diff options
Diffstat (limited to 'opentrack/quat.hpp')
| -rw-r--r-- | opentrack/quat.hpp | 48 |
1 files changed, 29 insertions, 19 deletions
diff --git a/opentrack/quat.hpp b/opentrack/quat.hpp index 6d777b28..aec87f4c 100644 --- a/opentrack/quat.hpp +++ b/opentrack/quat.hpp @@ -12,19 +12,19 @@ class Quat { private: static constexpr double pi = 3.141592653; static constexpr double r2d = 180./pi; - double a,b,c,d; // quaternion coefficients + double _0,_1,_2,_3; // quaternion coefficients public: - Quat() : a(1.),b(0.),c(0.),d(0.) {} - Quat(double yaw, double pitch, double roll) { from_euler_rads(yaw, pitch, roll); } - Quat(double a, double b, double c, double d) : a(a),b(b),c(c),d(d) {} + Quat() : _0(1.),_1(0.),_2(0.),_3(0.) {} + Quat(double yaw, double pitch, double roll) { *this = from_euler_rads(yaw, pitch, roll); } + Quat(double a, double b, double c, double d) : _0(a),_1(b),_2(c),_3(d) {} - Quat inv(){ - return Quat(a,-b,-c, -d); + Quat inv() const { + return Quat(_0,-_1,-_2, -_3); } // conversions // see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles - void from_euler_rads(double yaw, double pitch, double roll) + static Quat from_euler_rads(double yaw, double pitch, double roll) { const double sin_phi = sin(roll/2.); @@ -34,17 +34,21 @@ public: const double sin_psi = sin(yaw/2.); const double cos_psi = cos(yaw/2.); - a = cos_phi*cos_the*cos_psi + sin_phi*sin_the*sin_psi; - b = sin_phi*cos_the*cos_psi - cos_phi*sin_the*sin_psi; - c = cos_phi*sin_the*cos_psi + sin_phi*cos_the*sin_psi; - d = cos_phi*cos_the*sin_psi - sin_phi*sin_the*cos_psi; + Quat q; + + q._0 = cos_phi*cos_the*cos_psi + sin_phi*sin_the*sin_psi; + q._1 = sin_phi*cos_the*cos_psi - cos_phi*sin_the*sin_psi; + q._2 = cos_phi*sin_the*cos_psi + sin_phi*cos_the*sin_psi; + q._3 = cos_phi*cos_the*sin_psi - sin_phi*sin_the*cos_psi; + + return q; } void to_euler_rads(double& yaw, double& pitch, double& roll) const { - roll = atan2(2.*(a*b + c*d), 1. - 2.*(b*b + c*c)); - pitch = asin(2.*(a*c - b*d)); - yaw = atan2(2.*(a*d + b*c), 1. - 2.*(c*c + d*d)); + roll = atan2(2.*(_0*_1 + _2*_3), 1. - 2.*(_1*_1 + _2*_2)); + pitch = asin(2.*(_0*_2 - _1*_3)); + yaw = atan2(2.*(_0*_3 + _1*_2), 1. - 2.*(_2*_2 + _3*_3)); } void to_euler_degrees(double& yaw, double& pitch, double& roll) const @@ -58,9 +62,15 @@ public: const Quat operator*(const Quat& B) const { const Quat& A = *this; - return Quat(A.a*B.a - A.b*B.b - A.c*B.c - A.d*B.d, // quaternion multiplication - A.a*B.b + A.b*B.a + A.c*B.d - A.d*B.c, - A.a*B.c - A.b*B.d + A.c*B.a + A.d*B.b, - A.a*B.d + A.b*B.c - A.c*B.b + A.d*B.a); - } + const Quat ret(A._0*B._0 - A._1*B._1 - A._2*B._2 - A._3*B._3, + A._0*B._1 + A._1*B._0 + A._2*B._3 - A._3*B._2, + A._0*B._2 - A._1*B._3 + A._2*B._0 + A._3*B._1, + A._0*B._3 + A._1*B._2 - A._2*B._1 + A._3*B._0); + const double mag_2 = ret._0 * ret._0 + + ret._1 * ret._1 + + ret._2 * ret._2 + + ret._3 * ret._3; + const double inv_mag = 1./sqrt(mag_2); + return Quat(1., ret._1 * inv_mag, ret._2 * inv_mag, ret._3 * inv_mag); + } }; |