我正在阅读这本书Developing Games in Java。第8章介绍了如何加载Wavefront .obj文件。 我的obj文件位于 C：//pathToMyWorkspace//ProjectName//res//coffeCup.obj
当我尝试加载Wavefront .obj文件时，编译器会抛出错误：
java.io.FileNotFoundException: res\coffe
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:146)
at java.io.FileReader.<init>(FileReader.java:72)
at com.base.graphics.graphics3D.ObjectLoader.parseFile(ObjectLoader.java:141)
at com.base.graphics.graphics3D.ObjectLoader$ObjLineParser.parseLine(ObjectLoader.java:228)
at com.base.graphics.graphics3D.ObjectLoader.parseFile(ObjectLoader.java:169)
at com.base.graphics.graphics3D.ObjectLoader.loadObject(ObjectLoader.java:116)
at com.testGame.Texture3DTest.createPolygons(Texture3DTest.java:69)
at com.base.graphics.GameCore3D.init(GameCore3D.java:24)
at com.testGame.Texture3DTest.init(Texture3DTest.java:45)
at com.base.graphics.GameCore.start(GameCore.java:49)
at com.testGame.Texture3DTest.main(Texture3DTest.java:41)
由于某种原因，编译器尝试从＆＃34; res / res / coffeCup.obj＆＃34; 加载，但我指定的路径只是＆＃34; res /coffeCup.obj"
package com.base.graphics.graphics3D;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;
import com.base.math.PolygonGroup;
import com.base.math.ShadedSurface;
import com.base.math.ShadedTexture;
import com.base.math.TexturedPolygon3D;
import com.base.math.Vector3D;
/**
* The ObjectLoader class loads a subset of the Alias|Wavefront OBJ file
* specification.
*
* Lines that begin with '#' are comments.
*
* OBJ file keywords:
*
* <pre>
* mtllib [filename] - Load materials from an external .mtl
* file.
* v [x] [y] [z] - Define a vertex with floating-point
* coords (x,y,z).
* f [v1] [v2] [v3] ... - Define a new face. a face is a flat,
* convex polygon with vertices in
* counter-clockwise order. Positive
* numbers indicate the index of the
* vertex that is defined in the file.
* Negative numbers indicate the vertex
* defined relative to last vertex read.
* For example, 1 indicates the first
* vertex in the file, -1 means the last
* vertex read, and -2 is the vertex
* before that.
* g [name] - Define a new group by name. The faces
* following are added to this group.
* usemtl [name] - Use the named material (loaded from a
* .mtl file) for the faces in this group.
* </pre>
*
* MTL file keywords:
*
* <pre>
* newmtl [name] - Define a new material by name.
* map_Kd [filename] - Give the material a texture map.
* </pre>
*/
public class ObjectLoader {
/**
* The Material class wraps a ShadedTexture.
*/
public static class Material {
public File sourceFile;
public ShadedTexture texture;
}
/**
* A LineParser is an interface to parse a line in a text file. Separate
* LineParsers and are used for OBJ and MTL files.
*/
protected interface LineParser {
public void parseLine(String line) throws IOException, NumberFormatException, NoSuchElementException;
}
protected File path;
protected List vertices;
protected Material currentMaterial;
protected HashMap materials;
protected List lights;
protected float ambientLightIntensity;
protected HashMap parsers;
private PolygonGroup object;
private PolygonGroup currentGroup;
/**
* Creates a new ObjectLoader.
*/
public ObjectLoader() {
materials = new HashMap();
vertices = new ArrayList();
parsers = new HashMap();
parsers.put("obj", new ObjLineParser());
parsers.put("mtl", new MtlLineParser());
currentMaterial = null;
setLights(new ArrayList(), 1);
}
/**
* Sets the lights used for the polygons in the parsed objects. After
* calling this method calls to loadObject use these lights.
*/
public void setLights(List lights, float ambientLightIntensity) {
this.lights = lights;
this.ambientLightIntensity = ambientLightIntensity;
}
/**
* Loads an OBJ file as a PolygonGroup.
*/
public PolygonGroup loadObject(String parent, String filename) throws IOException {
object = new PolygonGroup();
object.setFilename(filename);
path = new File(parent);
vertices.clear();
currentGroup = object;
parseFile(filename);
return object;
}
/**
* Gets a Vector3D from the list of vectors in the file. Negative indeces
* count from the end of the list, postive indeces count from the beginning.
* 1 is the first index, -1 is the last. 0 is invalid and throws an
* exception.
*/
protected Vector3D getVector(String indexStr) {
int index = Integer.parseInt(indexStr);
if (index < 0) {
index = vertices.size() + index + 1;
}
return (Vector3D) vertices.get(index - 1);
}
/**
* Parses an OBJ (ends with ".obj") or MTL file (ends with ".mtl").
*/
protected void parseFile(String filename) throws IOException {
// get the file relative to the source path
File file = new File(path, filename);
BufferedReader reader = new BufferedReader(new FileReader(file));
// get the parser based on the file extention
LineParser parser = null;
int extIndex = filename.lastIndexOf('.');
if (extIndex != -1) {
String ext = filename.substring(extIndex + 1);
parser = (LineParser) parsers.get(ext.toLowerCase());
}
if (parser == null) {
parser = (LineParser) parsers.get("obj");
}
// parse every line in the file
while (true) {
String line = reader.readLine();
// no more lines to read
if (line == null) {
reader.close();
return;
}
line = line.trim();
// ignore blank lines and comments
if (line.length() > 0 && !line.startsWith("#")) {
// interpret the line
try {
parser.parseLine(line);
} catch (NumberFormatException ex) {
throw new IOException(ex.getMessage());
} catch (NoSuchElementException ex) {
throw new IOException(ex.getMessage());
}
}
}
}
/**
* Parses a line in an OBJ file.
*/
protected class ObjLineParser implements LineParser {
public void parseLine(String line) throws IOException, NumberFormatException, NoSuchElementException {
StringTokenizer tokenizer = new StringTokenizer(line);
String command = tokenizer.nextToken();
if (command.equals("v")) {
// create a new vertex
vertices.add(new Vector3D(Float.parseFloat(tokenizer.nextToken()), Float.parseFloat(tokenizer.nextToken()), Float.parseFloat(tokenizer.nextToken())));
} else if (command.equals("f")) {
// create a new face (flat, convex polygon)
List currVertices = new ArrayList();
while (tokenizer.hasMoreTokens()) {
String indexStr = tokenizer.nextToken();
// ignore texture and normal coords
int endIndex = indexStr.indexOf('/');
if (endIndex != -1) {
indexStr = indexStr.substring(0, endIndex);
}
currVertices.add(getVector(indexStr));
}
// create textured polygon
Vector3D[] array = new Vector3D[currVertices.size()];
currVertices.toArray(array);
TexturedPolygon3D poly = new TexturedPolygon3D(array);
// set the texture
ShadedSurface.createShadedSurface(poly, currentMaterial.texture, lights, ambientLightIntensity);
// add the polygon to the current group
currentGroup.addPolygon(poly);
} else if (command.equals("g")) {
// define the current group
if (tokenizer.hasMoreTokens()) {
String name = tokenizer.nextToken();
currentGroup = new PolygonGroup(name);
} else {
currentGroup = new PolygonGroup();
}
object.addPolygonGroup(currentGroup);
} else if (command.equals("mtllib")) {
// load materials from file
String name = tokenizer.nextToken();
parseFile(name);
} else if (command.equals("usemtl")) {
// define the current material
String name = tokenizer.nextToken();
currentMaterial = (Material) materials.get(name);
if (currentMaterial == null) {
System.out.println("no material: " + name);
}
} else {
// unknown command - ignore it
}
}
}
/**
* Parses a line in a material MTL file.
*/
protected class MtlLineParser implements LineParser {
public void parseLine(String line) throws NoSuchElementException {
StringTokenizer tokenizer = new StringTokenizer(line);
String command = tokenizer.nextToken();
if (command.equals("newmtl")) {
// create a new material if needed
String name = tokenizer.nextToken();
currentMaterial = (Material) materials.get(name);
if (currentMaterial == null) {
currentMaterial = new Material();
materials.put(name, currentMaterial);
}
} else if (command.equals("map_Kd")) {
// give the current material a texture
String name = tokenizer.nextToken();
File file = new File(path, name);
if (!file.equals(currentMaterial.sourceFile)) {
currentMaterial.sourceFile = file;
currentMaterial.texture = (ShadedTexture) Texture.createTexture(file.getPath(), true);
}
} else {
// unknown command - ignore it
}
}
}
}
package com.testGame;
import java.awt.event.KeyEvent;
import java.io.IOException;
import com.base.graphics.GameCore3D;
import com.base.graphics.graphics3D.ObjectLoader;
import com.base.graphics.graphics3D.Rectangle3D;
import com.base.graphics.graphics3D.Texture;
import com.base.graphics.graphics3D.ZBufferedRenderer;
import com.base.input.GameAction;
import com.base.input.InputManager;
import com.base.input.Mouse;
import com.base.math.PolygonGroup;
import com.base.math.TexturedPolygon3D;
import com.base.math.Transform3D;
import com.base.math.Vector3D;
import com.base.math.ViewWindow;
public class Texture3DTest extends GameCore3D {
protected InputManager inputManager;
protected GameAction exit = new GameAction("exit", GameAction.DETECT_INITAL_PRESS_ONLY);
protected GameAction moveForward = new GameAction("moveForward");
protected GameAction moveBackward = new GameAction("moveBackward");
protected GameAction moveUp = new GameAction("moveUp");
protected GameAction moveDown = new GameAction("moveDown");
protected GameAction moveLeft = new GameAction("moveLeft");
protected GameAction moveRight = new GameAction("moveRight");
protected GameAction rootUp = new GameAction("rootUp");
protected GameAction rootDown = new GameAction("rootDown");
protected GameAction rootLeft = new GameAction("rootLeft");
protected GameAction rootRight = new GameAction("rootRight");
protected final int SPEED = 6;
protected final float ROOTATION_SPEED = 0.01f;
public static void main(String[] args) {
new Texture3DTest().start();
}
public void init() {
super.init();
Mouse.hide(frame);
inputManager = new InputManager(frame);
inputManager.mapToKey(exit, KeyEvent.VK_ESCAPE);
inputManager.mapToKey(moveForward, KeyEvent.VK_W);
inputManager.mapToKey(moveBackward, KeyEvent.VK_S);
inputManager.mapToKey(moveLeft, KeyEvent.VK_A);
inputManager.mapToKey(moveRight, KeyEvent.VK_D);
inputManager.mapToKey(moveUp, KeyEvent.VK_SPACE);
inputManager.mapToKey(moveDown, KeyEvent.VK_SHIFT);
inputManager.mapToKey(rootUp, KeyEvent.VK_UP);
inputManager.mapToKey(rootDown, KeyEvent.VK_DOWN);
inputManager.mapToKey(rootLeft, KeyEvent.VK_LEFT);
inputManager.mapToKey(rootRight, KeyEvent.VK_RIGHT);
}
public void createPolygons() {
ObjectLoader objLoader = new ObjectLoader();
try {
PolygonGroup object = objLoader.loadObject("res/", "coffeCup.obj");
polygons.add(object);
} catch (IOException e) {
e.printStackTrace();
}
}
public void setTexture(TexturedPolygon3D poly, Texture texture) {
Vector3D origin = poly.getVertex(0);
Vector3D dv = new Vector3D(poly.getVertex(1));
dv.subtract(origin);
Vector3D du = new Vector3D();
du.setToCrossProduct(poly.getNormal(), dv);
Rectangle3D textureBounds = new Rectangle3D(origin, du, dv, texture.getWidth(), texture.getHeight());
poly.setTexture(texture, textureBounds);
}
public void update() {
if (exit.isPressed())
System.exit(0);
Transform3D camera = polygonRenderer.getCamera();
Vector3D cameraLoc = polygonRenderer.getCamera().getLocation();
if (moveForward.isPressed()) {
cameraLoc.x -= SPEED * camera.getSinAngleY();
cameraLoc.z -= SPEED * camera.getCosAngleY();
}
if (moveBackward.isPressed()) {
cameraLoc.x += SPEED * camera.getSinAngleY();
cameraLoc.z += SPEED * camera.getCosAngleY();
}
if (moveLeft.isPressed()) {
cameraLoc.x -= SPEED * camera.getCosAngleY();
cameraLoc.z += SPEED * camera.getSinAngleY();
}
if (moveRight.isPressed()) {
cameraLoc.x += SPEED * camera.getCosAngleY();
cameraLoc.z -= SPEED * camera.getSinAngleY();
}
if (moveUp.isPressed()) {
camera.getLocation().y += SPEED;
}
if (moveDown.isPressed()) {
camera.getLocation().y -= SPEED;
}
if (rootUp.isPressed())
camera.rotateAngleX(ROOTATION_SPEED);
if (rootDown.isPressed())
camera.rotateAngleX(-ROOTATION_SPEED);
if (rootLeft.isPressed())
camera.rotateAngleY(ROOTATION_SPEED);
if (rootRight.isPressed())
camera.rotateAngleY(-ROOTATION_SPEED);
}
public Texture loadTexture(String imageName) {
return Texture.createTexture(imageName, true);
}
public void createPolygonRenderer() {
viewWindow = new ViewWindow(0, 0, frame.getWidth(), frame.getHeight(), (float) Math.toRadians(75));
Transform3D camera = new Transform3D(0, 100, 0);
polygonRenderer = new ZBufferedRenderer(camera, viewWindow);
}
}
PS：我正在使用eclipse
非常感谢
答案 0 :(得分：1)
（此答案涉及问题的previous revision。问题已根据此答案进行了更新。请参阅评论以获取详细信息）
嗯，这里的问题是ObjectLoader类的路径处理是错误的。在这个最小的例子中可以看到相关的调用序列：
import java.io.File;
public class FilePathTest
{
public static void main(String[] args)
{
loadObject("res/SomeFile.txt");
loadObject("SomeFile.txt");
}
static File path;
static void loadObject(String filename)
{
File file = new File(filename);
path = file.getParentFile();
parseFile(filename);
}
static void parseFile(String filename)
{
File file = new File(path, filename);
System.out.println("File: "+file+" exists? "+file.exists());
}
}
从给定文件中，它获取＆＃34;父文件＆＃34; （即包含文件的目录）并将其存储为path。稍后，文件名再次附加到此路径，以获取最终文件名。因此，当filename以相对路径前缀（例如您的res/）开头时，此部分将重复。
（顺便说一句：他存储路径的原因是OBJ文件可能包含对假定位于同一目录中的其他文件的引用，例如MTL文件，反过来可能包含对纹理文件的进一步引用）。
最简单的＆＃34;我现在可以想象的解决方案是手动处理路径和文件名。这里概述了基本思想，应该可以将其转移到原来的ObjectLoader类：
import java.io.File;
public class FilePathTest
{
public static void main(String[] args)
{
loadObject("res/", "SomeFile.obj");
}
static File path;
static void loadObject(String parent, String filename)
{
File file = new File(parent+File.separator+filename);
path = new File(parent);
parseFile(file);
}
static void parseFile(File file)
{
System.out.println("File: "+file+" exists? "+file.exists());
String mtlName = "SomeFile.mtl";
File mtlFile = new File(path, mtlName);
System.out.println("MTL file: "+mtlFile+" exists? "+mtlFile.exists());
}
}
编辑：一个MVCE，通过从导致编译错误的原始代码中删除所有内容而创建
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;
import stackoverflow.objload.ObjectLoader.LineParser;
import stackoverflow.objload.ObjectLoader.Material;
import stackoverflow.objload.ObjectLoader.MtlLineParser;
import stackoverflow.objload.ObjectLoader.ObjLineParser;
public class ObjectLoaderTest
{
public static void main(String[] args)
{
ObjectLoader objLoader = new ObjectLoader();
try {
PolygonGroup object = objLoader.loadObject("res/", "coffeCup.obj");
} catch (IOException e) {
e.printStackTrace();
}
}
}
class PolygonGroup
{
public PolygonGroup(String name)
{
}
public PolygonGroup()
{
}
public void setFilename(String filename)
{
}
public void addPolygonGroup(PolygonGroup currentGroup)
{
}
}
class Vector3D
{
public Vector3D(float parseFloat, float parseFloat2, float parseFloat3)
{
}
}
class ObjectLoader {
/**
* The Material class wraps a ShadedTexture.
*/
public static class Material {
public File sourceFile;
}
/**
* A LineParser is an interface to parse a line in a text file. Separate
* LineParsers and are used for OBJ and MTL files.
*/
protected interface LineParser {
public void parseLine(String line) throws IOException, NumberFormatException, NoSuchElementException;
}
protected File path;
protected List vertices;
protected Material currentMaterial;
protected HashMap materials;
protected List lights;
protected float ambientLightIntensity;
protected HashMap parsers;
private PolygonGroup object;
private PolygonGroup currentGroup;
/**
* Creates a new ObjectLoader.
*/
public ObjectLoader() {
materials = new HashMap();
vertices = new ArrayList();
parsers = new HashMap();
parsers.put("obj", new ObjLineParser());
parsers.put("mtl", new MtlLineParser());
currentMaterial = null;
setLights(new ArrayList(), 1);
}
/**
* Sets the lights used for the polygons in the parsed objects. After
* calling this method calls to loadObject use these lights.
*/
public void setLights(List lights, float ambientLightIntensity) {
this.lights = lights;
this.ambientLightIntensity = ambientLightIntensity;
}
/**
* Loads an OBJ file as a PolygonGroup.
*/
public PolygonGroup loadObject(String parent, String filename) throws IOException {
object = new PolygonGroup();
object.setFilename(filename);
path = new File(parent);
vertices.clear();
currentGroup = object;
parseFile(filename);
return object;
}
/**
* Gets a Vector3D from the list of vectors in the file. Negative indeces
* count from the end of the list, postive indeces count from the beginning.
* 1 is the first index, -1 is the last. 0 is invalid and throws an
* exception.
*/
protected Vector3D getVector(String indexStr) {
int index = Integer.parseInt(indexStr);
if (index < 0) {
index = vertices.size() + index + 1;
}
return (Vector3D) vertices.get(index - 1);
}
/**
* Parses an OBJ (ends with ".obj") or MTL file (ends with ".mtl").
*/
protected void parseFile(String filename) throws IOException {
// get the file relative to the source path
File file = new File(path, filename);
System.out.println("Reading "+file+", exists "+file.exists());
BufferedReader reader = new BufferedReader(new FileReader(file));
// get the parser based on the file extention
LineParser parser = null;
int extIndex = filename.lastIndexOf('.');
if (extIndex != -1) {
String ext = filename.substring(extIndex + 1);
parser = (LineParser) parsers.get(ext.toLowerCase());
}
if (parser == null) {
parser = (LineParser) parsers.get("obj");
}
// parse every line in the file
while (true) {
String line = reader.readLine();
// no more lines to read
if (line == null) {
reader.close();
return;
}
line = line.trim();
// ignore blank lines and comments
if (line.length() > 0 && !line.startsWith("#")) {
// interpret the line
try {
parser.parseLine(line);
} catch (NumberFormatException ex) {
throw new IOException(ex.getMessage());
} catch (NoSuchElementException ex) {
throw new IOException(ex.getMessage());
}
}
}
}
/**
* Parses a line in an OBJ file.
*/
protected class ObjLineParser implements LineParser {
public void parseLine(String line) throws IOException, NumberFormatException, NoSuchElementException {
StringTokenizer tokenizer = new StringTokenizer(line);
String command = tokenizer.nextToken();
if (command.equals("v")) {
// create a new vertex
vertices.add(new Vector3D(Float.parseFloat(tokenizer.nextToken()), Float.parseFloat(tokenizer.nextToken()), Float.parseFloat(tokenizer.nextToken())));
} else if (command.equals("f")) {
// create a new face (flat, convex polygon)
List currVertices = new ArrayList();
while (tokenizer.hasMoreTokens()) {
String indexStr = tokenizer.nextToken();
// ignore texture and normal coords
int endIndex = indexStr.indexOf('/');
if (endIndex != -1) {
indexStr = indexStr.substring(0, endIndex);
}
currVertices.add(getVector(indexStr));
}
// create textured polygon
Vector3D[] array = new Vector3D[currVertices.size()];
currVertices.toArray(array);
} else if (command.equals("g")) {
// define the current group
if (tokenizer.hasMoreTokens()) {
String name = tokenizer.nextToken();
currentGroup = new PolygonGroup(name);
} else {
currentGroup = new PolygonGroup();
}
object.addPolygonGroup(currentGroup);
} else if (command.equals("mtllib")) {
// load materials from file
String name = tokenizer.nextToken();
parseFile(name);
} else if (command.equals("usemtl")) {
// define the current material
String name = tokenizer.nextToken();
currentMaterial = (Material) materials.get(name);
if (currentMaterial == null) {
System.out.println("no material: " + name);
}
} else {
// unknown command - ignore it
}
}
}
/**
* Parses a line in a material MTL file.
*/
protected class MtlLineParser implements LineParser {
public void parseLine(String line) throws NoSuchElementException {
StringTokenizer tokenizer = new StringTokenizer(line);
String command = tokenizer.nextToken();
if (command.equals("newmtl")) {
// create a new material if needed
String name = tokenizer.nextToken();
currentMaterial = (Material) materials.get(name);
if (currentMaterial == null) {
currentMaterial = new Material();
materials.put(name, currentMaterial);
}
} else if (command.equals("map_Kd")) {
// give the current material a texture
String name = tokenizer.nextToken();
File file = new File(path, name);
if (!file.equals(currentMaterial.sourceFile)) {
currentMaterial.sourceFile = file;
}
} else {
// unknown command - ignore it
}
}
}
}