Assets

Loading and preparing assets via AssetProvider

To load and prepare assets we have some handy delegates that AssetProviders provides that handles all of the hard work for us. This also prevents us from having to use var as a null or lateinit var. Note: We can not access any of these variables in the class’s init method or else we will get an exception for accessing too early. The Game class provides a create class which can be used similarly.

We must first create a provider:

val provider = AssetProvider(context)

Loading an asset we can use the load method with returns a GameAsset object which can be used as a delegate to access that actual asset we need, which in this case is the Texture.

val texture by provider.load<Texture>(resourcesVfs["texture.png"])

This loads a Texture via a delegate and assigns it to the texture variable. Great! Now if you are thinking how can use a top level variable that requires this texture to be loaded and prepared, such needing a slice from it. Well not to fret, we also have a delegate for that too!

If we need a top level variable, and need to avoid null and lateinit var we can use the prepare method.

val texture by provider.load<Texture>(resourcesVfs["texture.png"])
val slices by provider.prepare<TextureSlice> { texture.slice(16, 16) }

The prepare method is essentially the same as the Kotlin’s lazy delegate but will prepare each asset once all other assets have finished loading.

We can check if the AssetProvider has finished loading by using the isFullyLoaded property. We need to make sure we call update() in the render loop in order ensure the assets are finished loading and fully prepared.

class MyGame(context: Context) : ContextListener(context) {

    val provider = AssetProvider(context)
    val texture by provider.load<Texture>(resourcesVfs["texture.png"]) // loads on a separate thread
    val slices by provider.prepare<TextureSlice> { texture.slice(16, 16) }

    override suspend fun Context.start() {
        // access any of the variables from above
        // do any of the rendering and update logic here

        onRender {
            if(!provider.isFullyLoaded) {
                provider.update()
                return
            }
            // We are loading now! Do whatever logic we need to do here.
            gl.clear(ClearBufferMask.COLOR_BUFFER_BIT)
        }
    }
}