Fix edge-crossing PCB holes in board mesh rendering (#158)

* Fix edge-crossing PCB holes in board mesh rendering

* patch

* patch

Author: Abse2001

lib/utils/cut-board-mesh-outside-board-boundary.ts

@@ -0,0 +1,51 @@
+import * as geom3 from "@jscad/modeling/src/geometries/geom3"
+import measureBoundingBox from "@jscad/modeling/src/measurements/measureBoundingBox"
+import { subtract } from "@jscad/modeling/src/operations/booleans"
+import { rotateX } from "@jscad/modeling/src/operations/transforms"
+import type { PcbBoard, PcbHole, PcbPanel, PcbPlatedHole } from "circuit-json"
+import type { STLMesh } from "../types"
+import { batchedUnion } from "./batched-union"
+import type { BoardCutout } from "./pcb-board-cutouts"
+import { createCutoutGeoms } from "./pcb-board-cutouts"
+import {
+  createBoardOutlineGeom,
+  createBoundingBox,
+  createHoleGeoms,
+  geom3ToTriangles,
+} from "./pcb-board-geometry"
+
+export const cutBoardMeshOutsideBoardBoundary = ({
+  board,
+  center,
+  thickness,
+  holes,
+  platedHoles,
+  cutouts,
+  segments,
+}: {
+  board: PcbPanel | PcbBoard
+  center: { x: number; y: number }
+  thickness: number
+  holes: PcbHole[]
+  platedHoles: PcbPlatedHole[]
+  cutouts: BoardCutout[]
+  segments: number
+}): STLMesh => {
+  let boardGeom = createBoardOutlineGeom(board, center, thickness)
+  const subtractGeoms = [
+    ...createHoleGeoms(center, thickness, holes, platedHoles, segments),
+    ...createCutoutGeoms(center, thickness, cutouts, segments),
+  ]
+
+  if (subtractGeoms.length > 0) {
+    boardGeom = subtract(boardGeom, batchedUnion(subtractGeoms))
+  }
+
+  boardGeom = rotateX(-Math.PI / 2, boardGeom)
+
+  const polygons = geom3.toPolygons(boardGeom)
+  return {
+    triangles: geom3ToTriangles(boardGeom, polygons),
+    boundingBox: createBoundingBox(measureBoundingBox(boardGeom)),
+  }
+}

lib/utils/has-boundary-crossing-loops.ts

@@ -0,0 +1,53 @@
+import type { Vec2Point } from "./geometry-loops"
+
+const LOOP_CONTAINMENT_EPSILON = 1e-8
+
+export const hasBoundaryCrossingLoops = (
+  outerLoop: Vec2Point[],
+  innerLoops: Vec2Point[][],
+): boolean => {
+  return innerLoops.some((loop) =>
+    loop.some((point) => !isPointStrictlyInsideLoop(point, outerLoop)),
+  )
+}
+
+const isPointStrictlyInsideLoop = (
+  point: Vec2Point,
+  loop: Vec2Point[],
+): boolean => {
+  let inside = false
+
+  for (let i = 0, j = loop.length - 1; i < loop.length; j = i++) {
+    const a = loop[i]!
+    const b = loop[j]!
+
+    if (isPointOnSegment(point, a, b)) {
+      return false
+    }
+
+    const intersects =
+      a.y > point.y !== b.y > point.y &&
+      point.x < ((b.x - a.x) * (point.y - a.y)) / (b.y - a.y) + a.x
+
+    if (intersects) {
+      inside = !inside
+    }
+  }
+
+  return inside
+}
+
+const isPointOnSegment = (
+  point: Vec2Point,
+  a: Vec2Point,
+  b: Vec2Point,
+): boolean => {
+  const cross = (point.y - a.y) * (b.x - a.x) - (point.x - a.x) * (b.y - a.y)
+  if (Math.abs(cross) > LOOP_CONTAINMENT_EPSILON) return false
+
+  const dot = (point.x - a.x) * (b.x - a.x) + (point.y - a.y) * (b.y - a.y)
+  if (dot < -LOOP_CONTAINMENT_EPSILON) return false
+
+  const squaredLength = (b.x - a.x) ** 2 + (b.y - a.y) ** 2
+  return dot <= squaredLength + LOOP_CONTAINMENT_EPSILON
+}

lib/utils/pcb-board-geometry.ts

@@ -2,11 +2,7 @@ import * as geom3 from "@jscad/modeling/src/geometries/geom3"
 import type { Geom3 } from "@jscad/modeling/src/geometries/types"
 import type { Vec2 } from "@jscad/modeling/src/maths/types"
 import { extrudeLinear } from "@jscad/modeling/src/operations/extrusions"
-import {
-  rotateX,
-  rotateZ,
-  translate,
-} from "@jscad/modeling/src/operations/transforms"
+import { rotateZ, translate } from "@jscad/modeling/src/operations/transforms"
 import {
   polygon,
   rectangle,
@@ -20,6 +16,8 @@ import type {
   Point,
 } from "circuit-json"
 import type { BoundingBox, STLMesh, Triangle } from "../types"
+import { cutBoardMeshOutsideBoardBoundary } from "./cut-board-mesh-outside-board-boundary"
+import { hasBoundaryCrossingLoops } from "./has-boundary-crossing-loops"
 import { normalizeLoop, signedArea, type Vec2Point } from "./geometry-loops"
 import type { BoardCutout } from "./pcb-board-cutouts"
 import {
@@ -329,6 +327,18 @@ export const createBoardMesh = (
     }),
   ]
 
+  if (hasBoundaryCrossingLoops(outerLoop, holeLoops)) {
+    return cutBoardMeshOutsideBoardBoundary({
+      board,
+      center,
+      thickness,
+      holes,
+      platedHoles,
+      cutouts,
+      segments,
+    })
+  }
+
   return buildBoardMeshFromLoops({ outerLoop, holeLoops, thickness })
 }