epam/miew

import { Box3, Sphere, Vector3 } from 'three'

class CollisionSphere {
  constructor(position, radius) {
    this._position = position
    this._radius = radius
  }

  static _sphere = new Sphere()

  raycast(raycaster) {
    const sphere = CollisionSphere._sphere
    sphere.set(this._position, this._radius)

    const p = new Vector3()
    if (raycaster.ray.intersectSphere(sphere, p)) {
      return {
        distance: raycaster.ray.origin.distanceTo(p),
        point: p
      }
    }
    return null
  }
}

const SphereCollisionGeo = (base) =>
  class extends base {
    constructor(count, ...args) {
      super(...args)
      this._objects = new Array(count)
      this.boundingSphere = null
      this.boundingBox = null
    }

    setSphere(idx, position, radius) {
      this._objects[idx] = new CollisionSphere(position, radius)
    }

    raycast(raycaster, intersects) {
      // TODO raycast with bounding sphere? How to deal with updates?
      for (let i = 0, n = this._objects.length; i < n; ++i) {
        const inters = this._objects[i].raycast(raycaster)
        if (inters) {
          inters.chunkIdx = i
          intersects.push(inters)
        }
      }
    }

    computeBoundingBox() {
      const objects = this._objects
      let { boundingBox } = this
      if (boundingBox === null) {
        this.boundingBox = boundingBox = new Box3()
      }
      boundingBox.makeEmpty()
      for (let i = 0, n = objects.length; i < n; ++i) {
        boundingBox.expandByPoint(objects[i]._position)
      }
    }

    computeBoundingSphere() {
      this.computeBoundingBox()
      const objects = this._objects
      const { boundingBox } = this
      // Build bounding sphere
      let radiusSquared = 0.0
      const center = new Vector3()
      boundingBox.getCenter(center)
      for (let i = 0, n = objects.length; i < n; ++i) {
        const pos = objects[i]._position
        const lengthSquared = center.distanceToSquared(pos)
        if (radiusSquared < lengthSquared) {
          radiusSquared = lengthSquared
        }
      }
      if (this.boundingSphere === null) {
        this.boundingSphere = new Sphere()
      }
      this.boundingSphere.set(center, Math.sqrt(radiusSquared))
    }
  }
export default SphereCollisionGeo