mat4_multiply.dart

/// Print the calculation which multiplies two 4x4 matrices.
///
/// The matrices store their elements in a flat array in column order.
void main() {
  StringBuffer buffer = new StringBuffer();
  String l = "m1";
  String r = "m2";
  for (int col in new Iterable.generate(4)) {
    for (int row in new Iterable.generate(4)) {
      buffer.writeAll([
        "$l[${0 + row}]*$r[${col * 4 + 0}]",
        "$l[${4 + row}]*$r[${col * 4 + 1}]",
        "$l[${8 + row}]*$r[${col * 4 + 2}]",
        "$l[${12 + row}]*$r[${col * 4 + 3}]",
      ], " + ");
      buffer.write(",\n");
    }
  }
  print(buffer.toString());
}

/*
m1[0]*m2[0] + m1[4]*m2[1] + m1[8]*m2[2] + m1[12]*m2[3],
m1[1]*m2[0] + m1[5]*m2[1] + m1[9]*m2[2] + m1[13]*m2[3],
m1[2]*m2[0] + m1[6]*m2[1] + m1[10]*m2[2] + m1[14]*m2[3],
m1[3]*m2[0] + m1[7]*m2[1] + m1[11]*m2[2] + m1[15]*m2[3],
m1[0]*m2[4] + m1[4]*m2[5] + m1[8]*m2[6] + m1[12]*m2[7],
m1[1]*m2[4] + m1[5]*m2[5] + m1[9]*m2[6] + m1[13]*m2[7],
m1[2]*m2[4] + m1[6]*m2[5] + m1[10]*m2[6] + m1[14]*m2[7],
m1[3]*m2[4] + m1[7]*m2[5] + m1[11]*m2[6] + m1[15]*m2[7],
m1[0]*m2[8] + m1[4]*m2[9] + m1[8]*m2[10] + m1[12]*m2[11],
m1[1]*m2[8] + m1[5]*m2[9] + m1[9]*m2[10] + m1[13]*m2[11],
m1[2]*m2[8] + m1[6]*m2[9] + m1[10]*m2[10] + m1[14]*m2[11],
m1[3]*m2[8] + m1[7]*m2[9] + m1[11]*m2[10] + m1[15]*m2[11],
m1[0]*m2[12] + m1[4]*m2[13] + m1[8]*m2[14] + m1[12]*m2[15],
m1[1]*m2[12] + m1[5]*m2[13] + m1[9]*m2[14] + m1[13]*m2[15],
m1[2]*m2[12] + m1[6]*m2[13] + m1[10]*m2[14] + m1[14]*m2[15],
m1[3]*m2[12] + m1[7]*m2[13] + m1[11]*m2[14] + m1[15]*m2[15],
*/