//created=15 Oct 06
//description=Orbital dynamics simulator. Try a lunar orbit transfer.
//title=Satellite
//publish=true
 
int gres = 25;
Tuple3 [][] heights = new Tuple3[gres][gres];
float [][] radii = new float [gres][gres];
  point which = null;
Vector shells = new Vector();
 
PFont kartika;
 
float thrust = 0;
float power = .05;
 
boolean showPole = false;
boolean trailfades = true;
 
boolean paused = false;
 
int camMode = 0;
 
int time =0;
 
int numStars = 1500;
Tuple [] stars = new Tuple[numStars];
 
float viewRotate = 0, dViewRotate = 1;
float viewDist = 150, dViewDist = 0;
 
int maxTrail = 80;
int maxSats = 5;
int shellHeight = 75;
int shellThick = 40;
 
int mode = 0;
 
void setup() 
{
  size(550, 550,P3D); 
  rectMode(CENTER);
 
  sphereDetail(15);
  bump();
 
   for (int i = 0; i < numStars; i++){
    stars[i] = new Tuple(random(-50000,50000),random(-50000,50000),random(-50000,50000));
   }
 
  kartika = loadFont("Kartika-20.vlw");
  textFont(kartika);
  textMode(SCREEN);
   
 
 
}
 
void bump(){
 
  float z,r,x,y,offset;
  float zmax = 0, zmin =0;
 
  //clear heights
  for (int i= 0; i < gres; i++){
  for (int j= 0; j < gres; j++){
     radii[i][j] = 0;
  }
  } 
  
 for (int it =0; it < 150; it++){
  
  r = random(.1,5);
  x = random(0,gres);
  y = random(0,gres);
  offset = random(0,2);
  
   
    
  for (int i= 0; i < gres; i++){
  for (int j= 0; j < gres; j++){
    z =  -offset-((r*r)-((x - i)*(x-i) + (y - j)*(y - j)));
    if (z > 0) z = 0;
    radii[i][j] += z;
    if (z > zmax) zmax = z; 
    if (z < zmin) zmin = z;
  }
  } 
  }
 
  //normalize heights
  for (int i= 0; i < gres; i++){
  for (int j= 0; j < gres; j++){
     radii[i][j] = (radii[i][j] - zmin)/(zmax-zmin);
  }
  } 
  
  
  //create valleys
  for (int i= 0; i < gres; i++){
  for (int j= 0; j < gres; j++){
     radii[i][j] = 20 + 2*(radii[i][j]*radii[i][j]);
  }
  }  
 
  
 
  float radius = 10;
  float ang =0;
  float el = -PI;
 
  for (int j=0; j < gres; j++){
    
  for ( int i=0; i < gres; i++){
     ang += TWO_PI/gres;
     heights[i][j] = new Tuple3();
     heights[i][j].x = radii[i][j]*cos(ang)*sin(el);
     heights[i][j].y = radii[i][j]*sin(ang)*sin(el);
     heights[i][j].z = radii[i][j]*cos(el);
  }
  
  el += PI/gres;
  
  }
 
}
 
 
 
void draw() 
{   
  
  //do sky fading
  int sky = 255 - (int)viewDist*3;
  if (sky < 0 || camMode != 0) sky =0;
  background(4*sky/5,4*sky/5,sky); 
  time++;
  
  dViewRotate *=.9;
  viewRotate += dViewRotate;
 
  dViewDist *= .9;
  viewDist += dViewDist;
 
 
  if ( shells.size() < maxSats){
    Tuple loc = new Tuple(random(-1,1),random(-1,1),random(-1,1));
    loc.normalize();
    loc.times(shellHeight + random(0,shellThick));
    shells.add(new point(loc.x,loc.y,loc.z));
   }
   else if(shells.size() > maxSats && trailfades){
     shells.removeElementAt(0);
   }
 
  stroke(170);
  beginShape(POINTS);
  for (int i = 0; i < numStars; i++){
    vertex(stars[i].x,stars[i].y,stars[i].z);
  }
  endShape();
 
  //draw the poles
  if(showPole){
  stroke(100);
  noFill();
  beginShape(LINES);
    vertex(0,100,0);
    vertex(0,-100,0);
 
    endShape();
}
 
  lights();
 
 
 
  float interp = (viewDist - 30)/50.f;
  if (interp > 1) interp = 1.f;
  interp = 1.f-interp;
  
  
  Tuple lookAt = new Tuple(0,interp*-100,0);
  
  if (camMode > 0 && which == null){
    which = (point)shells.elementAt(0);
  }
  
  if (camMode == 0){
    camera(   viewDist*cos(viewRotate), 0 ,  viewDist*sin(viewRotate), lookAt.x, lookAt.y ,lookAt.z, 0, 1, 0);
  }
  else if (camMode == 1 || camMode == 2){
    Tuple toSat = new Tuple(which.x,which.y,which.z);
    toSat.normalize();
    toSat.times(viewDist);
    if (camMode == 1){
      camera(   toSat.x , toSat.y,  toSat.z , lookAt.x, lookAt.y ,lookAt.z, 0, 1, 0);
    }
    else{
      camera(   which.x , which.y,  which.z , which.x + which.dx, which.y + which.dy,which.z + which.dz, -toSat.x, -toSat.y, -toSat.z);
    }
  }
  else if (camMode == 3){
    Tuple toSat = new Tuple(which.x,which.y,which.z);
    Tuple lastSat = (Tuple)(which.hist.elementAt(which.hist.size()-5));
    Tuple camvec = toSat.cross(lastSat);
    camvec.normalize();
    camvec.times(viewDist);
 
    camera(   camvec.x , camvec.y,  camvec.z , 0,0,0, 0, 0,1);
  }
  else if (camMode == 4){
      camera(   which.x, viewDist, which.z , which.x,0,which.y, 0, 0,1);  
  }
  else if (camMode == 5){
      camera(   viewDist, which.y, which.z , 0,which.y,which.z, 0, 1,0);  
  } 
  
  //draw the earth
  noStroke();
  fill(0,0,200);
  sphere(22);
 
  //draw the moon
  pushMatrix();
  fill(200,200,200);
  translate(1320,0,0);
  sphere(11);
  popMatrix();
 
  fill(50,150,50);
  stroke(255);
  noStroke();
 
  for (int j =0; j < gres-1; j++){
    beginShape(QUAD_STRIP);   
    for (int i =0; i < gres-1; i++){
      vertex(heights[i][j+1].x,heights[i][j+1].y,heights[i][j+1].z);
      vertex(heights[i][j].x,heights[i][j].y,heights[i][j].z);
      vertex(heights[i+1][j+1].x,heights[i+1][j+1].y,heights[i+1][j+1].z);
      vertex(heights[i+1][j].x,heights[i+1][j].y,heights[i+1][j].z);
    }
      vertex(heights[0][j+1].x,heights[0][j+1].y,heights[0][j+1].z);
      vertex(heights[0][j].x,heights[0][j].y,heights[0][j].z);
        
    endShape();
    
  }
 
 
 
      
  noStroke();
  fill(255,255,255,50);
  sphere(35);
 
  point current;
 
  for (int i =0; i < shells.size(); i++){
     current = (point)shells.elementAt(i);
     current.draw();
     if (!paused) current.touch();
     if (!current.active) shells.remove(current);
  }
  
  fill(255);
  if (camMode == 0) text("Equatorial Camera", 10, 15);
  else if (camMode == 1) text("Fixed Sat", 10, 15);
  else if (camMode == 2) text("Forward Sat", 10, 15);
  else if (camMode == 3) text("Perpendicular Orbit", 10, 15);
  else if (camMode == 4) text("Z Look", 10, 15);
  else if (camMode == 5) text("Y Look", 10, 15);
  text("Thrust used: " + (int)(10*thrust), 10, 30);
  if (mode == 0) text("Lunar Transfer: Easy", 10, 45);
  else if (mode == 1) text("Lunar Transfer: Medium", 10, 45);
  else if (mode == 2) text("Lunar Transfer: Realistic", 10, 45);
}
 
class point{
  float x,y,z;
  float dx = 0,dy = 0, dz = 0;
  float dx2 = 0,dy2 = 0, dz2 =0;
  float lx ,ly;
  
  float radius = .2;
  int opacity = 255;
  
  Vector hist;
  
  boolean active;
  boolean selected = false;
 
 
  public point(float x, float y, float z){
    this.x = x;
    this.y = y;
    this.z = z;
    
    //we need to generate a vector perpendicular to the surface of the earth
    
    //get the down direction
    Tuple down = new Tuple(-x,-y,-z);
    
       Tuple direction;
    //cross it with the universal up vector
    if (random(0,100) < 50){ 
      direction = down.cross(new Tuple(0,0,1));
    }
    else{
      direction = down.cross(new Tuple(0,1,0));
    }
    direction.normalize();
    
    dx = direction.x;
    dy = direction.y;
    dz = direction.z;
    
    hist = new Vector();
    active = true;
    hist.add(new Tuple(x,y,z));
  }
 
  public void draw(){
   
   noStroke();
   pushMatrix();
   translate(x,y,z); 
 
   if (selected){
    
    fill(255,255,255,150);
    sphere(2);
  
  }   
   
   fill(255,255,255,opacity);
   box(1);
   
 
   
 
   popMatrix();
   stroke(255);
   Tuple a,b;
   noFill();
   int tColor;
   int hSize = hist.size();
   beginShape();
   if (hist.size() > 1){
     for (int i = 0; i < hSize; i++){
       a = (Tuple)hist.elementAt(i);
       tColor = (int)(255*((float)i/hSize));
       stroke(255,255,255,tColor);
       vertex(a.x,a.y,a.z);
    }
   }
   
   //delete old points 
   if (hist.size() > maxTrail && trailfades){
     hist.removeElementAt(0);
   }
   
   
   vertex(x,y,z);
   endShape();
   
 
  }
 
  public void touch(){
    //gravitate earth
    float dist = sqrt(x*x + y*y + z*z);
    
    if (dist < 20) active = false;
    
    float vx = (0-x)/dist;
    float vy = (0-y)/dist;
    float vz = (0-z)/dist;
    dx2 = 100*vx/(dist*dist); 
    dy2 = 100*vy/(dist*dist);
    dz2 = 100*vz/(dist*dist);
    dx += dx2;
    dy += dy2; 
    dz += dz2;
 
 
 
    //gravitate moon
    
    dist = sqrt((x-1320)*(x-1320) + y*y + z*z);
    if (dist < 15) active = false;
    vx = (1320-x)/dist;
    vy = -y/dist;
    vz = -z/dist;
    
    float mass;
    if (mode == 0 ) mass = 100;
    else if (mode == 1) mass = 12.3;
    else mass = 1.23; 
    
    dx2 = mass*vx/(dist*dist);
    dy2 = mass*vy/(dist*dist);
    dz2 = mass*vz/(dist*dist);
    dx += dx2;
    dy += dy2; 
    dz += dz2;
 
    x += dx;
    y += dy;    
    z += dz;
 
    if (time%5 == 0){
      hist.add(new Tuple(x,y,z));
    }
 
  }
 
 
  
}
 
 
 
void mousePressed(){
  //bump();
  //shells = new Vector();
  
  if (mouseButton == LEFT){
  if (which != null){
    which.selected = false;
  }
  which = null;
  point current;
  int sx,sy;
  float dist;
  float selectDist = 10000;
  for (int i =0; i < shells.size(); i++){
    current = (point)shells.elementAt(i);
    sx = (int)(mouseX - screenX(current.x,current.y,current.z));
    sy = (int)(mouseY - screenY(current.x,current.y,current.z));    
    
    //actually the distance squared
    dist = sx*sx + sy*sy;
    if (dist < selectDist){
      selectDist = dist;
      which = current;
    }
  }
  if (which != null){
 
    which.selected = true;
 
  }
  camMode = 1;
  }
}
void keyPressed(){
  
  if (key == 'z'){
    which.dx *= .98;
    which.dy *= .98;
    which.dz *= .98;
  }
  if (key == 'c'){
    camMode ++;
    if (camMode > 5) camMode =0;
  }
 
  else if (key == 'l'){
    bump();
  }    
  else if (key == '.'){
    maxSats++;
  }          
  else if (key == ','){
    maxSats--;
    if (maxSats == 0) maxSats = 1;
  }      
  else if (key == 'p'){
    if (showPole) showPole = false;
    else showPole = true;
  }    
  else if (key == ' '){
    if (paused) paused = false;
    else paused = true;
  }  
 
  else if (key == 'm'){
    mode++;
    if (mode == 3) mode = 0;
  }  
    
    else if (key == 't'){
    if (trailfades) trailfades = false;
    else trailfades = true;
  }   
    
  if (which != null){
  //prograde
  if (key == 'w'){
    thrust += power;
    
    Tuple forward = new Tuple(which.dx,which.dy,which.dz);
    forward.normalize();
    forward.times(power);
    
    which.dx += forward.x;
    which.dy += forward.y;
    which.dz += forward.z;
  }
  if (key == 's'){
    
    thrust += power;
    Tuple forward = new Tuple(which.dx,which.dy,which.dz);
    forward.normalize();
    forward.times(-power);  
    
    which.dx += forward.x;
    which.dy += forward.y;
    which.dz += forward.z;
  }
  
  //steer left
  if (key == 'a' || key == 'd'){
    if (camMode == 4 || camMode == 5){
      Tuple up;
      if (camMode == 4){
        up = new Tuple(0,1,0);
      }
      else{
        up = new Tuple(1,0,0);
      }
      Tuple forward = new Tuple(which.dx,which.dy,which.dz);
      Tuple right = forward.cross(up);
      right.normalize();
      
      thrust += power;
      
      if (key == 'a'){
        right.times(power);
      }
      else{
        right.times(-power);
      }
      which.dx += right.x;
      which.dy += right.y;
      which.dz += right.z;
    }
    else{
    //need to create an orthonormal basis
    Tuple down;
    down = new Tuple(-which.x,-which.y,-which.z);
    
    down.normalize();
    
    Tuple right = down.cross(new Tuple(which.dx,which.dy,which.dz));
    right.normalize();
    thrust += power;
    
    if (key == 'a'){
      right.times(power);
    }
    else{
      right.times(-power);
    }
    
    which.dx += right.x;
    which.dy += right.y;
    which.dz += right.z;
    }
  }
  
  //up/down
  if (key == '2' || key == 'x'){
    Tuple toSat = new Tuple(which.x,which.y,which.z);
    toSat.normalize();
    toSat.times(power);
    
        thrust += power;
    if (key == 'x'){
      which.dx -= toSat.x;
      which.dy -= toSat.y;
      which.dz -= toSat.z;
    }
    else{
      which.dx += toSat.x;
      which.dy += toSat.y;
      which.dz += toSat.z;
    }  
  }
  
 
  
  
  }
}
 
 
void mouseDragged(){
 
  if (mouseButton == RIGHT){
 
  dViewRotate =(mouseX-pmouseX)/50.f; 
  dViewDist = (mouseY - pmouseY);
 
  viewRotate += dViewRotate;
  viewDist += dViewDist;
  
  if (viewDist < 30){
    dViewDist = 0;
    viewDist  = 30;
  }
  }
}
 
 
class Tuple3{
  float x,y,z;
}
 
class Tuple{
  
  float x,y,z;
  public Tuple(float x, float y, float z){
    this.x = x;
    this.y = y;
    this.z = z; 
  }
  
  Tuple cross(Tuple other){
  
    return new Tuple(y*other.z - z*other.y,z*other.x - x*other.z,x*other.y-y*other.x);
  
  }
  
  void normalize(){
      float dist = sqrt(x*x + y*y + z*z);
      x /= dist;
      y /=dist;
      z /=dist;
  
  }
  void times(float t){
    x *=t;
    y *=t;
    z*=t;
  
  }
 
}