frustum hit test now works with faces also

client/src/helpers/circularFrustumIntersect.ts

@@ -147,42 +147,71 @@ export class CircularFrustumIntersection {
             intersectsBounds: (box: THREE.Box3) => intersectionResultToBvh(CircularFrustumIntersection.intersectsBox(box, localFrustum)),
 
             intersectsTriangle: (tri: ExtendedTriangle, _index: number, contained: boolean) => {
-                // If the whole node was CONTAINED, every triangle is inside — fast path
                 if (contained) {
                     const worldPoint = tri.a.clone().applyMatrix4(mesh.matrixWorld);
                     const depth = worldFrustum.axisNormalized.dot(worldPoint.clone().sub(worldFrustum.apex));
                     results.push({ object: mesh, point: worldPoint, depth, triangle: tri });
-                    return !findAll;  // stop if we only need first hit
+                    return !findAll;
                 }
 
-                // Test all three vertices; take the closest that's inside
                 let bestDepth = Infinity;
-                let bestLocal: THREE.Vector3 | null = null;
+                let bestLocal: THREE.Vector3 | undefined = undefined;
 
-                for (const v of [tri.a, tri.b, tri.c] as THREE.Vector3[]) {
+                const tryPoint = (v: THREE.Vector3) => {
                     const d = CircularFrustumIntersection.pointAxialDepth(v, localFrustum);
-                    if (d !== 'NOT_INTERSECTED') {
+                    if (d !== 'NOT_INTERSECTED' && (d as number) < bestDepth) {
-                        if (d < bestDepth) {
+                        bestDepth = d as number;
-                            bestDepth = d;
+                        bestLocal = v.clone();
-                            bestLocal = v;
-                        }
                     }
+                };
+
+                // 1. Test vertices
+                tryPoint(tri.a);
+                tryPoint(tri.b);
+                tryPoint(tri.c);
+
+                // 2. For each edge, find the point closest to the frustum axis ray,
+                //    and also the point closest to the apex.
+                //    This catches triangles that straddle the cone surface.
+                const edges: [THREE.Vector3, THREE.Vector3][] = [
+                    [tri.a, tri.b],
+                    [tri.b, tri.c],
+                    [tri.c, tri.a],
+                ];
+
+                for (const [a, b] of edges) {
+                    const edge = b.clone().sub(a);
+                    const toA = a.clone().sub(localFrustum.apex);
+
+                    // Closest point on edge segment to the axis ray
+                    const edgeDir = edge.clone().normalize();
+                    const axisDotEdge = localFrustum.axisNormalized.dot(edgeDir);
+                    const denom = 1 - axisDotEdge * axisDotEdge;
+
+                    if (Math.abs(denom) > 1e-10) {
+                        const t = (
+                            localFrustum.axisNormalized.dot(toA) * axisDotEdge
+                            - toA.dot(edgeDir)
+                        ) / denom;
+                        const edgeLen = edge.length();
+                        const tClamped = Math.max(0, Math.min(edgeLen, t));
+                        const pointOnEdge = a.clone().addScaledVector(edgeDir, tClamped);
+                        tryPoint(pointOnEdge);
                     }
 
-                // Also test closest point on triangle to the frustum axis ray
+                    // Closest point on edge to the apex itself
-                const ray = new THREE.Ray(localFrustum.apex, localFrustum.axisNormalized);
+                    const tApex = Math.max(0, Math.min(1, -toA.dot(edge) / edge.lengthSq()));
-                const closest = new THREE.Vector3();
+                    tryPoint(a.clone().addScaledVector(edge, tApex));
-                tri.closestPointToPoint(ray.origin, closest); // ExtendedTriangle has this
-                const d = CircularFrustumIntersection.pointAxialDepth(closest, localFrustum);
-                if (d !== 'NOT_INTERSECTED') {
-                    if (d < bestDepth) {
-                        bestDepth = d;
-                        bestLocal = closest;
-                    }
                 }
 
-                if (bestLocal) {
+                // 3. Closest point on the triangle face to the apex
-                    const worldPoint = bestLocal.clone().applyMatrix4(mesh.matrixWorld);
+                const closestOnFace = new THREE.Vector3();
+                tri.closestPointToPoint(localFrustum.apex, closestOnFace);
+                if (!isNaN(closestOnFace.x))
+                    tryPoint(closestOnFace);
+
+                if (bestLocal !== undefined) {
+                    const worldPoint = (bestLocal as THREE.Vector3).clone().applyMatrix4(mesh.matrixWorld);
                     const worldDepth = worldFrustum.axisNormalized.dot(worldPoint.clone().sub(worldFrustum.apex));
                     results.push({ object: mesh, point: worldPoint, depth: worldDepth, triangle: tri });
                     return !findAll;