some references:

previous work:

one big particle is attached with many others in a “random” position around the big one….to get different ratios i distributed the position using a sinusoidal function to variate the ratio in some range.
The little particles also are attached between them with a spring that is not drawn in the sketch with lines, like the springs that are connecting the big particle with the little ones.
For the character, the little particles take a random range for the ratio, between 1 and 20….and for the head between 1 and 3. The body is formed by 2 big particles connected by a spring very short, that’s why they never separate each other too much.

code:

// Marcela Godoy
// The Nature of Code // midterm project spring 2012
// Based on “Simple two particles and spring example” by D. Shiffman
import netscape.javascript.*;
import toxi.physics2d.*;
import toxi.physics2d.behaviors.*;
import toxi.geom.*;

// Reference to physics world
VerletPhysics2D physics;

ArrayList
allParticles;
ArrayList
allFace;

ArrayList allSprings;
ArrayList allConnections;

Particle n1; //nucleo
Particle n2; //nucleo
int particles_number= 60;
float angle=radians(random(360));
float u = radians(360/particles_number);
float v;
PImage b;

void setup() {
size(400, 400);
smooth();
frameRate(30);
b = loadImage(“c.png”);

allParticles = new ArrayList
();
allFace = new ArrayList
();
allSprings = new ArrayList();
allConnections = new ArrayList();

// Initialize the physics
physics=new VerletPhysics2D();
physics.addBehavior(new GravityBehavior(new Vec2D(0, 0.09)));

// This is the center of the world
Vec2D center = new Vec2D(width/2, height/2);
// these are the worlds dimensions (50%, a vector pointing out from the center in both directions)
Vec2D extent = new Vec2D(width/2, height/2);

// Set the world’s bounding box
physics.setWorldBounds(Rect.fromCenterExtent(center, extent));

fill(0, 100);
noStroke();
float x = random(width);
float y = 0;

n1 = new Particle(x,y);
n1.r = 150;
n1.opacity=0;

//physics.addBehavior(new AttractionBehavior(n1, width, 0.1));

n2 = new Particle(random(width),random(height));

VerletSpring2D spring_n = new VerletSpring2D(n2, n1, 40, 0.1);
physics.addSpring(spring_n);

//////////////////////////physics.addParticle(n1);

for (int i= 0; i< particles_number; i++) {

v = 100+5*sin(u*i*(particles_number/2.5));
Particle p = new Particle(x + v * cos(angle + i*u), y + v * sin(angle + i*u)); //arrange different ratios in a sinusoidal way
physics.addParticle(p);
allParticles.add(p);

// add a spring between n1 and every p

VerletSpring2D spring = new VerletSpring2D(n1, allParticles.get(i), v-20, 0.01);
physics.addSpring(spring);
allSprings.add(spring);

// add a spring between p’s

VerletParticle2D pi = (VerletParticle2D) allParticles.get(i);
for (int j = 0; j < i; j++) {
VerletParticle2D pj = (VerletParticle2D) allParticles.get(j);
VerletSpring2D connection = new VerletSpring2D(pi, pj, 100, 0.00001);
physics.addSpring(connection);
allConnections.add(connection);
}

}//////////////////////////physics.addParticle(n1);

//////////////////////////physics.addParticle(n2);

for (int i= 0; i< 150; i++) {

v = 90+5*sin(u*i*(particles_number/5.5));
Particle p = new Particle(x + v * cos(angle + i*u), y + v * sin(angle + i*u)); //arrange different ratios in a sinusoidal way
physics.addParticle(p);
allFace.add(p);
p.r=random(1,3);

// add a spring between n1 and every p

VerletSpring2D spring2 = new VerletSpring2D(n2, allFace.get(i), v-20, 0.01);
physics.addSpring(spring2);
allSprings.add(spring2);

// add a spring between p’s

VerletParticle2D pi = (VerletParticle2D) allFace.get(i);
for (int j = 0; j < i; j++) {
VerletParticle2D pj = (VerletParticle2D) allFace.get(j);
VerletSpring2D connection2 = new VerletSpring2D(pi, pj, 100, 0.00001);
physics.addSpring(connection2);
allConnections.add(connection2);
}

}//////////////////////////physics.addParticle(n2);

//n1.lock();

}

void draw() {

// Update the physics world
physics.update();

background(255);
float angle2 = u;

for (Particle p : allParticles) {
p.display();
stroke(0,40);
line(n1.x, n1.y, p.x, p.y);
}

for (Particle p : allFace) {
p.display();
stroke(0,40);
line(n2.x, n2.y, p.x, p.y);
}

n1.display();
n2.displayFace();

float distance = dist(n2.x, n2.y, mouseX, mouseY);
if(distance < 100){
n2.lock();
n2.x = mouseX;
n2.y = mouseY;
n2.unlock();

}

}

class Particle extends VerletParticle2D {

float r = random(1,20);
float opacity = 0;

Particle(float x, float y) {
super(x,y);
}

// All we’re doing really is adding a display() function to a VerletParticle
void display() {
fill(0 + opacity);
noStroke();
ellipse(x,y,r,r);

}

void displayFace() {
imageMode(CENTER);
image(b, x,y, 120, 120);

}

}

Filed under nature of code.