Angle.nxc

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/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*- */
/*
    Angle.nxc
    Copyright (C) 2008 Naba Kumar   <naba@gnome.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#ifndef __ANGLE_H_
#define __ANGLE_H_

#include "Debug.nxc"

inline int AngleAbsToRel(int absAngle)
{
    if (absAngle > 180)
        return (absAngle - 360);
    return absAngle;
}

inline int AngleRelToAbs(int relAngle)
{
    if (relAngle < 0)
        return (relAngle + 360);
    return relAngle;
}

inline int AngleAbsAdd(int absAngleA, int angle)
{
    int val = (absAngleA + angle) % 360;
    if (val < 0) val += 360;
    return val;
}

inline int AngleAbsSub(int absAngleA, int angle)
{
    int val = (absAngleA - angle) % 360;
    if (val < 0) val += 360;
    return val;
}

inline int AngleRelAdd(int relAngleA, int angle)
{
    int val = relAngleA + angle;
    val %= 360;
    if (val > 180) val -= 360;
    if (val < -180) val += 360;
    return val;
}

inline int AngleRelSub(int relAngleA, int angle)
{
    int val = relAngleA - angle;
    val %= 360;
    if (val > 180) val -= 360;
    if (val < -180) val += 360;
    return val;
}

/* Tests */

#ifdef ENABLE_TEST

void TestAngle()
{
    TEST((AngleAbsToRel(10) == 10), "AbsToRel 10");
    TEST((AngleAbsToRel(270) == -90), "AbsToRel 270");
    TEST((AngleAbsToRel(0) == 0), "AbsToRel 0");
    TEST((AngleAbsToRel(181) == -179), "AbsToRel 181");
    TEST((AngleAbsToRel(180) == 180), "AbsToRel 180");
    TEST((AngleAbsToRel(360) == 0), "AbsToRel 360");
    
    TEST((AngleRelToAbs(10) == 10), "AbsToRel 10");
    TEST((AngleRelToAbs(-90) == 270), "AbsToRel -90");
    TEST((AngleRelToAbs(0) == 0), "AbsToRel 0");
    TEST((AngleRelToAbs(-179) == 181), "AbsToRel -179");
    TEST((AngleRelToAbs(180) == 180), "AbsToRel 180");
    TEST((AngleRelToAbs(-180) == 180), "AbsToRel -180");

    TEST((AngleAbsAdd(270, 100) == 10), "AbsAdd 100");
    TEST((AngleAbsAdd(270, -100) == 170), "AbsAdd -100");
    TEST((AngleAbsAdd(0, 10) == 10), "AbsAdd 10");
    TEST((AngleAbsAdd(0, -10) == 350), "AbsAdd -10");
    TEST((AngleAbsAdd(10, 500) == 150), "AbsAdd 500");
    TEST((AngleAbsAdd(180, 180) == 0), "AbsAdd 180");

    TEST((AngleAbsSub(270, 100) == 170), "AbsSub 100");
    TEST((AngleAbsSub(270, -100) == 10), "AbsSub -100");
    TEST((AngleAbsSub(0, 10) == 350), "AbsSub 10");
    TEST((AngleAbsSub(0, -10) == 10), "AbsSub -10");
    TEST((AngleAbsSub(10, 500) == 230), "AbsSub 500");
    TEST((AngleAbsSub(180, 180) == 0), "AbsSub 180");

    TEST((AngleRelAdd(170, 100) == -90), "RelAdd 100");
    TEST((AngleRelAdd(10, -100) == -90), "RelAdd -100");
    TEST((AngleRelAdd(0, 10) == 10), "RelAdd 10");
    TEST((AngleRelAdd(0, -10) == -10), "RelAdd -10");
    TEST((AngleRelAdd(10, 500) == 150), "RelAdd 500");
    TEST((AngleRelAdd(10, -500) == -130), "RelAdd -500");
    TEST((AngleRelAdd(180, 180) == 0), "RelAdd 180");

    TEST((AngleRelSub(270, 100) == 170), "RelSub 100");
    TEST((AngleRelSub(270, -100) == 10), "RelSub -100");
    TEST((AngleRelSub(0, 10) == -10), "RelSub 10");
    TEST((AngleRelSub(0, -10) == 10), "RelSub -10");
    TEST((AngleRelSub(10, 500) == -130), "RelSub 500");
    TEST((AngleRelSub(180, 180) == 0), "RelSub 180");
}

#endif /* ENABLE_TEST */
#endif __ANGLE_H_