File content as of revision 30:9b0cd3caf0ec:

//=============================================================================================
// Mahony.h
//=============================================================================================
//
// Madgwick's implementation of Mayhony's AHRS algorithm.
// See: http://www.x-io.co.uk/open-source-imu-and-ahrs-algorithms/
//
// Date         Author          Notes
// 29/09/2011   SOH Madgwick    Initial release
// 02/10/2011   SOH Madgwick    Optimised for reduced CPU load
//
//=============================================================================================
#ifndef __Mahony_h__
#define __Mahony_h__
#include <math.h>

//--------------------------------------------------------------------------------------------
// Variable declaration

class Mahony {
private:
    float twoKp;        // 2 * proportional gain (Kp)
    float twoKi;        // 2 * integral gain (Ki)
    float q0, q1, q2, q3;   // quaternion of sensor frame relative to auxiliary frame
    float integralFBx, integralFBy, integralFBz;  // integral error terms scaled by Ki
    float invSampleFreq;
    float roll, pitch, yaw;
    static float invSqrt(float x);


//-------------------------------------------------------------------------------------------
// Function declarations

public:
    Mahony(float);
    void begin(float sampleFrequency) { invSampleFreq = 1.0f / sampleFrequency; }
    void update(float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz);
    void updateIMU(float gx, float gy, float gz, float ax, float ay, float az);
    char anglesComputed;
    void computeAngles();
    float getRoll() {
        if (!anglesComputed) computeAngles();
        return roll * 57.29578f;
    }
    float getPitch() {
        if (!anglesComputed) computeAngles();
        return pitch * 57.29578f;
    }
    float getYaw() {
        if (!anglesComputed) computeAngles();
        return yaw * 57.29578f + 180.0f;
    }
    float getRollRadians() {
        if (!anglesComputed) computeAngles();
        return roll;
    }
    float getPitchRadians() {
        if (!anglesComputed) computeAngles();
        return pitch;
    }
    float getYawRadians() {
        if (!anglesComputed) computeAngles();
        return yaw;
    }
    void getQuaternion(float *w, float *x, float *y, float *z) {
       *w = q0;
       *x = q1;
       *y = q2;
       *z = q3;
   }
};

#endif