quaternionf.h

/*
 * quaternion.h
 *
 *  Created on: 19/mar/2015
 *      Author: mauro
 */

#ifndef MY_MATH_INCLUDE_QUATERNIONF_H_
#define MY_MATH_INCLUDE_QUATERNIONF_H_

#include "vector3f.h"

struct Quaternion4f {
	float w, x, y, z;
};

static void conjugate(const struct Quaternion4f *origin, struct Quaternion4f *result) {
	result->x = -origin->x;
	result->y = -origin->y;
	result->z = -origin->z;
	result->w = origin->w;
}

static void multiply(const struct Quaternion4f *q1, const struct Quaternion4f *q2, struct Quaternion4f *result) {
	result->w = q1->w * q2->w - q1->x * q2->x - q1->y * q2->y - q1->z * q2->z;
	result->x = q1->w * q2->x + q2->w * q1->x + q1->y * q2->z - q1->z * q2->y;
	result->y = q1->w * q2->y + q2->w * q1->y - q1->x * q2->z + q1->z * q2->x;
	result->z = q1->w * q2->z + q2->w * q1->z + q1->x * q2->y - q1->y * q2->x;
}

static void transform(const struct Vector3f *v, const struct Quaternion4f *q, struct Vector3f *result) {
	struct Quaternion4f tmp1;
	struct Quaternion4f tmp2;

	conjugate(q, &tmp2); /* conijugate Q and put result in tmp2 */

	tmp1.x = v->x;
	tmp1.y = v->y;
	tmp1.z = v->z;
	tmp1.w = 0;

	multiply(&tmp1, &tmp2, &tmp2); /* mul tmp1 and tmp2, store in tmp2 */
	multiply(q, &tmp2, &tmp2); /* mul q and tmp2, store in tmp2 */

	result->x = tmp2.x;
	result->y = tmp2.y;
	result->z = tmp2.z;
}

static const struct {
	void (*conjugate)(const struct Quaternion4f*, struct Quaternion4f*);
	void (*multiply)(const struct Quaternion4f*, const struct Quaternion4f*, struct Quaternion4f*);
	void (*transform)(const struct Vector3f*, const struct Quaternion4f*, struct Vector3f*);
} quaterionf_helper = { conjugate, multiply, transform };

#endif /* MY_MATH_INCLUDE_QUATERNIONF_H_ */