From b9d8d239485a60550e52b332fbc472d0cd406ca8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Motiejus=20Jak=C5=A1tys?= <motiejus@uber.com>
Date: Sat, 1 May 2021 15:47:44 +0300
Subject: [PATCH] wm_elimination bugfixes

---
 IV/tests.sql |  2 +-
 IV/wm.sql    | 19 +++++++++++++------
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/IV/tests.sql b/IV/tests.sql
index 33fc541..02785dd 100644
--- a/IV/tests.sql
+++ b/IV/tests.sql
@@ -54,7 +54,7 @@ insert into wm_figures (name, way) values ('selfcrossing-1-rev',ST_Reverse(ST_Tr
 delete from wm_debug where name in (select distinct name from wm_figures);
 delete from wm_demo where name in (select distinct name from wm_figures);
 insert into wm_demo (name, way) select name, ST_SimplifyWM(way, .1, name) from wm_figures where name != 'fig8';
-insert into wm_demo (name, way) select name, ST_SimplifyWM(way, .1, name) from wm_figures where name = 'fig8';
+insert into wm_demo (name, way) select name, ST_SimplifyWM(way, 10, name) from wm_figures where name = 'fig8';
 
 
 do $$
diff --git a/IV/wm.sql b/IV/wm.sql
index 8cc5e2f..dde5c27 100644
--- a/IV/wm.sql
+++ b/IV/wm.sql
@@ -392,8 +392,8 @@ begin
       insert into wm_debug (stage, name, gen, nbend, way, props) values(
         'ebendattrs',
         dbgname,
-        i,
         dbggen,
+        i,
         bend,
         jsonb_build_object(
           'area', res.area,
@@ -449,16 +449,23 @@ begin
     continue when bendattrs[i].adjsize >= leftsize;
     continue when bendattrs[i].adjsize >= rightsize;
 
-    -- Local minimum. Elminate!
+    -- Local minimum. Elminate bend!
     mutated = true;
     tmpbendattrs.bend = st_makeline(
       st_pointn(bendattrs[i].bend, 1),
       st_pointn(bendattrs[i].bend, -1)
     );
     bendattrs[i] = tmpbendattrs;
-    -- jump over the next bend, because the current bend disappeared,
-    -- and there is no way the other one can be a "local minima".
-    i = i + 1;
+    -- remove last vertex of the previous bend and
+    -- first vertex of the next bend, because bends always
+    -- share a line segment together
+    tmpbendattrs.bend = st_removepoint(bendattrs[i-1].bend, st_npoints(bendattrs[i-1].bend)-1);
+    bendattrs[i-1] = tmpbendattrs;
+    tmpbendattrs.bend = st_removepoint(bendattrs[i+1].bend, 0);
+    bendattrs[i+1] = tmpbendattrs;
+    -- the next bend's adjsize is now messed up; it should not be taken
+    -- into consideration for other local minimas. Skip over 2.
+    i = i + 2;
   end loop;
 
   if dbgname is not null then
@@ -467,7 +474,7 @@ begin
     end loop;
 
     insert into wm_debug(stage, name, gen, nbend, way) values(
-      'eelimination',
+      'felimination',
       dbgname,
       dbggen,
       generate_subscripts(dbgbends, 1),