Threaded resource loading for LÖVE
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README.md

love-loader

This is an utility lib for LÖVE that loads resources (images, sounds) from the hard disk on a separate thread.

This allows for "doing stuff" while resources are being loaded; for example, playing an animation. The fact that the blocking calls happen in a separate thread ensures that the animation is fluid, without blocking calls dropping the framerate.

Version 2.0.0 of this lib only works with LÖVE 0.9.x. If you need to work with LÖVE 0.8 or before, please use earlier versions of this lib.

Example

local loader = require 'love-loader'

local images = {}
local sounds = {}

local finishedLoading = false

function love.load()
  loader.newImage(  images, 'rabbit', 'path/to/rabbit.png')
  loader.newSource( sounds, 'iiiik',  'path/to/iiik.ogg')
  loader.newSource( sounds, 'music',  'path/to/music.ogg', 'stream')

  loader.start(function()
    finishedLoading = true
  end)
end

function love.update(dt)
  if not finishedLoading then
    loader.update() -- You must do this on each iteration until all resources are loaded
  end
end

function love.draw()
  if finishedLoading then
    -- media contains the images and sounds. You can use them here safely now.
    love.graphics.draw(images.rabbit, 100, 200)
  else -- not finishedLoading
    local percent = 0
    if loader.resourceCount ~= 0 then percent = loader.loadedCount / loader.resourceCount end
    love.graphics.print(("Loading .. %d%%"):format(percent*100), 100, 100)
  end
end

You can also see a working demo in the demo branch of this repo.

Interface

  • loader.newImage(holder, key, path). Adds a new image to the list of images to load.
  • loader.newSource(holder, key, path, sourceType). Adds a new source to the list of images to load.
  • loader.start(finishCallback, loadedCallback). Starts doing the loading on a separate thread. When it finishes, it invokes finishCallback with no parameters. Every time it loads a new resource, it invokes loadedCallback. finishedCallback admits no parameters, and loadedCallback's signature is function(kind, holder, key). kind is a string ("image", "source" or "stream"). Neither loadedCallback or finishedCallback are mandatory.
  • loader.loadedCount integer returning the number of resources loaded. When loader.start gets invoked, it's 0.
  • loader.resourceCount integer containing the total number of resources to be loaded. It can be used in conjunction with loader.loadedCount to show progressbars etc.

Installation

Just copy the love-loader.lua file somewhere in your projects (maybe inside a /lib/ folder) and require it accordingly.

Remember to store the value returned by require somewhere! (I suggest a local variable named loader or love.loader)

local loader = require 'love-loader'

The second step is making sure that your "game loop" calls loader.update, at least while there are resources to load.

License

This library is distributed under the MIT License.

Credits

I took a lot of inspiration from Michael Enger's Stealth2D project. I learned the basic internals of threads from his loading state code.

https://github.com/michaelenger/Stealth2D

Tanner Rogalsky (https://github.com/TannerRogalsky) ported the library to LÖVE 0.9.0.