//pract_exc_5_6_enhanced
//using logical operators to color one of four quadrants based on mouse position

//these are variable that color the quadrants
int a = 255; //top right quad
int b = 255; //top left quad
int c = 255; //bottom left quad
int d = 255; //bottom right quad

void setup() {
  size(200,200);
  background(255);
}


void draw() {
  
  rectMode(CORNER);
  stroke(0);
  line(width/2,0,width/2,height); //vertical line down center of window
  line(0,height/2,width,height/2); //horizontal line across center of window

//quadrant a - when the mouse moves over this area, fade into black, when the mouse leaves, fade into white
  if(mouseX > width/2 && mouseY < height/2){  
    a = a - 1; //get darker
    fill(a);
    rect(width/2,0,width/2,height/2);
  }
  else{
    a = a + 1; //get lighter 
    fill(a); 
    rect(width/2,0,width/2,height/2);
  }


//quadrant b  - when the mouse moves over this area, fade into black, when the mouse leaves, fade into white
  if(mouseX < width/2 && mouseY < height/2){ 
    b = b - 1; //get darker
    fill(b);
    rect(0,0,width/2,height/2);
  }
  else{
    b = b + 1; //get lighter
    fill(b); 
    rect(0,0,width/2,height/2);
  }

//quadrant c  - when the mouse moves over this area, fade into black, when the mouse leaves, fade into white
  if(mouseX < width/2 && mouseY > height/2){ 
    c = c - 1; //get darker
    fill(c);
    rect(0,height/2,width/2,height/2);
  }
  else{
    c = c + 1; //get lighter
    fill(c); 
    rect(0,height/2,width/2,height/2);
  }


//quadrant d  - when the mouse moves over this area, fade into black, when the mouse leaves, fade into white
  if(mouseX > width/2 && mouseY > height/2){ 
    d = d - 1; //get darker
    fill(d);
    rect(width/2,height/2,width/2,height/2);
  }
  else{
    d = d + 1; //get lighter
    fill(d); 
    rect(width/2,height/2,width/2,height/2);
  }
  
//constrain the darkenesss variables
  a = constrain(a,0,255);
  b = constrain(b,0,255);
  c = constrain(c,0,255);
  d = constrain(d,0,255);
  
}