wm

commit 1deefa46707a67f54cb3c9ec0d036acebcc3d659 (tree)
parent a770776c04d2752acff9ee02ddc8716900f79ab5
Author: Motiejus Jakštys <motiejus@jakstys.lt>
Date:   Wed, 19 May 2021 22:57:46 +0300

add excuses

Diffstat:
M
wm.sql
 | 
5
++++-

1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/wm.sql b/wm.sql
@@ -228,6 +228,10 @@ begin
       continue when st_numgeometries(multi) = 2 and
         (st_contains(bends[j], a) or st_contains(bends[j], b));
 
+      -- Sincere apologies to someone who will need to debug the block below.
+      -- To understand it, I suggest you take a pencil and paper, draw a
+      -- self-crossing bend (fig6 from the article works well), and figure out
+      -- what happens here, by hand.
       prev_length = array_length(bends, 1);
       if j < i then
         -- remove first vertex of the following bend, because the last
@@ -251,7 +255,6 @@ begin
         bends = bends[1:i] || bends[j+1:prev_length];
       end if;
       j = j - prev_length + array_length(bends, 1);
-
     end loop;
 
   end loop;