diff --git a/src/level/doomdata.h b/src/level/doomdata.h
index 8b14f7c..a1adc19 100644
--- a/src/level/doomdata.h
+++ b/src/level/doomdata.h
@@ -120,6 +120,12 @@ struct MapSector
 	short	tag;
 };
 
+enum SecPlaneType
+{
+	PLANE_FLOOR,
+	PLANE_CEILING,
+};
+
 struct IntSector
 {
 	// none of the sector properties are used by the node builder
@@ -140,7 +146,14 @@ struct IntSector
 
 	bool controlsector;
 	TArray<IntSector*> x3dfloors;
-	bool skySector;
+
+	union
+	{
+		bool skyPlanes[2];
+		struct { bool skyFloor, skyCeiling; };
+	};
+
+	inline const char* GetTextureName(int plane) const { return plane != PLANE_FLOOR ? data.ceilingpic : data.floorpic; }
 
 	TArray<UDMFKey> props;
 
diff --git a/src/level/level_light.cpp b/src/level/level_light.cpp
index c823a5b..ac1d18a 100644
--- a/src/level/level_light.cpp
+++ b/src/level/level_light.cpp
@@ -78,7 +78,7 @@ void FLevel::SetupLights()
 				{
 					FString hex = FString("0x") + FString(key.value);
 					hex.StripChars("\"");
-					printf("Sun color: %s\n", hex);
+					printf("Sun color: %s\n", hex.GetChars());
 					int rgb = hex.ToULong();
 					lightcolor = (uint32_t)rgb;
 				}
@@ -124,23 +124,21 @@ void FLevel::SetupLights()
 
 void FLevel::CheckSkySectors()
 {
-	char name[65];
-
-	for (int i = 0; i < (int)Sectors.Size(); ++i)
+	for (auto& sector : Sectors)
 	{
-		//if (mapDef && mapDef->sunIgnoreTag != 0 && Sectors[i].data.tag == mapDef->sunIgnoreTag)
-		//	continue;
-
-		strncpy(name, Sectors[i].data.ceilingpic, 64);
-		name[64] = 0;
-
-		if (!strncmp(name, "F_SKY001", 64) || !strncmp(name, "F_SKY1", 64) || !strncmp(name, "F_SKY", 64))
+		for (int i = 0; i < 2; ++i)
 		{
-			Sectors[i].skySector = true;
-		}
-		else
-		{
-			Sectors[i].skySector = false;
+			sector.skyPlanes[i] = false;
+
+			//if (mapDef && mapDef->sunIgnoreTag != 0 && sector.data.tag == mapDef->sunIgnoreTag)
+			//	continue;
+
+			const auto name = sector.GetTextureName(i);
+
+			if (!strncmp(name, "F_SKY001", 64) || !strncmp(name, "F_SKY1", 64) || !strncmp(name, "F_SKY", 64))
+			{
+				sector.skyPlanes[i] = true;
+			}
 		}
 	}
 }
diff --git a/src/lightmap/gpuraytracer.cpp b/src/lightmap/gpuraytracer.cpp
index cdeec99..333fce2 100644
--- a/src/lightmap/gpuraytracer.cpp
+++ b/src/lightmap/gpuraytracer.cpp
@@ -97,7 +97,7 @@ void GPURaytracer::Raytrace(LevelMesh* level)
 		size_t maxTasks = (size_t)rayTraceImageSize * rayTraceImageSize;
 		for (size_t startTask = 0; startTask < tasks.size(); startTask += maxTasks)
 		{
-			printf("\r%.1f%%\t%d/%d", double(startTask) / double(tasks.size()) * 100, startTask, tasks.size());
+			printf("\r%.1f%%\t%llu/%llu", double(startTask) / double(tasks.size()) * 100, startTask, tasks.size());
 			size_t numTasks = std::min(tasks.size() - startTask, maxTasks);
 			UploadTasks(tasks.data() + startTask, numTasks);
 
@@ -145,7 +145,7 @@ void GPURaytracer::Raytrace(LevelMesh* level)
 			EndTracing();
 			DownloadTasks(tasks.data() + startTask, numTasks);
 		}
-		printf("\r%.1f%%\t%d/%d\n", 100.0, tasks.size(), tasks.size());
+		printf("\r%.1f%%\t%llu/%llu\n", 100.0, tasks.size(), tasks.size());
 	});
 
 	if (device->renderdoc)
@@ -405,7 +405,7 @@ void GPURaytracer::CreateVertexAndIndexBuffers()
 			info.EmissiveColor = vec3(0.0f, 0.0f, 0.0f);
 		}
 
-		info.SamplingDistance = surface->sampleDimension;
+		info.SamplingDistance = float(surface->sampleDimension);
 		surfaces.push_back(info);
 	}
 
diff --git a/src/lightmap/levelmesh.cpp b/src/lightmap/levelmesh.cpp
index 2107317..8f2dcb6 100644
--- a/src/lightmap/levelmesh.cpp
+++ b/src/lightmap/levelmesh.cpp
@@ -570,7 +570,17 @@ void LevelMesh::CreateSideSurfaces(FLevel &doomMap, IntSideDef *side)
 		// bottom seg
 		if (v1Bottom < v1BottomBack || v2Bottom < v2BottomBack)
 		{
-			if (side->bottomtexture[0] != '-')
+			bool bSky = false;
+
+			if (front->skyFloor && back->skyFloor)
+			{
+				if (front->data.floorheight != back->data.floorheight && side->bottomtexture[0] == '-')
+				{
+					bSky = true;
+				}
+			}
+
+			if (side->bottomtexture[0] != '-' || bSky)
 			{
 				float texWidth = 128.0f;
 				float texHeight = 128.0f;
@@ -593,6 +603,7 @@ void LevelMesh::CreateSideSurfaces(FLevel &doomMap, IntSideDef *side)
 				surf->plane.SetDistance(surf->verts[0]);
 				surf->type = ST_LOWERSIDE;
 				surf->typeIndex = typeIndex;
+				surf->bSky = bSky;
 				surf->controlSector = nullptr;
 				surf->sampleDimension = (surf->sampleDimension = side->GetSampleDistanceBottom()) ? surf->sampleDimension : defaultSamples;
 
@@ -620,7 +631,7 @@ void LevelMesh::CreateSideSurfaces(FLevel &doomMap, IntSideDef *side)
 		{
 			bool bSky = false;
 
-			if (front->skySector && back->skySector)
+			if (front->skyCeiling && back->skyCeiling)
 			{
 				if (front->data.ceilingheight != back->data.ceilingheight && side->toptexture[0] == '-')
 				{
@@ -726,6 +737,7 @@ void LevelMesh::CreateFloorSurface(FLevel &doomMap, MapSubsectorEx *sub, IntSect
 	surf->numVerts = sub->numlines;
 	surf->verts.resize(surf->numVerts);
 	surf->uvs.resize(surf->numVerts);
+	surf->bSky = sector->skyFloor;
 
 	if (!is3DFloor)
 	{
@@ -764,7 +776,7 @@ void LevelMesh::CreateCeilingSurface(FLevel &doomMap, MapSubsectorEx *sub, IntSe
 	surf->numVerts = sub->numlines;
 	surf->verts.resize(surf->numVerts);
 	surf->uvs.resize(surf->numVerts);
-	surf->bSky = sector->skySector;
+	surf->bSky = sector->skyCeiling;
 
 	if (!is3DFloor)
 	{