goog.provide('ol.vec.Mat4');

goog.require('goog.vec.Mat4');


/**
 * Returns true if mat1 and mat2 represent the same 2D transformation.
 * @param {goog.vec.Mat4.AnyType} mat1 Matrix 1.
 * @param {goog.vec.Mat4.AnyType} mat2 Matrix 2.
 * @return {boolean} Equal 2D.
 */
ol.vec.Mat4.equal2D = function(mat1, mat2) {
  return (
      goog.vec.Mat4.getElement(mat1, 0, 0) ==
      goog.vec.Mat4.getElement(mat2, 0, 0) &&
      goog.vec.Mat4.getElement(mat1, 1, 0) ==
      goog.vec.Mat4.getElement(mat2, 1, 0) &&
      goog.vec.Mat4.getElement(mat1, 0, 1) ==
      goog.vec.Mat4.getElement(mat2, 0, 1) &&
      goog.vec.Mat4.getElement(mat1, 1, 1) ==
      goog.vec.Mat4.getElement(mat2, 1, 1) &&
      goog.vec.Mat4.getElement(mat1, 0, 3) ==
      goog.vec.Mat4.getElement(mat2, 0, 3) &&
      goog.vec.Mat4.getElement(mat1, 1, 3) ==
      goog.vec.Mat4.getElement(mat2, 1, 3));
};


/**
 * Transforms the given vector with the given matrix storing the resulting,
 * transformed vector into resultVec. The input vector is multiplied against the
 * upper 2x4 matrix omitting the projective component.
 *
 * @param {goog.vec.Mat4.AnyType} mat The matrix supplying the transformation.
 * @param {Array.<number>} vec The 3 element vector to transform.
 * @param {Array.<number>} resultVec The 3 element vector to receive the results
 *     (may be vec).
 * @return {Array.<number>} return resultVec so that operations can be
 *     chained together.
 */
ol.vec.Mat4.multVec2 = function(mat, vec, resultVec) {
  var m00 = goog.vec.Mat4.getElement(mat, 0, 0);
  var m10 = goog.vec.Mat4.getElement(mat, 1, 0);
  var m01 = goog.vec.Mat4.getElement(mat, 0, 1);
  var m11 = goog.vec.Mat4.getElement(mat, 1, 1);
  var m03 = goog.vec.Mat4.getElement(mat, 0, 3);
  var m13 = goog.vec.Mat4.getElement(mat, 1, 3);
  var x = vec[0], y = vec[1];
  resultVec[0] = m00 * x + m01 * y + m03;
  resultVec[1] = m10 * x + m11 * y + m13;
  return resultVec;
};