68 lines
2.8 KiB
Swift
68 lines
2.8 KiB
Swift
internal import CPlaydate
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/// The cached `playdate->sound->effect` C API table.
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private var effectAPI: UnsafePointer<playdate_sound_effect> { Playdate.effectAPI.unsafelyUnwrapped }
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extension Sound {
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/// An effect that processes a channel's audio: the base class of the
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/// built-in effects. Wraps `SoundEffect`.
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public class Effect {
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let pointer: OpaquePointer
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let isOwned: Bool
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private var retainedMixModulator: SignalValue?
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private var processorBox: Unmanaged<ProcessorBox>?
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final class ProcessorBox {
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let processor: Processor
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init(_ processor: @escaping Processor) { self.processor = processor }
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}
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init(pointer: OpaquePointer, isOwned: Bool) {
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self.pointer = pointer
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self.isOwned = isOwned
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}
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/// Creates an effect that processes audio with a Swift callback.
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public init(processor: @escaping Processor) {
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let box = Unmanaged.passRetained(ProcessorBox(processor))
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processorBox = box
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pointer = effectAPI.pointee.newEffect.unsafelyUnwrapped({ effect, left, right, nsamples, bufactive in
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guard let effect, let left,
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let userdata = effectAPI.pointee.getUserdata.unsafelyUnwrapped(effect) else { return 0 }
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let box = Unmanaged<ProcessorBox>.fromOpaque(userdata).takeUnretainedValue()
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let leftBuffer = UnsafeMutableBufferPointer(start: left, count: Int(nsamples))
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let rightBuffer = right.map { UnsafeMutableBufferPointer(start: $0, count: Int(nsamples)) }
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return box.processor(leftBuffer, rightBuffer, bufactive != 0) ? 1 : 0
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}, box.toOpaque()).unsafelyUnwrapped
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isOwned = true
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}
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deinit {
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// Subclasses free the C object in their own deinit with the
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// subsystem's type-specific free (freeDelayLine, freeOverdrive,
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// ...); freeing here as well would double-free. The base class
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// owns only the custom-processor effects it creates itself.
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if let processorBox {
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if isOwned {
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effectAPI.pointee.freeEffect.unsafelyUnwrapped(pointer)
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}
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processorBox.release()
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}
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}
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/// The wet/dry mix: 1 is fully processed, 0 fully dry.
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public func setMix(_ level: Float) {
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effectAPI.pointee.setMix.unsafelyUnwrapped(pointer, level)
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}
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/// Modulates the wet/dry mix.
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public var mixModulator: SignalValue? {
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get { SignalValue.wrap(effectAPI.pointee.getMixModulator.unsafelyUnwrapped(pointer)) }
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set {
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retainedMixModulator = newValue
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effectAPI.pointee.setMixModulator.unsafelyUnwrapped(pointer, newValue?.pointer)
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}
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}
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}
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}
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