Transform.ts

import { Vec3 } from '../math/Vec3'
import { Quaternion } from '../math/Quaternion'

export type TransformOptions = ConstructorParameters<typeof Transform>[0]

/**
 * Transformation utilities.
 */
export class Transform {
  /**
   * position
   */
  position: Vec3
  /**
   * quaternion
   */
  quaternion: Quaternion

  constructor(
    options: {
      /**
       * position
       */
      position?: Vec3
      /**
       * quaternion
       */
      quaternion?: Quaternion
    } = {}
  ) {
    this.position = new Vec3()
    this.quaternion = new Quaternion()

    if (options.position) {
      this.position.copy(options.position)
    }

    if (options.quaternion) {
      this.quaternion.copy(options.quaternion)
    }
  }

  /**
   * Get a global point in local transform coordinates.
   */
  pointToLocal(worldPoint: Vec3, result?: Vec3): Vec3 {
    return Transform.pointToLocalFrame(this.position, this.quaternion, worldPoint, result)
  }

  /**
   * Get a local point in global transform coordinates.
   */
  pointToWorld(localPoint: Vec3, result?: Vec3): Vec3 {
    return Transform.pointToWorldFrame(this.position, this.quaternion, localPoint, result)
  }

  /**
   * vectorToWorldFrame
   */
  vectorToWorldFrame(localVector: Vec3, result = new Vec3()): Vec3 {
    this.quaternion.vmult(localVector, result)
    return result
  }

  /**
   * pointToLocalFrame
   */
  static pointToLocalFrame(position: Vec3, quaternion: Quaternion, worldPoint: Vec3, result = new Vec3()): Vec3 {
    worldPoint.vsub(position, result)
    quaternion.conjugate(tmpQuat)
    tmpQuat.vmult(result, result)
    return result
  }

  /**
   * pointToWorldFrame
   */
  static pointToWorldFrame(position: Vec3, quaternion: Quaternion, localPoint: Vec3, result = new Vec3()): Vec3 {
    quaternion.vmult(localPoint, result)
    result.vadd(position, result)
    return result
  }

  /**
   * vectorToWorldFrame
   */
  static vectorToWorldFrame(quaternion: Quaternion, localVector: Vec3, result = new Vec3()): Vec3 {
    quaternion.vmult(localVector, result)
    return result
  }

  /**
   * vectorToLocalFrame
   */
  static vectorToLocalFrame(position: Vec3, quaternion: Quaternion, worldVector: Vec3, result = new Vec3()): Vec3 {
    quaternion.w *= -1
    quaternion.vmult(worldVector, result)
    quaternion.w *= -1
    return result
  }
}

const tmpQuat = new Quaternion()