diff --git a/win/X11/tile2x11.c b/win/X11/tile2x11.c
index 774b6e636..762f95ba2 100644
--- a/win/X11/tile2x11.c
+++ b/win/X11/tile2x11.c
@@ -22,6 +22,9 @@ unsigned char tile_bytes[TILE_X * TILE_Y * (MAX_GLYPH + TILES_PER_ROW)];
 unsigned char *curr_tb = tile_bytes;
 unsigned char x11_colormap[MAXCOLORMAPSIZE][3];
 
+extern void NDECL(monst_globals_init);
+extern void NDECL(objects_globals_init);
+
 /* Look up the given pixel and return its colormap index. */
 static unsigned char
 pix_to_colormap(pix)
@@ -187,6 +190,10 @@ char **argv;
         exit(1);
     }
 
+    /* without this, the comparisons check uninitialized data and won't pass */
+    objects_globals_init();
+    monst_globals_init();
+
     fp = fopen(OUTNAME, "w");
     if (!fp) {
         Fprintf(stderr, "can't open output file\n");