// the best snow ever. coolbubble

int numFlakes = 1300;
float horizontalSpeed = 15.0f;
float verticalSpeed = 2.5f;
float progression = 0.0f;
BImage backgroundImage;
float mouseXOld=0.0f;
float mouseDelta;
boolean toggleMotionBlur=false;
boolean mouseHeld=false;

class CFlake
{

CFlake() {x=0.0f;y=0.0f;z=0.0f;}
  float x,y,z;
}

CFlake [] flakes;

void setup()
{
  backgroundImage = loadImage("hills.jpg");
  size(backgroundImage.width,backgroundImage.height);
  flakes = new CFlake[numFlakes];

  for (int i=0;i<numFlakes;i++)
  {
    flakes[i]= new CFlake();
    flakes[i].x=random(1.0f)*width;
    flakes[i].y=random(1.0f)*height;
    flakes[i].z=/*1.0f-sq*/(random(1.0f));
  }
  noStroke();
  rectMode(CENTER_DIAMETER);
  framerate(20);

}

void loop()
{

  if (toggleMotionBlur)
  {
    tint(255, 255, 255, 126);
    image(backgroundImage, 0, 0);
  }
  else
  {
    background(backgroundImage);
  }

  if (mousePressed && mouseHeld==false)
  {
    mouseHeld=true;
    if (toggleMotionBlur) toggleMotionBlur=false;
    else toggleMotionBlur=true;
  }

  if (!mousePressed)
  {
    mouseHeld=false;
  }

  progression+=0.01f;

  if (abs(mouseX-mouseXOld)<150)
  mouseDelta = (mouseDelta*0.98f) + ((mouseX-mouseXOld)*0.02f);

  for (int i=0;i<numFlakes;i++)
  {
    float depth=flakes[i].z;

    // move.
    float spd = (noise((depth*3.0f)+progression+(flakes[i].y/height))-0.5f)*horizontalSpeed;
    flakes[i].x+=spd+(mouseDelta*1.8f);
    flakes[i].y+=((1.0f-depth)+0.1f)*verticalSpeed;
    flakes[i].y+=spd*0.1f;

    // handle wrapping.
    if (flakes[i].x<0) flakes[i].x+=width;
    if (flakes[i].x>width) flakes[i].x-=width;
    if (flakes[i].y<0) flakes[i].y+=height;
    if (flakes[i].y>height) flakes[i].y-=height;

    //if (depth<0.3f)
    fill(255,55+((1.0f-depth)*200));
    //else
    //fill(255);

    if (random(1.0f)<0.01f)
    fill(255);

    // draw.
    rect(flakes[i].x,flakes[i].y,1.0f+((1.0f-depth)*3.0f),1.0f+((1.0f-depth)*3.0f));
  }

  mouseXOld=mouseX;
}