MathTest.java

/*
 * The MIT License (MIT)
 *
 * FXGL - JavaFX Game Library
 *
 * Copyright (c) 2015-2017 AlmasB (almaslvl@gmail.com)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package org.jbox2d;

import com.almasb.fxgl.core.math.Vec2;
import junit.framework.TestCase;
import org.jbox2d.common.JBoxUtils;
import org.jbox2d.common.Mat22;
import org.jbox2d.common.Mat33;
import org.jbox2d.common.Vec3;

import java.util.Random;

/**
 * @author Daniel Murphy
 */
public class MathTest extends TestCase {

    private final static int MAX = (int) (Float.MAX_VALUE / 1000);
    private final static int RAND_ITERS = 100;

    public void testFastMath() {
        Random r = new Random();
        for (int i = 0; i < RAND_ITERS; i++) {
            float a = r.nextFloat() * MAX - MAX / 2;
            assertEquals((int) Math.floor(a), JBoxUtils.floor(a));
        }

        for (int i = 0; i < RAND_ITERS; i++) {
            float a = r.nextFloat() * MAX - MAX / 2;
            assertEquals((int) Math.ceil(a), JBoxUtils.ceil(a));
        }

        for (int i = 0; i < RAND_ITERS; i++) {
            float a = r.nextFloat() * MAX - MAX / 2;
            float b = r.nextFloat() * MAX - MAX / 2;
            assertEquals(Math.max(a, b), JBoxUtils.max(a, b));
        }

        for (int i = 0; i < RAND_ITERS; i++) {
            float a = r.nextFloat() * MAX - MAX / 2;
            float b = r.nextFloat() * MAX - MAX / 2;
            assertEquals(Math.min(a, b), JBoxUtils.min(a, b));
        }

        for (int i = 0; i < RAND_ITERS; i++) {
            float a = r.nextFloat() * MAX - MAX / 2;
            assertEquals(Math.round(a), JBoxUtils.round(a));
        }

        for (int i = 0; i < RAND_ITERS; i++) {
            float a = r.nextFloat() * MAX - MAX / 2;
            assertEquals(Math.abs(a), JBoxUtils.abs(a));
        }
    }

    public void testVec2() {
        Vec2 v = new Vec2();
        v.x = 0;
        v.y = 1;
        v.subLocal(new Vec2(10, 10));
        assertEquals(-10f, v.x);
        assertEquals(-9f, v.y);

        Vec2 v2 = v.add(new Vec2(1, 1));
        assertEquals(-9f, v2.x);
        assertEquals(-8f, v2.y);
        assertFalse(v.equals(v2));
    }

    // Note this is specific for UI, so top-left is the origin
    public void testVec2Angle() {
        Vec2 v = new Vec2(1, 0);
        assertEquals(0, v.angle(), 0.0);

        v.set(0, 1);
        assertEquals(90, v.angle(), 0.0);

        v.set(-1, 0);
        assertEquals(180, v.angle(), 0.0);

        v.set(0, -1);
        assertEquals(-90, v.angle(), 0.0);

        v.set(1, 1);
        assertEquals(45, v.angle(), 0.0);

        v.set(-1, 1);
        assertEquals(135, v.angle(), 0.0);

        v.set(-1, -1);
        assertEquals(-135, v.angle(), 0.0);

        v.set(1, -1);
        assertEquals(-45, v.angle(), 0.0);
    }

    public void testMat22Unsafes() {
        Vec2 v1 = new Vec2(10, -1.3f);
        Mat22 m1 = new Mat22(1, 34, -3, 3);
        Mat22 m2 = new Mat22(2, -1, 4.1f, -4);
        Vec2 vo = new Vec2();
        Mat22 mo = new Mat22();

        Mat22.mulToOutUnsafe(m1, m2, mo);
        assertEquals(Mat22.mul(m1, m2), mo);

        Mat22.mulToOutUnsafe(m1, v1, vo);
        assertEquals(Mat22.mul(m1, v1), vo);

        Mat22.mulTransToOutUnsafe(m1, m2, mo);
        assertEquals(Mat22.mulTrans(m1, m2), mo);

        Mat22.mulTransToOutUnsafe(m1, v1, vo);
        assertEquals(Mat22.mulTrans(m1, v1), vo);
    }

    public void testMat33() {
        Mat33 mat = new Mat33();

        mat.ex.set(3, 19, -5);
        mat.ey.set(-1, 1, 4);
        mat.ez.set(-10, 4, 4);

        Vec3 b = new Vec3(4, 1, 2);
        assertEquals(new Vec3(0.096f, 1.1013334f, -.48133332f), mat.solve33(b));

        Vec2 b2 = new Vec2(4, 1);
        assertEquals(new Vec2(0.22727273f, -3.318182f), mat.solve22(b2));
    }

    public void testVec3() {
        Vec3 v1 = new Vec3();
        Vec3 v2 = new Vec3();

        assertEquals(new Vec3(1, -15, 36), Vec3.cross(v1.set(9, 3, 1), v2.set(3, 5, 2)));
    }
}