Fibonacci Cap

float R = 277;

float rotationX = 0;

float rotationY = 0;

float velocityX = 0;

float velocityY = 0;

float pushBack = 0;

​

float ga = (3 - sqrt(5)) * PI; 

​

int kMaxPoints = 100000;

int nbrPoints = 2000;

float capHeight = 0.75; 

float heightChanged = false;

​

// To add: Give each point a heading and velocity, adjust based on distance/heading to nearby points.

class SpherePoint {

  float  lat,lon;

  SpherePoint(float lat, float lon)

  {

    this.lat = lat;

    this.lon = lon;

  }

};

SpherePoint[] pts = new SpherePoint[kMaxPoints];

void initSphere()

{

  int usePts = (capHeight/2.0) * min(nbrPoints,pts.length);

  for (int i = 1; i <= usePts; ++i) {

    float lon = ga*i;

    lon /= 2*PI; lon -= floor(lon); lon *= 2*PI;

    if (lon > PI)  lon -= 2*PI;

    // Convert dome height (which is proportional to surface area) to latitude

    float lat = asin(1 - 2*i/(float)nbrPoints);

    pts[i] = new SpherePoint(lat, lon);

  }

}

void setup()

{

  // size(1024, 768, P3D); 

  size(600, 600, P3D); 

  R = .8 * height/2;

  initSphere();

  colorMode(HSB, 1);

  background(0);

}

void draw()

{   

  if(heightChanged)

  {

    initSphere();

    heightChanged = false;

  }

  background(0);           

  smooth();

  renderGlobe();

  rotationX += velocityX;

  rotationY += velocityY;

  velocityX *= 0.95;

  velocityY *= 0.95;

  // Implements mouse control (interaction will be inverse when sphere is  upside down)

  if(mousePressed){

    velocityX += (mouseY-pmouseY) * 0.01;

    velocityY -= (mouseX-pmouseX) * 0.01;

  }

}

void renderGlobe()

{

  pushMatrix();

  translate(width/2.0, height/2.0, pushBack);

  float xRot = radians(-rotationX);

  float yRot = radians(270 - rotationY - millis()*.01);

  rotateX( xRot ); 

  rotateY( yRot );

  strokeWeight(3);

  float elapsed = millis()*.001;

  float secs = floor(elapsed);

  float usePts = (capHeight/2.0) * min(nbrPoints,pts.length);

  for (int i = 1; i <= usePts; ++i)

  {

      float lat = pts[i].lat;

      float lon = pts[i].lon;

      pushMatrix();

      rotateY( lon);

      rotateZ( -lat);

      float lum = (cos(pts[i].lon+PI*.33+yRot)+1)/2;

      stroke(.5,.5*lum,.2+lum*.8);

      point(R,0,0);

      popMatrix();

  }

  popMatrix();

}

​

void keyPressed() 

{

  if (keyCode == UP) 

  {

    capHeight -= 0.1;

  }

  else if (keyCode == DOWN)

  {

    capHeight += 0.1; 

  }

  capHeight = min(capHeight, 2.0);

  capHeight = max(capHeight, 0.1);

  heightChanged = true;

}