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/******************************************************************************
*
* Copyright (C) 2012 Asahi Kasei Microdevices Corporation, Japan
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
#include "AKFS_Direction.h"
#include "AKFS_VNorm.h"
#include "AKFS_Math.h"
/*
Coordinate system is right-handed.
X-Axis: from left to right.
Y-Axis: from bottom to top.
Z-Axis: from reverse to obverse.
azimuth: Rotaion around Z axis, with positive values
when y-axis moves toward the x-axis.
pitch: Rotation around X axis, with positive values
when z-axis moves toward the y-axis.
roll: Rotation around Y axis, with positive values
when x-axis moves toward the z-axis.
*/
/*
This function is used internaly, so output is RADIAN!
*/
static void AKFS_Angle(
const AKFVEC* avec,
AKFLOAT* pitch, /* radian */
AKFLOAT* roll /* radian */
)
{
AKFLOAT av; /* Size of vector */
av = AKFS_SQRT((avec->u.x)*(avec->u.x) + (avec->u.y)*(avec->u.y) + (avec->u.z)*(avec->u.z));
*pitch = AKFS_ASIN(-(avec->u.y) / av);
*roll = AKFS_ASIN((avec->u.x) / av);
}
/*
This function is used internaly, so output is RADIAN!
*/
static void AKFS_Azimuth(
const AKFVEC* hvec,
const AKFLOAT pitch, /* radian */
const AKFLOAT roll, /* radian */
AKFLOAT* azimuth /* radian */
)
{
AKFLOAT sinP; /* sin value of pitch angle */
AKFLOAT cosP; /* cos value of pitch angle */
AKFLOAT sinR; /* sin value of roll angle */
AKFLOAT cosR; /* cos value of roll angle */
AKFLOAT Xh; /* X axis element of vector which is projected to horizontal plane */
AKFLOAT Yh; /* Y axis element of vector which is projected to horizontal plane */
sinP = AKFS_SIN(pitch);
cosP = AKFS_COS(pitch);
sinR = AKFS_SIN(roll);
cosR = AKFS_COS(roll);
Yh = -(hvec->u.x)*cosR + (hvec->u.z)*sinR;
Xh = (hvec->u.x)*sinP*sinR + (hvec->u.y)*cosP + (hvec->u.z)*sinP*cosR;
/* atan2(y, x) -> divisor and dividend is opposite from mathematical equation. */
*azimuth = AKFS_ATAN2(Yh, Xh);
}
int16 AKFS_Direction(
const int16 nhvec,
const AKFVEC hvec[],
const int16 hnave,
const int16 navec,
const AKFVEC avec[],
const int16 anave,
AKFLOAT* azimuth,
AKFLOAT* pitch,
AKFLOAT* roll
)
{
AKFVEC have, aave;
AKFLOAT azimuthRad;
AKFLOAT pitchRad;
AKFLOAT rollRad;
/* arguments check */
if ((nhvec <= 0) || (navec <= 0) || (hnave <= 0) || (anave <= 0)) {
return AKFS_ERROR;
}
if ((nhvec < hnave) || (navec < anave)) {
return AKFS_ERROR;
}
/* average */
if (AKFS_VbAve(nhvec, hvec, hnave, &have) != AKFS_SUCCESS) {
return AKFS_ERROR;
}
if (AKFS_VbAve(navec, avec, anave, &aave) != AKFS_SUCCESS) {
return AKFS_ERROR;
}
/* calculate pitch and roll */
AKFS_Angle(&aave, &pitchRad, &rollRad);
/* calculate azimuth */
AKFS_Azimuth(&have, pitchRad, rollRad, &azimuthRad);
*azimuth = RAD2DEG(azimuthRad);
*pitch = RAD2DEG(pitchRad);
*roll = RAD2DEG(rollRad);
/* Adjust range of azimuth */
if (*azimuth < 0) {
*azimuth += 360.0f;
}
return AKFS_SUCCESS;
}
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