67 lines
1.9 KiB
Markdown
67 lines
1.9 KiB
Markdown
 
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# Getting Started
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Bootstrap the bindings from your game's entry point and drive a frame loop.
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## Overview
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A Playdate game has a single C entry point, `eventHandler`, which the
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firmware calls with a `PlaydateAPI*` and an event code. Export it with
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`@_cdecl`, call ``Playdate/initialize(with:)`` on the first event, and
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install an update callback:
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```swift
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import CPlaydate
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import PlayDate
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@_cdecl("eventHandler")
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func eventHandler(
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pointer: UnsafeMutableRawPointer,
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event: PDSystemEvent,
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argument: UInt32
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) -> Int32 {
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if case .initialize = SystemEvent(event: event, argument: argument) {
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Playdate.initialize(with: pointer) // must happen before anything else
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Game.shared.start()
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}
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return 0
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}
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final class Game {
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nonisolated(unsafe) static let shared = Game()
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func start() {
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Display.setRefreshRate(50)
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System.setUpdateCallback {
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self.update()
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return true // true = redraw the display this frame
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}
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}
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func update() {
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let (_, pushed, _) = System.buttonState
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if pushed.contains(.a) {
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System.log("A pressed")
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}
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Graphics.clear(color: .white)
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Graphics.drawText("Hello, Playdate", x: 8, y: 8)
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System.drawFPS()
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}
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}
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```
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## Conventions to know
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- **Initialization.** Calling any wrapper before
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``Playdate/initialize(with:)`` is a programmer error and will crash.
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- **Errors.** Fallible operations use typed throws — ``PlaydateError``
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generally, ``Network/NetError`` for network I/O.
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- **Ownership.** A wrapper that creates a C object frees it on `deinit`;
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keep the wrapper referenced for as long as you use it. Wrappers vending
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OS-owned objects don't free them — keep the owner alive instead, as
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documented on each API.
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- **Threading.** The Playdate runtime is single-threaded; don't call the
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API from other threads.
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