multiplyMatrices method

Matrix4 multiplyMatrices(
  1. Matrix4 a,
  2. Matrix4 b
)

Implementation

Matrix4 multiplyMatrices(Matrix4 a, Matrix4 b) {
  var ae = a.elements;
  var be = b.elements;
  var te = elements;

  var a11 = ae[0], a12 = ae[4], a13 = ae[8], a14 = ae[12];
  var a21 = ae[1], a22 = ae[5], a23 = ae[9], a24 = ae[13];
  var a31 = ae[2], a32 = ae[6], a33 = ae[10], a34 = ae[14];
  var a41 = ae[3], a42 = ae[7], a43 = ae[11], a44 = ae[15];

  var b11 = be[0], b12 = be[4], b13 = be[8], b14 = be[12];
  var b21 = be[1], b22 = be[5], b23 = be[9], b24 = be[13];
  var b31 = be[2], b32 = be[6], b33 = be[10], b34 = be[14];
  var b41 = be[3], b42 = be[7], b43 = be[11], b44 = be[15];

  te[0] = a11 * b11 + a12 * b21 + a13 * b31 + a14 * b41;
  te[4] = a11 * b12 + a12 * b22 + a13 * b32 + a14 * b42;
  te[8] = a11 * b13 + a12 * b23 + a13 * b33 + a14 * b43;
  te[12] = a11 * b14 + a12 * b24 + a13 * b34 + a14 * b44;

  te[1] = a21 * b11 + a22 * b21 + a23 * b31 + a24 * b41;
  te[5] = a21 * b12 + a22 * b22 + a23 * b32 + a24 * b42;
  te[9] = a21 * b13 + a22 * b23 + a23 * b33 + a24 * b43;
  te[13] = a21 * b14 + a22 * b24 + a23 * b34 + a24 * b44;

  te[2] = a31 * b11 + a32 * b21 + a33 * b31 + a34 * b41;
  te[6] = a31 * b12 + a32 * b22 + a33 * b32 + a34 * b42;
  te[10] = a31 * b13 + a32 * b23 + a33 * b33 + a34 * b43;
  te[14] = a31 * b14 + a32 * b24 + a33 * b34 + a34 * b44;

  te[3] = a41 * b11 + a42 * b21 + a43 * b31 + a44 * b41;
  te[7] = a41 * b12 + a42 * b22 + a43 * b32 + a44 * b42;
  te[11] = a41 * b13 + a42 * b23 + a43 * b33 + a44 * b43;
  te[15] = a41 * b14 + a42 * b24 + a43 * b34 + a44 * b44;

  return this;
}