From 3c72eb43f90f18440e059ca289dc8f088b854762 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Tue, 25 Oct 2022 19:54:44 +0200
Subject: [PATCH] - split off one part of clipmove into a utility function.

---
 source/core/gamefuncs.cpp | 48 +++++++++++++++++++++++++++++++++++++++
 source/core/gamefuncs.h   |  1 +
 2 files changed, 49 insertions(+)

diff --git a/source/core/gamefuncs.cpp b/source/core/gamefuncs.cpp
index 0d7c75f3f..df329eb66 100644
--- a/source/core/gamefuncs.cpp
+++ b/source/core/gamefuncs.cpp
@@ -1606,6 +1606,54 @@ void collectClipObjects(MoveClipper& clip, int spritemask)
 //
 //==========================================================================
 
+int FindBestSector(const DVector3& pos)
+{
+	int bestnum = 1;
+	double bestdist = FLT_MAX;
+	for (int secnum = (int)sector.Size() - 1; secnum >= 0; secnum--)
+	{
+		auto sect = &sector[secnum];
+		if (inside(pos.X, pos.Y, sect))
+		{
+			double ceilz, floorz;
+			calcSlope(sect, pos.X, pos.Y, &ceilz, &floorz);
+
+			if (pos.Z < ceilz)
+			{
+				// above ceiling
+				double dist = ceilz - pos.Z;
+				if (dist < bestdist)
+				{
+					bestnum = secnum;
+					bestdist = dist;
+				}
+			}
+			else if (pos.Z > floorz)
+			{
+				// below floor
+				double dist = pos.Z - floorz;
+				if (dist < bestdist)
+				{
+					bestnum = secnum;
+					bestdist = dist;
+				}
+			}
+			else
+			{
+				// inside sector
+				return secnum;
+			}
+		}
+	}
+	return bestnum;
+}
+
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
 bool isAwayFromWall(DCoreActor* ac, double delta)
 {
 	sectortype* s1;
diff --git a/source/core/gamefuncs.h b/source/core/gamefuncs.h
index f82cfde7a..22d88e270 100644
--- a/source/core/gamefuncs.h
+++ b/source/core/gamefuncs.h
@@ -312,6 +312,7 @@ struct MoveClipper
 };
 
 void collectClipObjects(MoveClipper& clip, int spritemask);
+int FindBestSector(const DVector3& pos);
 
 int FindBestSector(const DVector3& pos);