From 746024becd62c8605522dfb1c928c47915117519 Mon Sep 17 00:00:00 2001
From: Klaus Basan <klaus.basan@klausbasan.de>
Date: Sun, 17 Jun 2018 00:38:39 +0200
Subject: [PATCH] Ref T275, use extrapolate for new situations in airspace
 monitor and provider

---
 src/blackcore/airspacemonitor.cpp             | 14 ++++++++-
 .../simulation/remoteaircraftprovider.cpp     | 29 ++++++++-----------
 2 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/src/blackcore/airspacemonitor.cpp b/src/blackcore/airspacemonitor.cpp
index 1d1903472..dc7cc0275 100644
--- a/src/blackcore/airspacemonitor.cpp
+++ b/src/blackcore/airspacemonitor.cpp
@@ -943,10 +943,22 @@ namespace BlackCore
         CAircraftSituation correctedSituation(this->testAddAltitudeOffsetToSituation(situation));
         if (!correctedSituation.hasGroundElevation() && !correctedSituation.canLikelySkipNearGroundInterpolation())
         {
-            const CLength distance(correctedSituation.getDistancePerTime(250)); // distnacee per ms
+            // fetch from cache or request
+            const CLength distance(correctedSituation.getDistancePerTime250ms()); // distnacee per ms
             const CElevationPlane ep = this->findClosestElevationWithinRangeOrRequest(correctedSituation, distance, callsign);
             Q_ASSERT_X(ep.isNull() || !ep.getRadius().isNull(), Q_FUNC_INFO, "null radius");
             correctedSituation.setGroundElevation(ep, CAircraftSituation::FromCache);
+            if (!correctedSituation.hasGroundElevation())
+            {
+                // values before updating
+                const CAircraftSituationList oldSituations = this->remoteAircraftSituations(callsign);
+                const CAircraftSituationChangeList oldChanges = this->remoteAircraftSituationChanges(callsign);
+                if (oldSituations.size() > 1)
+                {
+                    const bool extrapolated = correctedSituation.extrapolateElevation(oldSituations[0], oldSituations[1], oldChanges.frontOrDefault());
+                    Q_UNUSED(extrapolated);
+                }
+            }
         }
 
         // do we already have ground details?
diff --git a/src/blackmisc/simulation/remoteaircraftprovider.cpp b/src/blackmisc/simulation/remoteaircraftprovider.cpp
index 7fc8d513c..159b7d4cc 100644
--- a/src/blackmisc/simulation/remoteaircraftprovider.cpp
+++ b/src/blackmisc/simulation/remoteaircraftprovider.cpp
@@ -219,12 +219,14 @@ namespace BlackMisc
             }
 
             // list from new to old
+            CAircraftSituationList updatedSituations; // copy of updated situations
             {
                 const qint64 ts = QDateTime::currentMSecsSinceEpoch();
                 QWriteLocker lock(&m_lockSituations);
                 m_situationsAdded++;
                 m_situationsLastModified[cs] = ts;
                 CAircraftSituationList &newSituationsList = m_situationsByCallsign[cs];
+                newSituationsList.setAdjustedSortHint(CAircraftSituationList::AdjustedTimestampLatestFirst);
                 const int situations = newSituationsList.size();
                 if (situations < 1)
                 {
@@ -232,9 +234,9 @@ namespace BlackMisc
                 }
                 else
                 {
-                    newSituationsList.front().transferGroundElevation(situationCorrected); // transfer last situation elevation if possible
                     newSituationsList.push_frontKeepLatestFirstAdjustOffset(situationCorrected, true, IRemoteAircraftProvider::MaxSituationsPerCallsign);
                     newSituationsList.setAdjustedSortHint(CAircraftSituationList::AdjustedTimestampLatestFirst);
+                    newSituationsList.transferElevationForward(); // transfer elevations
 
                     // unify all inbound ground information
                     if (situation.hasInboundGroundDetails())
@@ -249,25 +251,18 @@ namespace BlackMisc
                     BLACK_VERIFY_X(newSituationsList.isSortedAdjustedLatestFirstWithoutNullPositions(), Q_FUNC_INFO, "wrong sort order");
                     BLACK_VERIFY_X(newSituationsList.size() <= IRemoteAircraftProvider::MaxSituationsPerCallsign, Q_FUNC_INFO, "Wrong size");
                 }
-            } // lock
 
-            CAircraftSituationList updatedSituations; // copy of updated situations
-            if (situation.hasInboundGroundDetails())
-            {
-                QReadLocker lock(&m_lockSituations);
+                if (!situation.hasInboundGroundDetails())
+                {
+                    // first use a version without standard deviations to guess "on ground
+                    const CAircraftSituationChange simpleChange(updatedSituations, situationCorrected.getCG(), aircraftModel.isVtol(), true, false);
+
+                    // guess GND
+                    newSituationsList.front().guessOnGround(simpleChange, aircraftModel);
+                }
                 updatedSituations = m_situationsByCallsign[cs];
-            }
-            else
-            {
-                // first use a version without standard deviations to guess "on ground
-                const CAircraftSituationChange simpleChange(updatedSituations, situationCorrected.getCG(), aircraftModel.isVtol(), true, false);
 
-                // guess GND
-                QWriteLocker lock(&m_lockSituations);
-                CAircraftSituationList &fixedSituationList = m_situationsByCallsign[cs];
-                fixedSituationList.front().guessOnGround(simpleChange, aircraftModel);
-                updatedSituations = fixedSituationList;
-            }
+            } // lock
 
             // calculate change AFTER gnd. was guessed
             Q_ASSERT_X(!updatedSituations.isEmpty(), Q_FUNC_INFO, "Missing situations");