PImage aUp;  // up arrow
PImage aLft;  // left arrow
PImage aDwn;  // down arrow
PImage aRt;  // right arrow

//WHITE VERSIONS
PImage aUpW;  // up arrow
PImage aLftW;  // left arrow
PImage aDwnW;  // down arrow
PImage aRtW;  // right arrow

int _y;
int [] _chordCoords = new int[5];
PImage [] _images = new PImage[4];

PImage Up;
PImage Dwn;
PImage Lft;
PImage Rt;

void setup() {
  size(600, 600);
  background(0);
  frameRate(90);
  
  //inactive images
  aUp = loadImage("images/upArrow.GIF");
  aLft = loadImage("images/leftArrow.GIF");
  aDwn = loadImage("images/downArrow.GIF");
  aRt = loadImage("images/rightArrow.GIF");  
  
  //active images
  aUpW = loadImage("images/upArrowWhite.GIF");
  aLftW = loadImage("images/leftArrowWhite.GIF");
  aDwnW = loadImage("images/downArrowWhite.GIF");
  aRtW = loadImage("images/rightArrowWhite.GIF");  
  
  Up = aUp;
  Dwn = aDwn;
  Lft = aLft;
  Rt = aRt;
  
//  _y = 0;
  
  position(Up, 1);
  position(Lft, 2);
  position(Dwn, 3);
  position(Rt, 4);

}

void position(PImage buttonImage, int xPlacement){
   
  if(xPlacement <= 0 || xPlacement >= 5) {return;}
  else if(xPlacement == 1) {
   _chordCoords[1] = 0;
   _images[0] = buttonImage;
  }
  else if(xPlacement == 2) {
   _chordCoords[2] = width/4;
  _images[1] = buttonImage; 
  }
  else if(xPlacement == 3) {
   _chordCoords[3] = width/2; 
   _images[2] = buttonImage;
  }
  else {
   _chordCoords[4] = width-width/4; 
   _images[3] = buttonImage;
  }

//  image(buttonImage,xPos,_y,width/4,height/4);
}

void cycle(){
  if(_y<600) {_y++;}
    _chordCoords[0] = _y;

  background(0);

  for(int i=0; i<4; i++){
    image(_images[i],_chordCoords[i+1],_chordCoords[0],width/4,height/4);
  }

}

void draw(){
 cycle();
}