I used my favorite language of all time, Ruby. With 1.9 Ruby has picked up speed and with Ocra you easily make a ~1-2 meg exe-file out of it. Also the excellent (and german precision engineered)  Gosu enables OpenGL accelerated 2D. On top of that I used my own Ruby/Gosu-specific framework Chingu to get game states, re-usable game logic and a boiler plate “game object”. To get a speedy get_pixel() I used the awesome Texplay by John Mair.

I have a pixel fetish. I love retro-looks in games, and I love pixel-perfect-collisions, a fetish that probably came into existence playing hours and hours of Lemmings 2-player mode on the classic Amiga 500.

So, the most time was spent up building a good pixel-perfect-collision algo, and it came out very playable, but not perfect. I ranted about it in my last blogpost.

With Ruby and Chingu my level-building got very clean, I think even ppl not into Ruby could understand what’s happening here:

class Level7 < Level
   def setup
     self.background = "level7.bmp"
     every(1000) { Enemy.create(:image => "acid_drop.bmp", x => 150, :velocity_y => 5) }
 every(1500) { Enemy.create(:image => "acid_drop.bmp", x => 250, :velocity_y => 5) }
   end
 end

or here (this is from the mainloop):

player.each_collision(Enemy) do |player, enemy|
 unless player.paused?
 player.pause!
 Sound["die.wav"].play(0.3)
 after(1000) {  player.x = @entry_x; player.y = @entry_y; player.unpause!; }
 end
 end

It’s nice when it’s silly simple building readable levels.

I also got a very basic and simple Map-class going so I could build on my matrix of screens that made up the game:

map = [
 [LevelUp, nil, nil, nil],
 [Level1, Level2,Level22, nil],
 [LevelAir, nil, Level3, nil],
 [LevelAir2, Level5, Level4, nil],
 [nil, Level6, Level7, nil],
 [nil, Level8, Level9, End],
 ]

Basically if you exited a screen to the right I would increment a column_counter and fetch a new screen from the matrix. If exiting downwards, increment row_counter an fetch a new screen.

If you like OO, short readable code and scripting languages in general and haven’t checked out Ruby or Gosu yet, now is the time to do it.