diff --git a/src/swrenderer/r_renderthread.cpp b/src/swrenderer/r_renderthread.cpp
index fa20da456..bb2816a94 100644
--- a/src/swrenderer/r_renderthread.cpp
+++ b/src/swrenderer/r_renderthread.cpp
@@ -103,23 +103,28 @@ namespace swrenderer
 		// calls to GetPixels for this to work.
 
 		static std::mutex loadmutex;
-		loadmutex.lock();
-		try
+
+		std::unique_lock<std::mutex> lock(loadmutex);
+
+		texture->GetPixels();
+		const FTexture::Span *spans;
+		texture->GetColumn(0, &spans);
+		if (Viewport->RenderTarget->IsBgra())
 		{
-			texture->GetPixels();
-			const FTexture::Span *spans;
-			texture->GetColumn(0, &spans);
-			if (Viewport->RenderTarget->IsBgra())
-			{
-				texture->GetPixelsBgra();
-				texture->GetColumnBgra(0, &spans);
-			}
-			loadmutex.unlock();
+			texture->GetPixelsBgra();
+			texture->GetColumnBgra(0, &spans);
 		}
-		catch (...)
+	}
+
+	void RenderThread::PreparePolyObject(subsector_t *sub)
+	{
+		static std::mutex polyobjmutex;
+
+		std::unique_lock<std::mutex> lock(polyobjmutex);
+
+		if (sub->BSP == nullptr || sub->BSP->bDirty)
 		{
-			loadmutex.unlock();
-			throw;
+			sub->BuildPolyBSP();
 		}
 	}
 }
diff --git a/src/swrenderer/r_renderthread.h b/src/swrenderer/r_renderthread.h
index 3a439421c..6bc23bba5 100644
--- a/src/swrenderer/r_renderthread.h
+++ b/src/swrenderer/r_renderthread.h
@@ -83,6 +83,9 @@ namespace swrenderer
 
 		// Make sure texture can accessed safely
 		void PrepareTexture(FTexture *texture);
+
+		// Setup poly object in a threadsafe manner
+		void PreparePolyObject(subsector_t *sub);
 		
 	private:
 		std::unique_ptr<SWTruecolorDrawers> tc_drawers;
diff --git a/src/swrenderer/scene/r_opaque_pass.cpp b/src/swrenderer/scene/r_opaque_pass.cpp
index 7d6d6b461..da820d7d2 100644
--- a/src/swrenderer/scene/r_opaque_pass.cpp
+++ b/src/swrenderer/scene/r_opaque_pass.cpp
@@ -390,10 +390,8 @@ namespace swrenderer
 
 	void RenderOpaquePass::AddPolyobjs(subsector_t *sub)
 	{
-		if (sub->BSP == nullptr || sub->BSP->bDirty)
-		{
-			sub->BuildPolyBSP();
-		}
+		Thread->PreparePolyObject(sub);
+
 		if (sub->BSP->Nodes.Size() == 0)
 		{
 			RenderSubsector(&sub->BSP->Subsectors[0]);