private N splitInternalNode()

in commons-geometry-core/src/main/java/org/apache/commons/geometry/core/partitioning/bsp/AbstractBSPTree.java [719:790]
48 lines of code
8 McCabe index (conditional complexity)

    private N splitInternalNode(final N node, final HyperplaneConvexSubset<P> partitioner) {
        // split the partitioner and node cut with each other's hyperplanes to determine their relative positions
        final Split<? extends HyperplaneConvexSubset<P>> partitionerSplit = partitioner.split(node.getCutHyperplane());
        final Split<? extends HyperplaneConvexSubset<P>> nodeCutSplit =
                node.getCut().split(partitioner.getHyperplane());

        final SplitLocation partitionerSplitSide = partitionerSplit.getLocation();
        final SplitLocation nodeCutSplitSide = nodeCutSplit.getLocation();

        final N result = createNode();

        final N resultMinus;
        final N resultPlus;

        if (partitionerSplitSide == SplitLocation.PLUS) {
            if (nodeCutSplitSide == SplitLocation.PLUS) {
                // partitioner is on node cut plus side, node cut is on partitioner plus side
                final N nodePlusSplit = splitSubtree(node.getPlus(), partitioner);

                resultMinus = nodePlusSplit.getMinus();

                resultPlus = copyNode(node);
                resultPlus.setSubtree(node.getCut(), importSubtree(node.getMinus()), nodePlusSplit.getPlus());
            } else {
                // partitioner is on node cut plus side, node cut is on partitioner minus side
                final N nodePlusSplit = splitSubtree(node.getPlus(), partitioner);

                resultMinus = copyNode(node);
                resultMinus.setSubtree(node.getCut(), importSubtree(node.getMinus()), nodePlusSplit.getMinus());

                resultPlus = nodePlusSplit.getPlus();
            }
        } else if (partitionerSplitSide == SplitLocation.MINUS) {
            if (nodeCutSplitSide == SplitLocation.MINUS) {
                // partitioner is on node cut minus side, node cut is on partitioner minus side
                final N nodeMinusSplit = splitSubtree(node.getMinus(), partitioner);

                resultMinus = copyNode(node);
                resultMinus.setSubtree(node.getCut(), nodeMinusSplit.getMinus(), importSubtree(node.getPlus()));

                resultPlus = nodeMinusSplit.getPlus();
            } else {
                // partitioner is on node cut minus side, node cut is on partitioner plus side
                final N nodeMinusSplit = splitSubtree(node.getMinus(), partitioner);

                resultMinus = nodeMinusSplit.getMinus();

                resultPlus = copyNode(node);
                resultPlus.setSubtree(node.getCut(), nodeMinusSplit.getPlus(), importSubtree(node.getPlus()));
            }
        } else if (partitionerSplitSide == SplitLocation.BOTH) {
            // partitioner and node cut split each other
            final N nodeMinusSplit = splitSubtree(node.getMinus(), partitionerSplit.getMinus());
            final N nodePlusSplit = splitSubtree(node.getPlus(), partitionerSplit.getPlus());

            resultMinus = copyNode(node);
            resultMinus.setSubtree(nodeCutSplit.getMinus(), nodeMinusSplit.getMinus(), nodePlusSplit.getMinus());

            resultPlus = copyNode(node);
            resultPlus.setSubtree(nodeCutSplit.getPlus(), nodeMinusSplit.getPlus(), nodePlusSplit.getPlus());
        } else {
            // partitioner and node cut are parallel or anti-parallel
            final boolean sameOrientation = partitioner.getHyperplane().similarOrientation(node.getCutHyperplane());

            resultMinus = importSubtree(sameOrientation ? node.getMinus() : node.getPlus());
            resultPlus = importSubtree(sameOrientation ? node.getPlus() : node.getMinus());
        }

        result.setSubtree(partitioner, resultMinus, resultPlus);

        return result;
    }