Processing slitscan

slitscan.pde

import processing.video.*;
MovieMaker movie;

boolean rec;
int n;
int varZero;
int prevN;
int prevZero;
int numPixels;
int prevPixels;
int[] prevLines;
Capture video;

void setup() {
  size(640, 480);
  frameRate = 30;
  video = new Capture(this, width, height, 72);
  numPixels = video.width * video.height;
  //Sets the number of pixels to be stored using
  //an algebric progression formula related
  //to the number of lines to be stored.
  prevPixels = ((numPixels*(height+1))/2); 
  //Sets the array to store these pixels.
  prevLines = new int[prevPixels];
  movie = new MovieMaker(this, width, height, "slitscan.mov", 
  72, MovieMaker.ANIMATION, MovieMaker.LOSSLESS);
  //Sets the movie recording function off by default.
  rec=false;
  loadPixels();
  noStroke();
}


void draw() {
  if (video.available()) {
    video.read();
    video.loadPixels();
    //For each line of the image:
    for (int y=1; y<height; y++) {
      //Declares the value of 'n', which will be used to index
      //to which of the "lines" stored for line 'y' shall the software
      //access to store current frame's line 'y'.
      n=(frameCount%y);
      //Indexes to the begining of the "line" in which to store
      //the current frame's line 'y' using an algebric progression
      //formula based on 'y' var and the indexing gave by 'n' var.
      varZero= round((n*width)+(((sq(y)+y)*width)/2));
      //Declares the value of 'prevN'. This var will
      //index to stored "line" the software shall
      //read to display at current frame's line 'y'.
      prevN=((frameCount-(y-1))%y);
      //Indexes to the begining of the "line" that the software
      //shall read to display currently at line 'y'. Uses the
      //same process of varZero expression, but with other vars.
      prevZero=round((prevN*width) +(((sq(y)+y)*width)/2));
      //For each pixel in line 'y':
      for (int i=1; i<width; i++) {
        //Declares a 'ind' var based on 'y' and 'i'
        //to index the displayed pixels.
        int ind=((y*width)+i);
        //Stores each pixel of line 'y' of current frame
        //captured from real-time video.
        prevLines[varZero+i]= video.pixels[ind];
        //Reads and displays the proper line of pixels from
        //the data stored.
        pixels[ind]=prevLines[prevZero+i];
      }
    }
    updatePixels();
    if (rec==true) {
      movie.addFrame();
    }
  }
}

void keyPressed () {
  //If SPACE key is pressed and recording is off, turn it on.
  if (key==' ' && rec==false) {
    rec=true;
    println("REC");
  }
  //If SPACE key is pressed and recording is on, turn it off.
  else if (key==' ' && rec==true) {
    rec=false;
    println("PAUSE");
  }
  //If ESCAPE key is pressed, finish movie.
  else if (key==ESC) {
    movie.finish();
    println("STOP");
  }
}