The m_align_rotation flag that follows is simply the flag we passed in from the checkbox. If this value is true, the particle will rotate itself to point in the direction it is moving. The m_rotation floating-point variable follows that. The attribute variable that holds the angle of the particle will be rotated based on the direction in which the particle is moving. Here is what these values look like in our code:
bool m_align_rotation;
float m_rotation;