problems with gears example

[Veko]

When I try to make the gears application I keep getting

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Loading file E:/SCHOOL/Java/JCPT_test/res/RedGear.3ds
[ Tue Dec 16 20:09:38 CET 2008 ] - ERROR: Couldn't read file E:/SCHOOL/Java/JCPT_test/res/RedGear.3ds
[ Tue Dec 16 20:09:38 CET 2008 ] - ERROR: Not a valid 3DS file!
Unknown file format: E:/SCHOOL/Java/JCPT_test/res/RedGear.3ds

I'm using the 3ds files that come with the example and I've just copied the original code from the example into a new application.

[EgonOlsen]

The error message may be a bit misleading. What it actually tries to say is, that the file can't be found. Check if your file is really located where the application looks for it (i.e. in "E:/SCHOOL/Java/JCPT_test/res/RedGear.3ds"). Most likely, it isn't...

[Veko]

it's in the right location :p (first thing I checked)

[EgonOlsen]

Which example is that? It's none of mine, so it has to be made by somebody else. Where can i get it? (I hope that i'm not hosting it myself and forgot about it... )

[Veko]

the example from the "How to create an Applet" thread (http://www.jpct.net/forum2/index.php/topic,1247.0.html)

[EgonOlsen]

I see...maybe Paul can comment on this then. May have something to do with the fact that it actually is an applet example and your path doesn't look very applet-like...but that's just a guess...

[paulscode]

In this demo applet, I recommend compiling the 3ds file into the JAR.  The problem may be that the AppletLoader is not able to access the 3ds file through a local directory, not sure.

--EDIT--
Oh, in case you already have compiled the 3ds file into the JAR but don't know how to access it in your code, the path you want to use is its JAR path, not the local path.  The path will usually look something like "Models/RedGear.3ds".  If you stick the file in the root directory of the JAR (i.e. the "<default package>"), just use the filename without any path - just "RedGear.3ds" (that is how I did it in the example, which is why the files are referenced that way in the source code).
--END EDIT--

It might be possible to tell applet loader about the file in the HTML part of the applet loader - I'll look into it and let you know.

That being said, an applet will normally be run from an online location, and in that case, you would not be accessing the file from a local directory.  You will have to either compile it into the JAR as I mentioned above, or access it through an instance of java.net.URL.  If you need help with the later, let me know.

[paulscode]

I just noticed that you used the word "application" in your initial post.  If you are actually trying to convert the gears demo into an application, I can help you with that as well (it isn't too difficult).

[fireside]

Loading file E:/SCHOOL/Java/JCPT_test/res/RedGear.3ds

Also, I don't know if you did it the same way, but you have "jcpt", which may be a transposition error for jpct.

[Veko]

alright I got the thing working in 2sec now :p (took some hours of coding to clear my head),
don't know what I did differently now, but it works

thnx for the fast responses !

+ paulscode, nono I meant to say applet

[paulscode]

Cool.  BTW, I updated the source code on the "How to create an applet" thread.  I had wrote this demo some time ago, so it had a couple of minor problems (I fixed a potential null-pointer exception in the paint() method, and I replaced the "loadMeshFile" method with a more versitile method compatible with both simple and complex 3DS files).  I also added in comments for how to convert it into an application (takes just a few lines of code), in case that is something you ever want to know how to do.  I recommend building on that source rather than what I had up there originally.

[Veko]

nice

I got myself a new problem now :p. I'm trying to work with a kind of gamestate system in the applet and I'm trying to use to the Gears demo as 1 of the states. But I think I'm not doing it correctly because he isn't drawing anything on screen when he is in the 'Gears-state'

I'm not very familiar with applets and I started working with them without jcpt using examples on the LWJGL-forums (That's why I use Display etc.),
but because I had no 3d animation support yet, I needed an easy to use engine with animation support and thats when I found Jcpt.

here's my code:

MainApp

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package testgame;

import java.util.HashMap;
import java.util.Iterator;
import java.awt.BorderLayout;
import java.awt.Canvas;

import org.lwjgl.Sys;
import org.lwjgl.LWJGLException;
import org.lwjgl.opengl.Display;

public class MainApp extends javax.swing.JApplet
{
    // DATAMEMBERS -----------------------------------

        protected Thread gameThread = null;
        private HashMap gameStates = new HashMap();
        private GameState currentState = null;
        public Canvas display_parent = null;
        private boolean running = false;

    // -----------------------------------------------

    @Override
    public void destroy()
    {
        remove(display_parent);
        super.destroy();
        System.out.println("Clear Up");
    }

    @Override
    public void start()
    {
        gameThread = new Thread()
        {

            @Override
            public void run()
            {
                running = true;
                try
                {
                    initGL();
                }
                catch(LWJGLException e)
                {
                    e.printStackTrace();
                }
                System.out.println("Entering Gameloop");
                gameLoop();
            }
        };
        // If setDaemon(true) the JVM will exit as soon as the main reaches completion?
        gameThread.setDaemon(true);
        gameThread.start();
    }

    @Override
    public void stop()
    {
        //
    }

    @Override
    public void init()
    {
        setLayout(new BorderLayout());
        try
        {
            display_parent = new Canvas()
            {

                @Override
                public final void removeNotify()
                {
                    destroyLWJGL();
                    super.removeNotify();
                }
            };
            display_parent.setSize(getWidth(),getHeight());
            add(display_parent);
            display_parent.setFocusable(true);
            display_parent.requestFocus();
            setVisible(true);
        }
        catch(Exception e)
        {
            System.err.println(e);
            throw new RuntimeException("Unable to create display");
        }
    }

    private void destroyLWJGL()
    {
        stopApplet();
        try
        {
            gameThread.join();
        }
        catch(InterruptedException e)
        {
            e.printStackTrace();
        }
    }
    private void stopApplet()
    {
        running = false;
    }

    private void addState(GameState state)
    {
        if (currentState == null) currentState = state;
        gameStates.put(state.GetName(), state);
    }

    private void initGL() throws LWJGLException
    {
        System.out.println("display_parent.isDisplayable() = " + display_parent.isDisplayable());
        // setParent needed for embedding screen in canvas
        Display.setParent(display_parent);
        Display.setVSyncEnabled(false);
        Display.create();

        // add the game states that build up our game
        addState(new GearsState());

        try
        {
            // initialise all the game states we've just created. This allows
            // them to load any resources they require
            Iterator states = gameStates.values().iterator();

            // loop through all the states that have been registered
            // causing them to initialise
            while (states.hasNext())
            {
                    GameState state = (GameState) states.next();

                    state.StateInitialize();
            }
        }
        catch (Exception e)
        {
                // if anything goes wrong, show an error message and then exit.
                // This is a bit abrupt but for the sake of this tutorial its
                // enough.
                Sys.alert("Error", "Unable to initialise state: " + e.getMessage());
                System.exit(0);
        }
    }

    private void gameLoop()
    {
        currentState.Enter(this);

        long oldTime = getTime();
        System.out.println("Got Time : " + oldTime);

        // while the game is running we loop round updating and rendering the current game state
        while (running)
        {
            long dTime = (getTime() - oldTime);
            oldTime = getTime();

            Display.update();

            if (Display.isCloseRequested())
            {
                running = false;
                break;
            }

            // the window is in the foreground, so we should play
            else if (Display.isActive())
            {
                int remainder = (int) (dTime % 10);
                int step = (int) (dTime / 10);
                for (int i=0;i<step;i++)
                {
                    currentState.StateCycle(10);
                }
                if (remainder != 0)
                {
                    currentState.StateCycle(remainder);
                }

                currentState.StatePaint();
                Display.sync(60);
            }
            else
            {
                try
                {
                    Thread.sleep(100);
                }
                catch (InterruptedException e)
                {
                    //
                }
                currentState.StateCycle(dTime);

                // only bother rendering if the window is visible or dirty
                if (Display.isVisible() || Display.isDirty())
                {
                    currentState.StatePaint();
                    Display.sync(60);
                }
            }
        }
    }

    // Change the current state being rendered and updated.
    // Note if no state with the specified name can be found no action is taken.
    protected void changeToState(String name)
    {
            GameState newState = (GameState) gameStates.get(name);
            if (newState == null)
            {
                    return;
            }

            currentState.Leave();
            currentState = newState;
            currentState.Enter(this);
    }
   
    private long getTime()
    {
            return (Sys.getTime() * 1000) / Sys.getTimerResolution();
    }
}

Gears-state

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package testgame;

import java.awt.BorderLayout;
import java.awt.Canvas;

import com.threed.jpct.Camera;
import com.threed.jpct.FrameBuffer;
import com.threed.jpct.IRenderer;
import com.threed.jpct.Lights;
import com.threed.jpct.Matrix;
import com.threed.jpct.Object3D;
import com.threed.jpct.SimpleVector;
import com.threed.jpct.World;

import java.awt.Color;

import testgame.modelloader.Loader3ds;

public class GearsState extends javax.swing.JPanel implements testgame.GameState//, MouseListener, MouseMotionListener, Runnable
{
    // -----------------------------------------------

        protected static final String NAME = "gears";
        private jPCTGears m_pWindow = null;
        private FrameBuffer m_Buffer = null;
        private World m_World = null;
        private Camera m_Camera = null;
        private Canvas myCanvas = null;
        private Object3D redGear, greenGear, blueGear, assemblyPivot;
        private float gear_rotation = 0.02f;
   
    // -----------------------------------------------
   
    public String GetName()
    {
        return NAME;
    }
       
    public void StateInitialize()
    {
        //
    }
       
    public void Enter(MainApp window)
    {
        System.out.println("Entering Menu state");

        m_pWindow = window;

        // sign the applet up to receive mouse messages:
        m_World = new World();  // create a new world

        World.setDefaultThread(Thread.currentThread());

        // create a new buffer to draw on:
        m_Buffer = new FrameBuffer( m_pWindow.getWidth(), m_pWindow.getHeight(), FrameBuffer.SAMPLINGMODE_HARDWARE_ONLY );
        m_Buffer.disableRenderer( IRenderer.RENDERER_SOFTWARE );

        myCanvas = m_Buffer.enableGLCanvasRenderer();

        m_pWindow.add( myCanvas, BorderLayout.CENTER);
        myCanvas.setVisible(true);
        myCanvas.requestFocus();

        Loader3ds temp = new Loader3ds();

        // load some 3D objects and make sure they have the correct orientation:
        redGear = temp.loadMeshFile("http://users.telenet.be/decoy/FacebookApp/models/RedGear.3ds");
        redGear.rotateY( (float)Math.PI / 2.0f );
        redGear.rotateMesh();
        redGear.setRotationMatrix( new Matrix() );
        redGear.setOrigin( new SimpleVector( 0, 0, 0 ) );
        redGear.build();
        greenGear = temp.loadMeshFile("http://users.telenet.be/decoy/FacebookApp/models/GreenGear.3ds");
        greenGear.rotateY( (float)Math.PI / 2.0f );
        greenGear.rotateZ( 0.35f );
        greenGear.rotateMesh();
        greenGear.setRotationMatrix( new Matrix() );
        greenGear.setOrigin( new SimpleVector( -145.0f, 0, 0 ) );
        greenGear.build();
        blueGear = temp.loadMeshFile("http://users.telenet.be/decoy/FacebookApp/models/BlueGear.3ds");
        blueGear.rotateY( (float)Math.PI / 2.0f );
        //blueGear.rotateZ( 0.40f );
        blueGear.rotateMesh();
        blueGear.setRotationMatrix( new Matrix() );
        blueGear.setOrigin( new SimpleVector( 0, -140.0f, 0 ) );
        blueGear.build();

        // Set up a pivot point for the entire gear assembly:
        assemblyPivot = Object3D.createDummyObj();
        assemblyPivot.setOrigin( new SimpleVector( 0, 0, 0 ) );
        // Make the gears children to assemblyPivot.
        // Translations and rotations to assemblyPivot
        // will affect the entire gear assembly:
        assemblyPivot.addChild(redGear);
        assemblyPivot.addChild(greenGear);
        assemblyPivot.addChild(blueGear);

        // add the objects our world:
        m_World.addObject(redGear);
        m_World.addObject(greenGear);
        m_World.addObject(blueGear);
       
        redGear.build();
        greenGear.build();
        blueGear.build();
        m_World.buildAllObjects();

        lookAt(redGear);  // make sure the camera is facing towards the object
        letThereBeLight();  // create light sources for the scene

        // receive mouse input from the main applet:
        //addMouseListener(m_pWindow);
        //addMouseMotionListener(m_pWindow);

        // also get mouse input picked up by the canvas:
        //myCanvas.addMouseListener(this);
        //myCanvas.addMouseMotionListener(this);
       
        //new Thread(this).start();
    }

    public void Leave()
    {
        m_pWindow = null;
        m_World.dispose();
    }
       
public void StatePaint()
    {
        // He enters and does StatePaint, but nothing happens.
        m_Buffer.clear(new Color(100, 100, 100));   // erase the previous frame

        // render the world onto the buffer:
        m_World.renderScene(m_Buffer);
        m_World.draw(m_Buffer);
        m_Buffer.update();

        m_Buffer.displayGLOnly();
        myCanvas.repaint();    // Paint the canvas onto the applet (hardware mode)

        System.out.println("Painting");
}
       
    public void StateCycle(long dTime)
    {
        redGear.rotateAxis( redGear.getZAxis(), -gear_rotation );
        greenGear.rotateAxis( greenGear.getZAxis(), 2.0f * gear_rotation );
        blueGear.rotateAxis( blueGear.getZAxis(), 2.0f * gear_rotation );
    }

    // create light sources for the scene
    private void letThereBeLight()
    {
        m_World.getLights().setOverbrightLighting (Lights.OVERBRIGHT_LIGHTING_DISABLED );
        m_World.getLights().setRGBScale(Lights.RGB_SCALE_2X);

        // Set the overall brightness of the world:
        m_World.setAmbientLight(50, 50, 50);

        // Create a main light-source:
        m_World.addLight(new SimpleVector(50, -50, 300 ), 20, 20, 20);
    }

    // point the camera toward the given object
    private void lookAt( Object3D obj )
    {
        m_Camera = m_World.getCamera();  // grab a handle to the camera
        m_Camera.setPosition( 0, 0, 500 );  // set its *relative* position
        m_Camera.lookAt( obj.getTransformedCenter() );  // look toward the object
    }
}

I'm not sure if creating a Display in my MainApp is causing interferance with the jcpt engine,
but when I run this applet he enters the GearsState with no problems (he even does the StatePaint etc.), but nothing is painted to screen, it just stays black (No errors in console though)

I tried clearing with a different color than black, but that didn't work (still the black screen),
then I added the "System.out.println("Painting");" to check if he actually uses StatePaint, and yes the applet does use it.

I haven't a clue what I'm doing wrong, but I suspect I'm painting the display_parent over the canvas of the GearsState

Is it possible to have world within worlds ?

[paulscode]

Just to test your suspicions about the display parent painting over the gears state, you could try setting the display parent to not visible to see if the gears state shows through.  Looking at the code, though, this doesn't look like it would be the problem unless calling Display.update() or Display.sync() causes the display_parent canvas to gain focus.  Another thing to try would be to create a different state with a canvas that is not using anything related to jPCT.  That might indicate whether or not the problem is related to a conflict between Display and jPCT.

[Veko]

I got another non jcpt canvas working :s
so it must be an interferance between Display and jpct.

Is there a way to work with 'gamestates' in jpct (like menustate, ingamestate, etc.) ?

[paulscode]

The problem appears to be a conflict between Display and jPCT, so you should be able to implement switching between different Canvases/gamestates in general, so long as you don't use Display.  Just write your gamestate switching code so that switching from one state to another sets the previous one to not visible and takes care of things like pausing the game, loading, freeing resources, etc.

I am going to try and create a working example of state switching, and I'll post the source for reference when I finish it.