let panel_size = 5

let cell_size

​

let path = []

let tracing = true

​

const Directions = {

  'UP': 0,

  'RIGHT': 1,

  'DOWN': 2,

  'LEFT': 3

}

​

function PathNode(row, col, entry = '', exit = '') {

  this.row = row

  this.col = col

  this.entry = entry

  this.exit = exit

}

​

function setup() {

  createCanvas(600, 600);

  cell_size = panel_size_px / panel_size

  path.push(new PathNode(0, 0))

}

​

function drawPanel(x_offset, y_offset) {

  drawNodes(x_offset, y_offset)

  drawPath(path, x_offset, y_offset)

}

​

function drawNodes(x_offset, y_offset) {

  forCellInPanel(panel_size, (row, col) => {

    let x = col * cell_size + x_offset

    let y = row * cell_size + y_offset

    ellipse(x, y, cell_size/4)

  })

}

​

function drawPath(path, x_offset, y_offset) {

  updatePath(path, x_offset, y_offset)

  for (let path_index = 0; path_index < path.length - 1; path_index++) {

    let start_row = path[path_index + 0].row

    let start_col = path[path_index + 0].col

    let end_row = path[path_index + 1].row

    let end_col = path[path_index + 1].col

    let s_y = start_row * cell_size + y_offset

    let s_x = start_col * cell_size + x_offset

    let e_y = end_row * cell_size + y_offset

    let e_x = end_col * cell_size + x_offset

    line(s_x, s_y, e_x, e_y)

​

  }

}

​

function updatePath(path, x_offset, y_offset) {

  if (tracing) {

    const last_node = path[path.length -1] 

    if (last_node) {

      let x = last_node.col * cell_size  + x_offset

      let y = last_node.row * cell_size  + y_offset

      let dx = mouseX - x

      let dy = mouseY - y

      let new_dir

      // More up

      if (dy < 0) {

        if (Math.abs(dx) > Math.abs(dy)) {

          if (dx < 0) {

            new_dir = Directions.LEFT

          }

          else {

            new_dir = Directions.RIGHT

          }

        }

        else

          new_dir = Directions.UP

      }

      // More down

      else {

        if (Math.abs(dx) > Math.abs(dy)) {

          if (dx < 0) {

            new_dir = Directions.LEFT

          }

          else {

            new_dir = Directions.RIGHT

          }

        }

        else

          new_dir = Directions.DOWN

      }

      console.log(new_dir)

    }

  }

}

​

function draw() {

  background(220);

  drawPanel(cell_size/2, cell_size/2)

}

​

​

function forCellInPanel(panel_size, callback) {

  for (let row = 0; row < panel_size; row++) {

    for (let col = 0; col < panel_size; col++) {

      callback(row, col)

    }

  }

}

​