diff --git a/src/p_map.c b/src/p_map.c
index 0a9107ee5..2380a6d52 100644
--- a/src/p_map.c
+++ b/src/p_map.c
@@ -3107,7 +3107,7 @@ static void P_HitSlideLine(line_t *ld)
 	lineangle >>= ANGLETOFINESHIFT;
 	deltaangle >>= ANGLETOFINESHIFT;
 
-	movelen = P_AproxDistance(tmxmove, tmymove);
+	movelen = R_PointToDist2(0, 0, tmxmove, tmymove);
 	newlen = FixedMul(movelen, FINECOSINE(deltaangle));
 
 	tmxmove = FixedMul(newlen, FINECOSINE(lineangle));