diff --git a/src/p_map.cpp b/src/p_map.cpp
index e6b189d7b..f757f089c 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -2220,7 +2220,7 @@ bool P_TryMove(AActor *thing, const DVector2 &pos,
 			// so that the renderer can properly calculate an interpolated position along the movement path.
 			if (thing == players[consoleplayer].camera)
 			{
-				divline_t dl1 = { besthit.Oldrefpos.X,besthit.Oldrefpos.Y, besthit.Refpos.X - besthit.Oldrefpos.Y, besthit.Refpos.Y - besthit.Oldrefpos.Y };
+				divline_t dl1 = { besthit.Oldrefpos.X,besthit.Oldrefpos.Y, besthit.Refpos.X - besthit.Oldrefpos.X, besthit.Refpos.Y - besthit.Oldrefpos.Y };
 				DVector3a hit = { {dl1.x + dl1.dx * bestfrac, dl1.y + dl1.dy * bestfrac, 0.},0. };
 
 				R_AddInterpolationPoint(hit);