Proper way of using Scene & Game<Scene> and using ttf font

[Its-Kenta]

Hi,

I'm rather confused by how to properly use Game & Scene and I can't seem to find much of this in the samples, or perhaps there is, but all the code being bunched together makes it difficult to read it imho. I like to separate my code to maintain clean workspace and I would like to separate my scenes from MainMenuScene and PlayScene.

• The main entry point should be Game correct?
• Normal Scene can't load assets (if I understand correctly), that means I have to load all of my assets in the main entry point and not the scenes respectively?
• How would I go about changing scenes from one scene to another? (e.g. From PlayScene to PauseScene and vice versa?)

I understand that there is still no documentation on how to load TTF, but is there any short info on how to exactly draw text using TTF font? Or if not, how would I go about converting it to .FNT bitmap?

Thanks!

[LeHaine]

Hey!

Th Game class is an optional class that contains a bunch of tidbits for handling and changing scenes. The Game class is completely optional and does not have to be used.

The main entry point should be Game correct?

As mentioned above it is completely optional. The only thing that needs to be passed in when creating the app is a ContextListener. The Game class is a ContextListener.

Normal Scene can't load assets (if I understand correctly), that means I have to load all of my assets in the main entry point and not the scenes respectively?

Not necessarily. A Scene has a reference to the Context when it's created. With Context we can access the resourcesVfs: VfsFile which we can use to load assets. We can load assets directly in a Scene when it's created by making us of the prepare delegate or we can use an AssetProvider which does a lot of the work for us.

How would I go about changing scenes from one scene to another? (e.g. From PlayScene to PauseScene and vice versa?)

We need to add those scenes to the Game instance and then set the scene:

class SampleGame(context: Context) : Game<Scene>(context) {

    override suspend fun Context.start() {
        setSceneCallbacks(this) // need to call this to subscribe to the scene callbacks in Game class

        // register the scenes - only need to do it once per scene. We can also register it later if we want.
        addScene(PlayScene())
        addScene(MenuScene())

        setScene<MenuScene>() // set initial scene - pass in by class type

        onRender {
            if (input.isKeyJustPressed(Key.BACKSPACE)) {
                if (currentScene !is MenuScene) {
                    setScene<MenuScene>()
                }
            }
        }
    }
}

I understand that there is still no documentation on how to load TTF, but is there any short info on how to exactly draw text using TTF font?

While we can load a TtfFont just fine there are still issues with rendering it with GpuFont. See issue #23.

Loading a Ttf:

val font: TtfFont = resourcesVfs["arial.ttf"].readTtfFont()

Using a GpuFont:

val batch = SpriteBatch(context)
val gpuFont = GpuFont(context, font)
gpuFont.addText("My Text!", x = 50, y = 100, pxSize = 16)

onRender {
    batch.use {
        gpuFont.useShaderWith(it) // need to set to GpuFont shader
        gpuFont.draw(it)
    }
    batch.shader = batch.defaultShader // set back to default SpriteBatch shader
}

Using a BitmapFont works great as well and has a lot more documentation for it. I personally use BMFont to convert a TTF to a Bitmap. But really any bitmap font generator can be used.

[Its-Kenta]

Thank you for the further info! That makes a lot more sense!