diff --git a/src/g_levellocals.h b/src/g_levellocals.h
index 7f7be16fc..e4d87934c 100644
--- a/src/g_levellocals.h
+++ b/src/g_levellocals.h
@@ -33,6 +33,7 @@ struct FLevelLocals
 	TStaticArray<sector_t> sectors;
 	TStaticArray<line_t> lines;
 	TStaticArray<side_t> sides;
+	TStaticArray<seg_t> segs;
 
 	TArray<FSectorPortal> sectorPortals;
 
@@ -109,6 +110,11 @@ inline int line_t::Index() const
 	return int(this - &level.lines[0]);
 }
 
+inline int seg_t::Index() const
+{
+	return int(this - &level.segs[0]);
+}
+
 inline FSectorPortal *line_t::GetTransferredPortal()
 {
 	return portaltransferred >= level.sectorPortals.Size() ? (FSectorPortal*)nullptr : &level.sectorPortals[portaltransferred];
diff --git a/src/gl/data/gl_data.cpp b/src/gl/data/gl_data.cpp
index 1515842b9..b83ced72c 100644
--- a/src/gl/data/gl_data.cpp
+++ b/src/gl/data/gl_data.cpp
@@ -389,13 +389,12 @@ CCMD(dumpgeometry)
 				{
 				Printf(PRINT_LOG, "      (%4.4f, %4.4f), (%4.4f, %4.4f) - seg %d, linedef %d, side %d", 
 					seg->v1->fX(), seg->v1->fY(), seg->v2->fX(), seg->v2->fY(),
-					int(seg-segs), seg->linedef->Index(), seg->sidedef != seg->linedef->sidedef[0]);
+					seg->Index(), seg->linedef->Index(), seg->sidedef != seg->linedef->sidedef[0]);
 				}
 				else
 				{
 					Printf(PRINT_LOG, "      (%4.4f, %4.4f), (%4.4f, %4.4f) - seg %d, miniseg", 
-						seg->v1->fX(), seg->v1->fY(), seg->v2->fX(), seg->v2->fY(),
-						int(seg-segs));
+						seg->v1->fX(), seg->v1->fY(), seg->v2->fX(), seg->v2->fY(), seg->Index());
 				}
 				if (seg->PartnerSeg) 
 				{
diff --git a/src/gl/data/gl_setup.cpp b/src/gl/data/gl_setup.cpp
index 6c314cdb7..1ecd74057 100644
--- a/src/gl/data/gl_setup.cpp
+++ b/src/gl/data/gl_setup.cpp
@@ -115,7 +115,7 @@ static int MergeMapSections(int num)
 	TArray<bool> sectvalid;
 	sectmap.Resize(num);
 	sectvalid.Resize(num);
-	for(int i=0;i<num;i++) 
+	for (int i = 0; i < num; i++)
 	{
 		sectmap[i] = -1;
 		sectvalid[i] = true;
@@ -126,31 +126,29 @@ static int MergeMapSections(int num)
 	cvertex_t vt;
 
 	// first step: Set mapsection for all vertex positions.
-	for(uint32_t i=0;i<(uint32_t)numsegs;i++)
+	for (auto &seg : level.segs)
 	{
-		seg_t * seg = &segs[i];
-		int section = seg->Subsector->mapsection;
-		for(int j=0;j<2;j++)
+		int section = seg.Subsector->mapsection;
+		for (int j = 0; j < 2; j++)
 		{
-			vt = j==0? seg->v1:seg->v2;
+			vt = j == 0 ? seg.v1 : seg.v2;
 			vmap[vt] = section;
 		}
 	}
 
 	// second step: Check if any seg references more than one mapsection, either by subsector or by vertex
-	for(uint32_t i=0;i<(uint32_t)numsegs;i++)
+	for (auto &seg : level.segs)
 	{
-		seg_t * seg = &segs[i];
-		int section = seg->Subsector->mapsection;
-		for(int j=0;j<2;j++)
+		int section = seg.Subsector->mapsection;
+		for (int j = 0; j < 2; j++)
 		{
-			vt = j==0? seg->v1:seg->v2;
+			vt = j == 0 ? seg.v1 : seg.v2;
 			int vsection = vmap[vt];
 
 			if (vsection != section)
 			{
 				// These 2 sections should be merged
-				for(int k=0;k<numsubsectors;k++)
+				for (int k = 0; k < numsubsectors; k++)
 				{
 					if (subsectors[k].mapsection == vsection) subsectors[k].mapsection = section;
 				}
@@ -159,20 +157,20 @@ static int MergeMapSections(int num)
 				{
 					if (pair->Value == vsection) pair->Value = section;
 				}
-				sectvalid[vsection-1] = false;
+				sectvalid[vsection - 1] = false;
 			}
 		}
 	}
-	for(int i=0;i<num;i++)
+	for (int i = 0; i < num; i++)
 	{
 		if (sectvalid[i]) sectmap[i] = mergecount++;
 	}
-	for(int i=0;i<numsubsectors;i++)
+	for (int i = 0; i < numsubsectors; i++)
 	{
-		subsectors[i].mapsection = sectmap[subsectors[i].mapsection-1];
-		assert(subsectors[i].mapsection!=-1);
+		subsectors[i].mapsection = sectmap[subsectors[i].mapsection - 1];
+		assert(subsectors[i].mapsection != -1);
 	}
-	return mergecount-1;
+	return mergecount - 1;
 }
 
 //==========================================================================
@@ -491,22 +489,20 @@ static void PrepareSegs()
 	// count the segs
 	memset(segcount, 0, numsides * sizeof(int));
 
-	for(int i=0;i<numsegs;i++)
+	for(auto &seg : level.segs)
 	{
-		seg_t *seg = &segs[i];
-
-		if (seg->sidedef == NULL) continue;	// miniseg
-		int sidenum = seg->sidedef->Index();
+		if (seg.sidedef == NULL) continue;	// miniseg
+		int sidenum = seg.sidedef->Index();
 
 		realsegs++;
 		segcount[sidenum]++;
-		DVector2 sidestart, sideend, segend = seg->v2->fPos();
+		DVector2 sidestart, sideend, segend = seg.v2->fPos();
 		GetSideVertices(sidenum, &sidestart, &sideend);
 
 		sideend -=sidestart;
 		segend -= sidestart;
 
-		seg->sidefrac = float(segend.Length() / sideend.Length());
+		seg.sidefrac = float(segend.Length() / sideend.Length());
 	}
 
 	// allocate memory
@@ -521,10 +517,9 @@ static void PrepareSegs()
 	delete [] segcount;
 
 	// assign the segs
-	for(int i=0;i<numsegs;i++)
+	for (auto &seg : level.segs)
 	{
-		seg_t *seg = &segs[i];
-		if (seg->sidedef != NULL) seg->sidedef->segs[seg->sidedef->numsegs++] = seg;
+		if (seg.sidedef != NULL) seg.sidedef->segs[seg.sidedef->numsegs++] = &seg;
 	}
 
 	// sort the segs
diff --git a/src/gl/dynlights/gl_shadowmap.cpp b/src/gl/dynlights/gl_shadowmap.cpp
index 9a23e4114..c9223082d 100644
--- a/src/gl/dynlights/gl_shadowmap.cpp
+++ b/src/gl/dynlights/gl_shadowmap.cpp
@@ -32,6 +32,7 @@
 #include "gl/renderer/gl_renderbuffers.h"
 #include "gl/shaders/gl_shadowmapshader.h"
 #include "r_state.h"
+#include "g_levellocals.h"
 
 /*
 	The 1D shadow maps are stored in a 1024x1024 texture as float depth values (R32F).
@@ -157,7 +158,9 @@ void FShadowMap::UploadLights()
 
 void FShadowMap::UploadAABBTree()
 {
-	if (numnodes != mLastNumNodes || numsegs != mLastNumSegs) // To do: there is probably a better way to detect a map change than this..
+	// Just comparing the level info is not enough. If two MAPINFO-less levels get played after each other, 
+	// they can both refer to the same default level info.
+	if (level.info != mLastLevel && numnodes != mLastNumNodes || level.segs.Size() != mLastNumSegs) 
 		Clear();
 
 	if (mAABBTree)
@@ -201,6 +204,7 @@ void FShadowMap::Clear()
 
 	mAABBTree.reset();
 
+	mLastLevel = level.info;
 	mLastNumNodes = numnodes;
-	mLastNumSegs = numsegs;
+	mLastNumSegs = level.segs.Size();
 }
diff --git a/src/gl/dynlights/gl_shadowmap.h b/src/gl/dynlights/gl_shadowmap.h
index e2b5b371f..45a3f6798 100644
--- a/src/gl/dynlights/gl_shadowmap.h
+++ b/src/gl/dynlights/gl_shadowmap.h
@@ -6,6 +6,7 @@
 #include <memory>
 
 class ADynamicLight;
+struct level_info_t;
 
 class FShadowMap
 {
@@ -49,8 +50,9 @@ private:
 	int mLinesBuffer = 0;
 
 	// Used to detect when a level change requires the AABB tree to be regenerated
+	level_info_t *mLastLevel = nullptr;
 	int mLastNumNodes = 0;
-	int mLastNumSegs = 0;
+	unsigned mLastNumSegs = 0;
 
 	// AABB-tree of the level, used for ray tests
 	std::unique_ptr<LevelAABBTree> mAABBTree;
diff --git a/src/nodebuild.h b/src/nodebuild.h
index c5297190d..09298ac19 100644
--- a/src/nodebuild.h
+++ b/src/nodebuild.h
@@ -194,7 +194,7 @@ public:
 	~FNodeBuilder ();
 
 	void Extract(node_t *&nodes, int &nodeCount,
-		seg_t *&segs, int &segCount,
+		TStaticArray<seg_t> &segs,
 		subsector_t *&ssecs, int &subCount,
 		TStaticArray<vertex_t> &vertexes);
 	const int *GetOldVertexTable();
diff --git a/src/nodebuild_extract.cpp b/src/nodebuild_extract.cpp
index 98ade3f78..f16b75524 100644
--- a/src/nodebuild_extract.cpp
+++ b/src/nodebuild_extract.cpp
@@ -53,7 +53,7 @@
 #endif
 
 void FNodeBuilder::Extract (node_t *&outNodes, int &nodeCount,
-	seg_t *&outSegs, int &segCount,
+	TStaticArray<seg_t> &outSegs,
 	subsector_t *&outSubs, int &subCount,
 	TStaticArray<vertex_t> &outVerts)
 {
@@ -114,10 +114,10 @@ void FNodeBuilder::Extract (node_t *&outNodes, int &nodeCount,
 			outSubs[i].firstline = (seg_t *)(size_t)(segs.Size() - numsegs);
 		}
 
-		segCount = segs.Size ();
-		outSegs = new seg_t[segCount];
+		auto segCount = segs.Size ();
+		outSegs.Alloc(segCount);
 
-		for (i = 0; i < segCount; ++i)
+		for (unsigned i = 0; i < segCount; ++i)
 		{
 			outSegs[i] = *(seg_t *)&segs[i];
 
@@ -135,9 +135,9 @@ void FNodeBuilder::Extract (node_t *&outNodes, int &nodeCount,
 	else
 	{
 		memcpy (outSubs, &Subsectors[0], subCount*sizeof(subsector_t));
-		segCount = Segs.Size ();
-		outSegs = new seg_t[segCount];
-		for (i = 0; i < segCount; ++i)
+		auto segCount = Segs.Size ();
+		outSegs.Alloc(segCount);
+		for (unsigned i = 0; i < segCount; ++i)
 		{
 			const FPrivSeg *org = &Segs[SegList[i].SegNum];
 			seg_t *out = &outSegs[i];
diff --git a/src/p_glnodes.cpp b/src/p_glnodes.cpp
index 2da9a0457..153c20949 100644
--- a/src/p_glnodes.cpp
+++ b/src/p_glnodes.cpp
@@ -135,25 +135,23 @@ static int CheckForMissingSegs()
 	int missing = 0;
 
 	memset(added_seglen, 0, sizeof(double)*numsides);
-	for(int i=0;i<numsegs;i++)
+	for (auto &seg : level.segs)
 	{
-		seg_t * seg = &segs[i];
-
-		if (seg->sidedef!=NULL)
+		if (seg.sidedef != nullptr)
 		{
 			// check all the segs and calculate the length they occupy on their sidedef
-			DVector2 vec1(seg->v2->fX() - seg->v1->fX(), seg->v2->fY() - seg->v1->fY());
-			added_seglen[seg->sidedef->Index()] += vec1.Length();
+			DVector2 vec1(seg.v2->fX() - seg.v1->fX(), seg.v2->fY() - seg.v1->fY());
+			added_seglen[seg.sidedef->Index()] += vec1.Length();
 		}
 	}
 
-	for(unsigned i=0;i<numsides;i++)
+	for (unsigned i = 0; i < numsides; i++)
 	{
 		double linelen = level.sides[i].linedef->Delta().Length();
 		missing += (added_seglen[i] < linelen - 1.);
 	}
 
-	delete [] added_seglen;
+	delete[] added_seglen;
 	return missing;
 }
 
@@ -183,7 +181,7 @@ bool P_CheckForGLNodes()
 		{
 			for(uint32_t j=0;j<sub->numlines;j++)
 			{
-				if (segs[j].linedef==NULL)	// miniseg
+				if (level.segs[j].linedef==NULL)	// miniseg
 				{
 					// We already have GL nodes. Great!
 					return true;
@@ -304,11 +302,11 @@ static bool LoadGLSegs(FileReader * lump)
 	int			i;
 	line_t		*ldef=NULL;
 	
-	numsegs = lump->GetLength();
+	int numsegs = lump->GetLength();
 	data= new char[numsegs];
 	lump->Seek(0, SEEK_SET);
 	lump->Read(data, numsegs);
-	segs=NULL;
+	auto &segs = level.segs;
 
 #ifdef _MSC_VER
 	__try
@@ -317,12 +315,13 @@ static bool LoadGLSegs(FileReader * lump)
 		if (!format5 && memcmp(data, "gNd3", 4))
 		{
 			numsegs/=sizeof(glseg_t);
-			segs = new seg_t[numsegs];
-			memset(segs,0,sizeof(seg_t)*numsegs);
+			level.segs.Alloc(numsegs);
+			memset(&segs[0],0,sizeof(seg_t)*numsegs);
 			
 			glseg_t * ml = (glseg_t*)data;
 			for(i = 0; i < numsegs; i++)
-			{							// check for gl-vertices
+			{		
+				// check for gl-vertices
 				segs[i].v1 = &level.vertexes[checkGLVertex(LittleShort(ml->v1))];
 				segs[i].v2 = &level.vertexes[checkGLVertex(LittleShort(ml->v2))];
 				segs[i].PartnerSeg = ml->partner == 0xFFFF ? nullptr : &segs[LittleShort(ml->partner)];
@@ -368,8 +367,8 @@ static bool LoadGLSegs(FileReader * lump)
 		{
 			if (!format5) numsegs-=4;
 			numsegs/=sizeof(glseg3_t);
-			segs = new seg_t[numsegs];
-			memset(segs,0,sizeof(seg_t)*numsegs);
+			level.segs.Alloc(numsegs);
+			memset(&segs[0],0,sizeof(seg_t)*numsegs);
 			
 			glseg3_t * ml = (glseg3_t*)(data+ (format5? 0:4));
 			for(i = 0; i < numsegs; i++)
@@ -428,8 +427,7 @@ static bool LoadGLSegs(FileReader * lump)
 		// (at least under MSVC. GCC can't do SEH even for Windows... :( )
 		Printf("Invalid GL segs. The BSP will have to be rebuilt.\n");
 		delete [] data;
-		delete [] segs;
-		segs = NULL;
+		level.segs.Clear();
 		return false;
 	}
 #endif
@@ -468,7 +466,7 @@ static bool LoadGLSubsectors(FileReader * lump)
 		for (i=0; i<numsubsectors; i++)
 		{
 			subsectors[i].numlines  = LittleShort(data[i].numsegs );
-			subsectors[i].firstline = segs + LittleShort(data[i].firstseg);
+			subsectors[i].firstline = &level.segs[LittleShort(data[i].firstseg)];
 
 			if (subsectors[i].numlines == 0)
 			{
@@ -487,7 +485,7 @@ static bool LoadGLSubsectors(FileReader * lump)
 		for (i=0; i<numsubsectors; i++)
 		{
 			subsectors[i].numlines  = LittleLong(data[i].numsegs );
-			subsectors[i].firstline = segs + LittleLong(data[i].firstseg);
+			subsectors[i].firstline = &level.segs[LittleLong(data[i].firstseg)];
 
 			if (subsectors[i].numlines == 0)
 			{
@@ -672,16 +670,14 @@ static bool DoLoadGLNodes(FileReader ** lumps)
 	}
 	if (!LoadGLSegs(lumps[1]))
 	{
-		delete [] segs;
-		segs = NULL;
+		level.segs.Clear();
 		return false;
 	}
 	if (!LoadGLSubsectors(lumps[2]))
 	{
 		delete [] subsectors;
 		subsectors = NULL;
-		delete [] segs;
-		segs = NULL;
+		level.segs.Clear();
 		return false;
 	}
 	if (!LoadNodes(lumps[3]))
@@ -690,8 +686,7 @@ static bool DoLoadGLNodes(FileReader ** lumps)
 		nodes = NULL;
 		delete [] subsectors;
 		subsectors = NULL;
-		delete [] segs;
-		segs = NULL;
+		level.segs.Clear();
 		return false;
 	}
 
@@ -708,8 +703,7 @@ static bool DoLoadGLNodes(FileReader ** lumps)
 			nodes = NULL;
 			delete [] subsectors;
 			subsectors = NULL;
-			delete [] segs;
-			segs = NULL;
+			level.segs.Clear();
 			return false;
 		}
 	}
@@ -864,7 +858,7 @@ bool P_LoadGLNodes(MapData * map)
 			try
 			{
 				subsectors = NULL;
-				segs = NULL;
+				level.segs.Clear();
 				nodes = NULL;
 				P_LoadZNodes (*map->file, id);
 				return true;
@@ -876,11 +870,7 @@ bool P_LoadGLNodes(MapData * map)
 					delete[] subsectors;
 					subsectors = NULL;
 				}
-				if (segs != NULL)
-				{
-					delete[] segs;
-					segs = NULL;
-				}
+				level.segs.Clear();
 				if (nodes != NULL)
 				{
 					delete[] nodes;
@@ -984,9 +974,7 @@ bool P_CheckNodes(MapData * map, bool rebuilt, int buildtime)
 		numnodes = 0;
 		subsectors = NULL;
 		numsubsectors = 0;
-		if (segs) delete [] segs;
-		segs = NULL;
-		numsegs = 0;
+		level.segs.Clear();
 
 		// Try to load GL nodes (cached or GWA)
 		loaded = P_LoadGLNodes(map);
@@ -1009,11 +997,11 @@ bool P_CheckNodes(MapData * map, bool rebuilt, int buildtime)
 			FNodeBuilder builder (leveldata, polyspots, anchors, true);
 			
 			builder.Extract (nodes, numnodes,
-				segs, numsegs,
+				level.segs,
 				subsectors, numsubsectors,
 				level.vertexes);
 			endTime = I_FPSTime ();
-			DPrintf (DMSG_NOTIFY, "BSP generation took %.3f sec (%d segs)\n", (endTime - startTime) * 0.001, numsegs);
+			DPrintf (DMSG_NOTIFY, "BSP generation took %.3f sec (%u segs)\n", (endTime - startTime) * 0.001, level.segs.Size());
 			buildtime = endTime - startTime;
 		}
 	}
@@ -1106,15 +1094,15 @@ static void CreateCachedNodes(MapData *map)
 		WriteLong(ZNodes, subsectors[i].numlines);
 	}
 
-	WriteLong(ZNodes, numsegs);
-	for(int i=0;i<numsegs;i++)
+	WriteLong(ZNodes, level.segs.Size());
+	for(auto &seg : level.segs)
 	{
-		WriteLong(ZNodes, segs[i].v1->Index());
-		WriteLong(ZNodes, segs[i].PartnerSeg == nullptr? 0xffffffffu : uint32_t(segs[i].PartnerSeg - segs));
-		if (segs[i].linedef)
+		WriteLong(ZNodes, seg.v1->Index());
+		WriteLong(ZNodes, seg.PartnerSeg == nullptr? 0xffffffffu : uint32_t(seg.PartnerSeg->Index()));
+		if (seg.linedef)
 		{
-			WriteLong(ZNodes, uint32_t(segs[i].linedef->Index()));
-			WriteByte(ZNodes, segs[i].sidedef == segs[i].linedef->sidedef[0]? 0:1);
+			WriteLong(ZNodes, uint32_t(seg.linedef->Index()));
+			WriteByte(ZNodes, seg.sidedef == seg.linedef->sidedef[0]? 0:1);
 		}
 		else
 		{
@@ -1247,11 +1235,7 @@ static bool CheckCachedNodes(MapData *map)
 			delete[] subsectors;
 			subsectors = NULL;
 		}
-		if (segs != NULL)
-		{
-			delete[] segs;
-			segs = NULL;
-		}
+		level.segs.Clear();
 		if (nodes != NULL)
 		{
 			delete[] nodes;
@@ -1438,30 +1422,30 @@ void P_SetRenderSector()
 
 	// Check for incorrect partner seg info so that the following code does not crash.
 
-	for (i = 0; i < numsegs; i++)
+	for (auto &seg : level.segs)
 	{
-		auto p = segs[i].PartnerSeg;
+		auto p = seg.PartnerSeg;
 		if (p != nullptr)
 		{
-			int partner = (int)(p - segs);
+			int partner = p->Index();
 
-			if (partner < 0 || partner >= numsegs || &segs[partner] != p)
+			if (partner < 0 || partner >= (int)level.segs.Size() || &level.segs[partner] != p)
 			{
-				segs[i].PartnerSeg = nullptr;
+				seg.PartnerSeg = nullptr;
 			}
 
 			// glbsp creates such incorrect references for Strife.
-			if (segs[i].linedef && segs[i].PartnerSeg != nullptr && !segs[i].PartnerSeg->linedef)
+			if (seg.linedef && seg.PartnerSeg != nullptr && !seg.PartnerSeg->linedef)
 			{
-				segs[i].PartnerSeg = segs[i].PartnerSeg->PartnerSeg = nullptr;
+				seg.PartnerSeg = seg.PartnerSeg->PartnerSeg = nullptr;
 			}
 		}
 	}
-	for (i = 0; i < numsegs; i++)
+	for (auto &seg : level.segs)
 	{
-		if (segs[i].PartnerSeg != nullptr && segs[i].PartnerSeg->PartnerSeg != &segs[i])
+		if (seg.PartnerSeg != nullptr && seg.PartnerSeg->PartnerSeg != &seg)
 		{
-			segs[i].PartnerSeg = nullptr;
+			seg.PartnerSeg = nullptr;
 		}
 	}
 
diff --git a/src/p_setup.cpp b/src/p_setup.cpp
index 4793dd7ea..908306a25 100644
--- a/src/p_setup.cpp
+++ b/src/p_setup.cpp
@@ -3914,7 +3914,7 @@ void P_SetupLevel (const char *lumpname, int position)
 		// if the different machines' am_textured setting differs.
 		FNodeBuilder builder (leveldata, polyspots, anchors, BuildGLNodes);
 		builder.Extract (nodes, numnodes,
-			segs, numsegs,
+			level.segs,
 			subsectors, numsubsectors,
 			level.vertexes);
 		endTime = I_FPSTime ();
diff --git a/src/r_defs.h b/src/r_defs.h
index 74c08e266..eeb2931a6 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -1375,9 +1375,11 @@ struct seg_t
 	subsector_t*	Subsector;
 
 	float			sidefrac;		// relative position of seg's ending vertex on owning sidedef
+
+	int Index() const;
 };
 
-extern seg_t *segs;
+//extern seg_t *segs;
 
 
 //
diff --git a/src/r_state.h b/src/r_state.h
index 6223c40b4..780a2767c 100644
--- a/src/r_state.h
+++ b/src/r_state.h
@@ -46,8 +46,8 @@ extern uint32_t NumStdSprites;
 
 extern TArray<vertexdata_t> vertexdatas;
 
-extern int				numsegs;
-extern seg_t*			segs;
+//extern int				numsegs;
+//extern seg_t*			segs;
 
 extern int				numsubsectors;
 extern subsector_t* 	subsectors;