diff --git a/source/core/gamefuncs.h b/source/core/gamefuncs.h
index 41941c3b4..e424a807d 100644
--- a/source/core/gamefuncs.h
+++ b/source/core/gamefuncs.h
@@ -87,6 +87,13 @@ extern int cameradist, cameraclock;
 void loaddefinitionsfile(const char* fn, bool cumulative = false, bool maingrp = false);
 
 bool calcChaseCamPos(int* px, int* py, int* pz, spritetype* pspr, int *psectnum, binangle ang, fixedhoriz horiz, double const smoothratio);
+inline bool calcChaseCamPos(int* px, int* py, int* pz, spritetype* pspr, sectortype** psectnum, binangle ang, fixedhoriz horiz, double const smoothratio)
+{
+	int sectnum;
+	bool res = calcChaseCamPos(px, py, pz, pspr, &sectnum, ang, horiz, smoothratio);
+	*psectnum = &sector[sectnum];
+	return res;
+}
 
 void PlanesAtPoint(const sectortype* sec, int dax, int day, float* ceilz, float* florz);
 inline void PlanesAtPoint(const sectortype* sec, float dax, float day, float* ceilz, float* florz) // this is just for warning evasion.
diff --git a/source/core/gamestruct.h b/source/core/gamestruct.h
index 03f82dcec..f44c3dc24 100644
--- a/source/core/gamestruct.h
+++ b/source/core/gamestruct.h
@@ -13,6 +13,7 @@ bool System_WantGuiCapture();	// During playing this tells us whether the game m
 class FSerializer;
 struct FRenderViewpoint;
 struct spritetype;
+struct sectortype;
 
 struct GameStats
 {
@@ -118,7 +119,7 @@ struct GameInterface
 	virtual void UpdateCameras(double smoothratio) {}
 	virtual void EnterPortal(spritetype* viewer, int type) {}
 	virtual void LeavePortal(spritetype* viewer, int type) {}
-	virtual bool GetGeoEffect(GeoEffect* eff, int viewsector) { return false; }
+	virtual bool GetGeoEffect(GeoEffect* eff, sectortype* viewsector) { return false; }
 	virtual int Voxelize(int sprnum) { return -1; }
 	virtual void AddExcludedEpisode(const FString& episode) {}
 	virtual int GetCurrentSkill() { return -1; }
diff --git a/source/core/rendering/scene/hw_drawinfo.cpp b/source/core/rendering/scene/hw_drawinfo.cpp
index e225515e4..e2b4e9d3c 100644
--- a/source/core/rendering/scene/hw_drawinfo.cpp
+++ b/source/core/rendering/scene/hw_drawinfo.cpp
@@ -403,7 +403,7 @@ void HWDrawInfo::CreateScene(bool portal)
 	int drawsect = effsect;
 	// RR geometry hack. Ugh...
 	// This just adds to the existing render list, so we must offset the effect areas to the same xy-space as the main one as we cannot change the view matrix.
-	if (gi->GetGeoEffect(&eff, effsect))
+	if (gi->GetGeoEffect(&eff, &sector[effsect]))
 	{
 		ingeo = true;
 		geoofs = { (float)eff.geox[0], (float)eff.geoy[0] };
diff --git a/source/games/duke/src/duke3d.h b/source/games/duke/src/duke3d.h
index 65ffde440..e230126ea 100644
--- a/source/games/duke/src/duke3d.h
+++ b/source/games/duke/src/duke3d.h
@@ -67,7 +67,7 @@ struct GameInterface : public ::GameInterface
 	void UpdateCameras(double smoothratio) override;
 	void EnterPortal(spritetype* viewer, int type) override;
 	void LeavePortal(spritetype* viewer, int type) override;
-	bool GetGeoEffect(GeoEffect* eff, int viewsector) override;
+	bool GetGeoEffect(GeoEffect* eff, sectortype* viewsector) override;
 	void AddExcludedEpisode(const FString& episode) override;
 	int GetCurrentSkill() override;
 
diff --git a/source/games/duke/src/prediction.cpp b/source/games/duke/src/prediction.cpp
index 599c4e4ce..485c3a0c8 100644
--- a/source/games/duke/src/prediction.cpp
+++ b/source/games/duke/src/prediction.cpp
@@ -117,12 +117,12 @@ void fakedomovethings(void)
 		actions = syn->actions;
 
 		psect = mycursectnum;
-		psectlotag = sector[psect].lotag;
+		psectlotag = psect->lotag;
 		spritebridge = 0;
 
 		shrunk = (p->GetActor()->s.yrepeat < (isRR()? 8 : 32));
 
-		if( ud.clipping == 0 && ( sector[psect].floorpicnum == MIRROR || psect < 0 || psect >= MAXSECTORS) )
+		if( ud.clipping == 0 && ( psect->floorpicnum == MIRROR || psect == nullptr) )
 		{
 			myx = omyx;
 			myy = omyy;
@@ -145,7 +145,7 @@ void fakedomovethings(void)
 		if(clz.type == kHitSector && psectlotag == 1 && abs(myz-j) > gs.playerheight+(16<<8) )
 			psectlotag = 0;
 
-		if( p->aim_mode == 0 && myonground && psectlotag != 2 && (sector[psect].floorstat&2) )
+		if( p->aim_mode == 0 && myonground && psectlotag != 2 && (psect->floorstat&2) )
 		{
 				x = myx + bcos(myang, -5);
 				y = myy + bsin(myang, -5);
@@ -296,7 +296,7 @@ void fakedomovethings(void)
 			}
 				 if(myz < (fz-(i<<8)) && (floorspace(psect)|ceilingspace(psect)) == 0 ) //falling
 				 {
-							if( (sb_snum&3) == 0 && !(p->OnMotorcycle || p->OnBoat) && myonground && (sector[psect].floorstat&2) && myz >= (fz-(i<<8)-(16<<8) ) )
+							if( (sb_snum&3) == 0 && !(p->OnMotorcycle || p->OnBoat) && myonground && (psect->floorstat&2) && myz >= (fz-(i<<8)-(16<<8) ) )
 									 myz = fz-(i<<8);
 							else
 							{
diff --git a/source/games/duke/src/render.cpp b/source/games/duke/src/render.cpp
index 0175398ca..17d2f8d85 100644
--- a/source/games/duke/src/render.cpp
+++ b/source/games/duke/src/render.cpp
@@ -141,9 +141,9 @@ void GameInterface::LeavePortal(spritetype* viewer, int type)
 	if (type == PORTAL_WALL_MIRROR) display_mirror--;
 }
 
-bool GameInterface::GetGeoEffect(GeoEffect* eff, int viewsector)
+bool GameInterface::GetGeoEffect(GeoEffect* eff, sectortype* viewsector)
 {
-	if (isRR() && sector[viewsector].lotag == 848)
+	if (isRR() && viewsector->lotag == 848)
 	{
 		eff->geocnt = geocnt;
 		eff->geosector = geosector;
@@ -252,7 +252,6 @@ static int getdrugmode(player_struct *p, int oyrepeat)
 void displayrooms(int snum, double smoothratio)
 {
 	int cposx, cposy, cposz, fz, cz;
-	int sect;
 	binangle cang, rotscrnang;
 	fixedhoriz choriz;
 	struct player_struct* p;
@@ -273,8 +272,8 @@ void displayrooms(int snum, double smoothratio)
 
 	videoSetCorrectedAspect();
 
-	sect = p->cursectnum;
-	if (sect < 0 || sect >= MAXSECTORS) return;
+	auto sect = p->cursector();
+	if (sect == nullptr) return;
 
 	GlobalMapFog = fogactive ? 0x999999 : 0;
 	GlobalFogDensity = fogactive ? 350.f : 0.f;
@@ -310,6 +309,7 @@ void displayrooms(int snum, double smoothratio)
 		// set screen rotation.
 		rotscrnang = !SyncInput() ? p->angle.rotscrnang : p->angle.interpolatedrotscrn(smoothratio);
 
+#if 0
 		if ((snum == myconnectindex) && (numplayers > 1))
 		{
 			cposx = interpolatedvalue(omyx, myx, smoothratio);
@@ -328,6 +328,7 @@ void displayrooms(int snum, double smoothratio)
 			sect = mycursectnum;
 		}
 		else
+#endif
 		{
 			cposx = interpolatedvalue(p->oposx, p->pos.x, smoothratio);
 			cposy = interpolatedvalue(p->oposy, p->pos.y, smoothratio);
@@ -355,7 +356,7 @@ void displayrooms(int snum, double smoothratio)
 			cposx = spr->pos.x;
 			cposy = spr->pos.y;
 			cposz = spr->pos.z;
-			sect = spr->sectnum;
+			sect = spr->sector();
 			rotscrnang = buildang(0);
 			smoothratio = MaxSmoothRatio;
 			viewer = spr;
@@ -394,23 +395,23 @@ void displayrooms(int snum, double smoothratio)
 			else if (cposz > (p->truefz - (4 << 8))) cposz = fz - (4 << 8);
 		}
 
-		if (sect >= 0)
+		if (sect)
 		{
-			getzsofslope(sect, cposx, cposy, &cz, &fz);
+			getzsofslopeptr(sect, cposx, cposy, &cz, &fz);
 			if (cposz < cz + (4 << 8)) cposz = cz + (4 << 8);
 			if (cposz > fz - (4 << 8)) cposz = fz - (4 << 8);
 		}
 
 		choriz = clamp(choriz, q16horiz(gi->playerHorizMin()), q16horiz(gi->playerHorizMax()));
 
-		if (isRR() && sector[sect].lotag == 848 && !testnewrenderer)
+		if (isRR() && sect->lotag == 848 && !testnewrenderer)
 		{
 			renderSetRollAngle((float)rotscrnang.asbuildf());
-			geometryEffect(cposx, cposy, cposz, cang, choriz, sect, (int)smoothratio);
+			geometryEffect(cposx, cposy, cposz, cang, choriz, sectnum(sect), (int)smoothratio);
 		}
 		else
 		{
-			renderView(viewer, sect, cposx, cposy, cposz, cang, choriz, rotscrnang, (int)smoothratio);
+			renderView(viewer, sectnum(sect), cposx, cposy, cposz, cang, choriz, rotscrnang, (int)smoothratio);
 		}
 	}
 	//GLInterface.SetMapFog(false);