diff --git a/src/swrenderer/line/r_line.cpp b/src/swrenderer/line/r_line.cpp
index 17a475862..ddecf5879 100644
--- a/src/swrenderer/line/r_line.cpp
+++ b/src/swrenderer/line/r_line.cpp
@@ -64,7 +64,6 @@ namespace swrenderer
 
 	void SWRenderLine::Render(seg_t *line, subsector_t *subsector, sector_t *sector, sector_t *fakebacksector, VisiblePlane *linefloorplane, VisiblePlane *lineceilingplane, bool infog, FDynamicColormap *colormap)
 	{
-		static sector_t tempsec;	// killough 3/8/98: ceiling/water hack
 		bool			solid;
 		DVector2		pt1, pt2;
 
@@ -284,11 +283,7 @@ namespace swrenderer
 			rw_floorstat = wallbottom.Project(frontsector->floorplane, &WallC, curline, renderportal->MirrorFlags & RF_XFLIP);
 		}
 
-		static SWRenderLine *self = this;
-		bool visible = Thread->ClipSegments->Clip(WallC.sx1, WallC.sx2, solid, [](int x1, int x2) -> bool
-		{
-			return self->RenderWallSegment(x1, x2);
-		});
+		bool visible = Thread->ClipSegments->Clip(WallC.sx1, WallC.sx2, solid, this);
 
 		if (visible)
 		{
diff --git a/src/swrenderer/line/r_line.h b/src/swrenderer/line/r_line.h
index 75b6d69b3..ef38e9e65 100644
--- a/src/swrenderer/line/r_line.h
+++ b/src/swrenderer/line/r_line.h
@@ -15,6 +15,7 @@
 
 #include "vectors.h"
 #include "r_wallsetup.h"
+#include "swrenderer/segments/r_clipsegment.h"
 
 struct seg_t;
 struct subsector_t;
@@ -48,7 +49,7 @@ namespace swrenderer
 		void InitFromLine(RenderThread *thread, const DVector2 &left, const DVector2 &right);
 	};
 
-	class SWRenderLine
+	class SWRenderLine : VisibleSegmentRenderer
 	{
 	public:
 		SWRenderLine(RenderThread *thread);
@@ -57,7 +58,7 @@ namespace swrenderer
 		RenderThread *Thread = nullptr;
 
 	private:
-		bool RenderWallSegment(int x1, int x2);
+		bool RenderWallSegment(int x1, int x2) override;
 		void SetWallVariables(bool needlights);
 		void RenderWallSegmentTextures(int x1, int x2);
 
@@ -133,5 +134,7 @@ namespace swrenderer
 		ProjectedWallLine wallupper;
 		ProjectedWallLine walllower;
 		ProjectedWallTexcoords walltexcoords;
+
+		sector_t tempsec; // killough 3/8/98: ceiling/water hack
 	};
 }
diff --git a/src/swrenderer/line/r_walldraw.cpp b/src/swrenderer/line/r_walldraw.cpp
index 9a07198e5..ea165ab04 100644
--- a/src/swrenderer/line/r_walldraw.cpp
+++ b/src/swrenderer/line/r_walldraw.cpp
@@ -41,6 +41,7 @@
 #include "swrenderer/line/r_walldraw.h"
 #include "swrenderer/line/r_wallsetup.h"
 #include "swrenderer/r_renderthread.h"
+#include "swrenderer/r_memory.h"
 
 namespace swrenderer
 {
@@ -188,14 +189,22 @@ namespace swrenderer
 			drawerargs.dc_viewpos.Z = (float)((viewport->CenterY - y1 - 0.5) / viewport->InvZtoScale * zcol);
 			drawerargs.dc_viewpos_step.Z = (float)(-zcol / viewport->InvZtoScale);
 
-			static TriLight lightbuffer[64 * 1024];
-			static int nextlightindex = 0;
+			// Calculate max lights that can touch column so we can allocate memory for the list
+			int max_lights = 0;
+			FLightNode *cur_node = light_list;
+			while (cur_node)
+			{
+				if (!(cur_node->lightsource->flags2&MF2_DORMANT))
+					max_lights++;
+				cur_node = cur_node->nextLight;
+			}
+
+			drawerargs.dc_num_lights = 0;
+			drawerargs.dc_lights = Thread->FrameMemory->AllocMemory<TriLight>(max_lights);
 
 			// Setup lights for column
-			drawerargs.dc_num_lights = 0;
-			drawerargs.dc_lights = lightbuffer + nextlightindex;
-			FLightNode *cur_node = light_list;
-			while (cur_node && nextlightindex < 64 * 1024)
+			cur_node = light_list;
+			while (cur_node)
 			{
 				if (!(cur_node->lightsource->flags2&MF2_DORMANT))
 				{
@@ -220,7 +229,6 @@ namespace swrenderer
 						uint32_t green = cur_node->lightsource->GetGreen();
 						uint32_t blue = cur_node->lightsource->GetBlue();
 
-						nextlightindex++;
 						auto &light = drawerargs.dc_lights[drawerargs.dc_num_lights++];
 						light.x = lconstant;
 						light.y = nlconstant;
@@ -232,9 +240,6 @@ namespace swrenderer
 
 				cur_node = cur_node->nextLight;
 			}
-
-			if (nextlightindex == 64 * 1024)
-				nextlightindex = 0;
 		}
 		else
 		{
diff --git a/src/swrenderer/r_renderthread.cpp b/src/swrenderer/r_renderthread.cpp
index 53b5f62f8..ba48993ca 100644
--- a/src/swrenderer/r_renderthread.cpp
+++ b/src/swrenderer/r_renderthread.cpp
@@ -56,9 +56,10 @@
 
 namespace swrenderer
 {
-	RenderThread::RenderThread(RenderScene *scene)
+	RenderThread::RenderThread(RenderScene *scene, bool mainThread)
 	{
 		Scene = scene;
+		MainThread = mainThread;
 		FrameMemory = std::make_unique<RenderMemory>();
 		DrawQueue = std::make_shared<DrawerCommandQueue>(this);
 		OpaquePass = std::make_unique<RenderOpaquePass>(this);
diff --git a/src/swrenderer/r_renderthread.h b/src/swrenderer/r_renderthread.h
index 8d60de5c7..8a4e8c54b 100644
--- a/src/swrenderer/r_renderthread.h
+++ b/src/swrenderer/r_renderthread.h
@@ -47,12 +47,13 @@ namespace swrenderer
 	class RenderThread
 	{
 	public:
-		RenderThread(RenderScene *scene);
+		RenderThread(RenderScene *scene, bool mainThread = true);
 		~RenderThread();
 
 		RenderScene *Scene;
 		int X1 = 0;
 		int X2 = MAXWIDTH;
+		bool MainThread = false;
 
 		std::unique_ptr<RenderMemory> FrameMemory;
 		std::unique_ptr<RenderOpaquePass> OpaquePass;
@@ -65,7 +66,11 @@ namespace swrenderer
 		std::unique_ptr<DrawSegmentList> DrawSegments;
 		std::unique_ptr<RenderClipSegment> ClipSegments;
 		DrawerCommandQueuePtr DrawQueue;
-		
+
+		// VisibleSprite working buffers
+		short clipbot[MAXWIDTH];
+		short cliptop[MAXWIDTH];
+
 		SWPixelFormatDrawers *Drawers();
 		
 	private:
diff --git a/src/swrenderer/scene/r_scene.cpp b/src/swrenderer/scene/r_scene.cpp
index 8c6ee7198..16a73ec91 100644
--- a/src/swrenderer/scene/r_scene.cpp
+++ b/src/swrenderer/scene/r_scene.cpp
@@ -52,6 +52,8 @@
 EXTERN_CVAR(Bool, r_shadercolormaps)
 EXTERN_CVAR(Int, r_clearbuffer)
 
+CVAR(Bool, r_scene_multithreaded, false, 0);
+
 namespace swrenderer
 {
 	cycle_t WallCycles, PlaneCycles, MaskedCycles, WallScanCycles;
@@ -100,8 +102,19 @@ namespace swrenderer
 		{
 			MainThread()->DrawQueue->Push<ApplySpecialColormapRGBACommand>(CameraLight::Instance()->ShaderColormap(), screen);
 		}
-		
-		DrawerThreads::Execute({ MainThread()->DrawQueue });
+
+		RenderDrawQueues();
+	}
+
+	void RenderScene::RenderDrawQueues()
+	{
+		// Use reverse order so main thread is drawn last
+		std::vector<DrawerCommandQueuePtr> queues;
+		for (auto it = Threads.rbegin(); it != Threads.rend(); ++it)
+		{
+			queues.push_back((*it)->DrawQueue);
+		}
+		DrawerThreads::Execute(queues);
 	}
 
 	void RenderScene::RenderActorView(AActor *actor, bool dontmaplines)
@@ -132,48 +145,7 @@ namespace swrenderer
 			camera->renderflags |= RF_INVISIBLE;
 		}
 
-		MainThread()->FrameMemory->Clear();
-		MainThread()->Clip3DFloors->Cleanup();
-		MainThread()->Clip3DFloors->ResetClip(); // reset clips (floor/ceiling)
-		MainThread()->Portal->CopyStackedViewParameters();
-		MainThread()->ClipSegments->Clear(0, viewwidth);
-		MainThread()->DrawSegments->Clear();
-		MainThread()->PlaneList->Clear();
-		MainThread()->TranslucentPass->Clear();
-		MainThread()->OpaquePass->ClearClip();
-		MainThread()->OpaquePass->ResetFakingUnderwater(); // [RH] Hack to make windows into underwater areas possible
-		MainThread()->Portal->SetMainPortal();
-
-		// Cull things outside the range seen by this thread
-		if (MainThread()->X1 > 0)
-			MainThread()->ClipSegments->Clip(0, MainThread()->X1, true, [](int, int) { return true; });
-		if (MainThread()->X2 < viewwidth)
-			MainThread()->ClipSegments->Clip(MainThread()->X2, viewwidth, true, [](int, int) { return true; });
-
-		WallCycles.Clock();
-		MainThread()->OpaquePass->RenderScene();
-		MainThread()->Clip3DFloors->ResetClip(); // reset clips (floor/ceiling)
-		WallCycles.Unclock();
-
-		NetUpdate();
-
-		if (viewactive)
-		{
-			PlaneCycles.Clock();
-			MainThread()->PlaneList->Render();
-			MainThread()->Portal->RenderPlanePortals();
-			PlaneCycles.Unclock();
-
-			MainThread()->Portal->RenderLinePortals();
-
-			NetUpdate();
-
-			MaskedCycles.Clock();
-			MainThread()->TranslucentPass->Render();
-			MaskedCycles.Unclock();
-
-			NetUpdate();
-		}
+		RenderThreadSlices();
 
 		camera->renderflags = savedflags;
 		interpolator.RestoreInterpolations();
@@ -186,6 +158,94 @@ namespace swrenderer
 		}
 	}
 
+	void RenderScene::RenderThreadSlices()
+	{
+		int numThreads = r_scene_multithreaded ? 8 : 1;
+
+		while (Threads.size() > (size_t)numThreads)
+		{
+			Threads.pop_back();
+		}
+
+		while (Threads.size() < (size_t)numThreads)
+		{
+			Threads.push_back(std::make_unique<RenderThread>(this));
+		}
+
+		for (int i = 0; i < numThreads; i++)
+		{
+			Threads[i]->X1 = viewwidth * i / numThreads;
+			Threads[i]->X2 = viewwidth * (i + 1) / numThreads;
+		}
+
+		for (int i = 0; i < numThreads; i++)
+		{
+			RenderThreadSlice(Threads[i].get());
+		}
+	}
+
+	void RenderScene::RenderThreadSlice(RenderThread *thread)
+	{
+		thread->FrameMemory->Clear();
+		thread->Clip3DFloors->Cleanup();
+		thread->Clip3DFloors->ResetClip(); // reset clips (floor/ceiling)
+		thread->Portal->CopyStackedViewParameters();
+		thread->ClipSegments->Clear(0, viewwidth);
+		thread->DrawSegments->Clear();
+		thread->PlaneList->Clear();
+		thread->TranslucentPass->Clear();
+		thread->OpaquePass->ClearClip();
+		thread->OpaquePass->ResetFakingUnderwater(); // [RH] Hack to make windows into underwater areas possible
+		thread->Portal->SetMainPortal();
+
+		// Cull things outside the range seen by this thread
+		VisibleSegmentRenderer visitor;
+		if (thread->X1 > 0)
+			thread->ClipSegments->Clip(0, thread->X1, true, &visitor);
+		if (thread->X2 < viewwidth)
+			thread->ClipSegments->Clip(thread->X2, viewwidth, true, &visitor);
+
+		if (thread->MainThread)
+			WallCycles.Clock();
+
+		thread->OpaquePass->RenderScene();
+		thread->Clip3DFloors->ResetClip(); // reset clips (floor/ceiling)
+
+		if (thread == MainThread())
+			WallCycles.Unclock();
+
+		if (thread->MainThread)
+			NetUpdate();
+
+		if (viewactive)
+		{
+			if (thread->MainThread)
+				PlaneCycles.Clock();
+
+			thread->PlaneList->Render();
+			thread->Portal->RenderPlanePortals();
+
+			if (thread->MainThread)
+				PlaneCycles.Unclock();
+
+			thread->Portal->RenderLinePortals();
+
+			if (thread->MainThread)
+				NetUpdate();
+
+			if (thread->MainThread)
+				MaskedCycles.Clock();
+
+			thread->TranslucentPass->Render();
+
+			if (thread->MainThread)
+				MaskedCycles.Unclock();
+
+			if (thread->MainThread)
+				NetUpdate();
+		}
+	}
+
 	void RenderScene::RenderViewToCanvas(AActor *actor, DCanvas *canvas, int x, int y, int width, int height, bool dontmaplines)
 	{
 		auto viewport = RenderViewport::Instance();
@@ -202,8 +262,7 @@ namespace swrenderer
 		viewport->SetViewport(width, height, WidescreenRatio);
 
 		RenderActorView(actor, dontmaplines);
-
-		DrawerThreads::Execute({ MainThread()->DrawQueue });
+		RenderDrawQueues();
 		
 		viewport->RenderTarget = screen;
 
diff --git a/src/swrenderer/scene/r_scene.h b/src/swrenderer/scene/r_scene.h
index a592ae1d3..d3053884c 100644
--- a/src/swrenderer/scene/r_scene.h
+++ b/src/swrenderer/scene/r_scene.h
@@ -46,6 +46,9 @@ namespace swrenderer
 
 	private:
 		void RenderActorView(AActor *actor, bool dontmaplines = false);
+		void RenderDrawQueues();
+		void RenderThreadSlices();
+		void RenderThreadSlice(RenderThread *thread);
 		
 		bool dontmaplines = false;
 		int clearcolor = 0;
diff --git a/src/swrenderer/segments/r_clipsegment.cpp b/src/swrenderer/segments/r_clipsegment.cpp
index 6cfaaa2a0..4e25daa35 100644
--- a/src/swrenderer/segments/r_clipsegment.cpp
+++ b/src/swrenderer/segments/r_clipsegment.cpp
@@ -86,7 +86,7 @@ namespace swrenderer
 		return true;
 	}
 
-	bool RenderClipSegment::Clip(int first, int last, bool solid, VisibleSegmentCallback callback)
+	bool RenderClipSegment::Clip(int first, int last, bool solid, VisibleSegmentRenderer *visitor)
 	{
 		cliprange_t *next, *start;
 		int i, j;
@@ -104,7 +104,7 @@ namespace swrenderer
 			if (last <= start->first)
 			{
 				// Post is entirely visible (above start).
-				if (!callback(first, last))
+				if (!visitor->RenderWallSegment(first, last))
 					return true;
 
 				// Insert a new clippost for solid walls.
@@ -131,7 +131,7 @@ namespace swrenderer
 			}
 
 			// There is a fragment above *start.
-			if (callback(first, start->first) && solid)
+			if (visitor->RenderWallSegment(first, start->first) && solid)
 			{
 				start->first = first; // Adjust the clip size for solid walls
 			}
@@ -146,7 +146,7 @@ namespace swrenderer
 		while (last >= (next + 1)->first)
 		{
 			// There is a fragment between two posts.
-			clipsegment = callback(next->last, (next + 1)->first);
+			clipsegment = visitor->RenderWallSegment(next->last, (next + 1)->first);
 			next++;
 
 			if (last <= next->last)
@@ -158,7 +158,7 @@ namespace swrenderer
 		}
 
 		// There is a fragment after *next.
-		clipsegment = callback(next->last, last);
+		clipsegment = visitor->RenderWallSegment(next->last, last);
 
 	crunch:
 		if (!clipsegment)
diff --git a/src/swrenderer/segments/r_clipsegment.h b/src/swrenderer/segments/r_clipsegment.h
index b2fde462e..48a083ba6 100644
--- a/src/swrenderer/segments/r_clipsegment.h
+++ b/src/swrenderer/segments/r_clipsegment.h
@@ -17,11 +17,18 @@ namespace swrenderer
 {
 	typedef bool(*VisibleSegmentCallback)(int x1, int x2);
 
+	class VisibleSegmentRenderer
+	{
+	public:
+		virtual ~VisibleSegmentRenderer() { }
+		virtual bool RenderWallSegment(int x1, int x2) { return true; }
+	};
+
 	class RenderClipSegment
 	{
 	public:
 		void Clear(short left, short right);
-		bool Clip(int x1, int x2, bool solid, VisibleSegmentCallback callback);
+		bool Clip(int x1, int x2, bool solid, VisibleSegmentRenderer *visitor);
 		bool Check(int first, int last);
 		bool IsVisible(int x1, int x2);
 		
diff --git a/src/swrenderer/things/r_playersprite.cpp b/src/swrenderer/things/r_playersprite.cpp
index 78e9975e6..0fb0b27c0 100644
--- a/src/swrenderer/things/r_playersprite.cpp
+++ b/src/swrenderer/things/r_playersprite.cpp
@@ -78,7 +78,6 @@ namespace swrenderer
 		DPSprite*	psp;
 		DPSprite*	weapon;
 		sector_t*	sec = NULL;
-		static sector_t tempsec;
 		int			floorlight, ceilinglight;
 		F3DFloor *rover;
 
diff --git a/src/swrenderer/things/r_playersprite.h b/src/swrenderer/things/r_playersprite.h
index 09274702a..588f9f8dc 100644
--- a/src/swrenderer/things/r_playersprite.h
+++ b/src/swrenderer/things/r_playersprite.h
@@ -88,5 +88,6 @@ namespace swrenderer
 		enum { BASEYCENTER = 100 };
 
 		TArray<HWAccelPlayerSprite> AcceleratedSprites;
+		sector_t tempsec;
 	};
 }
diff --git a/src/swrenderer/things/r_visiblesprite.cpp b/src/swrenderer/things/r_visiblesprite.cpp
index ac411db57..17996b5e9 100644
--- a/src/swrenderer/things/r_visiblesprite.cpp
+++ b/src/swrenderer/things/r_visiblesprite.cpp
@@ -43,8 +43,8 @@ namespace swrenderer
 {
 	void VisibleSprite::Render(RenderThread *thread)
 	{
-		static short clipbot[MAXWIDTH];
-		static short cliptop[MAXWIDTH];
+		short *clipbot = thread->clipbot;
+		short *cliptop = thread->cliptop;
 
 		VisibleSprite *spr = this;