Ole André Vadla Ravnås
2ab95ef638
Write each effect body-only against a preamble the host supplies, and let the build systems generate what each renderer needs -- a Swift catalog for OpenGL, a Metal fragment function through glslang and spirv-cross. Effects react to arriving events.
32 lines
1002 B
Swift
32 lines
1002 B
Swift
import Foundation
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/// Converts event-log arrivals into the 0..1 activity a shader effect reacts
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/// to. Answers nil while nothing is arriving, so a caller only touches the
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/// effect when there is news; the effect decays what it was last told.
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@MainActor
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public final class EventRate {
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/// Events per second that reads as fully busy.
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private let saturatingRate: Float = 40
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private var lastTotal: Int?
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private var lastObservedAt: TimeInterval = 0
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public init() {}
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public func observe(totalReceived: Int, at now: TimeInterval) -> Float? {
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defer {
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lastTotal = totalReceived
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lastObservedAt = now
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}
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guard let previousTotal = lastTotal, totalReceived > previousTotal else { return nil }
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let elapsed = Float(now - lastObservedAt)
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let arrived = Float(totalReceived - previousTotal)
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return min(arrived / max(elapsed, 0.001) / saturatingRate, 1)
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}
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public func reset() {
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lastTotal = nil
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}
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}
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