diff --git a/src/rendering/hwrenderer/scene/hw_walls.cpp b/src/rendering/hwrenderer/scene/hw_walls.cpp
index f44c727e68..8336a6847c 100644
--- a/src/rendering/hwrenderer/scene/hw_walls.cpp
+++ b/src/rendering/hwrenderer/scene/hw_walls.cpp
@@ -2024,7 +2024,7 @@ void HWWall::Process(HWDrawInfo *di, seg_t *seg, sector_t * frontsector, sector_
 			if (frontsector->GetTexture(sector_t::floor) != skyflatnum || backsector->GetTexture(sector_t::floor) != skyflatnum)
 			{
 				// the back sector's floor obstructs part of this wall
-				if (!seg->linedef->flags & ML_DRAWFULLHEIGHT)
+				if ((seg->linedef->flags & ML_DRAWFULLHEIGHT) == 0)
 				{
 					if (ffh1 > bch1 && ffh2 > bch2)
 					{
@@ -2108,7 +2108,7 @@ void HWWall::Process(HWDrawInfo *di, seg_t *seg, sector_t * frontsector, sector_
 
 		/* bottom texture */
 		// the back sector's ceiling obstructs part of this wall (specially important for sky sectors)
-		if (!seg->linedef->flags & ML_DRAWFULLHEIGHT)
+		if ((seg->linedef->flags & ML_DRAWFULLHEIGHT) == 0)
 		{
 			if (fch1 < bfh1 && fch2 < bfh2)
 			{