Quaternion to Euler angles algorithm - How to convert to 'Y = Up' and between handedness?

Question

I have an algorithm for converting between a Quaternion and Euler angles.

    public static Vector3 ToEulerAngles(this Quaternion q)
    {
        // Store the E         


        

Answer 1

Here are changed methods that use the same definition of yaw, pitch, roll:

public static Quaternion CreateFromYawPitchRoll(float yaw, float pitch, float roll)
{
    float rollOver2 = roll * 0.5f;
    float sinRollOver2 = (float)Math.Sin((double)rollOver2);
    float cosRollOver2 = (float)Math.Cos((double)rollOver2);
    float pitchOver2 = pitch * 0.5f;
    float sinPitchOver2 = (float)Math.Sin((double)pitchOver2);
    float cosPitchOver2 = (float)Math.Cos((double)pitchOver2);
    float yawOver2 = yaw * 0.5f;
    float sinYawOver2 = (float)Math.Sin((double)yawOver2);
    float cosYawOver2 = (float)Math.Cos((double)yawOver2);
    Quaternion result;
    result.X = cosYawOver2 * cosPitchOver2 * cosRollOver2 + sinYawOver2 * sinPitchOver2 * sinRollOver2;
    result.Y = cosYawOver2 * cosPitchOver2 * sinRollOver2 - sinYawOver2 * sinPitchOver2 * cosRollOver2;
    result.Z = cosYawOver2 * sinPitchOver2 * cosRollOver2 + sinYawOver2 * cosPitchOver2 * sinRollOver2;
    result.W = sinYawOver2 * cosPitchOver2 * cosRollOver2 - cosYawOver2 * sinPitchOver2 * sinRollOver2;
    return result;
} 

For ToEulerAngles (singularities ommitted):

pitchYawRoll.Y = (float)Math.Atan2(2f * q.X * q.W + 2f * q.Y * q.Z, 1 - 2f * (sqz  + sqw));     // Yaw 
pitchYawRoll.X = (float)Math.Asin(2f * ( q.X * q.Z - q.W * q.Y ) );                             // Pitch 
pitchYawRoll.Z = (float)Math.Atan2(2f * q.X * q.Y + 2f * q.Z * q.W, 1 - 2f * (sqy + sqz));      // Roll 

I performed the following test:

var q = CreateFromYawPitchRoll(0.2f, 0.3f, 0.7f);
var e = ToEulerAngles(q);
var q2 = CreateFromYawPitchRoll(e.Y, e.X, e.Z);

with the following results;

e = (0.3, 0.2, 0.7) //pitch, yaw, roll
q2 = q

Source: Wikipedia