Mathy problems <cmath>

[JCED]

I'm having a problem where one of my functions are resulting in nan and inf values. Here is the offending function:

void Ship::SetThrustSpeed(float ThrustSpeed)
{
        /*
         * Imagine a triangle ABC. Direction is the measure of angle A,
         * ThrustSpeed is the measure (in pixels) of segment AC, and also the
         * hypotenuse. SpeedX is the measure of segment BC and SpeedY is
         * the measure of segment AB. We need to find SpeedX and SpeedY, so we
         * get the sine of Direction to find the ratio of SpeedX to
         * ThrustSpeed, then we multiply it by ThrustSpeed (because it's SpeedX
         * over 1), to get SpeedX. SpeedY is just a matter of Pythagorean
         * Theorem.
         */
        float tmp = std::sin(Direction);
        SetSpeedX(ThrustSpeed * tmp);
        SetSpeedY(std::sqrt((ThrustSpeed * ThrustSpeed) /
                        (GetSpeed().x * GetSpeed().x)));
}

<cmath> is included.

The function takes a ThrustSpeed and translates it into a SpeedX and SpeedY based on Direction, which is an angle. Direction is a private member of Ship.

SetSpeedX and SetSpeedY are not doing anything but setting the values.
GetSpeed returns an sf::Vector2f, which is just a vector holding 2 floats: x and y.

After executing this function (ThrustSpeed = 50, Direction = 45), SpeedX is set to 0, and SpeedY is set to inf.

Tell me if you need any more information.

Thanks,
Jordy

[helios]

Given a polar vector of angle alpha and speed v, its equivalent rectangular vector is:
xv: cos(alpha)*v
yv: sin(alpha)*v