/// <summary>
/// Cals the angle with axis y.
/// </summary>
/// <returns>The angle with axis y.</returns>
/// <param name="forward">Forward.</param>
public static float CalAngleWithAxisY(UVector3 forward)
{
forward.y = 0;
forward.Normalized();
var acos = Math.Acos(forward.z) * MathHelper.Rad2Deg;
if (forward.x > 0)
{
return((float)acos);
}
else
{
return(360f - (float)(acos));
}
}
/// <summary>
/// Angles the axis.
/// </summary>
/// <returns>The axis.</returns>
/// <param name="angle">Angle.</param>
/// <param name="axis">Axis.</param>
public static UQuaternion AngleAxis(float angle, UVector3 axis)
{
if (Math.Abs(axis.sqrMagnitude) < MathHelper.Epsilon)
{
return(identity);
}
axis.Normalized();
var sin = (float)Math.Sin(angle * MathHelper.Deg2Rad * 0.5f);
var cos = (float)Math.Cos(angle * MathHelper.Deg2Rad * 0.5f);
float w = cos;
float x = axis.x * sin;
float y = axis.y * sin;
float z = axis.z * sin;
return(new UQuaternion(x, y, z, w));
}