diff --git a/TR5Main/Game/floordata.cpp b/TR5Main/Game/floordata.cpp
index 8128399fb..85c69f86a 100644
--- a/TR5Main/Game/floordata.cpp
+++ b/TR5Main/Game/floordata.cpp
@@ -2,41 +2,163 @@
 #include "trmath.h"
 #include "floordata.h"
 #include "room.h"
+#include "level.h"
 
-SECTOR_POSITION FLOOR_INFO::GetSectorPosition(ROOM_INFO* room, int x, int z)
+VectorInt2 FLOOR_INFO::GetRoomPosition(int roomNumber, int x, int z)
 {
-	SECTOR_POSITION pos;
-
-	pos.x = (z - room->z) / WALL_SIZE;
-	pos.y = (x - room->x) / WALL_SIZE;
+	auto& room = g_Level.Rooms[roomNumber];
+	auto xRoom = (x - room.x) / WALL_SIZE;
+	auto zRoom = (z - room.z) / WALL_SIZE;
+	auto pos = VectorInt2{xRoom, zRoom};
 
 	if (pos.x < 0)
 	{
 		pos.x = 0;
 	}
-	else if (pos.x > room->xSize - 1)
+	else if (pos.x > room.xSize - 1)
 	{
-		pos.x = room->xSize - 1;
+		pos.x = room.xSize - 1;
 	}
 
 	if (pos.y < 0)
 	{
 		pos.y = 0;
 	}
-	else if (pos.y > room->ySize - 1)
+	else if (pos.y > room.ySize - 1)
 	{
-		pos.y = room->ySize - 1;
+		pos.y = room.ySize - 1;
 	}
 
 	return pos;
 }
 
-FLOOR_INFO& FLOOR_INFO::GetFloor(ROOM_INFO* room, int x, int z)
+FLOOR_INFO& FLOOR_INFO::GetFloor(int roomNumber, VectorInt2 pos)
 {
-	return GetFloor(room, GetSectorPosition(room, x, z));
+	auto& room = g_Level.Rooms[roomNumber];
+	return room.floor[pos.x + room.xSize * pos.y];
 }
 
-FLOOR_INFO& FLOOR_INFO::GetFloor(ROOM_INFO* room, SECTOR_POSITION pos)
+FLOOR_INFO& FLOOR_INFO::GetFloor(int roomNumber, int x, int z)
 {
-	return room->floor[pos.x + pos.y * room->xSize];
+	return GetFloor(roomNumber, GetRoomPosition(roomNumber, x, z));
+}
+
+int FLOOR_INFO::GetBottomRoom(int startRoomNumber, int x, int z)
+{
+	auto roomNumber = startRoomNumber;
+	auto roomBelow = GetFloor(roomNumber, x, z).RoomBelow(x, z);
+
+	while (roomBelow)
+	{
+		roomNumber = *roomBelow;
+		roomBelow = GetFloor(roomNumber, x, z).RoomBelow(x, z);
+	}
+
+	return roomNumber;
+}
+
+int FLOOR_INFO::GetTopRoom(int startRoomNumber, int x, int z)
+{
+	auto roomNumber = startRoomNumber;
+	auto roomAbove = GetFloor(roomNumber, x, z).RoomAbove(x, z);
+
+	while (roomAbove)
+	{
+		roomNumber = *roomAbove;
+		roomAbove = GetFloor(roomNumber, x, z).RoomAbove(x, z);
+	}
+
+	return roomNumber;
+}
+
+int FLOOR_INFO::GetRoom(int startRoomNumber, int x, int y, int z)
+{
+	auto roomNumber = startRoomNumber;
+	auto pos = GetRoomPosition(roomNumber, x, z);
+	auto& room = g_Level.Rooms[roomNumber];
+	auto floor = GetFloor(roomNumber, pos);
+
+	if (pos.x > 0 && pos.y > 0 && pos.x < room.xSize - 1 && pos.y < room.ySize - 1)
+	{
+		if (y > floor.FloorHeight(x, z))
+		{
+			auto roomBelow = floor.RoomBelow(x, z);
+			if (roomBelow)
+				roomNumber = *roomBelow;
+		}
+		else if (y < floor.CeilingHeight(x, z))
+		{
+			auto roomAbove = floor.RoomAbove(x, z);
+			if (roomAbove)
+				roomNumber = *roomAbove;
+		}
+	}
+	else
+	{
+		auto roomSide = floor.RoomSide();
+		if (roomSide)
+			roomNumber = *roomSide;
+	}
+
+	return roomNumber;
+}
+
+VectorInt2 FLOOR_INFO::GetSectorPoint(int x, int z)
+{
+	auto xPoint = x % WALL_SIZE - WALL_SIZE / 2;
+	auto yPoint = z % WALL_SIZE - WALL_SIZE / 2;
+
+	return VectorInt2{xPoint, yPoint};
+}
+
+int FLOOR_INFO::SectorPlane(int x, int z)
+{
+	auto vector = GetSectorPoint(x, z);
+	auto matrix = Matrix::CreateRotationZ(FloorCollision.SplitAngle);
+	auto result = Vector2::Transform(Vector2(vector.x, vector.y), matrix);
+
+	return result.x < 0 ? 0 : 1;
+}
+
+std::optional<int> FLOOR_INFO::RoomBelow(int plane)
+{
+	auto room = FloorCollision.Portals[plane];
+	return room != -1 ? std::optional<int>{room} : std::nullopt;
+}
+
+std::optional<int> FLOOR_INFO::RoomBelow(int x, int z)
+{
+	return RoomBelow(SectorPlane(x, z));
+}
+
+std::optional<int> FLOOR_INFO::RoomAbove(int plane)
+{
+	auto room = CeilingCollision.Portals[plane];
+	return room != -1 ? std::optional<int>{room} : std::nullopt;
+}
+
+std::optional<int> FLOOR_INFO::RoomAbove(int x, int z)
+{
+	return RoomAbove(SectorPlane(x, z));
+}
+
+std::optional<int> FLOOR_INFO::RoomSide()
+{
+	return WallPortal != -1 ? std::optional<int>{WallPortal} : std::nullopt;
+}
+
+int FLOOR_INFO::FloorHeight(int x, int z)
+{
+	auto plane = SectorPlane(x, z);
+	auto vector = GetSectorPoint(x, z);
+
+	return FloorCollision.Planes[plane].x * vector.x + FloorCollision.Planes[plane].y * vector.y + FloorCollision.Planes[plane].z;
+}
+
+int FLOOR_INFO::CeilingHeight(int x, int z)
+{
+	auto plane = SectorPlane(x, z);
+	auto vector = GetSectorPoint(x, z);
+
+	return CeilingCollision.Planes[plane].x * vector.x + CeilingCollision.Planes[plane].y * vector.y + CeilingCollision.Planes[plane].z;
 }
diff --git a/TR5Main/Game/floordata.h b/TR5Main/Game/floordata.h
index de935bc6c..bfa944e54 100644
--- a/TR5Main/Game/floordata.h
+++ b/TR5Main/Game/floordata.h
@@ -1,6 +1,5 @@
 #pragma once
-
-struct ROOM_INFO;
+#include "trmath.h"
 
 struct SECTOR_COLLISION_INFO
 {
@@ -9,12 +8,6 @@ struct SECTOR_COLLISION_INFO
 	Vector3 Planes[2];
 };
 
-struct SECTOR_POSITION
-{
-	int x;
-	int y;
-};
-
 class FLOOR_INFO
 {
 public:
@@ -30,7 +23,20 @@ public:
 	SECTOR_COLLISION_INFO CeilingCollision;
 	int WallPortal;
 
-	static SECTOR_POSITION GetSectorPosition(ROOM_INFO* room, int x, int z);
-	static FLOOR_INFO& GetFloor(ROOM_INFO* room, int x, int z);
-	static FLOOR_INFO& GetFloor(ROOM_INFO* room, SECTOR_POSITION pos);
+	static VectorInt2 GetRoomPosition(int roomNumber, int x, int z);
+	static FLOOR_INFO& GetFloor(int roomNumber, VectorInt2 pos);
+	static FLOOR_INFO& GetFloor(int roomNumber, int x, int z);
+	static int GetBottomRoom(int startRoomNumber, int x, int z);
+	static int GetTopRoom(int startRoomNumber, int x, int z);
+	static int GetRoom(int startRoomNumber, int x, int y, int z);
+	static VectorInt2 GetSectorPoint(int x, int z);
+
+	int SectorPlane(int x, int z);
+	std::optional<int> RoomBelow(int plane);
+	std::optional<int> RoomBelow(int x, int z);
+	std::optional<int> RoomAbove(int plane);
+	std::optional<int> RoomAbove(int x, int z);
+	std::optional<int> RoomSide();
+	int FloorHeight(int x, int z);
+	int CeilingHeight(int x, int z);
 };
diff --git a/TR5Main/Game/trmath.h b/TR5Main/Game/trmath.h
index 0bd2da3bd..40af9f5ad 100644
--- a/TR5Main/Game/trmath.h
+++ b/TR5Main/Game/trmath.h
@@ -1,6 +1,19 @@
 #pragma once
 #include "phd_global.h"
 
+struct VectorInt2
+{
+	int x;
+	int y;
+};
+
+struct VectorInt3
+{
+	int x;
+	int y;
+	int z;
+};
+
 constexpr auto PI = 3.14159265358979323846f;
 constexpr auto RADIAN = 0.01745329252f;
 constexpr auto ONE_DEGREE = 182;