turbomath.h

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/*
 *
 * BSD 3-Clause License
 *
 * Copyright (c) 2017, James Jackson  BYU MAGICC Lab, Provo UT
 * All rights reserved.
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 * modification, are permitted provided that the following conditions are met:
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#ifndef TURBOMATH_TURBOMATH_H
#define TURBOMATH_TURBOMATH_H

#include <cstdint>

namespace turbomath
{

// float-based wrappers
float cos(float x);
float sin(float x);
float asin(float x);
float atan2(float y, float x);
float atan(float x);
float fsign(float y);

// turbo-speed approximation of (1.0 - pow(pressure/101325.0, 0.1902631)) * 39097.63
// Used for calculating altitude in m from atmospheric pressure in Pa
float alt(float x);

float inv_sqrt(float x);
float fabs(float x);

union float_converter_t
{
  float fvalue;
  int32_t ivalue;
};

class Vector
{
public:
  float arr[3];
  float &x;
  float &y;
  float &z;

  Vector();
  Vector(const Vector &v);
  Vector(float x_, float y_, float z_);

  float norm() const;
  float sqrd_norm() const;
  Vector &normalize();
  Vector normalized() const;

  float dot(const Vector &v) const;
  Vector cross(const Vector &v) const;

  Vector &operator= (const Vector &v);
  Vector operator* (float s) const;
  Vector operator/ (float s) const;
  Vector &operator*= (float s);
  Vector &operator/= (float s);
  Vector operator+ (const Vector &v) const;
  Vector operator- (const Vector &v) const;
  Vector &operator+= (const Vector &v);
  Vector &operator-= (const Vector &v);
};

inline Vector operator* (float s, const Vector &v)
{
  return v * s;
}
inline Vector operator/ (float s, const Vector &v)
{
  return v / s;
}


class Quaternion
{
public:
  float w;
  float x;
  float y;
  float z;

  Quaternion();
  Quaternion(float w_, float x_, float y_, float z_);
  Quaternion(const Vector &u, const Vector &v);
  Quaternion(float roll, float pitch, float yaw);

  Vector rotate(const Vector &v) const;
  Quaternion &normalize();
  Quaternion inverse() const;
  Quaternion &invert();
  Quaternion &from_two_unit_vectors(const Vector &u, const Vector &v);
  Quaternion &from_RPY(float roll, float pitch, float yaw);
  void get_RPY(float *roll, float *pitch, float *yaw) const;

  Vector operator* (const Vector &v) const;
  Quaternion operator* (const Quaternion &q) const;
  Quaternion &operator*= (const Quaternion &q);
  Vector boxminus(const Quaternion &q) const;
  static Vector log(const Quaternion &q)
  {
    Vector v{q.x, q.y, q.z};
    float norm_v = v.norm();

    Vector out;
    if (norm_v < 1e-8)
    {
      out.x = out.y = out.z = 0.0;
    }
    else
    {
      out = 2.0*atan2(norm_v, q.w)*v/norm_v;
    }
    return out;
  }

  Vector operator-(const Quaternion &q) const
  {
    return boxminus(q);
  }
};

} // namespace turbomath

#endif // TURBOMATH_TURBOMATH_H