Code reuse best practices

Questions
#1

Hello! Are there any best practices on code reuse when building a game in Defold?
Assume that we have an enemy character. He has an attached script with something like statemachine code. I want to make another enemy character and he will have a little bit different states and a little bit different behaviour in equals states. But in the same time I can share a lot of code between them.
What is the preferred way to do it? Should I split a script into small functions and move them to a lua module? Or may be I should prefer some oop cases like inheritance? Thx

#2

It depends on project setup and how you prefer your workflow.

If you have a lot of programmers then I would go with LUA module. Inheritance through meta-tables could be an option if you wish to lock down and prevent read/write to tables, but personally I think they only add overhead compared to the trust factor of a good code convention.

If you have Designers who like tweaking values and behaviours, then I would setup scripts that hook in to a shared table for the game-object. This allow you to create very modular systems, but the lack of editor tooling makes it a bit heavy to shift through. I made a similar thing in DefKit, but that relies on message-passing and could be less performant in large scale.

Since your implementation will be a bit more focused on states here, each script could be a separate state injected to a state-machine driven through another script.

State Flee

local state_machine = require "core.state_machine"

local function on_message(self, message_id, ...)
  state_machine.enter(hash("attack")
end

function init(self)
  state_machine.add(hash("flee"), {
    --on_enter = enter,
    --on_exit = exit,
    on_message = on_message,
    --on_update,
  }
end

State Machine

local M = {}

local obj_states = {}

function M.add(name, state)
   local gid = go.get_id()
   local states = obj_states[gid] or {}
   states[name] = state
   obj_states[gid] = states
end

...

return M
5 Likes