisc/simulation/interpolationhints.cpp |  6 ++++++
 src/blackmisc/simulation/interpolationhints.h   |  3 +++
 4 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/blackmisc/aviation/aircraftsituation.cpp b/src/blackmisc/aviation/aircraftsituation.cpp
index e87abaea0..2f20b4387 100644
--- a/src/blackmisc/aviation/aircraftsituation.cpp
+++ b/src/blackmisc/aviation/aircraftsituation.cpp
@@ -214,11 +214,13 @@ namespace BlackMisc
             return this->getAltitude() - gh;
         }
 
-        CAltitude CAircraftSituation::getCorrectedAltitude() const
+        CAltitude CAircraftSituation::getCorrectedAltitude(const CLength &centerOfGravity) const
         {
-            if (this->getGroundElevation().isNull()) { return this->getAltitude(); }
-            if (this->getAltitude().getReferenceDatum() != CAltitude::MeanSeaLevel) { return this->getAltitude(); }
-            if (this->getGroundElevation() < this->getAltitude()) { return this->getAltitude(); }
+            CAltitude altPlusCG = this->getAltitude();
+            if (!centerOfGravity.isNull()) { altPlusCG += centerOfGravity; }
+            if (this->getGroundElevation().isNull()) { return altPlusCG; }
+            if (this->getAltitude().getReferenceDatum() != CAltitude::MeanSeaLevel) { return altPlusCG; }
+            if (this->getGroundElevation() < this->getAltitude()) { return altPlusCG; }
             return this->getGroundElevation();
         }
 
diff --git a/src/blackmisc/aviation/aircraftsituation.h b/src/blackmisc/aviation/aircraftsituation.h
index a8a22b4fc..39ace5c7e 100644
--- a/src/blackmisc/aviation/aircraftsituation.h
+++ b/src/blackmisc/aviation/aircraftsituation.h
@@ -182,7 +182,7 @@ namespace BlackMisc
             const CAltitude &getAltitude() const { return m_position.geodeticHeight(); }
 
             //! Get altitude under consideration of ground elevation
-            CAltitude getCorrectedAltitude() const;
+            CAltitude getCorrectedAltitude(const PhysicalQuantities::CLength &centerOfGravity = {}) const;
 
             //! Set altitude
             void setAltitude(const CAltitude &altitude) { m_position.setGeodeticHeight(altitude); }
diff --git a/src/blackmisc/simulation/interpolationhints.cpp b/src/blackmisc/simulation/interpolationhints.cpp
index 8dae07e73..cabe8ba5e 100644
--- a/src/blackmisc/simulation/interpolationhints.cpp
+++ b/src/blackmisc/simulation/interpolationhints.cpp
@@ -45,6 +45,12 @@ namespace BlackMisc
             return m_elevationPlane.isWithinRange(coordinate);
         }
 
+        const CLength &CInterpolationHints::getCGAboveGroundOrZero() const
+        {
+            static const CLength zero;
+            return this->hasCGAboveGround() ? this->getCGAboveGround() : zero;
+        }
+
         void CInterpolationHints::setAircraftParts(const CAircraftParts &parts, bool hasParts)
         {
             m_hasParts = hasParts;
diff --git a/src/blackmisc/simulation/interpolationhints.h b/src/blackmisc/simulation/interpolationhints.h
index c28770ac1..b4534edb1 100644
--- a/src/blackmisc/simulation/interpolationhints.h
+++ b/src/blackmisc/simulation/interpolationhints.h
@@ -66,6 +66,9 @@ namespace BlackMisc
             //! Get CG above ground
             const PhysicalQuantities::CLength &getCGAboveGround() const { return m_cgAboveGround;}
 
+            //! Get CG above ground or 0 ("Zero")
+            const PhysicalQuantities::CLength &getCGAboveGroundOrZero() const;
+
             //! Has CG above ground
             bool hasCGAboveGround() const { return m_cgAboveGround.isNull(); }