Fix for #29241, ocean sim modifier crash when removing all vertices.

The object draw method did not check for valid data when mapping back to original face, constructive modifier on empty mesh does that.

source/blender/editors/space_view3d/drawobject.c

@@ -2696,7 +2696,8 @@ static int draw_em_fancy__setFaceOpts(void *UNUSED(userData), int index, int *UN
 {
 	EditFace *efa = EM_get_face_for_index(index);
 
-	if (efa->h==0) {
+	/* efa=0 for constructive modifier on empty mesh */
+	if (efa && efa->h==0) {
 		GPU_enable_material(efa->mat_nr+1, NULL);
 		return 1;
 	}