GameEngine

A rather creatively named 2D game engine written in Swift using the Metal API. I pretty much only make tile based games and this engine is very geared towards doing that efficiently.

It currently only works on iOS and partially on macOS, still need to test tvOS to see what needs to be done. I had plans to port it to Linux/Vulkan but swift linux is not fun and my video card is too old at the moment to even run Vulkan so I’ll be putting that on hold indefinitely.

Currently, the example projects are built into the main project because for whatever reason you can’t debug metal externally if it’s bundled into a framework. Maybe I just didn’t do it correctly.

current state

This is probably not close to being ready to go. It could technically be used now though.

Documentation can be here a good portion of the public API has been documented.

A ton of things left to do including:

• fix project layout I don’t think I need two frameworks
• create separate example projects for testing
• texture animation
• fix the data structures for font rendering
• fix up the text rendering shaders to have more options
• fix up text rendering in general, can probably move it over to the sprite pipeline.
• lighting system, probably will do next, needs to be redone again as macOS does not support buffer access like iOS does

I’m pretty sure this is as fast as it’ll ever be. It seems rather slow or maybe it’s because I’m kind of new to this. I can render 100 textured quads at ~15% CPU or 1.1ms CPU/GPU frame time. At 10000 I start to lose FPS. That is way more than I’ll ever need for the game I’m making.

Should you use it?

Probably not. I was having some performance issues using SpriteKit and I think (hope) this will address those issues but I don’t know what I’m doing really. This will also never be as robust as SpriteKit as I have fairly specific needs.

With that being said, feel free to use it.

howto

If you know SpriteKit you can probably skip this. One thing worth keeping in mind is the TextNode will take a really long time to create with no compiler optimization. The algorithm is pretty intense and the array bound checking kills it. It’s worth running once with optimizations to force the font textures to be saved to disk.

To just test stuff out you can just build the GameEngineTest target which is not actually a unit test target.
The TestGameViewController is already setup to display some stuff.

Otherwise, subclass GameViewController and in viewDidLoad():

if let view = self.view as? GameView {
  scene = Scene(size: view.bounds.size)
  view.presentScene(scene)
}

//this should probably be done in a subclass of `Scene` where it's easier to override the update method
let sprite = Sprite(named: "AnImageYouAdded")
scene.addNode(sprite)

And you should see the sprite at the bottom left corner of the screen.