    001/* ===========================================================
    002 * Orson Charts : a 3D chart library for the Java(tm) platform
    003 * ===========================================================
    004 *
    005 * (C)opyright 2013-2016, by Object Refinery Limited.  All rights reserved.
    006 *
    007 * http://www.object-refinery.com/orsoncharts/index.html
    008 *
    009 * This program is free software: you can redistribute it and/or modify
    010 * it under the terms of the GNU General Public License as published by
    011 * the Free Software Foundation, either version 3 of the License, or
    012 * (at your option) any later version.
    013 *
    014 * This program is distributed in the hope that it will be useful,
    015 * but WITHOUT ANY WARRANTY; without even the implied warranty of
    016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    017 * GNU General Public License for more details.
    018 *
    019 * You should have received a copy of the GNU General Public License
    020 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
    021 *
    022 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
    023 * Other names may be trademarks of their respective owners.]
    024 *
    025 * If you do not wish to be bound by the terms of the GPL, an alternative
    026 * commercial license can be purchased.  For details, please see visit the
    027 * Orson Charts home page:
    028 *
    029 * http://www.object-refinery.com/orsoncharts/index.html
    030 *
    031 */
    032
    033package com.orsoncharts.graphics3d;
    034
    035import com.orsoncharts.util.ArgChecks;
    036
    037/**
    038 * A line segment in 3D space.
    039 *
    040 * @since 1.5
    041 */
    042public class Line3D {
    043
    044    private Point3D start;
    045
    046    private Point3D end;
    047
    048    /**
    049     * Creates a new line in 3D space.
    050     *
    051     * @param start  the starting point ({@code null} not permitted).
    052     * @param end  the ending point ({@code null} not permitted).
    053     */
    054    public Line3D(Point3D start, Point3D end) {
    055        ArgChecks.nullNotPermitted(start, "start");
    056        ArgChecks.nullNotPermitted(end, "end");
    057        this.start = start;
    058        this.end = end;
    059    }
    060
    061    /**
    062     * Creates a new line in 3D space between the points {@code (x0, y0, z0)}
    063     * and {@code (x1, y1, z1)}.
    064     *
    065     * @param x0  the x-coordinate for the line's start point.
    066     * @param y0  the y-coordinate for the line's start point.
    067     * @param z0  the z-coordinate for the line's start point.
    068     * @param x1  the x-coordinate for the line's end point.
    069     * @param y1  the y-coordinate for the line's end point.
    070     * @param z1  the z-coordinate for the line's end point.
    071     */
    072    public Line3D(double x0, double y0, double z0, double x1, double y1,
    073            double z1) {
    074        this.start = new Point3D(x0, y0, z0);
    075        this.end = new Point3D(x1, y1, z1);
    076    }
    077
    078    /**
    079     * Returns the starting point for the line.
    080     *
    081     * @return The starting point (never {@code null}).
    082     */
    083    public Point3D getStart() {
    084        return this.start;
    085    }
    086
    087    /**
    088     * Returns the ending point for the line.
    089     *
    090     * @return The ending point (never {@code null}).
    091     */
    092    public Point3D getEnd() {
    093        return this.end;
    094    }
    095
    096    /**
    097     * Calculates and returns the line segment that is the result of cropping
    098     * the specified line segment to fit within an axis aligned bounding box.
    099     *
    100     * @param line  the original line segment ({@code null} not permitted).
    101     * @param x0  the lower x-bound.
    102     * @param x1  the upper x-bound.
    103     * @param y0  the lower y-bound.
    104     * @param y1  the upper y-bound.
    105     * @param z0  the lower z-bound.
    106     * @param z1  the upper z-bound.
    107     *
    108     * @return The cropped line segment (or {@code null} if the original line
    109     *     segment falls outside the bounding box).
    110     */
    111    public static Line3D cropLineToAxisAlignedBoundingBox(Line3D line,
    112            double x0, double x1, double y0, double y1, double z0, double z1) {
    113
    114        // we need this method to be fast, since it will get called a lot of
    115        // times during line chart rendering...there may be a faster method
    116        // than what is implemented below, in which case we should use it
    117        double xx0 = line.getStart().getX();
    118        double xx1 = line.getEnd().getX();
    119        int kx0 = 2;
    120        if (xx0 < x0) {
    121            kx0 = 1;
    122        } else if (xx0 > x1) {
    123            kx0 = 4;
    124        }
    125        int kx1 = 2;
    126        if (xx1 < x0) {
    127            kx1 = 1;
    128        } else if (xx1 > x1) {
    129            kx1 = 4;
    130        }
    131        if ((kx0 | kx1) == 1 || (kx0 | kx1) == 4) {
    132            return null;
    133        }
    134
    135        double yy0 = line.getStart().getY();
    136        double yy1 = line.getEnd().getY();
    137        int ky0 = 2;
    138        if (yy0 < y0) {
    139            ky0 = 1;
    140        } else if (yy0 > y1) {
    141            ky0 = 4;
    142        }
    143        int ky1 = 2;
    144        if (yy1 < y0) {
    145            ky1 = 1;
    146        } else if (yy1 > y1) {
    147            ky1 = 4;
    148        }
    149        if ((ky0 | ky1) == 1 || (ky0 | ky1) == 4) {
    150            return null;
    151        }
    152
    153        double zz0 = line.getStart().getZ();
    154        double zz1 = line.getEnd().getZ();
    155        int kz0 = 2;
    156        if (zz0 < z0) {
    157            kz0 = 1;
    158        } else if (zz0 > z1) {
    159            kz0 = 4;
    160        }
    161        int kz1 = 2;
    162        if (zz1 < z0) {
    163            kz1 = 1;
    164        } else if (zz1 > z1) {
    165            kz1 = 4;
    166        }
    167        if ((kz0 | kz1) == 1 || (kz0 | kz1) == 4) {
    168            return null;
    169        }
    170
    171        // if the X's, Y's and Z's are all inside, just return the line
    172        if ((kx0 | kx1 | ky0 | ky1 | kz0 | kz1) == 2) {
    173            return line;
    174        }
    175
    176        // now we know we have to do some clipping
    177        Point3D firstValidPoint = null;
    178        if (isPoint3DInBoundingBox(line.getStart(), x0, x1, y0, y1, z0, z1)) {
    179            firstValidPoint = line.getStart();
    180        }
    181        if (isPoint3DInBoundingBox(line.getEnd(), x0, x1, y0, y1, z0, z1)) {
    182            firstValidPoint = line.getEnd();
    183        }
    184        if (((kx0 | kx1) & 1) != 0) { // X's span the lower bound
    185            Point3D p = projectLineOnX(line, x0);
    186            if (isPoint3DInBoundingBox(p, x0, x1, y0, y1, z0, z1)) {
    187                if (firstValidPoint == null) {
    188                    firstValidPoint = p;
    189                } else {
    190                    return new Line3D(firstValidPoint, p);
    191                }
    192            }
    193        }
    194        if (((kx0 | kx1) & 4) != 0) { // X's span the upper bound
    195            Point3D p = projectLineOnX(line, x1);
    196            if (isPoint3DInBoundingBox(p, x0, x1, y0, y1, z0, z1)) {
    197                if (firstValidPoint == null) {
    198                    firstValidPoint = p;
    199                } else {
    200                    return new Line3D(firstValidPoint, p);
    201                }
    202            }
    203        }
    204
    205        if (((ky0 | ky1) & 1) != 0) { // Y's span the lower bound
    206            Point3D p = projectLineOnY(line, y0);
    207            if (isPoint3DInBoundingBox(p, x0, x1, y0, y1, z0, z1)) {
    208                if (firstValidPoint == null) {
    209                    firstValidPoint = p;
    210                } else {
    211                    return new Line3D(firstValidPoint, p);
    212                }
    213            }
    214        }
    215        if (((ky0 | ky1) & 4) != 0) { // Y's span the upper bound
    216            Point3D p = projectLineOnY(line, y1);
    217            if (isPoint3DInBoundingBox(p, x0, x1, y0, y1, z0, z1)) {
    218                if (firstValidPoint == null) {
    219                    firstValidPoint = p;
    220                } else {
    221                    return new Line3D(firstValidPoint, p);
    222                }
    223            }
    224        }
    225        if (((kz0 | kz1) & 1) != 0) { // X's span the lower bound
    226            Point3D p = projectLineOnZ(line, z0);
    227            if (isPoint3DInBoundingBox(p, x0, x1, y0, y1, z0, z1)) {
    228                if (firstValidPoint == null) {
    229                    firstValidPoint = p;
    230                } else {
    231                    return new Line3D(firstValidPoint, p);
    232                }
    233            }
    234        }
    235        if (((kz0 | kz1) & 4) != 0) { // X's span the upper bound
    236            Point3D p = projectLineOnZ(line, z1);
    237            if (isPoint3DInBoundingBox(p, x0, x1, y0, y1, z0, z1)) {
    238                if (firstValidPoint == null) {
    239                    firstValidPoint = p;
    240                } else {
    241                    return new Line3D(firstValidPoint, p);
    242                }
    243            }
    244        }
    245        return null;
    246    }
    247
    248    private static Point3D projectLineOnX(Line3D line, double x) {
    249        double x0 = line.getStart().getX();
    250        double x1 = line.getEnd().getX();
    251        double factor = 0.0;
    252        if (Math.abs(x1 - x0) > 0) {
    253            factor = (x - x0) / (x1 - x0);
    254        }
    255        if (factor >= 1.0) {
    256            return line.getEnd();
    257        } else if (factor <= 0.0) {
    258            return line.getStart();
    259        } else {
    260            double y0 = line.getStart().getY();
    261            double y1 = line.getEnd().getY();
    262            double z0 = line.getStart().getZ();
    263            double z1 = line.getEnd().getZ();
    264            return new Point3D(x0 + factor * (x1 - x0), y0 + factor * (y1 - y0),
    265                z0 + factor * (z1 - z0));
    266        }
    267    }
    268
    269    private static Point3D projectLineOnY(Line3D line, double y) {
    270        double y0 = line.getStart().getY();
    271        double y1 = line.getEnd().getY();
    272        double factor = 0.0;
    273        if (Math.abs(y1 - y0) > 0) {
    274            factor = (y - y0) / (y1 - y0);
    275        }
    276        if (factor >= 1.0) {
    277            return line.getEnd();
    278        } else if (factor <= 0.0) {
    279            return line.getStart();
    280        } else {
    281            double x0 = line.getStart().getX();
    282            double x1 = line.getEnd().getX();
    283            double z0 = line.getStart().getZ();
    284            double z1 = line.getEnd().getZ();
    285            return new Point3D(x0 + factor * (x1 - x0), y0 + factor * (y1 - y0),
    286                z0 + factor * (z1 - z0));
    287        }
    288    }
    289
    290    private static Point3D projectLineOnZ(Line3D line, double z) {
    291        double z0 = line.getStart().getZ();
    292        double z1 = line.getEnd().getZ();
    293        double factor = 0.0;
    294        if (Math.abs(z1 - z0) > 0) {
    295            factor = (z - z0) / (z1 - z0);
    296        }
    297        if (factor >= 1.0) {
    298            return line.getEnd();
    299        } else if (factor <= 0.0) {
    300            return line.getStart();
    301        } else {
    302            double x0 = line.getStart().getX();
    303            double x1 = line.getEnd().getX();
    304            double y0 = line.getStart().getY();
    305            double y1 = line.getEnd().getY();
    306            return new Point3D(x0 + factor * (x1 - x0), y0 + factor * (y1 - y0),
    307                z0 + factor * (z1 - z0));
    308        }
    309    }
    310
    311    private static boolean isPoint3DInBoundingBox(Point3D p, double x0,
    312            double x1, double y0, double y1, double z0, double z1) {
    313        double x = p.getX();
    314        if (x < x0) {
    315            return false;
    316        }
    317        if (x > x1) {
    318            return false;
    319        }
    320        double y = p.getY();
    321        if (y < y0) {
    322            return false;
    323        }
    324        if (y > y1) {
    325            return false;
    326        }
    327        double z = p.getZ();
    328        if (z < z0) {
    329            return false;
    330        }
    331        if (z > z1) {
    332            return false;
    333        }
    334        return true;
    335    }
    336}