When tracing perimeters, allow doubling back at a dead-end with exactly

1 lane (usually a cycleway or footway). This correctly produces a few
more blocks in some maps -- as the goldenfile diff (and manual
verificaton) shows!

Also allow jumping from LTN browse to debug mode, to conveniently work
on blockfinding problems.

game/src/ltn/browse.rs

@@ -3,12 +3,13 @@ use geom::Distance;
 use map_gui::tools::{CityPicker, DrawRoadLabels, Navigator, URLManager};
 use widgetry::mapspace::{World, WorldOutcome};
 use widgetry::{
-    Color, EventCtx, GfxCtx, HorizontalAlignment, Key, Outcome, Panel, State, TextExt,
+    lctrl, Color, EventCtx, GfxCtx, HorizontalAlignment, Key, Outcome, Panel, State, TextExt,
     VerticalAlignment, Widget,
 };
 
 use super::Neighborhood;
 use crate::app::{App, Transition};
+use crate::debug::DebugMode;
 use crate::ltn::partition::{NeighborhoodID, Partitioning};
 
 pub struct BrowseNeighborhoods {
@@ -88,6 +89,10 @@ impl State<App> for BrowseNeighborhoods {
             ));
         }
 
+        if ctx.input.pressed(lctrl(Key::D)) {
+            return Transition::Push(DebugMode::new_state(ctx, app));
+        }
+
         Transition::Keep
     }
 

geom/src/ring.rs

@@ -22,19 +22,19 @@ impl Ring {
             bail!("Can't make a ring with mismatching first/last points");
         }
 
-        if pts.windows(2).any(|pair| pair[0] == pair[1]) {
-            bail!("Ring has ~dupe adjacent pts");
+        if let Some(pair) = pts.windows(2).find(|pair| pair[0] == pair[1]) {
+            bail!("Ring has duplicate adjacent points near {}", pair[0]);
         }
 
         let result = Ring { pts };
 
         let mut seen_pts = HashSet::new();
         for pt in result.pts.iter().skip(1) {
+            if seen_pts.contains(&pt.to_hashable()) {
+                bail!("Ring has repeat non-adjacent points near {}", pt);
+            }
             seen_pts.insert(pt.to_hashable());
         }
-        if seen_pts.len() != result.pts.len() - 1 {
-            bail!("Ring has repeat non-adjacent points");
-        }
 
         Ok(result)
     }

map_model/src/objects/block.rs

@@ -423,15 +423,10 @@ impl Block {
             let lane1 = pair[0].get_outermost_lane(map);
             let road1 = map.get_parent(lane1.id);
             let lane2 = pair[1].get_outermost_lane(map);
-            // TODO What about tracing along a road with exactly one lane? False error. I'm not
-            // sure looking at lanes here is helpful at all...
-            if lane1.id == lane2.id {
-                bail!(
-                    "Perimeter road has duplicate adjacent roads at {}: {:?}",
-                    lane1.id,
-                    perimeter.roads
-                );
-            }
+            // If lane1 and lane2 are the same, then it just means we found a dead-end road with
+            // exactly one lane, which is usually a footway or cycleway that legitimately is a
+            // dead-end, or connects to some other road we didn't import. We'll just trace around
+            // it like a normal dead-end road.
             let mut pl = match pair[0].side {
                 SideOfRoad::Right => road1.center_pts.must_shift_right(road1.get_half_width()),
                 SideOfRoad::Left => road1.center_pts.must_shift_left(road1.get_half_width()),
@@ -481,6 +476,7 @@ impl Block {
                     // At dead-ends, trace around the intersection on the longer side
                     let longer = prev_i.is_deadend();
                     if let Some(slice) = ring.get_slice_between(*last_pt, pl.first_pt(), longer) {
+                        // TODO Only if it doesn't have repeat points?
                         pts.extend(slice.into_points());
                     }
                 }

tests/goldenfiles/blockfinding.txt

@@ -1,14 +1,14 @@
 data/system/us/seattle/maps/montlake.bin
-    158 single blocks (2 failures to blockify), 1 partial merges, 0 failures to blockify partitions
+    158 single blocks (1 failures to blockify), 1 partial merges, 0 failures to blockify partitions
 data/system/us/seattle/maps/downtown.bin
     1449 single blocks (21 failures to blockify), 8 partial merges, 0 failures to blockify partitions
 data/system/us/seattle/maps/lakeslice.bin
     1033 single blocks (4 failures to blockify), 5 partial merges, 1 failures to blockify partitions
 data/system/us/phoenix/maps/tempe.bin
-    407 single blocks (9 failures to blockify), 1 partial merges, 0 failures to blockify partitions
+    407 single blocks (8 failures to blockify), 1 partial merges, 0 failures to blockify partitions
 data/system/gb/leeds/maps/north.bin
-    2589 single blocks (20 failures to blockify), 10 partial merges, 1 failures to blockify partitions
+    2589 single blocks (17 failures to blockify), 10 partial merges, 1 failures to blockify partitions
 data/system/gb/bristol/maps/east.bin
-    1061 single blocks (13 failures to blockify), 6 partial merges, 1 failures to blockify partitions
+    1061 single blocks (9 failures to blockify), 6 partial merges, 1 failures to blockify partitions
 data/system/gb/london/maps/camden.bin
-    3519 single blocks (32 failures to blockify), 23 partial merges, 3 failures to blockify partitions
+    3519 single blocks (27 failures to blockify), 23 partial merges, 3 failures to blockify partitions