Slit camera simulation in Processing

slitcamera.pde

// just fire it up and dance slow in front of the camera...

import processing.video.*;
Capture device;

void setup() {
  size(640, 320);
  device = new Capture(this, width, height, 30);
  device.start(); 
}

int  dx      = 0;
int  sw      = 1;

void draw() {
  if (!device.available() || (dx > width)) return;
  device.read();
  int sx = (width / 2) - (sw / 2);
  copy(device, sx, 0, sw, height, dx, 0, sw, height);
  dx += sw;  
}