// Gravity Demonstrator

Vector chunks;
Chunk chunk;
float yRot = 0;
float xRot = -PI/8.0;

void initAll() {
  chunks=new Vector();
  for (int i=0;i<250;i++) addChunk();
  xRot = -PI/8.0;
  yRot = 0;
}

void setup() {
  size(640,480,P3D);
  ellipseMode(CENTER_RADIUS);
  noStroke();
  fill(255);
  initAll();
}

void keyPressed() {
  if (key=='s') initAll();
  if (key=='d') for (int i=0;i<chunks.size();i++) ((Chunk)(chunks.elementAt(i))).drag(0.95);
  if (key=='t') for (int i=0;i<chunks.size();i++) ((Chunk)(chunks.elementAt(i))).setTraces(!((Chunk)(chunks.elementAt(i))).getTraces());
  if (key=='+') for (int i=0;i<chunks.size();i++) ((Chunk)(chunks.elementAt(i))).increaseMassFactor();
  if (key=='-') for (int i=0;i<chunks.size();i++) ((Chunk)(chunks.elementAt(i))).decreaseMassFactor();
}

void draw() {
  background(0);
  
  Vec averagePos=new Vec(0,0,0);
  for (int i=0;i<chunks.size();i++) {
    chunk=(Chunk)(chunks.elementAt(i));
    chunk.update(chunks);
    averagePos.add(chunk.position);
  }
  averagePos.div(float(chunks.size()));
  
  
  if (mousePressed) {
    xRot+=HALF_PI*(pmouseY-mouseY)/(float)height;
    if (xRot>PI/4.0) xRot=PI/4.0;
    if (xRot<-PI/4.0) xRot=-PI/4.0;
    yRot-=PI*(pmouseX-mouseX)/(float)width;
  }
  translate(width/2.0,height/2.0,-500);
  rotateX(xRot);
  rotateY(yRot);
  for (int i=0;i<chunks.size();i++) {
    chunk=(Chunk)(chunks.elementAt(i));
    chunk.position.sub(averagePos);
    chunk.toScreen(xRot,yRot);
  }
  
  //saveFrame("./../../temp/Orbit######.tga");
}

void addChunk() {
  chunk=new Chunk(width,height);
  chunk.trace();
  chunks.add(chunk);
}