SlopeHeightMap.java

/*
 * Copyright (C) 2014 pepijn
 *
 * 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 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 org.pepsoft.worldpainter.heightMaps;

import java.awt.Rectangle;

import org.pepsoft.util.IconUtils;
import org.pepsoft.worldpainter.HeightMap;

import javax.swing.*;

/**
 * A height map which calculates the slope of an underlying height map, in
 * degrees from 0 to 90.
 *
 * @author pepijn
 */
public class SlopeHeightMap extends DelegatingHeightMap {
    public SlopeHeightMap(HeightMap baseHeightMap) {
        this(baseHeightMap, 1.0f);
    }

    public SlopeHeightMap(HeightMap baseHeightMap, String name) {
        this(baseHeightMap, 1.0f, name);
    }
    
    public SlopeHeightMap(HeightMap baseHeightMap, float verticalScaling) {
        super("baseHeightMap");
        setName(baseHeightMap.getName() != null ? "Slope of " + baseHeightMap.getName() : null);
        this.verticalScaling = verticalScaling;
        setHeightMap(0, baseHeightMap);
    }

    public SlopeHeightMap(HeightMap baseHeightMap, float verticalScaling, String name) {
        super("baseHeightMap");
        setName(name);
        this.verticalScaling = verticalScaling;
        setHeightMap(0, baseHeightMap);
    }

    public HeightMap getBaseHeightMap() {
        return children[0];
    }

    public void setBaseHeightMap(HeightMap baseHeightMap) {
        replace(0, baseHeightMap);
    }

    public float getVerticalScaling() {
        return verticalScaling;
    }

    public void setVerticalScaling(float verticalScaling) {
        this.verticalScaling = verticalScaling;
    }

    // HeightMap

    @Override
    protected float doGetHeight(float x, float y) {
        HeightMap baseHeightMap = children[0];
        if (verticalScaling != 1.0f) {
            return (float) (Math.tan(Math.max(Math.max(Math.abs(baseHeightMap.getHeight(x + 1, y) / verticalScaling - baseHeightMap.getHeight(x - 1, y) / verticalScaling) / 2,
                Math.abs(baseHeightMap.getHeight(x + 1, y + 1) / verticalScaling - baseHeightMap.getHeight(x - 1, y - 1) / verticalScaling) / ROOT_EIGHT),
                Math.max(Math.abs(baseHeightMap.getHeight(x, y + 1) / verticalScaling - baseHeightMap.getHeight(x, y - 1) / verticalScaling) / 2,
                Math.abs(baseHeightMap.getHeight(x - 1, y + 1) / verticalScaling - baseHeightMap.getHeight(x + 1, y - 1) / verticalScaling) / ROOT_EIGHT))) * RADIANS_TO_DEGREES);
        } else {
            return (float) (Math.tan(Math.max(Math.max(Math.abs(baseHeightMap.getHeight(x + 1, y) / verticalScaling - baseHeightMap.getHeight(x - 1, y)) / 2,
                Math.abs(baseHeightMap.getHeight(x + 1, y + 1) - baseHeightMap.getHeight(x - 1, y - 1)) / ROOT_EIGHT),
                Math.max(Math.abs(baseHeightMap.getHeight(x, y + 1) - baseHeightMap.getHeight(x, y - 1)) / 2,
                Math.abs(baseHeightMap.getHeight(x - 1, y + 1) - baseHeightMap.getHeight(x + 1, y - 1)) / ROOT_EIGHT))) * RADIANS_TO_DEGREES);
        }
    }

    @Override
    public Rectangle getExtent() {
        return children[0].getExtent();
    }

    @Override
    public SlopeHeightMap clone() {
        return new SlopeHeightMap(children[0].clone(), name);
    }

    @Override
    public Icon getIcon() {
        return ICON_SLOPE_HEIGHTMAP;
    }

    @Override
    public float[] getRange() {
        return RANGE;
    }

    private float verticalScaling;

    private static final long serialVersionUID = 1L;
    private static final double ROOT_EIGHT = Math.sqrt(8.0);
    private static final double RADIANS_TO_DEGREES = 180 / Math.PI;
    private static final Icon ICON_SLOPE_HEIGHTMAP = IconUtils.loadScaledIcon("org/pepsoft/worldpainter/icons/integral.png");
    private static final float[] RANGE = {0.0f, 90.0f};
}