From df263eb1f6c08aa4f693a57b5a0fbdd4034d5c2f Mon Sep 17 00:00:00 2001
From: aw20368 <aw20368@gmail.com>
Date: Tue, 4 Jun 2019 17:27:36 -0400
Subject: [PATCH] Fix #5896 Fences not always removed when building a tracked
 ride through (#9341)

Fence removal did not account for track direction. Added the rotation for the track/fence intersection test.
---
 distribution/changelog.txt                |  1 +
 src/openrct2/actions/TrackPlaceAction.hpp |  1 +
 src/openrct2/core/Numerics.hpp            | 24 +++++++++++++++++++++++
 src/openrct2/network/Network.cpp          |  2 +-
 4 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/distribution/changelog.txt b/distribution/changelog.txt
index 421d6fadca..ecee6c3e2b 100644
--- a/distribution/changelog.txt
+++ b/distribution/changelog.txt
@@ -16,6 +16,7 @@
 - Change: [#8427] Ghost elements now show up as white on the mini-map.
 - Change: [#8688] Move common actions from debug menu into cheats menu.
 - Fix: [#2294] Clients crashing the server with invalid object selection.
+- Fix: [#4568, #5896] Incorrect fences removed when building a tracked ride through
 - Fix: [#5103] OpenGL: ride track preview not rendered.
 - Fix: [#5889] Giant screenshot does not work while using OpenGL renderer.
 - Fix: [#5579] Network desync immediately after connecting.
diff --git a/src/openrct2/actions/TrackPlaceAction.hpp b/src/openrct2/actions/TrackPlaceAction.hpp
index d55e38745f..ef8e7c9443 100644
--- a/src/openrct2/actions/TrackPlaceAction.hpp
+++ b/src/openrct2/actions/TrackPlaceAction.hpp
@@ -491,6 +491,7 @@ public:
                     // Remove walls in the directions this track intersects
                     uint8_t intersectingDirections = (*wallEdges)[blockIndex];
                     intersectingDirections ^= 0x0F;
+                    intersectingDirections = rol4(intersectingDirections, _origin.direction);
                     for (int32_t i = 0; i < 4; i++)
                     {
                         if (intersectingDirections & (1 << i))
diff --git a/src/openrct2/core/Numerics.hpp b/src/openrct2/core/Numerics.hpp
index 4de93adfd8..e699e0c8a0 100644
--- a/src/openrct2/core/Numerics.hpp
+++ b/src/openrct2/core/Numerics.hpp
@@ -30,6 +30,18 @@ namespace Numerics
         return (((_UIntType)(x) << shift) | ((_UIntType)(x) >> (limits::digits - shift)));
     }
 
+    /**
+     * Bitwise left rotate of lowest 4 bits
+     * @param x unsigned 8-bit integer value
+     * @param shift positions to shift
+     * @return rotated value
+     */
+    [[maybe_unused]] static constexpr uint8_t rol4(uint8_t x, size_t shift)
+    {
+        x &= 0x0F;
+        return (x << shift | x >> (4 - shift)) & 0x0F;
+    }
+
     /**
      * Bitwise right rotate
      * @tparam _UIntType unsigned integral type
@@ -44,4 +56,16 @@ namespace Numerics
         return (((_UIntType)(x) >> shift) | ((_UIntType)(x) << (limits::digits - shift)));
     }
 
+    /**
+     * Bitwise right rotate of lowest 4 bits
+     * @param x unsigned 8-bit integer value
+     * @param shift positions to shift
+     * @return rotated value
+     */
+    [[maybe_unused]] static constexpr uint8_t ror4(uint8_t x, size_t shift)
+    {
+        x &= 0x0F;
+        return (x >> shift | x << (4 - shift)) & 0x0F;
+    }
+
 } // namespace Numerics
diff --git a/src/openrct2/network/Network.cpp b/src/openrct2/network/Network.cpp
index 4bc9502f69..cdb314d5c9 100644
--- a/src/openrct2/network/Network.cpp
+++ b/src/openrct2/network/Network.cpp
@@ -33,7 +33,7 @@
 // This string specifies which version of network stream current build uses.
 // It is used for making sure only compatible builds get connected, even within
 // single OpenRCT2 version.
-#define NETWORK_STREAM_VERSION "36"
+#define NETWORK_STREAM_VERSION "37"
 #define NETWORK_STREAM_ID OPENRCT2_VERSION "-" NETWORK_STREAM_VERSION
 
 static Peep* _pickup_peep = nullptr;