// Daniel Shiffman
// http://codingtra.in
// http://patreon.com/codingtrain

// Game of Life
// Video: https://youtu.be/FWSR_7kZuYg


function World() 
{ 
    
    

function make2DArray(cols, rows) {
  let arr = new Array(cols);
  for (let i = 0; i < arr.length; i++) {
    arr[i] = new Array(rows);
  }
  return arr;
}


function countNeighbors(grid, x, y) {
  let sum = 0;
  for (let i = -1; i < 2; i++) {
    for (let j = -1; j < 2; j++) {
      let col = (x + i + cols) % cols;
      let row = (y + j + rows) % rows;
      sum += grid[col][row];
    }
  }
  sum -= grid[x][y];
  return sum;
}
		

let grid;
let cols;
let rows;
let resolution = 10;



	
	this.newRun = function()
	{
 		threeworld.init (  "black"  ); 
 		
 			
        cols = width / resolution;
        rows = height / resolution;
    
        grid = make2DArray(cols, rows);
        for (let i = 0; i < cols; i++) {
            for (let j = 0; j < rows; j++) {
                grid[i][j] = floor(random(2));
            }
        }
	};


	this.nextStep = function()		 
	{
		// Code to execute every step. 
		// Can put P5 instructions to be executed every step here, or in draw() 
		
		  background(0);

      for (let i = 0; i < cols; i++) {
        for (let j = 0; j < rows; j++) {
          let x = i * resolution;
          let y = j * resolution;
          if (grid[i][j] == 1) {
            fill(255);
            stroke(0);
            rect(x, y, resolution - 1, resolution - 1);
          }
        }
      }
    
      let next = make2DArray(cols, rows);
    
      // Compute next based on grid
      for (let i = 0; i < cols; i++) {
        for (let j = 0; j < rows; j++) {
          let state = grid[i][j];
          // Count live neighbors!
          let sum = 0;
          let neighbors = countNeighbors(grid, i, j);
    
          if (state === 0 && neighbors == 3) {
            next[i][j] = 1;
          } else if (state == 1 && (neighbors < 2 || neighbors > 3)) {
            next[i][j] = 0;
          } else {
            next[i][j] = state;
          }
    
        }
      }
    
      grid = next;
    

 	};


	this.endRun = function()
	{
	};

}


//---- setup -------------------------------------------------------
// Do NOT make a setup function.
// This is done for you in the API. The API setup just creates a canvas.
// Anything else you want to run at the start should go into the following two functions.





function beforesetup()      // Optional 
{
	// Anything you want to run at the start BEFORE the canvas is created 

}


function aftersetup()       // Optional
{
	// Anything you want to run at the start AFTER the canvas is created 
	
		
    
}


//---- draw -------------------------------------------------------

function draw()             // Optional
{
	// Can put P5 instructions to be executed every step here, or in World.nextStep()  

  

}