diff --git a/src/swrenderer/line/r_line.cpp b/src/swrenderer/line/r_line.cpp
index 18db1752fb..60269bf1b1 100644
--- a/src/swrenderer/line/r_line.cpp
+++ b/src/swrenderer/line/r_line.cpp
@@ -550,7 +550,7 @@ namespace swrenderer
 		RenderWallSegmentTextures(start, stop);
 
 		if (fake3D & 7) {
-			return !(fake3D & FAKE3D_FAKEMASK);
+			return (fake3D & FAKE3D_FAKEMASK) == 0;
 		}
 
 		// save sprite clipping info
@@ -607,7 +607,7 @@ namespace swrenderer
 			WallPortals.Push(pds);
 		}
 
-		return !(fake3D & FAKE3D_FAKEMASK);
+		return (fake3D & FAKE3D_FAKEMASK) == 0;
 	}
 
 	void SWRenderLine::SetWallVariables(bool needlights)
diff --git a/src/swrenderer/segments/r_clipsegment.cpp b/src/swrenderer/segments/r_clipsegment.cpp
index 7a2d8b1f48..04bef89077 100644
--- a/src/swrenderer/segments/r_clipsegment.cpp
+++ b/src/swrenderer/segments/r_clipsegment.cpp
@@ -144,9 +144,9 @@ namespace swrenderer
 			}
 
 			// There is a fragment above *start.
-			if (!callback(first, start->first) && solid)
+			if (callback(first, start->first) && solid)
 			{
-				start->first = first;
+				start->first = first; // Adjust the clip size for solid walls
 			}
 		}