commons-geometry-core/src/test/java/org/apache/commons/geometry/core/partitioning/bsp/BSPTreeVisitorTest.java

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 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
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 *      http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.commons.geometry.core.partitioning.bsp;

import org.apache.commons.geometry.core.partition.test.TestBSPTree;
import org.apache.commons.geometry.core.partition.test.TestBSPTree.TestNode;
import org.apache.commons.geometry.core.partition.test.TestLine;
import org.apache.commons.geometry.core.partition.test.TestPoint2D;
import org.apache.commons.geometry.core.partitioning.bsp.BSPTreeVisitor.ClosestFirstVisitor;
import org.apache.commons.geometry.core.partitioning.bsp.BSPTreeVisitor.FarthestFirstVisitor;
import org.junit.Assert;
import org.junit.Test;

public class BSPTreeVisitorTest {

    @Test
    public void testDefaultVisitOrder() {
        // arrange
        BSPTreeVisitor<TestPoint2D, TestNode> visitor = n -> BSPTreeVisitor.Result.CONTINUE;

        // act/assert
        Assert.assertEquals(BSPTreeVisitor.Order.NODE_MINUS_PLUS, visitor.visitOrder(null));
    }

    @Test
    public void testClosestFirst() {
        // arrange
        TestBSPTree tree = new TestBSPTree();
        TestNode root = tree.getRoot();
        root.cut(TestLine.X_AXIS);
        root.getMinus().cut(TestLine.Y_AXIS);
        root.getPlus().cut(TestLine.Y_AXIS);

        // act
        checkClosestFirst(new TestPoint2D(1, 1), root, BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkClosestFirst(new TestPoint2D(1, 1), root.getMinus(), BSPTreeVisitor.Order.PLUS_NODE_MINUS);
        checkClosestFirst(new TestPoint2D(1, 1), root.getPlus(), BSPTreeVisitor.Order.PLUS_NODE_MINUS);

        checkClosestFirst(new TestPoint2D(-1, 1), root, BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkClosestFirst(new TestPoint2D(-1, 1), root.getMinus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkClosestFirst(new TestPoint2D(-1, 1), root.getPlus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);

        checkClosestFirst(new TestPoint2D(-1, -1), root, BSPTreeVisitor.Order.PLUS_NODE_MINUS);
        checkClosestFirst(new TestPoint2D(-1, -1), root.getMinus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkClosestFirst(new TestPoint2D(-1, -1), root.getPlus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);

        checkClosestFirst(new TestPoint2D(1, -1), root, BSPTreeVisitor.Order.PLUS_NODE_MINUS);
        checkClosestFirst(new TestPoint2D(1, -1), root.getMinus(), BSPTreeVisitor.Order.PLUS_NODE_MINUS);
        checkClosestFirst(new TestPoint2D(1, -1), root.getPlus(), BSPTreeVisitor.Order.PLUS_NODE_MINUS);

        checkClosestFirst(TestPoint2D.ZERO, root.getPlus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkClosestFirst(TestPoint2D.ZERO, root.getPlus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkClosestFirst(TestPoint2D.ZERO, root.getPlus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);
    }

    @Test
    public void testFarthestFirst() {
        // arrange
        TestBSPTree tree = new TestBSPTree();
        TestNode root = tree.getRoot();
        root.cut(TestLine.X_AXIS);
        root.getMinus().cut(TestLine.Y_AXIS);
        root.getPlus().cut(TestLine.Y_AXIS);

        // act
        checkFarthestFirst(new TestPoint2D(1, 1), root, BSPTreeVisitor.Order.PLUS_NODE_MINUS);
        checkFarthestFirst(new TestPoint2D(1, 1), root.getMinus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkFarthestFirst(new TestPoint2D(1, 1), root.getPlus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);

        checkFarthestFirst(new TestPoint2D(-1, 1), root, BSPTreeVisitor.Order.PLUS_NODE_MINUS);
        checkFarthestFirst(new TestPoint2D(-1, 1), root.getMinus(), BSPTreeVisitor.Order.PLUS_NODE_MINUS);
        checkFarthestFirst(new TestPoint2D(-1, 1), root.getPlus(), BSPTreeVisitor.Order.PLUS_NODE_MINUS);

        checkFarthestFirst(new TestPoint2D(-1, -1), root, BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkFarthestFirst(new TestPoint2D(-1, -1), root.getMinus(), BSPTreeVisitor.Order.PLUS_NODE_MINUS);
        checkFarthestFirst(new TestPoint2D(-1, -1), root.getPlus(), BSPTreeVisitor.Order.PLUS_NODE_MINUS);

        checkFarthestFirst(new TestPoint2D(1, -1), root, BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkFarthestFirst(new TestPoint2D(1, -1), root.getMinus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkFarthestFirst(new TestPoint2D(1, -1), root.getPlus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);

        checkFarthestFirst(TestPoint2D.ZERO, root.getPlus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkFarthestFirst(TestPoint2D.ZERO, root.getPlus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);
        checkFarthestFirst(TestPoint2D.ZERO, root.getPlus(), BSPTreeVisitor.Order.MINUS_NODE_PLUS);
    }

    private static void checkClosestFirst(TestPoint2D target, TestNode node, BSPTreeVisitor.Order order) {
        ClosestFirstStubVisitor visitor = new ClosestFirstStubVisitor(target);

        Assert.assertSame(target, visitor.getTarget());
        Assert.assertEquals(order, visitor.visitOrder(node));
    }

    private static void checkFarthestFirst(TestPoint2D target, TestNode node, BSPTreeVisitor.Order order) {
        FarthestFirstStubVisitor visitor = new FarthestFirstStubVisitor(target);

        Assert.assertSame(target, visitor.getTarget());
        Assert.assertEquals(order, visitor.visitOrder(node));
    }

    private static class ClosestFirstStubVisitor extends ClosestFirstVisitor<TestPoint2D, TestNode> {

        public ClosestFirstStubVisitor(TestPoint2D target) {
            super(target);
        }

        @Override
        public Result visit(TestNode node) {
            return Result.CONTINUE;
        }
    }

    private static class FarthestFirstStubVisitor extends FarthestFirstVisitor<TestPoint2D, TestNode> {

        public FarthestFirstStubVisitor(TestPoint2D target) {
            super(target);
        }

        @Override
        public Result visit(TestNode node) {
            return Result.CONTINUE;
        }
    }
}