BGraphics g2;
int bufID;
int blendF;
float scl,iscl;

void setup() {
  size(400,1680);
  scl=width/400.0;
  iscl=400.0/width;
  background(255);
  g2=new BGraphics(width,height);
  g2.background(255);
}

void loop() {
  if (blendF>128) {
    blendF=0;
    float x=width*0.5;
    float nx=random(4096);
    float ny=random(4096);
    float ns=random(0.5,1)*0.01;
    float maxX=random(1,5);
    float maxW=random(5,30);
    g2.beginShape(LINE_STRIP);
    for(int y=0;y<height; y++) {
      float w=noise((ny+y)*ns)*maxW*min(y*0.005,1)*scl;
      float xoff=noise((nx+y)*ns);
      x+=(xoff-0.5)*maxX*min(y*0.005,1);
      g2.stroke(255,220,220,10);
      g2.vertex(x-w*2,y);
      g2.stroke(x*iscl);
      g2.vertex(x-w,y);
      g2.stroke(0);
      g2.vertex(x+w,y);
      g2.stroke(255,220,220,10);
      g2.vertex(x+w*2,y);
    }
    g2.endShape();
  } else {
    setAlpha(g2,blendF);
    blend(g2,0,0,width,height,0,0,width,height,BLEND);
    blendF+=8;
  }
  if (mousePressed) g2.background(255);
}

void setAlpha(BImage img, int alpha) {
  alpha<<=24;
  for(int i=0; i<img.pixels.length; i++)
  img.pixels[i]=img.pixels[i] & 0xffffff | alpha;
}