int position;
Sperm s[];
int num;
float newTime,oldTime,diffTime;
float toggle;
float moveX, moveY;
Vec2D mouseMoved;


void setup() {
  size(500,500);
  background (240,170,216);
  smooth();
  position=0;
  num = 50;
  oldTime=0;
  newTime=0;
  toggle=1;
  mouseMoved = new Vec2D(0,1);

  s = new Sperm[num];
  for (int i=0; i<num; i++) s[i] = new Sperm(random(width),random(height));
}

void loop()  {
  background (240,170,216);
// Update the current time.
  newTime=millis();
  if (position==10) position=0;
  if (toggle==1) {
    moveX = mouseMoved.x/15;
    moveY = mouseMoved.y/15;
    for (int i=0; i<num; i++) { 
      s[i].drawSperm(); 
      s[i].moveSperm(moveX,moveY); 
    }
  }
  position++;
}


void mousePressed() {
  oldTime=newTime;
  toggle=0;
  mouseMoved.set(mouseX,mouseY);
}

void mouseReleased() {
    diffTime=newTime-oldTime;
    num = (int)(diffTime/25);
    s = new Sperm[num];
    for (int i=0; i<num; i++) s[i] = new Sperm(random(width),random(height));
    toggle=1;
    mouseMoved.sub(mouseX,mouseY);
}



class Sperm {
Vec2D pos;

  Sperm (float _x, float _y){
    pos = new Vec2D();
    pos.set(_x,_y);
  }

  void drawSperm() {
    noStroke();
   fill(255,255,255,150);
   push();
   translate (pos.x,pos.y);
   rotate(mouseMoved.angle()-radians(90));
   ellipse(0,0,12,30);
    stroke(255);

    if (position==0) curve(6,30,3,36,9,44,6,50); 
    if (position==1) curve(6,30,4,36,8,44,6,50);
    if (position==2) curve(6,30,5,36,7,44,6,50);
    if (position==3) curve(6,30,7,36,5,44,6,50);
    if (position==4) curve(6,30,8,36,4,44,6,50);
    if (position==5) curve(6,30,9,36,3,44,6,50);
    if (position==6) curve(6,30,8,36,4,44,6,50);
    if (position==7) curve(6,30,7,36,5,44,6,50);
    if (position==8) curve(6,30,5,36,7,44,6,50);
    if (position==9) curve(6,30,4,36,8,44,6,50);
    pop();
  }
  
  void moveSperm(float _x, float _y) {
    pos.sub(_x,_y);
    if (pos.x > width) pos.x = 0;
    else if (pos.x < 0) pos.x = width;
    if (pos.y > height) pos.y = 0;
    else if (pos.y < 0) pos.y = height;
  }

}

// General vector class for 2D vectors
class Vec2D {
  float x,y;

// Constructor with no parameters
  Vec2D() {
    x=0;
    y=0;
  }
  
  Vec2D(float _x,float _y) {
    x=_x;
    y=_y;
  }

  Vec2D(Vec2D v) {
    x=v.x;
    y=v.y;
  }

  void set(float _x,float _y) {
    x=_x;
    y=_y;
  }

  void set(Vec2D v) {
    x=v.x;
    y=v.y;
  }

  void add(float _x,float _y) {
    x+=_x;
    y+=_y;
  }

  void add(Vec2D v) {
    x+=v.x;
    y+=v.y;
  }

  void sub(float _x,float _y) {
    x-=_x;
    y-=_y;
  }

  void sub(Vec2D v) {
    x-=v.x;
    y-=v.y;
  }

  void mult(float m) {
    x*=m;
    y*=m;
  }

  void div(float m) {
    x/=m;
    y/=m;
  }

  float length() {
    return sqrt(x*x+y*y);
  }

  float angle() {
    return atan2(y,x);
  }

  void normalise() {
    float l=length();
    if(l!=0) {
      x/=l;
      y/=l;
    }
  }

  Vec2D tangent() {
    return new Vec2D(-y,x);
  }

  void rotate(float val) {
    // Due to float not being precise enough, double is used for the calculations
    double cosval=Math.cos(val);
    double sinval=Math.sin(val);
    double tmpx=x*cosval - y*sinval;
    double tmpy=x*sinval + y*cosval;

    x=(float)tmpx;
    y=(float)tmpy;
  }
}