That's right i'm tackling JBullet. Going good except that last few days on working with getting Quat to Euler. I just can't get it to work right. No matter what I do a physics box will always show Object3D primitive Box at an angle with the corner stiking through the floor.

import sre.roam.JPCTLib;

import javax.vecmath.Vector3f;
import javax.vecmath.Quat4f;

import com.threed.jpct.SimpleVector;
import com.threed.jpct.Object3D;
import com.threed.jpct.Matrix;

import javabullet.linearmath.MotionState;
import javabullet.linearmath.Transform;


public class JPCTBulletMotionState implements MotionState{
public final Transform graphicsWorldTrans = new Transform();
public final Transform centerOfMassOffset = new Transform();
public final Transform startWorldTrans = new Transform();
 
  private Object3D obj3d;
 
  private float tran_x, tran_y, tran_z; // empty place spots
  private SimpleVector rotate = new SimpleVector();
  private SimpleVector last_rotate = new SimpleVector();
 
  public JPCTBulletMotionState()
  {
graphicsWorldTrans.setIdentity();
centerOfMassOffset.setIdentity();
startWorldTrans.setIdentity();
  }
 
public JPCTBulletMotionState(Transform startTrans)
  {
    this.graphicsWorldTrans.set(startTrans);
centerOfMassOffset.setIdentity();
this.startWorldTrans.set(startTrans);
} 
 
public JPCTBulletMotionState(Transform startTrans, Transform centerOfMassOffset)
  {
    this.graphicsWorldTrans.set(startTrans);
this.centerOfMassOffset.set(centerOfMassOffset);
this.startWorldTrans.set(startTrans);
} 
 
  public void setObject(Object3D obj)
  {
    obj3d = obj;
  }
 
  public void getWorldTransform(Transform worldTrans){
  worldTrans.set(graphicsWorldTrans);
    //worldTrans.inverse(centerOfMassOffset);
    //worldTrans.set(centerOfMassOffset);
//worldTrans.mul(graphicsWorldTrans);
    return;
  }
 
  public void setWorldTransform(Transform worldTrans)
  {
    SimpleVector pos = obj3d.getTransformedCenter();
   
    tran_x = worldTrans.origin.x - pos.x;
    tran_y = worldTrans.origin.y - pos.y;
    tran_z = worldTrans.origin.z - pos.z;
    obj3d.translate(tran_x, tran_y, tran_z);
   
    Quat4f quat = worldTrans.getRotation();
    quat.inverse();
    quat.normalize();
    QuatToEuler(quat);
   
    graphicsWorldTrans.origin.set(tran_x, tran_y, tran_z);

    float rx = last_rotate.x - rotate.x;
    float rz = last_rotate.y - rotate.y;
    float ry = last_rotate.z - rotate.z;
    quat.set(rx,rz,ry, quat.w);
    graphicsWorldTrans.setRotation(quat);

    if(obj3d != null)
    {
      obj3d.rotateX(rx);
      obj3d.rotateY(ry);
      obj3d.rotateZ(rz);
    }
  }


  public void QuatToEuler(Quat4f quat)
  {
  double sqw;
  double sqx;
  double sqy;
  double sqz;

  double rotxrad;
  double rotyrad;
  double rotzrad;

  sqw = quat.w * quat.w;
  sqx = quat.x * quat.x;
  sqy = quat.y * quat.y;
  sqz = quat.z * quat.z;
  rotxrad = (double)Math.atan2(2.0 * ( quat.y * quat.z + quat.x * quat.w ) , ( -sqx - sqy + sqz + sqw ));
  rotyrad = (double)Math.asin(-2.0 * ( quat.x * quat.z - quat.y * quat.w ));
  rotzrad = (double)Math.atan2(2.0 * ( quat.x * quat.y + quat.z * quat.w ) , (  sqx - sqy - sqz + sqw ));
   
    last_rotate.set((float)rotate.x, (float)rotate.y, (float)rotate.z);
  rotate.set((float)rotxrad, (float)rotyrad, (float)rotzrad);
    return;
  }
 
}
The conversion code above has worked in other graphical cases. Other uses of Bullet+Irrelect, Ode and ogre. I just can't get it to work with JBullet and JPCT.


maybe i'm missing something silly. I don't know. So I'm thinking of using cyberkilla skeletal
Matrix.setQuaternionRotation(). Which converts a quat to a float mat[16].
Will changing a quat to a JPCT.Matrix cause any troubles. Will children rotate with the new matrix or will I have to continue with trying to work a way with Object3D.rotate().

I'm not sure how to do this.

I load my 3ds file, but the model loads at a "wrong" angle. I don't have the skill to know what the hell i'm doing in an edit.
What i'm trying to do is rotate the object so it's along the angle I want it. Then set the current values as new 0.

Why. I'm trying to add a camera satellite, but when I do the orientation of the model is so off it's really hard to figure out where to put, rotate the satellite for the camera. So if I can get the objected rotated the right way then add the satellite using 0,0,0 as the starting refernce then it would make my life so much easier.

If I knew more about modeling I would probably model in a target and cam location.

I tried the .setRotationMatrix(new Matrix())
but that just put's it back to the original rotational.

nope not yet. I'm still playing around with getting some of the other stuff up once. I get moving working I will start playing with the skybox some more.

I'm sorry to be a pest. All my projects typicly use Primitive shapes. This is the first time I've tried to use a model. I'm experimenting with a advanced model that I downloaded from the web.

I noticed that the Loader loads an array of Object[]. What I'm wondering is there a guide to this.

Are these Objects attached to each other. Do these objects have ID that corrospond to their editor name?
Will I need to Object[0].add(Object).  how do textures get loaded and applied. Is this automatic or do I have
to go through the Objects.

The model i'm using has 57 materials & textures, 32000 faces and I'm not sure how many parts. I think 50. It's a Obj whatever that editor is from. I'm only using it temporarily until I can get some one to help with some low poly models.

So I have been thinking about this.

Currently one form of display would be this
   
buffer.clear(Color.blue);   // erase the previous frame
// render the world onto the buffer:
world.renderScene( buffer );
world.draw( buffer );
buffer.update();
buffer.displayGLOnly();
canvas.repaint();

what if
buffer.clear(Color.blue);   // erase the previous frame
skyWorld.renderScene( buffer );
skyWorld.draw( buffer );
world.renderScene( buffer );
world.draw( buffer );
buffer.update();
buffer.displayGLOnly();
canvas.repaint();

of course this would require 2 cameras. What's the point of all this.

Well i'v never played with skyboxes much. So I was thinking of using a different skybox rendering system to just play with elements like size, texture res relative to box distance.

Thanks I will look into that.

Pretty simple question. How do I get the Object3D rotation radian value.