#include <math.h>
#include "invensense.h"

#define	gx	(data->gyro[0])
#define	gy	(data->gyro[1])
#define	gz	(data->gyro[2])
#define ax	(data->accel[0])
#define ay	(data->accel[1])
#define az	(data->accel[2])
#ifdef USE_MAGNETOMETER
#define mx	(data->mag[0])
#define my	(data->mag[1])
#define mz	(data->mag[2])
#endif

#define sampleFreq	1000.0f			// sample frequency in Hz
float deltat = 1.0f / sampleFreq;	// integration interval

#define rad2grad	(180.0f / M_PI)

// gyroscope measurement error in rads/s (start at 60 deg/s), then reduce after ~10 s to 3
//float beta = sqrt(3.0f / 4.0f) * M_PI * (60.0f / 180.0f);
float beta = 0.1;	//увеличивать не стоит

float q0, q1, q2, q3;

// Fast inverse square-root. See: http://en.wikipedia.org/wiki/Fast_inverse_square_root
float invSqrt(float x)
{
	unsigned int i = 0x5F1F1412 - (*(unsigned int*)&x >> 1);
	float tmp = *(float*)&i;
	float y = tmp * (1.69000231f - 0.714158168f * x * tmp * tmp);
	return y;
}

// Implementation of Sebastian Madgwick's "...efficient orientation filter for... inertial/magnetic sensor arrays"
// (see http://www.x-io.co.uk/category/open-source/ for examples and more details)
// which fuses acceleration, rotation rate, and magnetic moments to produce a quaternion-based estimate of absolute
// device orientation -- which can be converted to yaw, pitch, and roll. Useful for stabilizing quadcopters, etc.
// The performance of the orientation filter is at least as good as conventional Kalman-based filtering algorithms
// but is much less computationally intensive---it can be performed on a 3.3 V Pro Mini operating at 8 MHz!

//MadgwickAHRSupdate( tdelta, gyr[X], gyr[Y], gyr[Z], acc[X], acc[Y], acc[Z], mag[X], mag[Y], mag[Z])
//tdelta - добавленный мной аргумент - пройденное между итерациями время;
//gyr[X] - показания гироскопа обязательно в рад/сек;
//acc[X] - показания акселерометра в исходных единицах;
//mag[X] - показания магнитометра в исходных единицах;
#ifdef USE_MAGNETOMETER
void MadgwickQuaternionUpdate(invensense_data_p data)
{
	q0 = data->q[0], q1 = data->q[1], q2 = data->q[2], q3 = data->q[3];

	float recipNorm;
	float s0, s1, s2, s3;
	float qDot1, qDot2, qDot3, qDot4;
	float hx, hy;
	float _2q0mx, _2q0my, _2q0mz, _2q1mx, _2bx, _2bz, _4bx, _4bz, _2q0, _2q1, _2q2, _2q3;
	float _2q0q2, _2q2q3, q0q0, q0q1, q0q2, q0q3, q1q1, q1q2, q1q3, q2q2, q2q3, q3q3;
//	float _8bx, _8bz;
/*
	// Use IMU algorithm if magnetometer measurement invalid (avoids NaN in magnetometer normalisation)
	if((mx == 0.0f) && (my == 0.0f) && (mz == 0.0f))
	{
		MadgwickAHRSupdateIMU(data);
		return;
	}
*/
	// Rate of change of quaternion from gyroscope
	qDot1 = 0.5f * (-q1 * gx - q2 * gy - q3 * gz);
	qDot2 = 0.5f * (q0 * gx + q2 * gz - q3 * gy);
	qDot3 = 0.5f * (q0 * gy - q1 * gz + q3 * gx);
	qDot4 = 0.5f * (q0 * gz + q1 * gy - q2 * gx);

	// Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
	if(!((ax == 0.0f) && (ay == 0.0f) && (az == 0.0f)))
	{
		// Normalise accelerometer measurement
		recipNorm = invSqrt(ax * ax + ay * ay + az * az);
		ax *= recipNorm;	ay *= recipNorm;	az *= recipNorm;

		// Normalise magnetometer measurement
		recipNorm = invSqrt(mx * mx + my * my + mz * mz);
		mx *= recipNorm;	my *= recipNorm;	mz *= recipNorm;

		// Auxiliary variables to avoid repeated arithmetic
		_2q0mx = 2.0f * q0 * mx;	_2q0my = 2.0f * q0 * my;
		_2q0mz = 2.0f * q0 * mz;	_2q1mx = 2.0f * q1 * mx;
		_2q0 = 2.0f * q0;	_2q1 = 2.0f * q1;	_2q2 = 2.0f * q2;	_2q3 = 2.0f * q3;
		_2q0q2 = 2.0f * q0 * q2;	_2q2q3 = 2.0f * q2 * q3;
		q0q0 = q0 * q0;		q0q1 = q0 * q1;		q0q2 = q0 * q2;		q0q3 = q0 * q3;
		q1q1 = q1 * q1;		q1q2 = q1 * q2;		q1q3 = q1 * q3;
		q2q2 = q2 * q2;		q2q3 = q2 * q3;		q3q3 = q3 * q3;

		// Reference direction of Earth's magnetic field
		hx = mx * q0q0 - _2q0my * q3 + _2q0mz * q2 + mx * q1q1 + _2q1 * my * q2 + _2q1 * mz * q3 - mx * q2q2 - mx * q3q3;
		hy = _2q0mx * q3 + my * q0q0 - _2q0mz * q1 + _2q1mx * q2 - my * q1q1 + my * q2q2 + _2q2 * mz * q3 - my * q3q3;
		_2bx = sqrt(hx * hx + hy * hy);
		_2bz = -_2q0mx * q2 + _2q0my * q1 + mz * q0q0 + _2q1mx * q3 - mz * q1q1 + _2q2 * my * q3 - mz * q2q2 + mz * q3q3;
		_4bx = 2.0f * _2bx;		_4bz = 2.0f * _2bz;
	    _8bx = 2.0f * _4bx;		_8bz = 2.0f * _4bz;

		// Gradient decent algorithm corrective step

		s0 = -_2q2 * (2.0f * q1q3 - _2q0q2 - ax) + _2q1 * (2.0f * q0q1 + _2q2q3 - ay) -
				_2bz * q2 * (_2bx * (0.5f - q2q2 - q3q3) + _2bz * (q1q3 - q0q2) - mx) +
				(-_2bx * q3 + _2bz * q1) * (_2bx * (q1q2 - q0q3) + _2bz * (q0q1 + q2q3) - my) +
				_2bx * q2 * (_2bx * (q0q2 + q1q3) + _2bz * (0.5f - q1q1 - q2q2) - mz);
		s1 = _2q3 * (2.0f * q1q3 - _2q0q2 - ax) + _2q0 * (2.0f * q0q1 + _2q2q3 - ay) -
				4.0f * q1 * (1 - 2.0f * q1q1 - 2.0f * q2q2 - az) +
				_2bz * q3 * (_2bx * (0.5f - q2q2 - q3q3) + _2bz * (q1q3 - q0q2) - mx) +
				(_2bx * q2 + _2bz * q0) * (_2bx * (q1q2 - q0q3) + _2bz * (q0q1 + q2q3) - my) +
				(_2bx * q3 - _4bz * q1) * (_2bx * (q0q2 + q1q3) + _2bz * (0.5f - q1q1 - q2q2) - mz);
		s2 = -_2q0 * (2.0f * q1q3 - _2q0q2 - ax) + _2q3 * (2.0f * q0q1 + _2q2q3 - ay) -
				4.0f * q2 * (1 - 2.0f * q1q1 - 2.0f * q2q2 - az) +
				(-_4bx * q2 - _2bz * q0) * (_2bx * (0.5f - q2q2 - q3q3) + _2bz * (q1q3 - q0q2) - mx) +
				(_2bx * q1 + _2bz * q3) * (_2bx * (q1q2 - q0q3) + _2bz * (q0q1 + q2q3) - my) +
				(_2bx * q0 - _4bz * q2) * (_2bx * (q0q2 + q1q3) + _2bz * (0.5f - q1q1 - q2q2) - mz);
		s3 = _2q1 * (2.0f * q1q3 - _2q0q2 - ax) + _2q2 * (2.0f * q0q1 + _2q2q3 - ay) +
				(-_4bx * q3 + _2bz * q1) * (_2bx * (0.5f - q2q2 - q3q3) + _2bz * (q1q3 - q0q2) - mx) +
				(-_2bx * q0 + _2bz * q2) * (_2bx * (q1q2 - q0q3) + _2bz * (q0q1 + q2q3) - my) +
				_2bx * q1 * (_2bx * (q0q2 + q1q3) + _2bz * (0.5f - q1q1 - q2q2) - mz);
/*
		s0= -_2q2 * (2.0f * (q1q3 - q0q2) - ax) + _2q1 * (2.0f * (q0q1 + q2q3) - ay) +
				-_4bz * q2 * (_4bx * (0.5 - q2q2 - q3q3) + _4bz * (q1q3 - q0q2) - mx) +
				(-_4bx * q3+_4bz * q1)*(_4bx * (q1q2 - q0q3) + _4bz * (q0q1 + q2q3) - my) +
				_4bx * q2 * (_4bx*(q0q2 + q1q3) + _4bz * (0.5 - q1q1 - q2q2) - mz);
		s1= _2q3 * (2.0f * (q1q3 - q0q2) - ax) + _2q0 * (2.0f * (q0q1 + q2q3) - ay) +
				-4.0f * q1 * (2.0f * (0.5 - q1q1 - q2q2) - az) +
				_4bz * q3 * (_4bx * (0.5 - q2q2 - q3q3) + _4bz * (q1q3 - q0q2) - mx) +
				(_4bx * q2+_4bz * q0) * (_4bx * (q1q2 - q0q3) + _4bz * (q0q1 + q2q3) - my) +
				(_4bx * q3-_8bz * q1) * (_4bx * (q0q2 + q1q3) + _4bz * (0.5 - q1q1 - q2q2) - mz);
		s2= -_2q0 * (2.0f * (q1q3 - q0q2) - ax) + _2q3 * (2.0f * (q0q1 + q2q3) - ay) +
				(-4.0f * q2) * (2.0f * (0.5 - q1q1 - q2q2) - az) +
				(-_8bx * q2-_4bz * q0) * (_4bx * (0.5 - q2q2 - q3q3) + _4bz * (q1q3 - q0q2) - mx) +
				(_4bx * q1+_4bz * q3) * (_4bx * (q1q2 - q0q3) + _4bz * (q0q1 + q2q3) - my) +
				(_4bx * q0-_8bz * q2) * (_4bx * (q0q2 + q1q3) + _4bz * (0.5 - q1q1 - q2q2) - mz);
		s3= _2q1 * (2.0f * (q1q3 - q0q2) - ax) + _2q2 * (2.0f * (q0q1 + q2q3) - ay) +
				(-_8bx * q3+_4bz * q1) * (_4bx * (0.5 - q2q2 - q3q3) + _4bz * (q1q3 - q0q2) - mx) +
				(-_4bx * q0+_4bz * q2) * (_4bx * (q1q2 - q0q3) + _4bz * (q0q1 + q2q3) - my) +
				(_4bx * q1) * (_4bx * (q0q2 + q1q3) + _4bz * (0.5 - q1q1 - q2q2) - mz);
*/
		recipNorm = invSqrt(s0 * s0 + s1 * s1 + s2 * s2 + s3 * s3); // normalise step magnitude
		s0 *= recipNorm;	s1 *= recipNorm;	s2 *= recipNorm;	s3 *= recipNorm;

		// Apply feedback step
		qDot1 -= beta * s0;	qDot2 -= beta * s1;	qDot3 -= beta * s2;	qDot4 -= beta * s3;
	}

	// Integrate rate of change of quaternion to yield quaternion
	q0 += qDot1 * deltat;	q1 += qDot2 * deltat;	q2 += qDot3 * deltat;	q3 += qDot4 * deltat;
	// Normalise quaternion
	recipNorm = invSqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3);
    q0 *= recipNorm;	q1 *= recipNorm;	q2 *= recipNorm;    q3 *= recipNorm;
    //сохраняем кватернион
    data->q[0] = q0;	data->q[1] = q1;	data->q[2] = q2;	data->q[3] = q3;
}
#else
void MadgwickAHRSupdateIMU(invensense_data_p data)
{
	q0 = data->q[0], q1 = data->q[1], q2 = data->q[2], q3 = data->q[3];

	float recipNorm;
	float s0, s1, s2, s3;
	float qDot1, qDot2, qDot3, qDot4;
	float _2q0, _2q1, _2q2, _2q3, _4q0, _4q1, _4q2 ,_8q1, _8q2, q0q0, q1q1, q2q2, q3q3;

	// Rate of change of quaternion from gyroscope
	qDot1 = 0.5f * (-q1 * gx - q2 * gy - q3 * gz);
	qDot2 = 0.5f * (q0 * gx + q2 * gz - q3 * gy);
	qDot3 = 0.5f * (q0 * gy - q1 * gz + q3 * gx);
	qDot4 = 0.5f * (q0 * gz + q1 * gy - q2 * gx);

	// Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
	if(!((ax == 0.0f) && (ay == 0.0f) && (az == 0.0f)))
	{
		// Normalise accelerometer measurement
		recipNorm = invSqrt(ax * ax + ay * ay + az * az);
		ax *= recipNorm;	ay *= recipNorm;	az *= recipNorm;

		// Auxiliary variables to avoid repeated arithmetic
		_2q0 = 2.0f * q0;	_2q1 = 2.0f * q1;	_2q2 = 2.0f * q2;	_2q3 = 2.0f * q3;
		_4q0 = 4.0f * q0;	_4q1 = 4.0f * q1;	_4q2 = 4.0f * q2;
		_8q1 = 8.0f * q1;	_8q2 = 8.0f * q2;
		q0q0 = q0 * q0;		q1q1 = q1 * q1;		q2q2 = q2 * q2;		q3q3 = q3 * q3;

		// Gradient decent algorithm corrective step
		s0 = _4q0 * q2q2 + _2q2 * ax + _4q0 * q1q1 - _2q1 * ay;
		s1 = _4q1 * q3q3 - _2q3 * ax + 4.0f * q0q0 * q1 - _2q0 * ay - _4q1 + _8q1 * q1q1 + _8q1 * q2q2 + _4q1 * az;
		s2 = 4.0f * q0q0 * q2 + _2q0 * ax + _4q2 * q3q3 - _2q3 * ay - _4q2 + _8q2 * q1q1 + _8q2 * q2q2 + _4q2 * az;
		s3 = 4.0f * q1q1 * q3 - _2q1 * ax + 4.0f * q2q2 * q3 - _2q2 * ay;
		recipNorm = invSqrt(s0 * s0 + s1 * s1 + s2 * s2 + s3 * s3); // normalise step magnitude
		s0 *= recipNorm;	s1 *= recipNorm;	s2 *= recipNorm;	s3 *= recipNorm;

		// Apply feedback step
		qDot1 -= beta * s0;	qDot2 -= beta * s1;	qDot3 -= beta * s2;	qDot4 -= beta * s3;
	}

	// Integrate rate of change of quaternion to yield quaternion
	q0 += qDot1 * deltat;	q1 += qDot2 * deltat;	q2 += qDot3 * deltat;	q3 += qDot4 * deltat;
	// Normalise quaternion
	recipNorm = invSqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3);
    q0 *= recipNorm;	q1 *= recipNorm;	q2 *= recipNorm;	q3 *= recipNorm;
    //сохраняем кватернион
    data->q[0] = q0;	data->q[1] = q1;	data->q[2] = q2;	data->q[3] = q3;
}
#endif

void get_angles(invensense_data_p data)
{
/*
	float test = q1 * q2 + q3 * q0;

	if (test > 0.499)
	{
		data->pitch = 0;
		data->roll = -2 * atan2(q1, q0) * rad2grad;
		data->yaw = 90;//M_PI * 180 / (2 * M_PI);
	}
	else if (test< -0.499)
	{
		data->pitch = 0;
		data->roll = 2 * atan2(q1, q0) * rad2grad;
		data->yaw = -90;//-M_PI * 180 / (2 * M_PI);
	}
	else
	{
		data->pitch	= -atan2(2 * (q1 * q0 - q2 * q3), 1 - 2 * (q1 * q1 - q3 * q3)) * rad2grad;
		data->roll	= -atan2(2 * (q2 * q0 - q1 * q3), 1 - 2 * (q2 * q2 - q3 * q3)) * rad2grad;
		data->yaw	= asin (2 * (q1 * q2 + q3 * q0)) * rad2grad;
	}
*/

	// For more see http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles
	//pitch - наклон головы вперёд/назад - вокруг оси X
	//roll - наклон головы влево/вправо - вокруг оси Y
	//yaw - поворот головы влево/вправо - вокруг оси Z
	data->pitch	= atan2(2.0f * (q0 * q1 + q2 * q3), q0 * q0 - q1 * q1 - q2 * q2 + q3 * q3) * rad2grad;
	data->roll	= -asin(2.0f * (q1 * q3 - q0 * q2)) * rad2grad;
#ifdef HID_JOYSTIK
	data->yaw	= atan2(2.0f * (q1 * q2 + q0 * q3), q0 * q0 + q1 * q1 - q2 * q2 - q3 * q3) * rad2grad;

	data->pitch *= 2.0;	//увеличиваем чувствительность в 2 раза - наклон до +-90градусов
	data->roll  *= 4.0;	//увеличиваем чувствительность в 4 раза - наклон до +-45градусов
	data->yaw   *= 4.0;	//увеличиваем чувствительность в 4 раза - поворот до +-45градусов

	//ограничиваем углы
	if (data->pitch > 180.0)	data->pitch = 180.0;
	if (data->pitch < -180.0)	data->pitch = -180.0;
	if (data->roll > 180.0)		data->roll = 180.0;
	if (data->roll < -180.0)	data->roll = -180.0;
	if (data->yaw > 180.0)		data->yaw = 180.0;
	if (data->yaw < -180.0)		data->yaw = -180.0;
#else
	data->yaw	= -atan2(2.0f * (q1 * q2 + q0 * q3), q0 * q0 + q1 * q1 - q2 * q2 - q3 * q3) * rad2grad;

	data->pitch *= 20.0;	//увеличиваем чувствительность в 20 раз - наклон
	data->yaw   *= 20.0;	//увеличиваем чувствительность в 20 раз - поворот
#endif
}