diff --git a/src/polyrenderer/scene/poly_plane.cpp b/src/polyrenderer/scene/poly_plane.cpp
index 88ae14e10..ad471b4f0 100644
--- a/src/polyrenderer/scene/poly_plane.cpp
+++ b/src/polyrenderer/scene/poly_plane.cpp
@@ -33,7 +33,7 @@
 
 EXTERN_CVAR(Int, r_3dfloors)
 
-void RenderPolyPlane::RenderPlanes(const TriMatrix &worldToClip, const PolyClipPlane &clipPlane, PolyCull &cull, subsector_t *sub, uint32_t subsectorDepth, uint32_t stencilValue, double skyCeilingHeight, double skyFloorHeight, std::vector<std::unique_ptr<PolyDrawSectorPortal>> &sectorPortals)
+void RenderPolyPlane::RenderPlanes(const TriMatrix &worldToClip, const PolyClipPlane &clipPlane, PolyCull &cull, subsector_t *sub, uint32_t ceilingSubsectorDepth, uint32_t floorSubsectorDepth, uint32_t stencilValue, double skyCeilingHeight, double skyFloorHeight, std::vector<std::unique_ptr<PolyDrawSectorPortal>> &sectorPortals)
 {
 	RenderPolyPlane plane;
 
@@ -61,7 +61,7 @@ void RenderPolyPlane::RenderPlanes(const TriMatrix &worldToClip, const PolyClipP
 			double fakeHeight = fakeFloor->top.plane->ZatPoint(frontsector->centerspot);
 			if (fakeHeight < viewpoint.Pos.Z && fakeHeight > frontsector->floorplane.ZatPoint(frontsector->centerspot))
 			{
-				plane.Render3DFloor(worldToClip, clipPlane, sub, subsectorDepth, stencilValue, false, fakeFloor);
+				plane.Render3DFloor(worldToClip, clipPlane, sub, floorSubsectorDepth, stencilValue, false, fakeFloor);
 			}
 		}
 
@@ -82,13 +82,13 @@ void RenderPolyPlane::RenderPlanes(const TriMatrix &worldToClip, const PolyClipP
 			double fakeHeight = fakeFloor->bottom.plane->ZatPoint(frontsector->centerspot);
 			if (fakeHeight > viewpoint.Pos.Z && fakeHeight < frontsector->ceilingplane.ZatPoint(frontsector->centerspot))
 			{
-				plane.Render3DFloor(worldToClip, clipPlane, sub, subsectorDepth, stencilValue, true, fakeFloor);
+				plane.Render3DFloor(worldToClip, clipPlane, sub, ceilingSubsectorDepth, stencilValue, true, fakeFloor);
 			}
 		}
 	}
 
-	plane.Render(worldToClip, clipPlane, cull, sub, subsectorDepth, stencilValue, true, skyCeilingHeight, sectorPortals);
-	plane.Render(worldToClip, clipPlane, cull, sub, subsectorDepth, stencilValue, false, skyFloorHeight, sectorPortals);
+	plane.Render(worldToClip, clipPlane, cull, sub, ceilingSubsectorDepth, stencilValue, true, skyCeilingHeight, sectorPortals);
+	plane.Render(worldToClip, clipPlane, cull, sub, floorSubsectorDepth, stencilValue, false, skyFloorHeight, sectorPortals);
 }
 
 void RenderPolyPlane::Render3DFloor(const TriMatrix &worldToClip, const PolyClipPlane &clipPlane, subsector_t *sub, uint32_t subsectorDepth, uint32_t stencilValue, bool ceiling, F3DFloor *fakeFloor)
diff --git a/src/polyrenderer/scene/poly_plane.h b/src/polyrenderer/scene/poly_plane.h
index ce2192594..bb022aea9 100644
--- a/src/polyrenderer/scene/poly_plane.h
+++ b/src/polyrenderer/scene/poly_plane.h
@@ -30,7 +30,7 @@ class PolyCull;
 class RenderPolyPlane
 {
 public:
-	static void RenderPlanes(const TriMatrix &worldToClip, const PolyClipPlane &clipPlane, PolyCull &cull, subsector_t *sub, uint32_t subsectorDepth, uint32_t stencilValue, double skyCeilingHeight, double skyFloorHeight, std::vector<std::unique_ptr<PolyDrawSectorPortal>> &sectorPortals);
+	static void RenderPlanes(const TriMatrix &worldToClip, const PolyClipPlane &clipPlane, PolyCull &cull, subsector_t *sub, uint32_t ceilingSubsectorDepth, uint32_t floorSubsectorDepth, uint32_t stencilValue, double skyCeilingHeight, double skyFloorHeight, std::vector<std::unique_ptr<PolyDrawSectorPortal>> &sectorPortals);
 
 private:
 	struct UVTransform
diff --git a/src/polyrenderer/scene/poly_scene.cpp b/src/polyrenderer/scene/poly_scene.cpp
index ad0d88d34..2e5b04840 100644
--- a/src/polyrenderer/scene/poly_scene.cpp
+++ b/src/polyrenderer/scene/poly_scene.cpp
@@ -30,7 +30,6 @@
 #include "polyrenderer/poly_renderer.h"
 #include "polyrenderer/scene/poly_light.h"
 
-CVAR(Bool, r_debug_cull, 0, 0)
 EXTERN_CVAR(Int, r_portal_recursions)
 
 /////////////////////////////////////////////////////////////////////////////
@@ -92,19 +91,52 @@ void RenderPolyScene::ClearBuffers()
 
 void RenderPolyScene::RenderSectors()
 {
-	if (r_debug_cull)
+	int count = (int)Cull.PvsSectors.size();
+	auto subsectors = Cull.PvsSectors.data();
+
+	int nextCeilingZChange = 0;
+	int nextFloorZChange = 0;
+	uint32_t ceilingSubsectorDepth = 0;
+	uint32_t floorSubsectorDepth = 0;
+
+	for (int i = 0; i < count; i++)
 	{
-		for (auto it = Cull.PvsSectors.rbegin(); it != Cull.PvsSectors.rend(); ++it)
-			RenderSubsector(*it);
-	}
-	else
-	{
-		for (auto it = Cull.PvsSectors.begin(); it != Cull.PvsSectors.end(); ++it)
-			RenderSubsector(*it);
+		// The software renderer only updates the clipping if the sector height changes.
+		// Find the subsector depths for when that happens.
+		if (i == nextCeilingZChange)
+		{
+			double z = subsectors[i]->sector->ceilingplane.Zat0();
+			nextCeilingZChange++;
+			while (nextCeilingZChange < count)
+			{
+				double nextZ = subsectors[nextCeilingZChange]->sector->ceilingplane.Zat0();
+				if (nextZ > z)
+					break;
+				z = nextZ;
+				nextCeilingZChange++;
+			}
+			ceilingSubsectorDepth = NextSubsectorDepth + nextCeilingZChange - i - 1;
+		}
+		if (i == nextFloorZChange)
+		{
+			double z = subsectors[i]->sector->floorplane.Zat0();
+			nextFloorZChange++;
+			while (nextFloorZChange < count)
+			{
+				double nextZ = subsectors[nextFloorZChange]->sector->floorplane.Zat0();
+				if (nextZ < z)
+					break;
+				z = nextZ;
+				nextFloorZChange++;
+			}
+			floorSubsectorDepth = NextSubsectorDepth + nextFloorZChange - i - 1;
+		}
+
+		RenderSubsector(subsectors[i], ceilingSubsectorDepth, floorSubsectorDepth);
 	}
 }
 
-void RenderPolyScene::RenderSubsector(subsector_t *sub)
+void RenderPolyScene::RenderSubsector(subsector_t *sub, uint32_t ceilingSubsectorDepth, uint32_t floorSubsectorDepth)
 {
 	sector_t *frontsector = sub->sector;
 	frontsector->MoreFlags |= SECF_DRAWN;
@@ -147,7 +179,7 @@ void RenderPolyScene::RenderSubsector(subsector_t *sub)
 
 	if (sub->sector->CenterFloor() != sub->sector->CenterCeiling())
 	{
-		RenderPolyPlane::RenderPlanes(WorldToClip, PortalPlane, Cull, sub, subsectorDepth, StencilValue, Cull.MaxCeilingHeight, Cull.MinFloorHeight, SectorPortals);
+		RenderPolyPlane::RenderPlanes(WorldToClip, PortalPlane, Cull, sub, ceilingSubsectorDepth, floorSubsectorDepth, StencilValue, Cull.MaxCeilingHeight, Cull.MinFloorHeight, SectorPortals);
 	}
 
 	if (mainBSP)
diff --git a/src/polyrenderer/scene/poly_scene.h b/src/polyrenderer/scene/poly_scene.h
index 8dafc949b..e4a1dff4f 100644
--- a/src/polyrenderer/scene/poly_scene.h
+++ b/src/polyrenderer/scene/poly_scene.h
@@ -86,7 +86,7 @@ private:
 	void ClearBuffers();
 	void RenderPortals(int portalDepth);
 	void RenderSectors();
-	void RenderSubsector(subsector_t *sub);
+	void RenderSubsector(subsector_t *sub, uint32_t ceilingSubsectorDepth, uint32_t floorSubsectorDepth);
 	void RenderLine(subsector_t *sub, seg_t *line, sector_t *frontsector, uint32_t subsectorDepth);
 	void RenderSprite(AActor *thing, double sortDistance, const DVector2 &left, const DVector2 &right);
 	void RenderSprite(AActor *thing, double sortDistance, DVector2 left, DVector2 right, double t1, double t2, void *node);