ObjLoader.java

gehe zur Dokumentation dieser Datei

package de.lathanda.eos.robot.geom3d;
 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Hashtable;
import de.lathanda.eos.base.ResourceLoader;
 
public class ObjLoader {
    public static final Polyhedron loadObj(String path, String filename) {
        try (BufferedReader data = openStream(path + filename)) {
            return readPolyhedron(data, path, 100);
        } catch (Exception e) {
            System.err.println("missing file "+path+filename);
            System.exit(-1);
            return null;
        }
    }
 
    public static final Polyhedron loadObj(String path, String filename, int hint) {
        try (BufferedReader data = openStream(path + filename)) {
            return readPolyhedron(data, path, hint);
        } catch (Exception e) {
            System.err.println("missing file "+path+filename);
            System.exit(-1);
            return null;
        }
    }
 
    private static final Polyhedron readPolyhedron(BufferedReader data, String path, int hint)
            throws IOException, NFaceException {
        final Polyhedron ph = new Polyhedron();
        final Hashtable<String, Material> matIndex = new Hashtable<>();
        final ArrayList<Vertice> v = new ArrayList<>(hint);
        final ArrayList<VerticeTexture> vt = new ArrayList<>(hint);
        final ArrayList<VerticeNormal> vn = new ArrayList<>(hint);
        String line;
        Material mat = null;
        while ((line = data.readLine()) != null) {
            if (line.startsWith("#")) {
                // comment
            } else if (line.equals("")) {
                // empty line
            } else if (line.startsWith("v ")) { // read in vertex data
                v.add(new Vertice(readFloat(line, 2)));
            } else if (line.startsWith("vt ")) { // read texture coordinates
                vt.add(new VerticeTexture(readFloat(line, 3)));
            } else if (line.startsWith("vn ")) { // read normal coordinates
                vn.add(new VerticeNormal(readFloat(line, 3)));
            } else if (line.startsWith("f ")) { // read face data
                ph.faces.add(readFace(line.substring(2), ph, mat, v, vt, vn));
            } else if (line.startsWith("mtllib ")) { // load material file
                loadMtl(path, line.substring(7), ph, matIndex);
            } else if (line.startsWith("usemtl ")) { // use material
                mat = matIndex.get(line.substring(7).trim());
            } else {
                // one of many tags we do not process
                // o new object
                // g new group
                // s smooth shading
                // ...
            }
        }
        return ph;
    }
 
    private static final void loadMtl(String path, String filename, Polyhedron ph, Hashtable<String, Material> matIndex)
            throws IOException {
        try (BufferedReader data = openStream(path + filename)) {
            String line;
            Material mat = new Material();
            while ((line = data.readLine()) != null) {
                if (line.startsWith("#")) {
                    // comment
                } else if (line.equals("")) {
                    // empty line
                } else if (line.startsWith("newmtl ")) {
                    mat = new Material();
                    matIndex.put(line.substring(7).trim(), mat);
                } else if (line.startsWith("map_Kd ")) {
                    mat.setImage(ResourceLoader.loadResourceImage(path + line.substring(6).trim()));
                } else if (line.startsWith("Ka ")) {
                    // Ka spectral color
                    mat.setKA(readFloat(line, 3));
                } else if (line.startsWith("Kd ")) {
                    // Kd diffuse reflectivity
                    mat.setKD(readFloat(line, 3));
                } else if (line.startsWith("Ks ")) {
                    // Ks spectral reflectivity
                    mat.setKS(readFloat(line, 3));
                } else {
                    // one of many tags we do not process
                    // Tf transmission filter
                    // d dissolve
                    // illum illumination model
                    // 0. Color on and Ambient off
                    // 1. Color on and Ambient on
                    // 2. Highlight on
                    // 3. Reflection on and Ray trace on
                    // 4. Transparency: Glass on, Reflection: Ray trace on
                    // 5. Reflection: Fresnel on and Ray trace on
                    // 6. Transparency: Refraction on, Reflection: Fresnel off
                    // and Ray trace on
                    // 7. Transparency: Refraction on, Reflection: Fresnel on
                    // and Ray trace on
                    // 8. Reflection on and Ray trace off
                    // 9. Transparency: Glass on, Reflection: Ray trace off
                    // 10. Casts shadows onto invisible surfaces
                    // Ns spectral exponent
                    // Ni optical density
                    // ...
                }
            }
        }
    }
 
    private static final float[] readFloat(String line, int from) {
        String[] values = line.substring(from).split(" ");
        float[] numbers = new float[values.length];
        for (int i = 0; i < values.length; i++) {
            try {
                numbers[i] = Float.parseFloat(values[i]);
            } catch (Exception e) {
                System.out.println(line);
            }
        }
        return numbers;
    }
 
    private static final Face readFace(String values, Polyhedron ph, Material mat, ArrayList<Vertice> v,
            ArrayList<VerticeTexture> vt, ArrayList<VerticeNormal> vn) throws NFaceException {
        String[] vertices = values.split(" ");
        Vertice[] fv = new Vertice[vertices.length];
        VerticeTexture[] fvt = new VerticeTexture[vertices.length];
        VerticeNormal[] fvn = new VerticeNormal[vertices.length];
        for (int i = 0; i < vertices.length; i++) {
            String[] vert = vertices[i].split("/");
            fv[i] = v.get(Integer.parseInt(vert[0]) - 1);
            if (!vert[1].isEmpty()) {
                fvt[i] = vt.get(Integer.parseInt(vert[1]) - 1);
            } else {
                fvt = null;
            }
            if (!vert[2].isEmpty()) {
                fvn[i] = vn.get(Integer.parseInt(vert[2]) - 1);
            } else {
                fvn = null;
            }
        }
        return new Face(fv, fvt, fvn, mat);
    }
 
    private static final BufferedReader openStream(String filename) throws IOException {
        return new BufferedReader(new InputStreamReader(ResourceLoader.getResourceAsStream(filename)));
    }
}