README.md

Everyones got one (usually somewhere in the kitchen). Junk Drawer is a collection of tools & utils for developing games in the wonderful Janet Lang.

[sudo] jpm install https://github.com/AlecTroemel/junk-drawer

Contents:

• ecs: A sparse set based Entity Component System.
• directed graph: graph implementation with path finding function.
• vectors: common 2d vector functions.
• fsm: Finite(ish) State Machine (built off of directed graph).
• gamestate: Easy gamestate management (built off of directed graph).
• timers: Delayed & Scheduled functions (requires using ECS).
• messages: Communication between systems (requires using ECS).
• tweens: Some common tweening functions and a way to interpolate components with them (mostly requires ECS).
• envelopes: Multi stage tweens from the world of music (built off of directed graph and tweens).

Here's an obligitory example that uses most the stuff here.

(use junk-drawer)

(fsm/define
 colors
 (fsm/state :green)
 (fsm/transition :next :green :yellow)

 (fsm/state :yellow)
 (fsm/transition :next :yellow :red)

 (fsm/state :red)
 (fsm/transition :next :red :yellow))

(def-tag next-color)

(def-component-alias position vector/from-named)

(def-system colored-printer
  {color-fsms [:colors]}
  (each [c] color-fsms
    (printf "current color: %q" (c :current))))

(def-system colored-switcher
  {wld :world
   msgs [:message :next-color]
   color-fsms [:colors]}
  (when (> (length msgs) 0)
    (each [msg] msgs
      (each [c] color-fsms
        ((msg :content) c))
      (messages/consume msg))))

(def GS (gamestate/init))

(gamestate/def-state example
   :name "Example Gamestate"
   :world (create-world)
   :init (fn [self]
           (let [world (get self :world)]
             (add-entity world (colors :green)
                               (position :x 1 :y 2))
             (add-entity world (colors :red))
             (register-system world timers/update-sys)
             (register-system world messages/update-sys)
             (register-system world colored-printer)
             (register-system world colored-switcher)
             (timers/every world 4
                           (fn [wld dt]
                             (messages/send wld :next next-color)))
             (timers/after world 7
                           (fn [wld dt]
                             (messages/send wld :next next-color)))))
   :update (fn [self dt]
             (:update (self :world) dt)))

(:add-state GS example)
(:goto GS :example)

(for i 0 20
  (:update GS 1))

Each module, and most of the public functions, have detailed doc strings for your reading.

(doc junk-drawer)
(doc junk-drawer/ecs)
(doc junk-drawer/ecs/def-component)

If you're looking for more complete examples...check out the examples/ folder!