dont reach into DrawRoad's polygon directly from DrawIntersection

TODO.md

@@ -45,6 +45,14 @@
 		- https://gis-kingcounty.opendata.arcgis.com/datasets/traffic-signs--sign-point/
 
 - multiple lanes
+	- prep: get rid of other_side
+	- display + mouseover parking lane and sidewalk
+		- all roads have sidewalk on both sides, oneways only have parking lane on one side
+	- model bikes in driving lanes (as slow cars)
+	- add random bike lanes, figure out how turns would work
+	- be able to convert between parking and bike lanes, recompute the turns
+
+	- when rendering sidewalks, have an option for a grass buffer
 
 ## Code cleanup
 

docs/lanes.md

@@ -34,3 +34,22 @@ Some modeling questions:
 	- maintaining directional sanity could be useful
 	- what's the UI for changing lane types?
 	- it's a bit arbitrary which lane should draw the yellow center lines
+
+
+
+Initial design:
+- "Road" becomes "Lane" with a type
+- don't need to know sibling lanes yet
+- arbitrarily, one lane might have extra bits/geometry for yellow center line markings
+- ideally, get rid of one-wayness and original center points, and plumb along pre-shifted lines
+	- but due to the polyline problem (affecting both geom center line layer that agents follow, and polygons for drawing), can't do this. encapsulate the messiness at least.
+	- so, store one way and orig points and index, but have an accessor
+	- as a compromise, dont interpet OSM points on a one-way road as the center, but as the edge.
+
+
+
+The polyline problem:
+- https://www.codeproject.com/Articles/226569/Drawing-polylines-by-tessellation
+- https://stackoverflow.com/questions/36475254/polylines-outline-construction-drawing-thick-polylines
+- Will lengths change? Is this a problem?
+- Drawing cars as rectangles is funky, because if their front is aligned to a new line segment, their back juts into the center of the road

editor/src/render/intersection.rs

@@ -29,16 +29,15 @@ impl DrawIntersection {
         bounds: &Bounds,
     ) -> DrawIntersection {
         let mut pts: Vec<Vec2d> = Vec::new();
-        // TODO this smashes encapsulation to bits :D
         for r in &map.get_roads_to_intersection(inter.id) {
-            let dr = &roads[r.id.0];
-            pts.push(dr.polygons.last().unwrap()[2]);
-            pts.push(dr.polygons.last().unwrap()[3]);
+            let (pt1, pt2) = roads[r.id.0].get_end_crossing();
+            pts.push(pt1);
+            pts.push(pt2);
         }
         for r in &map.get_roads_from_intersection(inter.id) {
-            let dr = &roads[r.id.0];
-            pts.push(dr.polygons[0][0]);
-            pts.push(dr.polygons[0][1]);
+            let (pt1, pt2) = roads[r.id.0].get_start_crossing();
+            pts.push(pt1);
+            pts.push(pt2);
         }
 
         let center = geometry::gps_to_screen_space(&inter.point, bounds);

editor/src/render/road.rs

@@ -129,4 +129,16 @@ impl DrawRoad {
         lines.extend(r.osm_tags.iter().cloned());
         lines
     }
+
+    // Get the line marking the end of the road, perpendicular to the direction of the road
+    pub(crate) fn get_end_crossing(&self) -> (Vec2d, Vec2d) {
+        (
+            self.polygons.last().unwrap()[2],
+            self.polygons.last().unwrap()[3],
+        )
+    }
+
+    pub(crate) fn get_start_crossing(&self) -> (Vec2d, Vec2d) {
+        (self.polygons[0][0], self.polygons[0][1])
+    }
 }

geom/src/geometry.rs

@@ -67,7 +67,8 @@ pub fn thick_multiline(style: &ThickLine, pts: &[Pt2D]) -> Vec<Vec<Vec2d>> {
         let quad2 = thick_line(style, pt2, pt3);
         // Of course, the original quad
         polygons.push(quad1.clone());
-        // Add some triangles to fill in the gaps.
+        // Add some triangles to fill in the gaps. Comment this out to see part of the polyline
+        // problem more clearly.
         polygons.push(vec![
             [pt2.x(), pt2.y()],
             quad1[3],

map_model/src/lib.rs

@@ -151,11 +151,16 @@ pub struct Map {
 #[derive(Debug)]
 pub struct Road {
     pub id: RoadID,
-    // The orientation is implied by the order of these points
-    pub points: Vec<Pt2D>,
     pub osm_tags: Vec<String>,
     pub osm_way_id: i64,
+
+    // Ideally all of these would just become translated center points immediately, but this is
+    // hard due to the polyline problem.
+
+    // The orientation is implied by the order of these points
+    pub points: Vec<Pt2D>,
     pub other_side: Option<RoadID>,
+    //offset: u8,
 }
 
 impl PartialEq for Road {