ProcessingでLifeGameをScala実装

LifeGame.scala

import processing.core.PApplet
import processing.core.PConstants._

class App extends PApplet {
  private[this] val CELL_SIZE = 10
  private[this] val W = 102
  private[this] val H = 76
  private[this] val arr = new Array[Boolean](W * H)
  private[this] val tmp_arr = new Array[Boolean](W * H)

  override def settings(): Unit = {
    size(W * CELL_SIZE, H * CELL_SIZE, JAVA2D)
  }

  override def setup(): Unit = {
    //frameRate(10)
    fill(60)
  }

  override def mousePressed(): Unit = {
    for (x <- 0 to W * H - 1) {
      arr(x) = if (random(1.0f) < 0.5f) {
        true
      } else {
        false
      }
    }
  }

  override def draw(): Unit = {
    background(200)
    write_lines()
    update_cells()
    write_cells()
  }

  private[this] def write_lines() = {
    for (x <- 0 to W * CELL_SIZE by CELL_SIZE) line(x, 0, x, height)
    for (y <- 0 to H * CELL_SIZE by CELL_SIZE) line(0, y, width, y)
  }

  private[this] def update_cells(): Unit = {
    for (i <- 0 to W * H - 1) {
      var c = 0
      // 左側
      if (i % W > 0 && arr(i - 1)) {
        c += 1
      }

      // 右側
      if (i % W != W - 1 && arr(i + 1)) {
        c += 1
      }

      // 上、右上、左上
      if (i / W > 0) {
        if (arr(i - W)) c += 1
        if (i % W != W - 1 && arr(i + 1 - W)) c += 1
        if (i % W > 0 && arr(i - 1 - W)) c += 1
      }

      // 下、左下、右下
      if (i / W < H - 1) {
        if (arr(i + W)) c += 1
        if (i % W != W - 1 && arr(i + 1 + W)) c += 1
        if (i % W > 0 && arr(i - 1 + W)) c += 1
      }

      // 生存判定
      if (arr(i) && (c == 2 || c == 3)) {
        tmp_arr(i) = true
      } else if (arr(i)) {
        tmp_arr(i) = false
      } else if (c == 3) {
        tmp_arr(i) = true
      } else {
        tmp_arr(i) = false
      }
    }

    tmp_arr.copyToArray(arr)
  }

  private[this] def write_cells(): Unit = {
    for (i <- 0 to W * H - 1) {
      val y = i / W
      val x = i % W
      if (arr(i)) {
        rect(x * CELL_SIZE, y * CELL_SIZE, CELL_SIZE, CELL_SIZE)
      }
    }
  }
}