/* puff
Ira Greenberg, October 22, 2005 */
// for puff head
float headX;
float headY;
float speedX = .7;
float speedY = .9;
// for puff body
int cells = 100;
float[]px= new float[cells];
float[]py= new float[cells];
float[]radiiX = new float[cells];
float[]radiiY = new float[cells];
float[]angle = new float[cells];
float[]frequency = new float[cells];
float[]cellRadius = new float[cells];



void setup(){
 
size(400,400);
// begin in the center
headX = width/2;
headY = height/2;
//fill body arrays
for (int i=0; i< cells; i++){
radiiX[i] = random(-7,7);
radiiY[i] = random(-4,15);
frequency[i]= random(-9, 9);
cellRadius[i] = random(1, 100);
}
frameRate(30);
}


  
void draw(){
  
  
  b = loadImage("fondo_fade.png");
image(b, 0, 0);


//background(#FF006F);
//fill (#FF0842,20);
//rect (0,0,width,height);





noStroke();
smooth();
fill(255, 255, 255);
//follow the leader
for (int i =0; i< cells; i++){
if (i==0){
px[i] = headX+sin(radians(angle[i]))*radiiX[i];
py[i] = headY+cos(radians(angle[i]))*radiiY[i];
}
else{
px[i] = px[i-1]+cos(radians(angle[i]))*radiiX[i];
py[i] = py[i-1]+sin(radians(angle[i]))*radiiY[i];
//check collision of body
if (px[i] >= width-cellRadius[i]/2 || px[i] <= cellRadius[i]/2){
radiiX[i]*=-1;
cellRadius[i] = random(1, 40);
frequency[i]= random(-3, 13);
}
if (py[i] >= height-cellRadius[i]/2 || py[i] <= cellRadius[i]/2){
radiiY[i]*=-1;
cellRadius[i] = random(1, 40);
frequency[i]= random(-9, 9);
}
}
// draw puff
ellipse(px[i], py[i], cellRadius[i], cellRadius[i]);
// set speed of body
angle[i]+=frequency[i];
}
// set velocity of head
headX+=speedX;
headY+=speedY;
//check boundary collision of head
if (headX >= width-cellRadius[0]/2 || headX <=cellRadius[0]/2){
speedX*=-1;
}
if (headY >= height-cellRadius[0]/2 || headY <= cellRadius[0]/2){
speedY*=-1;
}
}  

PImage b;
void setup(){
 ...
 b = loadImage("fondo_fade.png");
 ...
}
  
void draw(){
 image(b, 0, 0); 
 ...
}