setDiagonal method
Sets the diagonal of the matrix to be arg.
Implementation
void setDiagonal(Vector4 arg) {
final Float32List argStorage = arg._v4storage;
_m4storage[0] = argStorage[0];
_m4storage[5] = argStorage[1];
_m4storage[10] = argStorage[2];
_m4storage[15] = argStorage[3];
}