jme3utilities.sky.LunarPhase Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of SkyControl Show documentation
A sky-simulation library for jMonkeyEngine
The newest version!
/*
 Copyright (c) 2014-2023, Stephen Gold

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
 * Redistributions of source code must retain the above copyright
 notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright
 notice, this list of conditions and the following disclaimer in the
 documentation and/or other materials provided with the distribution.
 * Neither the name of the copyright holder nor the names of its contributors
 may be used to endorse or promote products derived from this software without
 specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package jme3utilities.sky;

import com.jme3.math.FastMath;
import jme3utilities.Validate;

/**
 * Enumerate some phases of the moon.
 *
 * @author Stephen Gold [email protected]
 */
public enum LunarPhase {
    // *************************************************************************
    // values

    /**
     * full moon: phase angle = 180 degrees
     */
    FULL,
    /**
     * 65% past full: phase angle = 297 degrees
     */
    WANING_CRESCENT,
    /**
     * 1/4 past full: phase angle = 225 degrees
     */
    WANING_GIBBOUS,
    /**
     * 35% past new: phase angle = 63 degrees
     */
    WAXING_CRESCENT,
    /**
     * 3/4 past new: phase angle = 135 degrees
     */
    WAXING_GIBBOUS,
    /**
     * custom phase: phase angle not defined
     */
    CUSTOM;
    // *************************************************************************
    // new methods exposed

    /**
     * Look up the textual description of this phase. Unlike toString(), the
     * description is in lower case.
     *
     * @return descriptive string of text (not null)
     */
    public String describe() {
        String result;
        switch (this) {
            case CUSTOM:
                result = "custom";
                break;
            case FULL:
                result = "full";
                break;
            case WANING_CRESCENT:
                result = "waning-crescent";
                break;
            case WANING_GIBBOUS:
                result = "waning-gibbous";
                break;
            case WAXING_CRESCENT:
                result = "waxing-crescent";
                break;
            case WAXING_GIBBOUS:
                result = "waxing-gibbous";
                break;
            default:
                result = String.format("ordinal=%d", ordinal());
        }
        return result;
    }

    /**
     * Find a phase based on its textual description.
     *
     * @param description returned by describe() (not null, not empty)
     * @return phase, or null if the description does not match any value
     */
    public static LunarPhase fromDescription(String description) {
        Validate.nonEmpty(description, "description");

        for (LunarPhase phase : values()) {
            String d = phase.describe();
            if (d.equals(description)) {
                return phase;
            }
        }

        return null;
    }

    /**
     * Look up the asset path to the color map for this phase.
     *
     * @param suffix folder name suffix ("" → default)
     * @return asset path (not null)
     */
    public String imagePath(String suffix) {
        if (this == CUSTOM) {
            throw new IllegalStateException("custom phase has no color map");
        }
        String description = describe();
        String assetPath = String.format(
                "Textures/skies/moon%s/%s.png", suffix, description);

        return assetPath;
    }

    /**
     * Look up the celestial longitude difference for this phase.
     *
     * @return radians east of the sun (<2*Pi. ≥0)
     */
    public float longitudeDifference() {
        switch (this) {
            case FULL:
                return FastMath.PI;
            case WANING_CRESCENT:
                return 1.65f * FastMath.PI;
            case WANING_GIBBOUS:
                return 1.25f * FastMath.PI;
            case WAXING_CRESCENT:
                return 0.35f * FastMath.PI;
            case WAXING_GIBBOUS:
                return 0.75f * FastMath.PI;
            default:
                throw new IllegalStateException(describe());
        }
    }
}