@turbox3d/math/src/base/Box3.ts

Large-scale graphics application math library

import { Matrix4 } from './Matrix4';
import { Vector3 } from './Vector3';
import { Tolerance } from './Tolerance';
import { MathUtils } from '../MathUtils';

const _points = [
  new Vector3(),
  new Vector3(),
  new Vector3(),
  new Vector3(),
  new Vector3(),
  new Vector3(),
  new Vector3(),
  new Vector3(),
];

const _vector = new Vector3();

class Box3 {
  min: Vector3;
  max: Vector3;
  readonly isBox3: boolean;

  constructor(min?: Vector3, max?: Vector3) {
    this.isBox3 = true;
    this.min = (min !== undefined) ? min : new Vector3(+Infinity, +Infinity, +Infinity);
    this.max = (max !== undefined) ? max : new Vector3(-Infinity, -Infinity, -Infinity);
  }

  set(min: Vector3, max: Vector3) {
    this.min.copy(min);
    this.max.copy(max);

    return this;
  }

  setFromArray(array: ArrayLike<number>) {
    let minX = +Infinity;
    let minY = +Infinity;
    let minZ = +Infinity;

    let maxX = -Infinity;
    let maxY = -Infinity;
    let maxZ = -Infinity;

    for (let i = 0, l = array.length; i < l; i += 3) {
      const x = array[i];
      const y = array[i + 1];
      const z = array[i + 2];

      if (x < minX) minX = x;
      if (y < minY) minY = y;
      if (z < minZ) minZ = z;

      if (x > maxX) maxX = x;
      if (y > maxY) maxY = y;
      if (z > maxZ) maxZ = z;
    }

    this.min.set(minX, minY, minZ);
    this.max.set(maxX, maxY, maxZ);

    return this;
  }

  setFromPoints(points: Vector3[]) {
    this.makeEmpty();

    for (let i = 0, il = points.length; i < il; i++) {
      this.expandByPoint(points[i]);
    }

    return this;
  }

  setFromCenterAndSize(center: Vector3, size: Vector3) {
    const halfSize = _vector.copy(size).multiplyScalar(0.5);

    this.min.copy(center).sub(halfSize);
    this.max.copy(center).add(halfSize);

    return this;
  }

  clone() {
    return new Box3().copy(this);
  }

  copy(box: Box3) {
    this.min.copy(box.min);
    this.max.copy(box.max);

    return this;
  }

  makeEmpty() {
    // eslint-disable-next-line no-multi-assign
    this.min.x = this.min.y = this.min.z = +Infinity;
    // eslint-disable-next-line no-multi-assign
    this.max.x = this.max.y = this.max.z = -Infinity;

    return this;
  }

  isEmpty() {
    // this is a more robust check for empty than ( volume <= 0 ) because volume can get positive with two negative axes
    return (this.max.x < this.min.x) || (this.max.y < this.min.y) || (this.max.z < this.min.z);
  }

  getCenter(target: Vector3) {
    return this.isEmpty() ? target.set(0, 0, 0) : target.addVectors(this.min, this.max).multiplyScalar(0.5);
  }

  getSize(target: Vector3) {
    return this.isEmpty() ? target.set(0, 0, 0) : target.subVectors(this.max, this.min);
  }

  expandByPoint(point: Vector3) {
    this.min.min(point);
    this.max.max(point);

    return this;
  }

  expandByVector(vector: Vector3) {
    this.min.sub(vector);
    this.max.add(vector);

    return this;
  }

  expandByScalar(scalar: number) {
    this.min.addScalar(-scalar);
    this.max.addScalar(scalar);

    return this;
  }

  containsPoint(point: Vector3, distTol = Tolerance.global.distTol) {
    return !(
      MathUtils.isSmaller(point.x, this.min.x, distTol) ||
      MathUtils.isBigger(point.x, this.max.x, distTol) ||
      MathUtils.isSmaller(point.y, this.min.y, distTol) ||
      MathUtils.isBigger(point.y, this.max.y, distTol) ||
      MathUtils.isSmaller(point.z, this.min.z, distTol) ||
      MathUtils.isBigger(point.z, this.max.z, distTol)
    );
  }

  containsBox(box: Box3, distTol = Tolerance.global.distTol) {
    return MathUtils.isSmallerOrEqual(this.min.x, box.min.x, distTol) &&
      MathUtils.isSmallerOrEqual(box.max.x, this.max.x, distTol) &&
      MathUtils.isSmallerOrEqual(this.min.y, box.min.y, distTol) &&
      MathUtils.isSmallerOrEqual(box.max.y, this.max.y, distTol) &&
      MathUtils.isSmallerOrEqual(this.min.z, box.min.z, distTol) &&
      MathUtils.isSmallerOrEqual(box.max.z, this.max.z, distTol);
  }

  isOverlapping(box: Box3, distTol = Tolerance.global.distTol) {
    if (!box.isValid()) {
      return false;
    }
    if (MathUtils.isSmaller(this.max.x, box.min.x, distTol) || MathUtils.isBigger(this.min.x, box.max.x, distTol)) {
      return false;
    }
    if (MathUtils.isSmaller(this.max.y, box.min.y, distTol) || MathUtils.isBigger(this.min.y, box.max.y, distTol)) {
      return false;
    }
    if (MathUtils.isSmaller(this.max.z, box.min.z, distTol) || MathUtils.isBigger(this.min.z, box.max.z, distTol)) {
      return false;
    }

    return true;
  }

  getParameter(point: Vector3, target: Vector3) {
    // This can potentially have a divide by zero if the box
    // has a size dimension of 0.
    return target.set(
      (point.x - this.min.x) / (this.max.x - this.min.x),
      (point.y - this.min.y) / (this.max.y - this.min.y),
      (point.z - this.min.z) / (this.max.z - this.min.z)
    );
  }

  intersectsBox(box: Box3) {
    // using 6 splitting planes to rule out intersections.
    return !(box.max.x < this.min.x || box.min.x > this.max.x ||
      box.max.y < this.min.y || box.min.y > this.max.y ||
      box.max.z < this.min.z || box.min.z > this.max.z);
  }

  clampPoint(point: Vector3, target: Vector3) {
    return target.copy(point).clamp(this.min, this.max);
  }

  distanceToPoint(point: Vector3) {
    const clampedPoint = _vector.copy(point).clamp(this.min, this.max);

    return clampedPoint.sub(point).length;
  }

  intersect(box: Box3) {
    this.min.max(box.min);
    this.max.min(box.max);

    // ensure that if there is no overlap, the result is fully empty, not slightly empty with non-inf/+inf values that will cause subsequence intersects to erroneously return valid values.
    if (this.isEmpty()) this.makeEmpty();

    return this;
  }

  union(box: Box3) {
    this.min.min(box.min);
    this.max.max(box.max);

    return this;
  }

  applyMatrix4(matrix: Matrix4) {
    // transform of empty box is an empty box.
    if (this.isEmpty()) return this;

    // NOTE: I am using a binary pattern to specify all 2^3 combinations below
    _points[0].set(this.min.x, this.min.y, this.min.z).applyMatrix4(matrix); // 000
    _points[1].set(this.min.x, this.min.y, this.max.z).applyMatrix4(matrix); // 001
    _points[2].set(this.min.x, this.max.y, this.min.z).applyMatrix4(matrix); // 010
    _points[3].set(this.min.x, this.max.y, this.max.z).applyMatrix4(matrix); // 011
    _points[4].set(this.max.x, this.min.y, this.min.z).applyMatrix4(matrix); // 100
    _points[5].set(this.max.x, this.min.y, this.max.z).applyMatrix4(matrix); // 101
    _points[6].set(this.max.x, this.max.y, this.min.z).applyMatrix4(matrix); // 110
    _points[7].set(this.max.x, this.max.y, this.max.z).applyMatrix4(matrix); // 111

    this.setFromPoints(_points);

    return this;
  }

  translate(offset: Vector3) {
    this.min.add(offset);
    this.max.add(offset);

    return this;
  }

  equals(box: Box3, distTol = Tolerance.global.distTol) {
    return box.min.equals(this.min, distTol) && box.max.equals(this.max, distTol);
  }

  isValid() {
    return this.min.x <= this.max.x &&
      this.min.y <= this.max.y &&
      this.min.z <= this.max.z;
  }
}

export { Box3 };