PImage danimage;
int index;

void setup() {
  size(400,400); //size of window
  noSmooth(); //no antialiasing on edges causes program to fun faster
  fill(0); //color of background
  danimage = loadImage("danimage.jpg"); //loads image in variable danimage
  danimage.loadPixels(); //loads pixel data from danimage variable into pixels[] array
}

void draw() {
  float rnd = random(400); //creates random variable from 0-400
  background(255,mouseX,mouseY); //background color controlled by user mouse control
  int mx = constrain (mouseX,0,danimage.width-1); //sets a constrained value into mx with a minimum and maximum limit to mouseX
  int offset = mx *danimage.width; //sets a value into offset
  beginShape(LINES); //beginShape allows creation of more complex forms, this time being lines
  for (int i = 0; i < danimage.width; i += 2){ //beginning of for loop for assigning values
    float r1 = blue(danimage.pixels[offset + i]); //reads pixel array data for blue color and adds to variable i which is used in below variable assignments
    float r2 = blue(danimage.pixels[offset + i + 1]); //same as top
    float tx = map(rnd,0,255,0,height); //x coordinate used in vertex below    
    float ty = map(r2,0,255,0,height);  //y coordinate
    float ux = map(0,255,0,r1,height);  //x coordinate 
    float uy = map(0,255,0,r2,height);  //y coordinate 
    float vx = map(255,r1,0,0,height);  //x coordinate
    float vy = map(255,r2,0,0,height);  //y coordinate
    vertex(tx,ty); //specifies vertex coordinates for LINES function called by the above beginShape
    vertex(ux,uy); //same as above
    vertex(vx,vy); //same as above
  }
  endShape(); //ends LINES
  color c = danimage.pixels[index]; //associates all pixel color values of danimage.pixels[] array in variable c
  float g = green(c) / rnd; //g is assigned all green values of c(see above for description of c)
  ellipse (mouseX, mouseY, mouseY,mouseX); //ellipse drawn with user mouse input
  index++; //adds 1 to index
  if (index == width*height) { //starts index loop to figure out if index equals screen area
      index = 0; //resets index value
  }
}