From 731275613a38e4554ae49a17d789156ec030d932 Mon Sep 17 00:00:00 2001
From: Gymnasiast <m.o.steenbeek@gmail.com>
Date: Tue, 30 Jan 2024 01:34:00 +0100
Subject: [PATCH] Create flag to allow building track segment partly
 underground

---
 src/openrct2/actions/TrackPlaceAction.cpp | 22 ++++++++++++++--------
 src/openrct2/ride/Track.h                 |  1 +
 src/openrct2/ride/TrackData.cpp           |  2 +-
 src/openrct2/ride/TrackData.h             |  2 +-
 4 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/src/openrct2/actions/TrackPlaceAction.cpp b/src/openrct2/actions/TrackPlaceAction.cpp
index 5a63658df6..8001ac381e 100644
--- a/src/openrct2/actions/TrackPlaceAction.cpp
+++ b/src/openrct2/actions/TrackPlaceAction.cpp
@@ -265,11 +265,14 @@ GameActions::Result TrackPlaceAction::Query() const
 
         const auto clearanceData = canBuild.GetData<ConstructClearResult>();
         uint8_t mapGroundFlags = clearanceData.GroundFlags & (ELEMENT_IS_ABOVE_GROUND | ELEMENT_IS_UNDERGROUND);
-        if (resultData.GroundFlags != 0 && (resultData.GroundFlags & mapGroundFlags) == 0)
+        if (!(ted.Flags & TRACK_ELEM_FLAG_CAN_BE_PARTLY_UNDERGROUND))
         {
-            return GameActions::Result(
-                GameActions::Status::Disallowed, STR_RIDE_CONSTRUCTION_CANT_CONSTRUCT_THIS_HERE,
-                STR_CANT_BUILD_PARTLY_ABOVE_AND_PARTLY_BELOW_GROUND);
+            if (resultData.GroundFlags != 0 && (resultData.GroundFlags & mapGroundFlags) == 0)
+            {
+                return GameActions::Result(
+                    GameActions::Status::Disallowed, STR_RIDE_CONSTRUCTION_CANT_CONSTRUCT_THIS_HERE,
+                    STR_CANT_BUILD_PARTLY_ABOVE_AND_PARTLY_BELOW_GROUND);
+            }
         }
 
         resultData.GroundFlags = mapGroundFlags;
@@ -508,11 +511,14 @@ GameActions::Result TrackPlaceAction::Execute() const
 
         const auto clearanceData = canBuild.GetData<ConstructClearResult>();
         uint8_t mapGroundFlags = clearanceData.GroundFlags & (ELEMENT_IS_ABOVE_GROUND | ELEMENT_IS_UNDERGROUND);
-        if (resultData.GroundFlags != 0 && (resultData.GroundFlags & mapGroundFlags) == 0)
+        if (!(ted.Flags & TRACK_ELEM_FLAG_CAN_BE_PARTLY_UNDERGROUND))
         {
-            return GameActions::Result(
-                GameActions::Status::Disallowed, STR_RIDE_CONSTRUCTION_CANT_CONSTRUCT_THIS_HERE,
-                STR_CANT_BUILD_PARTLY_ABOVE_AND_PARTLY_BELOW_GROUND);
+            if (resultData.GroundFlags != 0 && (resultData.GroundFlags & mapGroundFlags) == 0)
+            {
+                return GameActions::Result(
+                    GameActions::Status::Disallowed, STR_RIDE_CONSTRUCTION_CANT_CONSTRUCT_THIS_HERE,
+                    STR_CANT_BUILD_PARTLY_ABOVE_AND_PARTLY_BELOW_GROUND);
+            }
         }
 
         resultData.GroundFlags = mapGroundFlags;
diff --git a/src/openrct2/ride/Track.h b/src/openrct2/ride/Track.h
index 3020e6e258..4a7b9bc6a5 100644
--- a/src/openrct2/ride/Track.h
+++ b/src/openrct2/ride/Track.h
@@ -259,6 +259,7 @@ enum
     TRACK_ELEM_FLAG_CURVE_ALLOWS_LIFT = (1 << 13),
     TRACK_ELEM_FLAG_INVERSION_TO_NORMAL = (1 << 14),
     TRACK_ELEM_FLAG_BANKED = (1 << 15), // Also set on Spinning Tunnel and Log Flume reverser, probably to save a flag.
+    TRACK_ELEM_FLAG_CAN_BE_PARTLY_UNDERGROUND = (1 << 16),
 };
 
 namespace TrackElemType
diff --git a/src/openrct2/ride/TrackData.cpp b/src/openrct2/ride/TrackData.cpp
index cd0bc5c00b..26ce6305d4 100644
--- a/src/openrct2/ride/TrackData.cpp
+++ b/src/openrct2/ride/TrackData.cpp
@@ -5956,7 +5956,7 @@ static constexpr uint8_t TrackSequenceElementAllowedWallEdges[][MaxSequencesPerP
 static_assert(std::size(TrackSequenceElementAllowedWallEdges) == TrackElemType::Count);
 
 /** rct2: 0x0099423C */
-static constexpr uint16_t TrackFlags[] = {
+static constexpr uint32_t TrackFlags[] = {
     /* TrackElemType::Flat                                          */   TRACK_ELEM_FLAG_ALLOW_LIFT_HILL,
     /* TrackElemType::EndStation                                    */   0,
     /* TrackElemType::BeginStation                                  */   0,
diff --git a/src/openrct2/ride/TrackData.h b/src/openrct2/ride/TrackData.h
index e9e796cd90..a4f432a8d5 100644
--- a/src/openrct2/ride/TrackData.h
+++ b/src/openrct2/ride/TrackData.h
@@ -87,7 +87,7 @@ struct TrackElementDescriptor
     uint32_t PriceModifier;
     track_type_t MirrorElement;
     uint32_t HeightMarkerPositions;
-    uint16_t Flags;
+    uint32_t Flags;
 
     std::array<uint8_t, MaxSequencesPerPiece> SequenceElementAllowedWallEdges;
     std::array<uint8_t, MaxSequencesPerPiece> SequenceProperties;