/** applet No. 1153
 *
 * meteor - astro object 3D (discrete element method)
 * - multi thread  AO3D :: display - asynchronous
 *
 * Created by Ikeuchi Mitsuru on April 08 2007.
 * Copyright (c) 2007 Ikeuchi Mitsuru. All rights reserved.
 *
 * ver 0.0.1   2007.04.08  created
 * ver 0.0.2   2007.06.19  improved code
 *
 */

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class meteorMtAO3D extends Applet
  implements MouseListener, MouseMotionListener,
    ItemListener, ActionListener, AdjustmentListener, Runnable {

  // ------------------------------------ preset field -----------

  Thread th = null; // for run()-paint() thread
  AO3D d3d = null;
  DisplayD3D dsp = new DisplayD3D();

  // for event
  Choice ch_mat,ch_view;
  Button bt_reset, bt_startStop, bt_step;
  Scrollbar sc_vx0, sc_scale;

  // for off-paint buffer
  Dimension dim;
  Image imgOff;
  Graphics gOff;

  int dgX, dgY, dgXb, dgYb;

  int sleepTime = 30;
  int dispMode = 0;
  int thCount = 0;


  // ------------------------------ applet main thread -----------

  public void init() {
    resize(630,460);
    setBackground(Color.white);

    dim = getSize();
    imgOff = createImage(dim.width,dim.height);
    gOff = imgOff.getGraphics();

    ch_mat = new Choice();
    ch_mat.add("fixed");
    ch_mat.add("A");
    ch_mat.add("B");
    ch_mat.add("C");
    ch_mat.addItemListener(this);
    ch_mat.select("B");

    ch_view = new Choice();
    ch_view.add("ball");
    ch_view.add("openBall"); 
    ch_view.add("velocity");
    ch_view.addItemListener(this);
    ch_view.select("ball");

    bt_reset = new Button("reset");
    bt_reset.addActionListener(this);

    bt_startStop = new Button("start/stop");
    bt_startStop.addActionListener(this);

    bt_step = new Button("step");
    bt_step.addActionListener(this);

    sc_vx0 = new Scrollbar(Scrollbar.HORIZONTAL,135,10,0,210);
    sc_vx0.addAdjustmentListener(this);

    sc_scale = new Scrollbar(Scrollbar.HORIZONTAL,100,10,50,510);
    sc_scale.addAdjustmentListener(this);

    addMouseListener(this);  
    addMouseMotionListener(this);

    setLayout(new BorderLayout());
    Panel pnl = new Panel();
    pnl.setLayout(new GridLayout(1,6,5,0));
    /* pnl.add(new Label("  ")); */
    pnl.add(bt_reset);
    pnl.add(bt_startStop);
    pnl.add(sc_vx0);
    pnl.add(new Label("  "));
    pnl.add(sc_scale);
    pnl.add(ch_view);
    add(pnl,"North");

  }

  public void start() {
    if (d3d == null) {
      d3d = new AO3D();
      d3d.start();
    }
    if (th == null) {
      th = new Thread(this);
      th.start();
    }
  }

  public void stop() {
    if (th != null) th = null;
    if (d3d != null) d3d = null;
  }


  // ---------------------------------- event listener -----------

  public void itemStateChanged(ItemEvent ev){
    if (ev.getSource() == ch_view){
      dispMode = ch_view.getSelectedIndex();
    }
  }

  public void actionPerformed(ActionEvent ev){
    if(ev.getSource() == bt_reset){ 
      d3d.reset();
      thCount = 0;
    } else if (ev.getSource() == bt_startStop){
      if (d3d.getStartSW()==0) {
        d3d.setStartSW(1);
      } else {
        d3d.setStartSW(0);
      }
    } else if (ev.getSource() == bt_step){
      if (d3d.getStartSW()==0) {
        d3d.setStepSW();
      }
    }
  }

  public void adjustmentValueChanged(AdjustmentEvent ev){
    if (ev.getSource() == sc_vx0) { 
      d3d.setVx0( 1.0*(double)(sc_vx0.getValue())-100.0 );
    } else if (ev.getSource() == sc_scale) { 
      dsp.setViewScale( 0.01*(double)(sc_scale.getValue()) );
    }
  }

  public void mousePressed(MouseEvent ev){ }
  public void mouseReleased(MouseEvent ev){
    dgXb = 0; dgYb = 0;
    dgX = 0; dgY = 0;
  }
  public void mouseClicked(MouseEvent ev){ }
  public void mouseEntered(MouseEvent ev){ } 
  public void mouseExited (MouseEvent ev){ }

  public void mouseMoved  (MouseEvent ev){ }

  public void mouseDragged(MouseEvent ev){
    dgXb = dgX; dgYb = dgY;
    dgX=ev.getX();
    dgY=ev.getY();
    if (dgXb==0 && dgYb==0) {
      dgXb = dgX; dgYb = dgY;
    }
    dsp.setViewDelta( (dgX-dgXb), (dgY-dgYb) );
  }



  // ========================= run() - paint() loop ==============

  public void run() {
    while (th != null) {
      try {
        Thread.sleep(sleepTime);
      } catch (InterruptedException e) { }
      thCount += 1;
      offPaint();
      repaint();
    }
  }

  public void update(Graphics g) {
    paint(g);
  }

  public void paint(Graphics g) {
    g.drawImage(imgOff,0,0,this);
  }

  private void offPaint() {
    if (d3d != null) {
      dsp.plotGraph(gOff, d3d, dispMode, thCount);
    }
  }

}  



// ================================= display D3D class ===========

class DisplayD3D {

  Graphics gOff;
  AO3D d3d;

  private int Nmt;

  private double xMax = 100.0*1.0e5;;
  private double yMax = 100.0*1.0e5;;
  private double zMax = 100.0*1.0e5;;
  private double AU = d3d.AU;
  private double AA = d3d.AA;

  private double zDepth = xMax;
  private double dispWidth = 250.0;
  private double dispScale = (dispWidth/xMax);
  private double viewScale = 1.0;

  private double cx = 0.5*xMax;
  private double cy = 0.5*yMax;
  private double cz = 0.5*zMax;
  private double theta = -20.0*3.14/180.0;
  private double fai = 10.0*3.14/180.0;

  private int NN = 10000;
  private int srtz[][] = new int[2][NN];

  private double px[] = new double[NN]; 
  private double py[] = new double[NN]; 
  private double pz[] = new double[NN]; 

  private double wkx[] = new double[8]; 
  private double wky[] = new double[8]; 
  private double wkz[] = new double[8]; 

  private double pwkx[] = new double[8]; 
  private double pwky[] = new double[8]; 
  private double pwkz[] = new double[8]; 

  private int boxp[][] = {
   {0,1},{0,2},{0,4},{1,3},{1,5},{2,3},{2,6},{4,5},{4,6},{3,7},{5,7},{6,7}
  };

  private int drawnCount = 0;


  // ------------------------------- class constructor -----------

  DisplayD3D() {
    setWaku();
  }


  // ----------------------------------- class methods -----------

  public void plotGraph(Graphics gg, AO3D ad3d, int dispMode, int thCount) {
    int d3dCount, gbx, gby, gx;

    gOff = gg;
    d3d = ad3d;

    if (d3d==null) return;
    d3dCount = d3d.getCount();
    if (d3dCount==drawnCount) return;
    drawnCount = d3dCount;

    Nmt = d3d.getNmt();

    gOff.setColor(Color.black);
    gOff.fillRect(0,0,630,460);

    rotate(theta,fai);
    zSort();

    gbx = 70;
    gby = 120;

    if (dispMode==0) {
	  ballPlot(gbx,gby, 0);

    } else if (dispMode==1) {
      ballPlot(gbx,gby, 1);

    } else if (dispMode==2) {
      velocity3DPlot(gbx,gby, 20.0);

    } else if (dispMode==3) {
      ;

    }

    gbx = 630/6;
    gOff.setColor(Color.yellow);
    gOff.drawString("t="+(int)(d3d.getTime()+0.5)+" s",gbx*0+10,40);
    if (d3d.getStartSW()==1) {
      gOff.drawString("started",630/6*1+10,40);
    } else {
      gOff.drawString("stop",630/6*1+10,40);
    }
    gOff.drawString("vx0="+(int)(d3d.getVx0()*10.0+0.5)/10.0+"m/s",gbx*2+10,40);
    gOff.drawString("scale="+(int)(viewScale*100.0+0.5)+"%",gbx*4+10,40);
    gOff.drawString("view",gbx*5+10,40);

    gOff.setColor(Color.yellow);
    gOff.drawString("Box="+(int)(xMax/1000.0+0.5)+" x "+(int)(yMax/1000.0+0.5)+" x "+(int)(zMax/1000.0+0.5)+" km",400,60);
    gOff.drawString("thread AO3D = "+d3d.getCount()+" ",400,80);
    gOff.drawString("thread disp = "+thCount+" ",400,100);
  }


  // ------------------------------------ plot methods -----------

  private void ballPlot(int gbx, int gby,int imode) {
    int i,j,gx,gy,gr;
    double sz,sc,den;

    drawWaku(gbx,gby,0);

    sc = dispScale*viewScale;
    sz = 1.0*viewScale/AA;

    for (i=0; i<Nmt; i++) {
      j = srtz[0][i];
      gx = (int)(sc*px[j])+gbx;
      gy = (int)(sc*py[j])+gby;
      gr = (int)(sz*d3d.getr0(j)*(0.3*(pz[j]/zDepth)+0.7));
      if (gr<2) gr = 2;
      den = 0.4*pz[j]/zDepth+0.3; if (den>0.999) den = 0.999;
	  if (den<0.3) den = 0.3;
      gOff.setColor(Color.getHSBColor(d3d.getColorOf(j),0.8f,(float)(den)));
      if (imode==0) {
        gOff.fillOval(gx-gr/2,gy-gr/2, gr, gr);
      } else if (imode==1) {
        gOff.drawOval(gx-gr/2,gy-gr/2, gr, gr);
      }
    }
    drawWaku(gbx,gby,1);
  }

  private void velocity3DPlot(int gbx, int gby, double mag) {
    int i,j,gx,gy,g2x,g2y,gr;
    double sc,sz,m,p2x,p2y,p2z,rotp2x,rotp2y,rotp2z,dt,den;
    double cosTh,sinTh,cosFi,sinFi;

    dt = d3d.getdt();
    drawWaku(gbx,gby,0);

    cosTh = Math.cos(theta); sinTh = Math.sin(theta);
    cosFi = Math.cos(fai); sinFi = Math.sin(fai);
    sc = dispScale*viewScale;
    sz = 0.3*viewScale/AA;

    for (i=0; i<Nmt; i++) {
      j = srtz[0][i];
      gx = (int)(sc*px[j])+gbx;
      gy = (int)(sc*py[j])+gby;

      gr = (int)(sz*d3d.getr0(j)*(0.3*(pz[j]/zDepth)+0.7));
      if (gr<2) gr = 2;

      p2x = d3d.getxx(j)+mag*d3d.getvx(j)*20*dt;
      p2y = d3d.getyy(j)+mag*d3d.getvy(j)*20*dt;
      p2z = d3d.getzz(j)+mag*d3d.getvz(j)*20*dt;

      rotp2y = cosFi*(p2y-cy)+sinFi*(p2z-cz) + cy; 
      rotp2z = -sinFi*(p2y-cy)+cosFi*(p2z-cz) + cz;
      rotp2x = cosTh*(p2x-cx)+sinTh*(rotp2z-cz) + cx; 
      rotp2z = -sinTh*(p2x-cx)+cosTh*(rotp2z-cz) + cz;

      g2x = (int)(sc*rotp2x)+gbx;
      g2y = (int)(sc*rotp2y)+gby;
      if (d3d.getvx(j)>0) {
        gOff.setColor(Color.cyan);
      } else {
        gOff.setColor(Color.red);
      }
      gOff.drawLine(gx,gy, g2x,g2y);

      den = 0.4*pz[j]/zDepth+0.3; if (den>0.999) den = 0.999;
	  if (den<0.3) den = 0.3;
      gOff.setColor(Color.getHSBColor(d3d.getColorOf(j),0.8f,(float)(den)));
      gOff.fillOval(gx-gr/2,gy-gr/2, gr, gr);
    }

    drawWaku(gbx,gby,1);
  }


  private void drawWaku(int gbx, int gby, int imode) {
    int i,gx,gy,g2x,g2y,farPoint;
    double sc,tmp;

    sc = dispScale*viewScale;
    farPoint = findMin();

    for (i=0; i<12; i++) {
      gx = (int)(sc*pwkx[boxp[i][0]])+gbx;
      gy = (int)(sc*pwky[boxp[i][0]])+gby;
      g2x = (int)(sc*pwkx[boxp[i][1]])+gbx;
      g2y = (int)(sc*pwky[boxp[i][1]])+gby;
      if (imode==0) {
        if (boxp[i][0]==farPoint || boxp[i][1]==farPoint) { 
          gOff.setColor(Color.darkGray);
          gOff.drawLine(gx,gy, g2x, g2y);
        }
      } else if (imode==1) {
        if (boxp[i][0]!=farPoint && boxp[i][1]!=farPoint) { 
          gOff.setColor(Color.gray);
          gOff.drawLine(gx,gy, g2x, g2y);
        }
      }
    }
  }

  private int findMin() {
    int i,im;
    double m;

    im = 0; m = pwkz[im];
    for (i=0; i<8; i++) {
      if (pwkz[i]<m) {
        m = pwkz[i];
        im = i;
      }
    }
    return(im);
  }

  //

  private void setWaku() {
    int i,ix,iy,iz;
    double sgm;

    sgm = 4.0e-10;
    i=0;
    for (ix=0; ix<2; ix++) {
      for (iy=0; iy<2; iy++) {
        for (iz=0; iz<2; iz++) {
          wkx[i] = -0.5*sgm+(xMax+sgm)*(double)(ix);
          wky[i] = -0.5*sgm+(yMax+sgm)*(double)(iy);
          wkz[i] = -0.5*sgm+(zMax+sgm)*(double)(iz);
          i += 1;
        }
      }
    }
  }

  // sort z

  private void zSort() {
    int i,j,w;

    for (i=0; i<Nmt; i++) {
      srtz[0][i] = i;
      srtz[1][i] = (int)(32767.0*pz[i]/zMax);
    }
    qSort(0,Nmt-1);    
  }

  private void qSort(int i,int j) {
    int k,p;

    if(i==j) return;
	p = i+1;
    while (p<=j && srtz[1][i]==srtz[1][p]) p++;
    if (p<=j) {
      if (srtz[1][i]>=srtz[1][p]) p = i;
      k = qSortPartition(i,j,srtz[1][p]);
      qSort(i,k-1);
      qSort(k,j);
    }
  }

  private int qSortPartition(int i,int j, int x) {
    int l,r,w;

    l = i; r = j;
    while (l<=r) {
      while (l<=j && srtz[1][l]<x) l++;
      while (r>=i && srtz[1][r]>=x) r--;
      if (l>r) break;
      w = srtz[0][l]; srtz[0][l] = srtz[0][r]; srtz[0][r] = w;
      w = srtz[1][l]; srtz[1][l] = srtz[1][r]; srtz[1][r] = w;
      l++; r--;
    }
    return ( l );
  }

  // rotate 

  private void rotate(double th,double fi) {
    int i;
    double cosTh,sinTh,cosFi,sinFi,x,y,z;

    cosTh = Math.cos(th); sinTh = Math.sin(th);
    cosFi = Math.cos(fi); sinFi = Math.sin(fi);
    for (i=0; i<Nmt; i++) {
	  x = d3d.getxx(i); y = d3d.getyy(i); z = d3d.getzz(i);
      py[i] = cosFi*(y-cy)+sinFi*(z-cz) + cy; 
      pz[i] = -sinFi*(y-cy)+cosFi*(z-cz) + cz;
      px[i] = cosTh*(x-cx)+sinTh*(pz[i]-cz) + cx; 
      pz[i] = -sinTh*(x-cx)+cosTh*(pz[i]-cz) + cz;
    } 

    for (i=0; i<8; i++) {
      pwky[i] = cosFi*(wky[i]-cy)+sinFi*(wkz[i]-cz) + cy; 
      pwkz[i] = -sinFi*(wky[i]-cy)+cosFi*(wkz[i]-cz) + cz;
      pwkx[i] = cosTh*(wkx[i]-cx)+sinTh*(pwkz[i]-cz) + cx; 
      pwkz[i] = -sinTh*(wkx[i]-cx)+cosTh*(pwkz[i]-cz) + cz;
    }  
  }


  // ------------------------------------- I/O methods -----------

  public void setViewDelta(double xDisplacement, double yDisplacement) {
    theta += 0.5*3.14/180.0*xDisplacement;
    fai += 0.5*3.14/180.0*yDisplacement;
  }

  public void setViewScale(double s) { viewScale = s; }
  public double getViewScale() { return viewScale; }
}



// ============================= astro object 3D class ===========

class AO3D extends Thread {

  private double t = 0.0;
  private double dt = 10.0;

  private int Nmt = 1000;

  private double gg = 6.673e-11; // m^3kg^-1s-2
  private int incRate = 10;
  private double vx0 = 35.0; 

  public static double AU = 1.0e18; // kg
  public static double AA = 1.0e5; // m
  public static double AD = 1.0e10; // dump

  private double aObject[][] = {
  // 0:mass(AU) 1:r0(AA) 2:dump 3:color
    {  1.0*AU, 0.8*AA, 2.0*AD, 0.85 }, // fixed ball
    {  1.0*AU, 0.8*AA, 1.0*AD, 0.01 }, // 1 A
    {  5.0*AU, 0.8*AA, 2.0*AD, 0.10 }, // 2 B
    { 10.0*AU, 0.8*AA, 1.0*AD, 0.20 }  // 3 C
  };

  private String materialStr[] = {
    "fixed" ,"A" ,"B","C"
  };
  private int NmatKind = 4;

  private int NN = Nmt + 1;
  private int kind[] = new int[NN];
  private double xx[] = new double[NN];
  private double yy[] = new double[NN];
  private double zz[] = new double[NN];
  private double vx[] = new double[NN];
  private double vy[] = new double[NN];
  private double vz[] = new double[NN];
  private double ffx[] = new double[NN];
  private double ffy[] = new double[NN];
  private double ffz[] = new double[NN];

  private int resetSW = 0;
  private int startSW = 1;
  private int stepSW = 0;
  private int sleepTime = 1;
  private int stopSleepTime = 100;
  private int count = 0;


  // ------------------------------- class constructor -----------

  AO3D() {
    setInitialCondition();
  }


  // -------------------------------------- thread run -----------

  public void run() {
    while (true) {
      count += 1;
      timeEvolution();
      if (sleepTime>0) {
        try {
          Thread.sleep(sleepTime);
        } catch (InterruptedException e) { }
      }
    }
  }


  // --------------------------- set initial condition -----------

  private void setInitialCondition() {
    int i; 

    t = 0.0;
    count = 0;

    i = 0;
    i = setNNCloud(i,6, 3.0e6,0.0,5.0e6, vx0,0.0,0.0, 2);
    i = setNNCloud(i,6, 3.0e6,5.0e6,5.0e6, -vx0,0.0,0.0, 2);
	//i = setNNMeteor(i,5, 13.0e6,2.5e6,5.0e6, 0.0,0.0,0.0, 2.0e-4, 2);
    Nmt = i;

  }

  private int setNNCloud(int ii,int nn, double xPos, double yPos, double zPos, double vvx0, double vvy0, double vvz0, int mat) {
    int i,ix,iy,iz;
    double a;

    i = ii;

    a = 3.0e5;
    for (ix=0; ix<nn; ix++) {
      for (iy=0; iy<nn; iy++) {
        for (iz=0; iz<nn; iz++) {
          kind[i] = mat;
          xx[i] = a*ix + xPos;
          yy[i] = a*iy + yPos;
          zz[i] = a*iz + zPos;
          vx[i] = 1.0*(Math.random()-0.5) + vvx0;
          vy[i] = 1.0*(Math.random()-0.5) + vvy0;
          vz[i] = 1.0*(Math.random()-0.5) + vvz0;
          ffx[i] = 0.0;
          ffy[i] = 0.0;
          ffz[i] = 0.0;

          i += 1;
		}
      }
    }
    return ( i );
  }

  private int setNNMeteor(int ii,int nn, double xPos, double yPos, double zPos, double vvx0, double vvy0, double vvz0, double omega, int mat) {
    int i,ir,ith,nth;
    double a,r,th;

    i = ii;

    kind[i] = mat;
    xx[i] = xPos;
    yy[i] = yPos;
    zz[i] = zPos;
    vx[i] = 1.0*(Math.random()-0.5) + vvx0;
    vy[i] = 1.0*(Math.random()-0.5) + vvy0;
    vz[i] = 1.0*(Math.random()-0.5) + vvz0;
    ffx[i] = 0.0;
    ffy[i] = 0.0;
    ffz[i] = 0.0;
    i += 1;

    a = 1.277*aObject[mat][1];
    for (ir=1; ir<nn; ir++) {
	  r = a*ir;
	  nth = (int)(2.0*Math.PI*r/a);
      for (ith=0; ith<nth; ith++) {
	    th = (2.0*Math.PI*ith)/nth;
        kind[i] = mat;
        xx[i] = r*Math.cos(th) + xPos;
        yy[i] = r*Math.sin(th) + yPos;
        zz[i] = 0.0 + zPos;
        vx[i] = 1.0*(Math.random()-0.5) + r*omega*Math.cos(th+Math.PI/2.0) + vvx0;
        vy[i] = 1.0*(Math.random()-0.5) + r*omega*Math.sin(th+Math.PI/2.0) + vvy0;
        vz[i] = 1.0*(Math.random()-0.5) + vvz0;
        ffx[i] = 0.0;
        ffy[i] = 0.0;

        i += 1;
      }
    }
    return ( i );
  }


  // ---------------------------------- time evolution -----------

  private void timeEvolution(){

    if (resetSW==1) {
      setInitialCondition();
      resetSW = 0;
    }

    if (startSW==1) {
      timeStep();

    } else {
      if (stepSW==1) {
        timeStep();
        stepSW = 0;
      }
      try {
        Thread.sleep(stopSleepTime);
      } catch (InterruptedException e) { }
    }
  }

  private void timeStep() {
    int i;

    for (i=0; i<incRate; i++) {
      timeStep1();
    }
  }

  private void timeStep1() {
    int i; 
    double dtv2, a2, rr;

    t += dt;

    dtv2 = dt/2.0;
    for (i=0; i<Nmt; i++) {
      if (kind[i]>0) {
        a2 = dtv2/aObject[kind[i]][0];
        vx[i] += a2*ffx[i];
        vy[i] += a2*ffy[i];
        vz[i] += a2*ffz[i];
        xx[i] += vx[i]*dt;
        yy[i] += vy[i]*dt;
        zz[i] += vz[i]*dt;
      }
    }
    forceCalc();
    for (i=0; i<Nmt; i++) {
      if (kind[i]>0) {
        a2 = dtv2/aObject[kind[i]][0];
        vx[i] += a2*ffx[i];
        vy[i] += a2*ffy[i];
        vz[i] += a2*ffz[i];
      }
    }

  }

  private void forceCalc() {
    int i,j,k, ki,kj;
    double xij,yij,zij;
    double r2,rij,f,fxij,fyij,fzij;

    for(i=0;i<Nmt;i++) {
      ffx[i] = 0.0;
      ffy[i] = 0.0;
      ffz[i] = 0.0;
    }

    for(i=0;i<Nmt;i++) {
      for(j=i+1;j<Nmt;j++) {
        xij = xx[i]-xx[j]; yij = yy[i]-yy[j]; zij = zz[i]-zz[j];
        r2 = xij*xij + yij*yij + zij*zij;
        rij = Math.sqrt(r2);
		ki = kind[i]; kj = kind[j];
        f = force(rij,ki,kj);
		if (rij<0.638*(aObject[ki][1]+aObject[kj][1])) {
          f += -0.5*(aObject[ki][2]+aObject[kj][2])*(xij*(vx[i]-vx[j])+yij*(vy[i]-vy[j])+zij*(vz[i]-vz[j]));
        }
        fxij = f*xij/rij;
        fyij = f*yij/rij;
        fzij = f*zij/rij;

        ffx[i] +=  fxij;
        ffy[i] +=  fyij;
        ffz[i] +=  fzij;

        ffx[j] += -fxij;
        ffy[j] += -fyij;
        ffz[j] += -fzij;
      }
    }

  }

  private double force(double r, int ki, int kj) {
    double r0,gmm,s,s4;

    r0 = 0.5*(aObject[ki][1]+aObject[kj][1]);
    gmm = gg*aObject[ki][0]*aObject[kj][0];
    s = (r0/r); s4 = s*s*s*s;
    return (gmm/r0)*(s/r)*(9*s4*s4-1.0);
  }


  // ------------------------------------- I/O methods -----------

  // control
  public void reset() { resetSW = 1; }
  public void setStartSW(int sw) { startSW = sw; }
  public int getStartSW() { return startSW; }
  public void setStepSW() { stepSW = 1; }
  public int getCount() { return count; }

  public void setVx0(double v) { vx0 = v; }
  public double getVx0() { return vx0; }

  // get data
  public int getNmt() { return Nmt; }
  public double getTime() { return t; }
  public double getdt() { return dt; }

  public double getxx(int i) { return xx[i]; }
  public double getyy(int i) { return yy[i]; }
  public double getzz(int i) { return zz[i]; }
  public double getvx(int i) { return vx[i]; }
  public double getvy(int i) { return vy[i]; }
  public double getvz(int i) { return vz[i]; }
  public double getr0(int i) { return 1.277*aObject[kind[i]][1]; }
  public float getColorOf(int i) { return (float)(aObject[kind[i]][3]); }

}