Fix #16791: rotodrop top piece is replicated (#19970)

* Fix rotodrop top piece replication issue (#16791)

* Add changelog entry

* Raise network version

* Move changelog entry

contributors.md

@@ -219,6 +219,7 @@ The following people are not part of the development team, but have been contrib
 * Joel H. (HtotheTML)
 * John Mulcahy (jayjay300)
 * Chase Percy (Chase-Percy)
+* Wenzhao Qiu (qwzhaox)
 
 ## Toolchain
 * (Balletie) - macOS

distribution/changelog.txt

@@ -15,6 +15,7 @@
 - Improved: [#19953] Add keyboard shortcut to Keyboard Shortcuts window.
 - Fix: [#12598] Number of holes is not set correctly when saving track designs.
 - Fix: [#13130] Android always defaulting to UK locale for language, currency and temperature.
+- Fix: [#16791] Rotodrop top piece replicates when walls are placed around it and clearance checks are disabled (original bug).
 - Fix: [#18895] Responding mechanic blocked at level crossing.
 - Fix: [#19231] Crash due to null pointer to previously deleted banner in tile copy/paste functionality
 - Fix: [#19296] Crash due to a race condition for parallel object loading.

src/openrct2/ride/thrill/RotoDrop.cpp

@@ -186,6 +186,12 @@ static void PaintRotoDropTowerSection(
     PaintAddImageAsParent(session, imageId, { 0, 0, height }, { { 8, 8, height }, { 2, 2, 30 } });
 
     const TileElement* nextTileElement = reinterpret_cast<const TileElement*>(&trackElement) + 1;
+
+    while (nextTileElement->GetType() != TileElementType::Track && !nextTileElement->IsLastForTile())
+    {
+        nextTileElement++;
+    }
+
     if (trackElement.IsLastForTile() || trackElement.GetClearanceZ() != nextTileElement->GetBaseZ())
     {
         imageId = session.TrackColours[SCHEME_TRACK].WithIndex(SPR_ROTO_DROP_TOWER_SEGMENT_TOP);