diff --git a/src/r_segs.h b/src/r_segs.h
index 1c852ddc7..4d88ee071 100644
--- a/src/r_segs.h
+++ b/src/r_segs.h
@@ -21,5 +21,6 @@
 void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2);
 void R_RenderThickSideRange(drawseg_t *ds, INT32 x1, INT32 x2, ffloor_t *pffloor);
 void R_StoreWallRange(INT32 start, INT32 stop);
+transnum_t R_GetLinedefTransTable(fixed_t alpha);
 
 #endif