RegionBSPTree3D build()

in commons-geometry-euclidean/src/main/java/org/apache/commons/geometry/euclidean/threed/shape/Sphere.java [276:328]
36 lines of code
2 McCabe index (conditional complexity)

        RegionBSPTree3D build() {
            final RegionBSPTree3D tree = RegionBSPTree3D.empty();

            final Vector3D center = sphere.getCenter();
            final double radius = sphere.getRadius();
            final Precision.DoubleEquivalence precision = sphere.getPrecision();

            // insert the primary split planes
            final Plane plusXPlane = Planes.fromPointAndNormal(center, Vector3D.Unit.PLUS_X, precision);
            final Plane plusYPlane = Planes.fromPointAndNormal(center, Vector3D.Unit.PLUS_Y, precision);
            final Plane plusZPlane = Planes.fromPointAndNormal(center, Vector3D.Unit.PLUS_Z, precision);

            tree.insert(plusXPlane.span(), RegionCutRule.INHERIT);
            tree.insert(plusYPlane.span(), RegionCutRule.INHERIT);
            tree.insert(plusZPlane.span(), RegionCutRule.INHERIT);

            // create the vertices for the octahedron
            final double cx = center.getX();
            final double cy = center.getY();
            final double cz = center.getZ();

            final Vector3D maxX = Vector3D.of(cx + radius, cy, cz);
            final Vector3D minX = Vector3D.of(cx - radius, cy, cz);

            final Vector3D maxY = Vector3D.of(cx, cy + radius, cz);
            final Vector3D minY = Vector3D.of(cx, cy - radius, cz);

            final Vector3D maxZ = Vector3D.of(cx, cy, cz + radius);
            final Vector3D minZ = Vector3D.of(cx, cy, cz - radius);

            // partition and subdivide the face triangles and insert them into the tree
            final RegionNode3D root = tree.getRoot();

            try {
                partitionAndInsert(root.getMinus().getMinus().getMinus(), minX, minZ, minY, 0);
                partitionAndInsert(root.getMinus().getMinus().getPlus(), minX, minY, maxZ, 0);

                partitionAndInsert(root.getMinus().getPlus().getMinus(), minX, maxY, minZ, 0);
                partitionAndInsert(root.getMinus().getPlus().getPlus(), minX, maxZ, maxY, 0);

                partitionAndInsert(root.getPlus().getMinus().getMinus(), maxX, minY, minZ, 0);
                partitionAndInsert(root.getPlus().getMinus().getPlus(), maxX, maxZ, minY, 0);

                partitionAndInsert(root.getPlus().getPlus().getMinus(), maxX, minZ, maxY, 0);
                partitionAndInsert(root.getPlus().getPlus().getPlus(), maxX, maxY, maxZ, 0);
            } catch (final IllegalStateException | IllegalArgumentException exc) {
                // standardize any tree construction failure as an IllegalStateException
                throw new IllegalStateException("Failed to construct sphere approximation with subdivision count " +
                        subdivisions + ": " + exc.getMessage(), exc);
            }

            return tree;
        }