com.badlogic.gdx.math.collision.BoundingBox.java Source code

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/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.math.collision;

import java.io.Serializable;
import java.util.List;

import com.badlogic.gdx.math.Matrix4;
import com.badlogic.gdx.math.Vector3;

/** Encapsulates an axis aligned bounding box represented by a minimum and a maximum Vector. Additionally you can query for the
 * bounding box's center, dimensions and corner points.
 * 
 * @author badlogicgames@gmail.com, Xoppa */
public class BoundingBox implements Serializable {
    private static final long serialVersionUID = -1286036817192127343L;

    private final static Vector3 tmpVector = new Vector3();

    public final Vector3 min = new Vector3();
    public final Vector3 max = new Vector3();

    private final Vector3 cnt = new Vector3();
    private final Vector3 dim = new Vector3();

    @Deprecated
    private Vector3[] corners;

    /** @deprecated Use {@link #getCenter(Vector3)}
     * @return the center of the bounding box */
    @Deprecated
    public Vector3 getCenter() {
        return cnt;
    }

    /** @param out The {@link Vector3} to receive the center of the bounding box.
     * @return The vector specified with the out argument. */
    public Vector3 getCenter(Vector3 out) {
        return out.set(cnt);
    }

    public float getCenterX() {
        return cnt.x;
    }

    public float getCenterY() {
        return cnt.y;
    }

    public float getCenterZ() {
        return cnt.z;
    }

    @Deprecated
    protected void updateCorners() {
    }

    /** @deprecated Use the getCornerXYZ methods instead
     * @return the corners of this bounding box */
    @Deprecated
    public Vector3[] getCorners() {
        if (corners == null) {
            corners = new Vector3[8];
            for (int i = 0; i < 8; i++)
                corners[i] = new Vector3();
        }
        corners[0].set(min.x, min.y, min.z);
        corners[1].set(max.x, min.y, min.z);
        corners[2].set(max.x, max.y, min.z);
        corners[3].set(min.x, max.y, min.z);
        corners[4].set(min.x, min.y, max.z);
        corners[5].set(max.x, min.y, max.z);
        corners[6].set(max.x, max.y, max.z);
        corners[7].set(min.x, max.y, max.z);
        return corners;
    }

    public Vector3 getCorner000(final Vector3 out) {
        return out.set(min.x, min.y, min.z);
    }

    public Vector3 getCorner001(final Vector3 out) {
        return out.set(min.x, min.y, max.z);
    }

    public Vector3 getCorner010(final Vector3 out) {
        return out.set(min.x, max.y, min.z);
    }

    public Vector3 getCorner011(final Vector3 out) {
        return out.set(min.x, max.y, max.z);
    }

    public Vector3 getCorner100(final Vector3 out) {
        return out.set(max.x, min.y, min.z);
    }

    public Vector3 getCorner101(final Vector3 out) {
        return out.set(max.x, min.y, max.z);
    }

    public Vector3 getCorner110(final Vector3 out) {
        return out.set(max.x, max.y, min.z);
    }

    public Vector3 getCorner111(final Vector3 out) {
        return out.set(max.x, max.y, max.z);
    }

    /** @deprecated Use {@link #getDimensions(Vector3)} instead
     * @return The dimensions of this bounding box on all three axis */
    @Deprecated
    public Vector3 getDimensions() {
        return dim;
    }

    /** @param out The {@link Vector3} to receive the dimensions of this bounding box on all three axis.
     * @return The vector specified with the out argument */
    public Vector3 getDimensions(final Vector3 out) {
        return out.set(dim);
    }

    public float getWidth() {
        return dim.x;
    }

    public float getHeight() {
        return dim.y;
    }

    public float getDepth() {
        return dim.z;
    }

    /** @deprecated Use {@link #getMin(Vector3)} instead.
     * @return The minimum vector */
    @Deprecated
    public Vector3 getMin() {
        return min;
    }

    /** @param out The {@link Vector3} to receive the minimum values.
     * @return The vector specified with the out argument */
    public Vector3 getMin(final Vector3 out) {
        return out.set(min);
    }

    /** @deprecated Use {@link #getMax(Vector3)} instead
     * @return The maximum vector */
    @Deprecated
    public Vector3 getMax() {
        return max;
    }

    /** @param out The {@link Vector3} to receive the maximum values.
     * @return The vector specified with the out argument */
    public Vector3 getMax(final Vector3 out) {
        return out.set(max);
    }

    /** Constructs a new bounding box with the minimum and maximum vector set to zeros. */
    public BoundingBox() {
        clr();
    }

    /** Constructs a new bounding box from the given bounding box.
     * 
     * @param bounds The bounding box to copy */
    public BoundingBox(BoundingBox bounds) {
        this.set(bounds);
    }

    /** Constructs the new bounding box using the given minimum and maximum vector.
     * 
     * @param minimum The minimum vector
     * @param maximum The maximum vector */
    public BoundingBox(Vector3 minimum, Vector3 maximum) {
        this.set(minimum, maximum);
    }

    /** Sets the given bounding box.
     * 
     * @param bounds The bounds.
     * @return This bounding box for chaining. */
    public BoundingBox set(BoundingBox bounds) {
        return this.set(bounds.min, bounds.max);
    }

    /** Sets the given minimum and maximum vector.
     * 
     * @param minimum The minimum vector
     * @param maximum The maximum vector
     * @return This bounding box for chaining. */
    public BoundingBox set(Vector3 minimum, Vector3 maximum) {
        min.set(minimum.x < maximum.x ? minimum.x : maximum.x, minimum.y < maximum.y ? minimum.y : maximum.y,
                minimum.z < maximum.z ? minimum.z : maximum.z);
        max.set(minimum.x > maximum.x ? minimum.x : maximum.x, minimum.y > maximum.y ? minimum.y : maximum.y,
                minimum.z > maximum.z ? minimum.z : maximum.z);
        cnt.set(min).add(max).scl(0.5f);
        dim.set(max).sub(min);
        return this;
    }

    /** Sets the bounding box minimum and maximum vector from the given points.
     * 
     * @param points The points.
     * @return This bounding box for chaining. */
    public BoundingBox set(Vector3[] points) {
        this.inf();
        for (Vector3 l_point : points)
            this.ext(l_point);
        return this;
    }

    /** Sets the bounding box minimum and maximum vector from the given points.
     * 
     * @param points The points.
     * @return This bounding box for chaining. */
    public BoundingBox set(List<Vector3> points) {
        this.inf();
        for (Vector3 l_point : points)
            this.ext(l_point);
        return this;
    }

    /** Sets the minimum and maximum vector to positive and negative infinity.
     * 
     * @return This bounding box for chaining. */
    public BoundingBox inf() {
        min.set(Float.POSITIVE_INFINITY, Float.POSITIVE_INFINITY, Float.POSITIVE_INFINITY);
        max.set(Float.NEGATIVE_INFINITY, Float.NEGATIVE_INFINITY, Float.NEGATIVE_INFINITY);
        cnt.set(0, 0, 0);
        dim.set(0, 0, 0);
        return this;
    }

    /** Extends the bounding box to incorporate the given {@link Vector3}.
     * @param point The vector
     * @return This bounding box for chaining. */
    public BoundingBox ext(Vector3 point) {
        return this.set(min.set(min(min.x, point.x), min(min.y, point.y), min(min.z, point.z)),
                max.set(Math.max(max.x, point.x), Math.max(max.y, point.y), Math.max(max.z, point.z)));
    }

    /** Sets the minimum and maximum vector to zeros.
     * @return This bounding box for chaining. */
    public BoundingBox clr() {
        return this.set(min.set(0, 0, 0), max.set(0, 0, 0));
    }

    /** Returns whether this bounding box is valid. This means that {@link #max} is greater than {@link #min}.
     * @return True in case the bounding box is valid, false otherwise */
    public boolean isValid() {
        return min.x < max.x && min.y < max.y && min.z < max.z;
    }

    /** Extends this bounding box by the given bounding box.
     * 
     * @param a_bounds The bounding box
     * @return This bounding box for chaining. */
    public BoundingBox ext(BoundingBox a_bounds) {
        return this.set(min.set(min(min.x, a_bounds.min.x), min(min.y, a_bounds.min.y), min(min.z, a_bounds.min.z)),
                max.set(max(max.x, a_bounds.max.x), max(max.y, a_bounds.max.y), max(max.z, a_bounds.max.z)));
    }

    /** Extends this bounding box by the given transformed bounding box.
     * 
     * @param bounds The bounding box
     * @param transform The transformation matrix to apply to bounds, before using it to extend this bounding box.
     * @return This bounding box for chaining. */
    public BoundingBox ext(BoundingBox bounds, Matrix4 transform) {
        ext(tmpVector.set(bounds.min.x, bounds.min.y, bounds.min.z).mul(transform));
        ext(tmpVector.set(bounds.min.x, bounds.min.y, bounds.max.z).mul(transform));
        ext(tmpVector.set(bounds.min.x, bounds.max.y, bounds.min.z).mul(transform));
        ext(tmpVector.set(bounds.min.x, bounds.max.y, bounds.max.z).mul(transform));
        ext(tmpVector.set(bounds.max.x, bounds.min.y, bounds.min.z).mul(transform));
        ext(tmpVector.set(bounds.max.x, bounds.min.y, bounds.max.z).mul(transform));
        ext(tmpVector.set(bounds.max.x, bounds.max.y, bounds.min.z).mul(transform));
        ext(tmpVector.set(bounds.max.x, bounds.max.y, bounds.max.z).mul(transform));
        return this;
    }

    /** Multiplies the bounding box by the given matrix. This is achieved by multiplying the 8 corner points and then calculating
     * the minimum and maximum vectors from the transformed points.
     * 
     * @param transform The matrix
     * @return This bounding box for chaining. */
    public BoundingBox mul(Matrix4 transform) {
        final float x0 = min.x, y0 = min.y, z0 = min.z, x1 = max.x, y1 = max.y, z1 = max.z;
        inf();
        ext(tmpVector.set(x0, y0, z0).mul(transform));
        ext(tmpVector.set(x0, y0, z1).mul(transform));
        ext(tmpVector.set(x0, y1, z0).mul(transform));
        ext(tmpVector.set(x0, y1, z1).mul(transform));
        ext(tmpVector.set(x1, y0, z0).mul(transform));
        ext(tmpVector.set(x1, y0, z1).mul(transform));
        ext(tmpVector.set(x1, y1, z0).mul(transform));
        ext(tmpVector.set(x1, y1, z1).mul(transform));
        return this;
    }

    /** Returns whether the given bounding box is contained in this bounding box.
     * @param b The bounding box
     * @return Whether the given bounding box is contained */
    public boolean contains(BoundingBox b) {
        return !isValid() || (min.x <= b.min.x && min.y <= b.min.y && min.z <= b.min.z && max.x >= b.max.x
                && max.y >= b.max.y && max.z >= b.max.z);
    }

    /** Returns whether the given bounding box is intersecting this bounding box (at least one point in).
     * @param b The bounding box
     * @return Whether the given bounding box is intersected */
    public boolean intersects(BoundingBox b) {
        if (!isValid())
            return false;

        // test using SAT (separating axis theorem)

        float lx = Math.abs(this.cnt.x - b.cnt.x);
        float sumx = (this.dim.x / 2.0f) + (b.dim.x / 2.0f);

        float ly = Math.abs(this.cnt.y - b.cnt.y);
        float sumy = (this.dim.y / 2.0f) + (b.dim.y / 2.0f);

        float lz = Math.abs(this.cnt.z - b.cnt.z);
        float sumz = (this.dim.z / 2.0f) + (b.dim.z / 2.0f);

        return (lx <= sumx && ly <= sumy && lz <= sumz);

    }

    /** Returns whether the given vector is contained in this bounding box.
     * @param v The vector
     * @return Whether the vector is contained or not. */
    public boolean contains(Vector3 v) {
        return min.x <= v.x && max.x >= v.x && min.y <= v.y && max.y >= v.y && min.z <= v.z && max.z >= v.z;
    }

    @Override
    public String toString() {
        return "[" + min + "|" + max + "]";
    }

    /** Extends the bounding box by the given vector.
     * 
     * @param x The x-coordinate
     * @param y The y-coordinate
     * @param z The z-coordinate
     * @return This bounding box for chaining. */
    public BoundingBox ext(float x, float y, float z) {
        return this.set(min.set(min(min.x, x), min(min.y, y), min(min.z, z)),
                max.set(max(max.x, x), max(max.y, y), max(max.z, z)));
    }

    static final float min(final float a, final float b) {
        return a > b ? b : a;
    }

    static final float max(final float a, final float b) {
        return a > b ? a : b;
    }
}