Gosu examples: available keys?

[rubyFeedback]

Hey guys,

I am currently SLOWLY (really slowly) ... learning Gosu.

I know a lot of ruby; also a lot of ruby-gtk.

I am also reading other people's old Gosu code. :D
(I work so much faster with working examples that I can tweak).

Anyway - I am currently studying and modifying an old tetris game
written in gosu from 2012 (almost 10 years old!).

There is a lot of code checks like:

if button_down?(Gosu::KbSpace)
if button_down?(Gosu::KbEscape)

I assume these are keys gosu registered. I am sure I can look
up somewhere too BUT! Being a very lazy person, I was
wondering whether the examples/ directory could simply
have a tiny widget that outputs the name of the keys when
pressed?

That way gosu-users can quickly find out on their own,
without even having to read online documentation. I am
sure I'll find out in a few hours from now on anyway (that
happened to me with ruby-gtk; I found solutions accidentally
heheh), but before I forget it, I wanted to suggest to
add such a small .rb file as an example.

Really simple!

Something that, in pseudo code, says:

"if user hits the escape-key, output the name of the constant on the commandline".

[rubyFeedback]

Hmm found it already.

Via google though. :D

https://www.rubydoc.info/gems/minigl/2.0.4/MiniGL/KB

Perhaps I will contribute my own implementation here some time later;
right now I am fixing the old example code here:

https://www.gamedev.net/blogs/entry/2254256-tetris-in-ruby/

By the way, perhaps we could have a meta-gem for gosu-games
that is also available on rubygems.org where multiple folks
are authors. As it is, we tend to lose old code like this eventually. :(

People move on a lot, due to reallife and stuff. But for new generation
of ruby users it is VERY helpful to have code that still works!

[mblumtritt]

I use this

require 'gosu'

module Gosu
  module Button
    NAME_MAP =
      constants
        .each_with_object({}.compare_by_identity) do |name, ret|
          ret[Button.const_get(name)] = name
        end
        .freeze

    def self.name(button_id)
      NAME_MAP[button_id] || button_id.to_s
    end
  end
end

With this you can call Gosu::Button.name(button_id) :)

[jlnr]

Iterating through constants is a good approach 👍
By the way, both of you are using "kind of deprecated" names for the buttons. Gosu::Button::KbSpace is now Gosu::KB_SPACE for brevity, and to match the more popular SCREAMING_SNAKE_CASE convention for constants. I don't think the old names will go away anytime soon, though. It's hard to deprecate constants in Ruby without potentially breaking code that uses include Gosu.

[mblumtritt]

Mmmm - I prefer to have such "magic constants" in a separate module - it works like a namespace and allows something like the code above.

Ruby Module#deprecate_constant is a good helper to pushing developers a little bit ;)

[jlnr]

Ooohh, thanks for the pointer! Looks like it has been introduced in Ruby 2.4, which is safe to use in Gosu now.

[jlnr]

By the way, you can work around the lack of a namespace in the global Gosu module by grepping for /KB_|MS_|GP_/, but I realize that it isn't quite as pretty.

[jlnr]

@mblumtritt Resurrecting this issue because I just got a chance to play around with Module#deprecate_constant. Does it work for you? It has almost no documentation and doesn't emit anything in quick tests. Maybe I'm doing it wrong? (Haven't checked out the C source code yet.)

[cyberarm]

module Gosu
  KB_SPACE = 0
  KbSpace = KB_SPACE
  
  deprecate_constant :KbSpace
end

puts Gosu::KbSpace, Gosu::KB_SPACE

I just ran this and also didn't get any warning. I added the -w flag, ruby -w deprecate_constant_test.rb, and it displayed.

PS C:\Users\cyber\Code> ruby -w .\deprecate_constant_test.rb
./deprecate_constant_test.rb:8: warning: constant Gosu::KbSpace is deprecated
0
0

[jlnr]

Oooohh, I forgot about -w 🤦‍♂️ Well, it's almost useless then, but I'll start using it regardless. Our own const deprecation mechanism still has the issue that include Gosu breaks it.

Edit: Also, thanks!

[mblumtritt]

Hint https://github.com/mblumtritt/deprecations :)

[jlnr]

@mblumtritt Thanks, but unlike in a "normal" Ruby project I'm trying my best to avoid dependencies, mostly because I've been burned by all the sketchy deployment processes that are in use for Ruby/Gosu games.