first day of spring

//import gifAnimation.*;

import java.util.Iterator;

ArrayList<Part> parts;

float w = 500;

float h = 500;

PVector g = new PVector(0, .2);

​

float noiseoff=0;

//GifMaker gifExport;

color bgc = #212121;

color c1 = #61A523; 

color c2 = #C164B0;

float coloroff=random(255);

boolean record=false;

void setup() {

  size(500, 500);

  smooth();

  background(bgc);

  frameRate(25);

  parts = new ArrayList();

  //  gifExport = new GifMaker(this, "export.gif");

  //  gifExport.setRepeat(0);  

  //createParticles();

}

Part paint(float x, float y, float dx, float dy, float size, Part parent, boolean bymouse) {

  float tx = x;

  float ty = y;

​

  float t=15+random(20);

  //color c = lerpColor(c1, c2, random(1)); 

  coloroff++;

  if (coloroff>255) {

    coloroff=0;

  }

  colorMode(HSB);

  color c = color(coloroff, 155, 255); 

  Part p = new Part(tx, ty, size, c);

  if (!bymouse) {

    p.c=parent.c;

  }

​

  p.velocity.x=0;

  p.velocity.y=0;

  if (dy == 0 && dx == 0) {

     dx=random(1)-.5; 

     dy=random(1)-.5;

  }

  p.acceleration.x=dx;

  p.acceleration.y=dy; 

  p.or_a.x = dx;

  p.or_a.y = dy;

  p.par=parent;

  //  p.acceleration.mult(-.5);

  parts.add(p);

  return p;

}

int fr = 0;

Part lastp=null;

​

void draw() {

  noStroke();

  fill(bgc, 125);

  rectMode(CORNER);

  rect(0, 0, width, height);

  //background(bgc);

  if (record) {

​

    lastp=paint(mouseX, mouseY, (pmouseX-mouseX)*-.1, (pmouseY-mouseY)*-.1, random(9), lastp, true);

  }

  else {

    lastp=null;

  }

  updateParticles();

​

}

void mousePressed() {

  record=true;

}

void mouseReleased() {

  record=false;

}

​

//void updateParticles() {

//  if (parts.size()>0) {

//    Iterator<Part> it = parts.iterator();

//    while (it.hasNext ()) {

//      Part p = it.next();

//      p.update();

//      //p.render();

//      if (p.life<0) {

//        it.remove();

//      }

//      if (random(1)>.9) {

//        //      paint(p.position.x,p.position.y,random(5)-2,random(5)-2,random(5)-2);

//      }

//    }

//    for (Part p:parts) {

//

//      // p.update();

//      p.render();

//    }

//  }

//}

void rotate2D(PVector v, float theta) {

  float xTemp = v.x;

  v.x = v.x*cos(theta) - v.y*sin(theta);

  v.y = xTemp*sin(theta) + v.y*cos(theta);

}

​

void updateParticles() {

  if (parts.size()>0) {

    noiseoff+=.1;

    int s = parts.size()-1;

    //PVector prevpos = parts.get(parts.size()-1).position;

    for (int i = s; i >= 0; i--) {

      Part p = (Part) parts.get(i);      

      p.update();

​

      //      prevpos = p.position;

      //p.render();

      if (p.life<0) {

        parts.remove(p);

      }    

      if (p.life<.9 && p.spawned<25 && parts.size()<650 && p.life>.5) {

        p.spawned++;

        if (random(1)>.9) {

          //paint(p.position.x, p.position.y, random(10)-5, random(10)-5, random(5)-2, p);

          PVector dir = p.or_a;

          dir.normalize();

          rotate2D(dir, radians(random(45)-22.5));

          dir.mult(3);

          Part np = paint(p.position.x, p.position.y,dir.x, dir.y, p.size*.9, p, false);

          np.spawned=p.spawned;

        }

      }

      stroke(p.c, 5+p.life*255);

     // strokeWeight(noise(i+noiseoff)*3);

      //line(p.position.x, p.position.y, par.x, prevpos.y);

      if (p.par!=null) {

        line(p.position.x, p.position.y, p.par.position.x, p.par.position.y);

      }

      p.render();

    }

  }

}

void keyPressed() {

  if (key == 's') {

    saveFrame("images/screen_#####.png");

  }

​

  if (key == 'a') {

    background(bgc);

    parts = new ArrayList();

​

    //createParticles();

  }

}

class Part {

  Part par=null;

  float spawned = 0;

  float life = 1;

  float maxspeed=10;

  float r=random(360);

  // float g=1.8;

  PVector position = new PVector(0, 0);

  PVector velocity = new PVector(0, 0);

  PVector acceleration = new PVector(0, 0);

  PVector or_a = new PVector(0, 0);

  float size = 10;

  color c;

  float min_d = 5;

  Part nei = null;

​

  Part(float x, float y, float size, color c) {

    position.x=x;

    position.y=y;

    this.size = size;

    this.c=c;

  }

  void update() {

    life-=.01;

    /*for (Part p:parts) {

      if (p!=this) {        

        float d = PVector.dist(p.position, position);

        if (d<min_d*size) {

          //                    acceleration.add(PVector.sub(p.position, position));

          //                    acceleration.normalize();

          //                    acceleration.mult(-.06*p.size);

          pushMatrix();

          translate(position.x, position.y);

          //stroke(c, 110-d/min_d*100);

          stroke(c, 1+life*155);

          //line(p.position.x-position.x, p.position.y-position.y, 0, 0);

          popMatrix();

        }

      }

    }

*/

​

​

    velocity.add(acceleration);

​

    velocity.limit(15);

    // size=random(5);

    velocity.mult(.95);

    position.add(velocity);

​

    acceleration.mult(0);

  }

  void render() {    

    pushMatrix();

    translate(position.x, position.y);

    rotate(radians(r));

    //    r+=size;

    //stroke(c);

    //    line(-velocity.x, -velocity.y, 0, 0);

    //line(nei.position.x-position.x, nei.position.y-position.y, 0, 0);

    noStroke();

​

    fill(c, 5+life*255);

    //fill(c);

    rectMode(CENTER);

    rect(0, 0, size, size);

​

    //ellipse(0, 0, size*2, size*2);

    stroke(c, 3+life*255);

    noFill();

    //    ellipse(0, 0, size*5, size*5);

​

    popMatrix();

  }

  void applyForce(PVector force) {

    acceleration.add(force);

  }

}