autorouter,router: route only single layer at a time

It makes no sense to route multiple layers at once until we implement
automatic via placement, which is going to take a lot of time.

src/autorouter/autorouter.rs

@@ -1,26 +1,47 @@
-use std::sync::{Arc, Mutex};
+use std::{
+    iter::Peekable,
+    sync::{Arc, Mutex},
+};
 
 use geo::Point;
 use petgraph::{
-    graph::EdgeIndices,
+    graph::{EdgeIndex, EdgeIndices, NodeIndex},
     visit::{EdgeRef, IntoEdgeReferences},
 };
 use spade::InsertionError;
 
 use crate::{
     autorouter::ratsnest::{Ratsnest, RatsnestVertexIndex},
-    drawing::{dot::FixedDotIndex, rules::RulesTrait},
+    drawing::{dot::FixedDotIndex, graph::GetLayer, rules::RulesTrait},
     layout::{connectivity::BandIndex, Layout},
     router::{navmesh::Navmesh, Router, RouterObserverTrait, RoutingError},
     triangulation::GetVertexIndex,
 };
 
 pub struct Autoroute {
-    edge_indices: EdgeIndices<usize>,
+    edge_indices: Peekable<EdgeIndices<usize>>,
     navmesh: Navmesh, // Useful for debugging.
 }
 
 impl Autoroute {
+    pub fn new(
+        edge_indices: EdgeIndices<usize>,
+        autorouter: &mut Autorouter<impl RulesTrait>,
+    ) -> Option<Self> {
+        let mut peekable_edge_indices = edge_indices.peekable();
+        let Some(ratline) = peekable_edge_indices.peek() else {
+            return None;
+        };
+
+        let mut layout = autorouter.layout.lock().unwrap();
+        let (from_dot, to_dot) = Self::terminating_dots(autorouter, &mut layout, ratline);
+        let navmesh = Self::next_navmesh(&layout, from_dot);
+        Some(Self {
+            edge_indices: peekable_edge_indices,
+            navmesh,
+        })
+    }
+
     pub fn next<R: RulesTrait>(
         &mut self,
         autorouter: &mut Autorouter<R>,
@@ -29,11 +50,33 @@ impl Autoroute {
         let Some(ratline) = self.edge_indices.next() else {
             return None;
         };
-        let (from, to) = autorouter.ratsnest.graph().edge_endpoints(ratline).unwrap();
 
         let (navmesh, from_dot, to_dot) = {
             let mut layout = autorouter.layout.lock().unwrap();
-            let navmesh = Navmesh::new(&layout).unwrap();
+            let (from_dot, to_dot) = Self::terminating_dots(autorouter, &mut layout, &ratline);
+            let navmesh = Self::next_navmesh(&layout, from_dot);
+            (navmesh, from_dot, to_dot)
+        };
+
+        let router = Router::new_with_navmesh(
+            &mut autorouter.layout,
+            from_dot,
+            std::mem::replace(&mut self.navmesh, navmesh),
+        );
+        router.unwrap().route_band(to_dot, 100.0, observer);
+        Some(())
+    }
+
+    fn terminating_dots<R: RulesTrait>(
+        autorouter: &Autorouter<R>,
+        layout: &mut Layout<R>,
+        ratline: &EdgeIndex<usize>,
+    ) -> (FixedDotIndex, FixedDotIndex) {
+        let (from, to) = autorouter
+            .ratsnest
+            .graph()
+            .edge_endpoints(*ratline)
+            .unwrap();
 
         let from_dot = match autorouter
             .ratsnest
@@ -57,17 +100,12 @@ impl Autoroute {
             RatsnestVertexIndex::Zone(zone) => layout.zone_apex(zone),
         };
 
-            (navmesh, from_dot, to_dot)
-        };
+        (from_dot, to_dot)
+    }
 
-        let router = Router::new_with_navmesh(
-            &mut autorouter.layout,
-            std::mem::replace(&mut self.navmesh, navmesh),
-        );
-        router
-            .unwrap()
-            .route_band(from_dot, to_dot, 100.0, observer);
-        Some(())
+    fn next_navmesh(layout: &Layout<impl RulesTrait>, from: FixedDotIndex) -> Navmesh {
+        let layer = layout.drawing().primitive(from).layer();
+        Navmesh::new(layout, layer).unwrap()
     }
 
     pub fn navmesh(&self) -> &Navmesh {
@@ -86,18 +124,16 @@ impl<R: RulesTrait> Autorouter<R> {
         Ok(Self { ratsnest, layout })
     }
 
-    pub fn autoroute(&mut self, observer: &mut impl RouterObserverTrait<R>) {
-        let mut it = self.autoroute_iter();
+    pub fn autoroute(&mut self, layer: u64, observer: &mut impl RouterObserverTrait<R>) {
+        if let Some(mut it) = self.autoroute_iter() {
             while let Some(()) = it.next(self, observer) {
                 //
             }
         }
-
-    pub fn autoroute_iter(&mut self) -> Autoroute {
-        Autoroute {
-            edge_indices: self.ratsnest.graph().edge_indices(),
-            navmesh: Navmesh::new(&self.layout.lock().unwrap()).unwrap(),
     }
+
+    pub fn autoroute_iter(&mut self) -> Option<Autoroute> {
+        Autoroute::new(self.ratsnest.graph().edge_indices(), self)
     }
 
     pub fn layout(&self) -> &Arc<Mutex<Layout<R>>> {

src/bin/topola-egui/app.rs

@@ -199,7 +199,7 @@ impl eframe::App for App {
 
                         execute(async move {
                             let mut autorouter = Autorouter::new(layout).unwrap();
-                            let mut it = autorouter.autoroute_iter();
+                            if let Some(mut it) = autorouter.autoroute_iter() {
                                 shared_data.lock().unwrap().navmesh = Some(it.navmesh().clone());
 
                                 while let Some(()) = it.next(
@@ -208,7 +208,9 @@ impl eframe::App for App {
                                         shared_data: shared_data.clone(),
                                     },
                                 ) {
-                                shared_data.lock().unwrap().navmesh = Some(it.navmesh().clone());
+                                    shared_data.lock().unwrap().navmesh =
+                                        Some(it.navmesh().clone());
+                                }
                             }
                         });
                     }

src/router/navmesh.rs

@@ -83,7 +83,7 @@ pub struct Navmesh {
 }
 
 impl Navmesh {
-    pub fn new(layout: &Layout<impl RulesTrait>) -> Result<Self, InsertionError> {
+    pub fn new(layout: &Layout<impl RulesTrait>, layer: u64) -> Result<Self, InsertionError> {
         let mut this = Self {
             triangulation: Triangulation::new(layout.drawing().geometry().graph().node_bound()),
             vertex_to_triangulation_vertex: Vec::new(),
@@ -91,7 +91,7 @@ impl Navmesh {
         this.vertex_to_triangulation_vertex
             .resize(layout.drawing().geometry().graph().node_bound(), None);
 
-        for node in layout.drawing().primitive_nodes() {
+        for node in layout.drawing().layer_primitive_nodes(layer) {
             let center = node.primitive(layout.drawing()).shape().center();
 
             match node {
@@ -113,7 +113,7 @@ impl Navmesh {
             }
         }
 
-        for node in layout.drawing().primitive_nodes() {
+        for node in layout.drawing().layer_primitive_nodes(layer) {
             // Add rails as vertices. This is how the navmesh differs from the triangulation.
             match node {
                 PrimitiveIndex::LooseBend(bend) => {

src/router/router.rs

@@ -6,6 +6,7 @@ use petgraph::visit::EdgeRef;
 use spade::InsertionError;
 use thiserror::Error;
 
+use crate::drawing::graph::GetLayer;
 use crate::geometry::primitive::PrimitiveShapeTrait;
 use crate::layout::connectivity::BandIndex;
 use crate::layout::Layout;
@@ -59,6 +60,7 @@ pub trait RouterObserverTrait<R: RulesTrait> {
 
 pub struct Router<'a, R: RulesTrait> {
     layout: &'a mut Arc<Mutex<Layout<R>>>,
+    from: FixedDotIndex,
     navmesh: Navmesh,
 }
 
@@ -143,37 +145,48 @@ impl<'a, RO: RouterObserverTrait<R>, R: RulesTrait> AstarStrategy<&Navmesh, f64>
 }
 
 impl<'a, R: RulesTrait> Router<'a, R> {
-    pub fn new(layout: &'a mut Arc<Mutex<Layout<R>>>) -> Result<Self, InsertionError> {
-        let navmesh = Navmesh::new(&layout.lock().unwrap())?;
-        Self::new_with_navmesh(layout, navmesh)
+    pub fn new(
+        layout: &'a mut Arc<Mutex<Layout<R>>>,
+        from: FixedDotIndex,
+    ) -> Result<Self, InsertionError> {
+        let navmesh = {
+            let layout = layout.lock().unwrap();
+            let layer = layout.drawing().primitive(from).layer();
+            Navmesh::new(&layout, layer)?
+        };
+        Self::new_with_navmesh(layout, from, navmesh)
     }
 
     pub fn new_with_navmesh(
         layout: &'a mut Arc<Mutex<Layout<R>>>,
+        from: FixedDotIndex,
         navmesh: Navmesh,
     ) -> Result<Self, InsertionError> {
-        Ok(Self { layout, navmesh })
+        Ok(Self {
+            layout,
+            from,
+            navmesh,
+        })
     }
 
     pub fn route_band(
         &mut self,
-        from: FixedDotIndex,
         to: FixedDotIndex,
         width: f64,
         observer: &mut impl RouterObserverTrait<R>,
     ) -> Result<BandIndex, RoutingError> {
         let mut tracer = self.tracer();
 
-        let trace = tracer.start(from, width);
+        let trace = tracer.start(self.from, width);
         let band = trace.band;
 
         let (_cost, _path) = astar(
             &self.navmesh,
-            from.into(),
+            self.from.into(),
             &mut RouterAstarStrategy::new(tracer, trace, to.into(), observer),
         )
         .ok_or(RoutingError {
-            from,
+            from: self.from,
             to,
             source: RoutingErrorKind::AStar,
         })?;
@@ -198,7 +211,7 @@ impl<'a, R: RulesTrait> Router<'a, R> {
             (from_dot, to_dot)
         };
 
-        self.route_band(from_dot, to_dot, width, observer)
+        self.route_band(to_dot, width, observer)
     }
 
     fn tracer(&mut self) -> Tracer<R> {