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Triangle.java

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/*******************************************************************************
 * Copyright (c) 2012 Stefan Profanter. All rights reserved. This program and the accompanying
 * materials are made available under the terms of the GNU Public License v3.0 which accompanies
 * this distribution, and is available at http://www.gnu.org/licenses/gpl.html
 * 
 * Contributors: Stefan Profanter - initial API and implementation, Year: 2012
 ******************************************************************************/
package edu.tum.cs.vis.model.util;

import java.awt.Color;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.locks.Lock;

import javax.vecmath.Point2f;
import javax.vecmath.Point3f;
import javax.vecmath.Vector3d;
import javax.vecmath.Vector3f;

import org.apache.log4j.Logger;

import processing.core.PConstants;
import processing.core.PGraphics;

public class Triangle extends DrawObject {

        private static final long       serialVersionUID        = -5164768039180386782L;

        private static Logger           logger                          = Logger.getLogger(Triangle.class);

        protected Point2f                       texPosition[];

        protected Vector3f                      normalVector            = null;

        protected Vector3f                      cornerarea                      = null;

        protected Point3f                       centroid;

        protected Set<Triangle>         neighbors                       = new HashSet<Triangle>(3);

        public Triangle() {
                super(3);
        }

        public boolean addNeighbor(Triangle neighbor, Lock lock) {
                boolean add = false;

                if (neighbors.size() >= 3) // for better performance skip if triangle has already all
                                                                        // neighbors set
                        return false;

                add = isDirectNeighbor(neighbor);

                if (add) {
                        if (lock != null)
                                lock.lock();
                        // to make sure neighbors is not cached
                        synchronized (neighbors) {
                                neighbors.add(neighbor);
                        }
                        synchronized (neighbor.neighbors) {
                                neighbor.neighbors.add(this);
                        }
                        if (lock != null)
                                lock.unlock();
                }
                return add;
        }

        public void removeNeighbor(Triangle n) {
                if (neighbors != null) {
                        synchronized (neighbors) {
                                neighbors.remove(n);
                        }
                }
                if (n.neighbors != null) {
                        synchronized (n.neighbors) {
                                n.neighbors.remove(this);
                        }
                }
        }

        public void draw(PGraphics g, Color overrideColor) {
                applyColor(g, overrideColor);
                g.beginShape(PConstants.TRIANGLES);
                if (appearance == null || appearance.getImageReference() == null || overrideColor != null
                                || position[0].getNormalVector() != null) {
                        // no texture only color

                        for (int i = 0; i < position.length; i++) {

                                if (position[i].overrideColor != null) {
                                        g.fill(position[i].overrideColor.getRed(),
                                                        position[i].overrideColor.getGreen(),
                                                        position[i].overrideColor.getBlue());
                                } else if (overrideColor == null && position[i].color != null) {
                                        g.fill(position[i].color.getRed(), position[i].color.getGreen(),
                                                        position[i].color.getBlue());
                                }

                                if (position[i].getNormalVector() != null)
                                        g.normal(position[i].getNormalVector().x, position[i].getNormalVector().y,
                                                        position[i].getNormalVector().z);
                                g.vertex(position[i].x, position[i].y, position[i].z);
                        }

                } else {
                        // has texture
                        g.texture(appearance.getImageReference());

                        for (int i = 0; i < position.length; i++) {

                                g.vertex(position[i].x, position[i].y, position[i].z, texPosition[i].x,
                                                texPosition[i].y);

                        }

                }
                g.endShape();
        }

        public float getArea() {
                if (position.length == 3) {

                        Point3f v = (Point3f) position[1].clone();
                        v.sub(position[0]);
                        Point3f w = (Point3f) position[2].clone();
                        w.sub(position[0]);

                        Vector3f v1 = new Vector3f(v);
                        Vector3f w1 = new Vector3f(w);

                        Vector3f cross = new Vector3f();
                        cross.cross(v1, w1);
                        return cross.length() / 2f;
                }

                logger.error("getArea not implemented for " + position.length + "-Triangle");
                return 0;
        }

        public Point3f getCentroid() {
                return centroid;
        }

        public Vector3f getCornerarea() {
                return cornerarea;
        }

        public Set<Triangle> getNeighbors() {
                return neighbors;
        }

        public double getDihedralAngle(Triangle t) {
                double dot = this.getNormalVector().dot(t.getNormalVector());
                dot = Math.max(-1, dot);
                dot = Math.min(1, dot);
                return Math.acos(dot);
        }

        public Vector3f getNormalVector() {
                return normalVector;
        }

        public Point2f[] getTexPosition() {
                return texPosition;
        }

        public boolean intersectsRay(Point3f rayStart, Point3f rayEnd) {
                return intersectsRay(rayStart, rayEnd, null);
        }

        public boolean calculateNormalVector() {
                // Calculate normal vector for triangle
                Vector3f avgVertexNorm = new Vector3f();
                for (int i = 0; i < 3; i++) {
                        if (position[i].getNormalVector() == null) {
                                avgVertexNorm = null;
                                break;
                        }
                        avgVertexNorm.add(position[i].getNormalVector());
                }
                if (avgVertexNorm != null) {
                        avgVertexNorm.scale(1f / 3f);
                }

                Vector3f a = new Vector3f(position[0]);
                a.sub(position[1]);
                Vector3f b = new Vector3f(position[1]);
                b.sub(position[2]);

                /*Vector3f a = new Vector3f(position[1]);
                a.sub(position[0]);
                Vector3f b = new Vector3f(position[2]);
                b.sub(position[0]);*/
                Vector3f norm = new Vector3f();
                norm.cross(a, b);
                if (norm.lengthSquared() == 0) {
                        return false;
                }
                norm.normalize();

                if (avgVertexNorm != null && avgVertexNorm.dot(norm) < 0)
                        norm.scale(-1f);

                this.normalVector = norm;
                return true;
        }

        public boolean intersectsRay(Point3f p1, Point3f p2, Point3f intersectionPoint) {

                if (position.length != 3) {
                        System.out.println("intersectRay not implemented for not triangles!!");
                        return false;
                }

                Vector3d u, v, n; // triangle vectors
                Vector3d dir, w0, w; // ray vectors
                double r, a, b; // params to calc ray-plane intersect

                // get triangle edge vectors and plane normal
                u = new Vector3d(position[1]);
                u.sub(new Vector3d(position[0]));
                v = new Vector3d(position[2]);
                v.sub(new Vector3d(position[0]));

                n = new Vector3d();
                n.cross(u, v); // Normal vector
                if (n.equals(new Vector3d(0, 0, 0))) // triangle is degenerate
                        return false; // do not deal with this case

                dir = new Vector3d(p2);// ray direction vector
                dir.sub(new Vector3d(p1));

                w0 = new Vector3d(p1);
                w0.sub(new Vector3d(position[0]));

                a = -n.dot(w0);
                b = n.dot(dir);
                // SMALL_NUM 0.00000001 // anything that avoids division overflow
                if (Math.abs(b) < 0.00000001) { // ray is parallel to triangle plane
                        if (a == 0) // ray lies in triangle plane
                                return false;

                        return false; // ray disjoint from plane
                }

                // get intersect point of ray with triangle plane
                r = a / b;

                // if (r < 0.0) // ray goes away from triangle
                // return false; // => no intersect
                // for a segment, also test if (r > 1.0) => no intersect

                Point3f intersect = intersectionPoint;

                if (intersect == null)
                        intersect = new Point3f();

                intersect.set(dir); // intersect point of ray and plane
                intersect.scale((float) r);
                intersect.add(p1);

                // is I inside T?
                double uu, uv, vv, wu, wv, D;
                uu = new Vector3d(u).dot(u);
                uv = new Vector3d(u).dot(v);
                vv = new Vector3d(v).dot(v);
                w = new Vector3d(intersect);
                w.sub(new Vector3d(position[0]));
                wu = new Vector3d(w).dot(u);
                wv = new Vector3d(w).dot(v);
                D = uv * uv - uu * vv;

                // get and test parametric coords
                double s, t;
                s = (uv * wv - vv * wu) / D;
                if (s < 0.0 || s > 1.0) // I is outside T
                        return false;
                t = (uv * wu - uu * wv) / D;
                if (t < 0.0 || (s + t) > 1.0) // I is outside T
                        return false;

                return true; // I is in T
        }

        public boolean isDirectNeighbor(Triangle tr) {

                int eqCnt = 0;
                boolean isNeighbor = false;

                for (int i = 0; i < 3; i++) {
                        if (i == 2 && eqCnt == 0)
                                break; // if 2 of 3 points aren't equal, it is no neighbor
                        Point3f p1 = position[i];
                        for (Point3f p2 : tr.position) {
                                if (p1.x == p2.x && p1.y == p2.y && p1.z == p2.z) {
                                        // if (p1 == p2) {
                                        eqCnt++;
                                        if (eqCnt == 2) {
                                                isNeighbor = true;
                                        } else if (eqCnt == 3) {
                                                // if triangle has same position but is backface
                                                return false;
                                        }
                                        break;
                                }

                        }
                }
                return isNeighbor;
        }

        public boolean isAdjacentNeighbor(Triangle tr) {

                int eqCnt = 0;
                boolean isNeighbor = false;

                for (int i = 0; i < 3; i++) {
                        if (i == 2 && eqCnt == 0)
                                break; // if 2 of 3 points aren't equal, it is no neighbor
                        Point3f p1 = position[i];
                        for (Point3f p2 : tr.position) {
                                if (p1 == p2) {
                                        eqCnt++;
                                        if (eqCnt == 2) {
                                                isNeighbor = true;
                                        }
                                        if (eqCnt == 3) {
                                                // if triangle has same position but is backface
                                                isNeighbor = false;
                                        }
                                        break;
                                }

                        }
                }
                return isNeighbor;
        }

        public void setCornerarea(Vector3f cornerarea) {
                this.cornerarea = cornerarea;
        }

        public void setNeighbors(Set<Triangle> neighbors) {
                this.neighbors = neighbors;
        }

        public void setNormalVector(Vector3f normalVector) {
                this.normalVector = normalVector;
        }

        public void setTexPosition(Point2f[] texPosition) {
                this.texPosition = texPosition;
        }

        @Override
        public void updateCentroid() {
                centroid = new Point3f(0, 0, 0);

                for (int i = 0; i < position.length; i++) {
                        centroid.add(position[i]);
                }
                centroid.scale(1f / position.length);
        }

}

---

knowrob_cad_parser
Author(s): Stefan Profanter
autogenerated on Tue Mar 5 12:15:33 2013