modeling/src/maths/mat4/isIdentity.js

  1. /**
  2.  * Determine whether the given matrix is the identity transform.
  3.  * This is equivalent to (but much faster than):
  4.  *
  5.  *     mat4.equals(mat4.create(), matrix)
  6.  *
  7.  * @param {mat4} matrix - the matrix
  8.  * @returns {Boolean} true if matrix is the identity transform
  9.  * @alias module:modeling/maths/mat4.isIdentity
  10.  * @example
  11.  * if (mat4.isIdentity(mymatrix)) ...
  12.  */
  13. const isIdentity = (matrix) => (
  14.   matrix[0] === 1 && matrix[1] === 0 && matrix[2] === 0 && matrix[3] === 0 &&
  15.   matrix[4] === 0 && matrix[5] === 1 && matrix[6] === 0 && matrix[7] === 0 &&
  16.   matrix[8] === 0 && matrix[9] === 0 && matrix[10] === 1 && matrix[11] === 0 &&
  17.   matrix[12] === 0 && matrix[13] === 0 && matrix[14] === 0 && matrix[15] === 1
  18. )
  20. module.exports = isIdentity