Swift 6 and Metal 4 all the way down — no runtime, no translation layer, no editor you are required to learn. Your game is a Swift package.
$swift run WindageSample
A game is a Swift file
Pacing, frames in flight and the fixed timestep are the engine's. Your pipelines, your draws and your rules are yours — the line sits exactly where every renderer it came from stopped being the same.
import Metal import WindageEngine final class Game: GameLoop { var body = CharacterController(feet: .zero) var world = CharacterController.Surroundings() func beginFrame() {} func step(deltaTime: Float) { body.step(yaw: 0, input: MovementInput(forward: 1), deltaTime: deltaTime, in: world) } func viewportSizeChanged(width: Int, height: Int) {} func encode(into encoder: MTL4RenderCommandEncoder, frameSlot: Int, interpolation: Float) { // your pipelines, your draws } }
The whole contract: GameLoop. Everything above it is the engine's.
Shows its work
Every feature was pulled out of a working game, and every claim on this page is a number you can reproduce on your own machine, with the check that holds it.
Apex of a 6.3 m/s jump, in meters. The height it should reach is 0.992.
| Steps a second | Stepped simply | Windage Engine |
|---|---|---|
| 30 | 0.890 | 0.992 |
| 60 | 0.940 | 0.992 |
| 120 | 0.966 | 0.992 |
| 240 | 0.979 | 0.992 |
Stepped simply, a game at 60 misses a ledge one at 120 clears. In Windage Engine one course of walking, jumping, sliding and landing ends in the same place at all four rates.
Found by drawing one frame
The scene read shadow maps that the same command buffer was still writing. In play it looked right — last frame's maps were there — and nothing said otherwise.
Drawing a single frame into a file showed it: the first frame came out different every run. Two barriers later, four runs of that frame are the same bytes, and the frame is a check.
What a native Mac game needs to ship, and was identical every time somebody wrote it.
Frames in flight, a fixed timestep, a clock that keeps time with the window hidden.
FrameRenderer · FixedTimestepCascaded sun shadows, and spot and point lights binned into clusters that each cast.
ShadowCascades · ClusteredLightsSkinned animation from USD, cross-fades, and things hung off joints.
SkeletonPose · TransformHierarchyStairs, lifts, turntables, being pushed — and the same at any step rate.
CharacterControllerA versioned level format, and an editor you use inside your running game.
Level · LevelEditorPositional audio, keys and pads a player rebinds, settings that save.
AudioEngine · InputBindingsInstanced drawing: a wood of trees or a field of debris in one draw per kind.
InstanceBatches · InstanceBufferSimpler versions of every mesh, made when it loads; each copy draws the one its distance earns.
MeshDetailEach of these is something the engine leaves to you, or to a game that proves it is needed.
Your game owns its objects. The engine owns when things happen.
Structure your game the way your game wants to be structured.
A level editor embeds in your game and edits its levels in place. A standalone editor is a separate product built on the engine, not part of it.
Mac first. Another platform means a native port, not a wrapper.
On every change, before it's called done.
Each new one shown to fail with its feature switched off.
swift testThe sample played by script, invisibly — one course of them at four step rates.
python3 Tools/walks.pyDrawn with no window and compared pixel by pixel against the last good one.
python3 Tools/frames.py