modeling/src/geometries/geom2/transform.js

  1. const mat4 = require('../../maths/mat4')
  3. const reverse = require('./reverse.js')
  5. /**
  6.  * Transform the given geometry using the given matrix.
  7.  * This is a lazy transform of the sides, as this function only adjusts the transforms.
  8.  * The transforms are applied when accessing the sides via toSides().
  9.  * @param {mat4} matrix - the matrix to transform with
  10.  * @param {geom2} geometry - the geometry to transform
  11.  * @returns {geom2} a new geometry
  12.  * @alias module:modeling/geometries/geom2.transform
  13.  *
  14.  * @example
  15.  * let newgeometry = transform(fromZRotation(degToRad(90)), geometry)
  16.  */
  17. const transform = (matrix, geometry) => {
  18.   const transforms = mat4.multiply(mat4.create(), matrix, geometry.transforms)
  19.   const transformed = Object.assign({}, geometry, { transforms })
  20.   // determine if the transform is mirroring in 2D
  21.   if (matrix[0] * matrix[5] - matrix[4] * matrix[1] < 0) {
  22.     // reverse the order to preserve the orientation
  23.     return reverse(transformed)
  24.   }
  25.   return transformed
  26. }
  28. module.exports = transform