void set_rotate(Matrix33f &m, float radian)
{
float sina = std::sin(radian);
m.makeIdentity();
m[0][0] = m[1][1] = std::cos(radian);
m[0][1] = -sina;
m[1][0] = sina;
}
void set_scale(Matrix33f &m, float sx, float sy)
{
m.makeIdentity();
m[0][0] = sx;
m[1][1] = sy;
}
void set_translate(Matrix33f &m, float dx, float dy)
{
m.makeIdentity();
m[0][2] = dx;
m[1][2] = dy;
}