- fixed and simplified the vertex counter for wall polygons.

This is now allowed to overestimate the number of vertices to reduce computation time for a rarely occuring special case that was eating most of the time and was causing errors with some walls.

src/hwrenderer/scene/hw_walls.cpp

@@ -1522,6 +1522,7 @@ void GLWall::Process(HWDrawInfo *di, seg_t *seg, sector_t * frontsector, sector_
 		}
 		v1 = seg->v1;
 		v2 = seg->v2;
+		flags |= GLWF_NOSPLITLOWER | GLWF_NOSPLITLOWER;	// seg-splitting not needed for single segs.
 	}