8. November 2010

This ornament with a spiral-like motive is animated. It fades in and out continually to conserve the symmetry.

void setup()
{
  size(600,600);      // def. fenstergroesse
  noFill();
  smooth();           // aktiviere antialiasing
  strokeWeight(1);    // linienbreite
}

void draw()
{
  background(255);    // def. hintergrundfarbe
  boolean select=false;
  float rot = 0;
  for(int x = 0; x <= width; x+=134)
  {
    for(int y = 0; y <= height; y+=124)
    {
      pushMatrix();
      translate(x,y);
      scale(0.5);
      rotate(PI/(rot+=1)%4);
      figure(select, random(255.0));
      popMatrix();
    }
  }
}

void keyPressed()
{
  switch(key)
  {
  case 's':
    save("screenShot.jpg");
    println("save the screen to screenShot.jpg");
    break;
  }
}


//funktion
void figure(boolean select, float al) {
  
  float r = 0;  //radius

  boolean flag=true; //fade-in/fade-out
  
  for(float theta=0; theta<50.0; theta+=0.01){  //incement angle
    stroke(0, 0, 0, al);
    r=theta*5.0;  //increase radius
    
    // Polar to Cartesian conversion
    float x = r * cos(theta);
    float y = r * sin(theta);
    
    if(select)
      ellipse(x, y, 16, 16);  
    else
       point(x,y);
       
    if(al >= 255.0)  //alpha = 255
      flag = true;
    if(al <= 0.0)  //alpha = 0
      flag = false;
    
    if(flag)  //if alpha = 255, then reduce alpha
      al-=0.1;
    else      //if alpha = 0, then augment alpha
      al+=0.1;
     
  }
}