Angle.java

/*
 * Copyright (C) 2014  James Lawrence.
 *
 *     This file is part of LibLab.
 *
 *     LibLab 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 3 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, see <http://www.gnu.org/licenses/>.
 */

package com.sqrt.liblab.threed;

/**
 * Represents an angle for rotation
 */
public class Angle {
    /**
     * No rotation (0 degrees)
     */
    public static final Angle zero = new Angle(0);


    private boolean hasRads;
    private float rads;
    /**
     * The angle in degrees
     */
    public final float degrees;

    /**
     * Constructs a new Angle with the specified angle...
     * @param degrees the angle in degrees
     */
    public Angle(float degrees) {
        this.degrees = degrees;
    }

    /**
     * Copies an angle
     * @param a the angle to copy
     */
    public Angle(Angle a) {
        this.degrees = a.degrees;
    }

    /**
     * Normalizes this angle to the specified central angle and returns it
     * @param low the central angle
     * @return the result
     */
    public Angle normalize(float low) {
        return new Angle(getDegrees(low));
    }

    /**
     * Clamps this angle to a range within the specified magnitude
     * @param mag the magnitude
     * @return the clamped angle
     */
    public Angle clamp(float mag) {
        float degrees = getDegrees(-180f);
        if(degrees > mag)
            degrees = mag;
        else if(degrees < -mag)
            degrees = -mag;
        return new Angle(degrees);
    }

    /**
     * Returns this angle normalized around the specified central point
     * @param low the center point of this angle
     * @return the result
     */
    public float getDegrees(float low) {
        return normalize(degrees, low);
    }

    /**
     * Adds this angle to the specified angle and returns the result
     * @param a the angle to add
     * @return the result of the addition
     */
    public Angle add(Angle a) {
        return new Angle(a.degrees + degrees);
    }

    /**
     * Multiplies this angle against the specified float value and returns the result
     * @param f the multiplication factor
     * @return the result
     */
    public Angle mult(float f) {
        return new Angle(degrees*f);
    }

    /**
     * Subtracts the specified angle from this angle and returns the result
     * @param a the angle to subtract
     * @return the result
     */
    public Angle sub(Angle a) {
        return new Angle(degrees - a.degrees);
    }

    /**
     * Returns this angle in radians
     * @return this angle in radians
     */
    public float radians() {
        if(!hasRads) {
            rads = (float) Math.toRadians(degrees);
            hasRads = true;
        }
        return rads;
    }

    public static float normalize(float degrees, float low) {
        if (degrees >= low + 360.f) {
            float x = (float) Math.floor((degrees - low) / 360f);
            degrees -= 360.f * x;
        } else if (degrees < low) {
            float x = (float) Math.floor((degrees - low) / 360.f);
            degrees -= 360.f * x;
        }
        return degrees;
    }

    public static Angle fromRadians(float rads) {
        Angle a = new Angle((float) Math.toDegrees(rads));
        a.hasRads = true;
        a.rads = rads;
        return a;
    }
}