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[Richard Hefner]

Hi all,

I have to implement my own game loop in a class that I'm taking, but he's letting us borrow a scenegraph implementation.  So, I have a md2 model I've loaded and I want to be able to get it's geometry information without using the Xith3D rendering portion.. 

Is this possible...?  If so, how?  Sorry for the stupid post, i've been looking at it for a while and just can't find out.

[Marvin Fröhlich]

Hi, Richard

First of all: Welcome to Xith3D and this board .

I have to implement my own game loop in a class that I'm taking, but he's letting us borrow a scenegraph implementation.  So, I have a md2 model I've loaded and I want to be able to get it's geometry information without using the Xith3D rendering portion.. 

Is this possible...?  If so, how?  Sorry for the stupid post, i've been looking at it for a while and just can't find out.

I think, you'll have to explain a little more...

Who is "he", who is letting you borrow a scenegraph implementation? Your teacher?
Are you working on a school project, where your job is to implement a RenderLoop? We have a class called RenderLoop. You can either use it or copy it and tell your teacher, it's yours .

What do you want to know about the Geometry?

Based on a guess you can use this:

Code:

List<Shape3D> shapes = org.xith3d.scenegraph.traversal.impl.ShapeFinder.findAllShapes( model );

Please be aware, that I added this method just a minute ago. So please do a fresh SVN checkout.

This will return a List filled with all the Shape3Ds in the model. A Shape3D provides method to everything going on in it. e.g. invoke getGeometry() to retrieve the geometry, your model is built of. Or invoke getAppearance() to retrieve the Appearance to "air-brushes" you model.

Please tell me, if I guessed right or if I missed your point.

Marvin

[Richard Hefner]

Hi Marvin,

Thanks for the welcome.    Yes, my teacher is letting us borrow the scenegraph structure and model loader, so I tried out Java3D and it didn't quite do what I wanted..  I don't know if Xith can or can't.

Basically, my teacher said it's not a good idea to use Java3D for what we are doing in the class, but Xith may be a good option..  So, what I need to do is load in an MD2 model into the Xith scenegraph and then manipulate the scenegraph (with the model and such) in my own program..  like, pull out the geometry, texture coordinates, etc..  But, I wanted to use the scenegraph's built-in animation features (we're going to use keyframe animation), collision detection, etc.

So, the function you gave me may work just fine for what I need..  but, if there's a different way to go about it, lemme know.  OR, if there's a better alternative to Xith I'm open to all ears..  I just don't know enough about *game* programming to tell if it's the best option or not.

Thanks!!

[Marvin Fröhlich]

So, the function you gave me may work just fine for what I need..  but, if there's a different way to go about it, lemme know.  OR, if there's a better alternative to Xith I'm open to all ears..  I just don't know enough about *game* programming to tell if it's the best option or not.

Well, of course, there's no better option than Xith3D . There's jmonkey-engine. I've never used it... There may be some differences... But I tell you, that Xith3D will be fine for you. If there's anything missing, just tell us, and we will see, if we can add it .

For the keyframe animation and collision detection thing: I've never used keyframe animation. Well, if it is, what the MD2Model does when its own animations are used, then I have. Anyway MDS supports animations, our loader supports them, too. And they're displayed in a xith3d scenegraph.
We also have a collision system built in in xith3d. But it's quite slow and doesn't alsways work. We're currently discussing, how to go to better way. This better way, which is already working very well, is to use JOODE. It is a full featured physics lib, which of course has a collision system.

So you don't need to check all the vertices, normals, etc. from the geometry on your own. JOODE does everything for you .

Marvin

[Richard Hefner]

Hehehe...  Ok.  Well, I'm giving it another try.  I went and did some research and found out that the support for Java3D "keyframe" animation is little to none with the file formats I wanted to use.  First, I wanted to use OBJ's, but there's no animation support of course.  Then, I tried out MD2's to run into a snag that you may just have fixed for me.  So, I looked at lightwave files and the Java3D loader for that isn't loading my newer LWS files correctly (I guess you have to use lightwave scene's that are version 5 or below?) ...  Yah, what a mess.  Heheh.

Anywho, I have to turn in my project on Friday, so we'll see how far I get.  Score -1 for starting late and getting sick before the projects due. 

Thanks for all your help and I'll let you know how it all works for me.

[Marvin Fröhlich]

Wow they have a Lightwave loader in Java3D. Maybe we should see, if we can port it to Xith. I found so nice models on may sites on the internet. Well, I hope they are not all newer than 5 .

Marvin

['n ddrylliog]

Hi Richard Hefner (are you Hugh's cousin or what ?  ) Welcome to Xith3D boards !

Well, of course, there's no better option than Xith3D .

As he says..

Here's the API I think you will use (mostly) :

Code:

// Load
MD2Model model = new MD2Loader().loadModel( modelName, skin );

// Get anim names
List<String> anims = model.getAnimationNames();

// Choose an anim
model.setCurrentAnimation( anims.get( currentAnim ) );

// Interpolate the anim
model.interpolateAnimation( (float)frameTime / 100.0f );

// Get the Shape3D of the MD2 model
Shape3D shape = ShapeFinder.findFirstShape(model);

// Get the Appearance of the Shape
Appearance app = shape.getAppearance();

// Get the Texture of it (note that you won't get the file
Texture tex = app.getTexture();

// Get the Geometry of the Shape
Geometry geom = shape.getGeometry();

// 99% of the time it will be a TriangleArray
TriangleArray ta = (TriangleArray) geom;

// Get all we can
Point3f[] coords = new Point3f[ta.getVertexCount()];
ta.getCoordinates(0, coords);
float[] uv = new float[ta.getVertexCout()];
ta.getTextureCoordinates(0, 0, uv);

Note : code not proof-tested. Ask any questions..

[Marvin Fröhlich]

There's a method getShapeNodes() in all loaded models and scenes (inherited from LoadedGraph->Model/Scene). It returns a List<Shape3D> containing all the Shape3Ds in the loaded model. In MD2Model and AseModel/AseScene they were not filled so far. This is done now and you don't need to use the ShapeFinder for this task, since the shapes can be simply retrieved from this prefilled list .

And an MD2 model seems to always contain two shapes. So the findFirstShape method wouldn't anyway be the right method. There's findAllShapes(), that does the job. Well, if you only need the first shape, the findFirstShape() method is faster. But none of them is faster than using the prefilled List .

Marvin