Add 4-layer routing test

examples/assets/e2e4layer.json

@@ -0,0 +1,22 @@
+{
+  "layerCount": 4,
+  "minTraceWidth": 0.15,
+  "obstacles": [],
+  "connections": [
+    {
+      "name": "conn1",
+      "pointsToConnect": [
+        { "x": 1, "y": 1, "layer": "top", "pcb_port_id": "p1" },
+        { "x": 9, "y": 9, "layer": "bottom", "pcb_port_id": "p2" }
+      ]
+    },
+    {
+      "name": "conn2",
+      "pointsToConnect": [
+        { "x": 9, "y": 1, "layer": "top", "pcb_port_id": "p3" },
+        { "x": 1, "y": 9, "layer": "bottom", "pcb_port_id": "p4" }
+      ]
+    }
+  ],
+  "bounds": { "minX": 0, "maxX": 10, "minY": 0, "maxY": 10 }
+}

lib/data-structures/FlatbushIndex.ts

@@ -7,7 +7,7 @@ export class FlatbushIndex<T> implements ISpatialIndex<T> {
   private currentIndex = 0
 
   constructor(numItems: number) {
-    this.index = new Flatbush(numItems)
+    this.index = new Flatbush(Math.max(numItems, 1))
   }
 
   insert(item: T, minX: number, minY: number, maxX: number, maxY: number) {
@@ -30,6 +30,6 @@ export class FlatbushIndex<T> implements ISpatialIndex<T> {
 
   clear() {
     this.items = []
-    this.index = new Flatbush(0)
+    this.index = new Flatbush(1)
   }
 }

lib/data-structures/ObstacleTree.ts

@@ -19,8 +19,11 @@ export class ObstacleSpatialHashIndex {
     implementation: "native" | "rbush" | "flatbush" = "native",
     obstacles: Obstacle[] = [],
   ) {
-    if (implementation === "flatbush") {
+    if (implementation === "flatbush" && obstacles.length > 0) {
       this.idx = new FlatbushIndex<Obstacle>(obstacles.length)
+    } else if (implementation === "flatbush" && obstacles.length === 0) {
+      // flatbush cannot index zero items, fall back to rbush
+      this.idx = new RbushIndex<Obstacle>()
     } else if (implementation === "rbush") {
       this.idx = new RbushIndex<Obstacle>()
     } else {
@@ -50,7 +53,9 @@ export class ObstacleSpatialHashIndex {
 
     // bulk-load initial obstacles
     obstacles.forEach((o) => this.insert(o))
-    if (implementation === "flatbush") this.idx.finish?.()
+    if (implementation === "flatbush" && obstacles.length > 0) {
+      this.idx.finish?.()
+    }
   }
 
   insert(o: Obstacle) {

tests/core3.test.tsx

@@ -47,4 +47,4 @@ test("core3 - 0402 columns", async () => {
   expect(convertCircuitJsonToPcbSvg(circuitJson)).toMatchSvgSnapshot(
     import.meta.path,
   )
-})
+}, 20_000)

tests/e2e3.test.ts

@@ -0,0 +1,18 @@
+import { expect, test } from "bun:test"
+import { CapacityMeshSolver } from "../lib"
+import type { SimpleRouteJson } from "lib/types"
+import { convertSrjToGraphicsObject } from "./fixtures/convertSrjToGraphicsObject"
+import e2e4layer from "../examples/assets/e2e4layer.json"
+
+// Simple end-to-end test for 4 layer routing
+
+test("should solve a 4-layer board", async () => {
+  const srj: SimpleRouteJson = e2e4layer as any
+  const solver = new CapacityMeshSolver(srj)
+  await solver.solve()
+  const result = solver.getOutputSimpleRouteJson()
+  expect(result.layerCount).toBe(4)
+  expect(convertSrjToGraphicsObject(result)).toMatchGraphicsSvg(
+    import.meta.path,
+  )
+})

tests/fixtures/convertSrjToGraphicsObject.ts

@@ -10,7 +10,7 @@ export const convertSrjToGraphicsObject = (srj: SimpleRouteJson) => {
   const points: Point[] = []
 
   const colorMap: Record<string, string> = getColorMap(srj)
-  const layerCount = 2
+  const layerCount = srj.layerCount
 
   // Add points for each connection's pointsToConnect
   if (srj.connections) {