83 lines
1.9 KiB
Nim
83 lines
1.9 KiB
Nim
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import std/math
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import nymph
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const PluginUri = "urn:nymph:examples:amp"
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type
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CSample = cfloat
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CSamples = UncheckedArray[CSample]
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PortIndex = enum
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INPUT = 0,
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OUTPUT = 1,
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GAIN = 2
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Amp = object
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input: ptr CSamples
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output: ptr CSamples
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gain: ptr cfloat
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template db2coeff(db: cfloat): cfloat =
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pow(10.0, db / 20.0)
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proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
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bundlePath: cstring; features: ptr ptr Lv2Feature):
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Lv2Handle {.cdecl.} =
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return createShared(Amp)
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proc connectPort(instance: Lv2Handle; port: cuint;
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dataLocation: pointer) {.cdecl.} =
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let amp = cast[ptr Amp](instance)
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case cast[PortIndex](port)
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of INPUT:
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amp.input = cast[ptr CSamples](dataLocation)
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of OUTPUT:
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amp.output = cast[ptr CSamples](dataLocation)
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of GAIN:
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amp.gain = cast[ptr cfloat](dataLocation)
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proc activate(instance: Lv2Handle) {.cdecl.} =
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discard
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proc run(instance: Lv2Handle; nSamples: cuint) {.cdecl.} =
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let amp = cast[ptr Amp](instance)
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for pos in 0 ..< nSamples:
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amp.output[pos] = amp.input[pos] * db2coeff(amp.gain[])
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proc deactivate(instance: Lv2Handle) {.cdecl.} =
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discard
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proc cleanup(instance: Lv2Handle) {.cdecl.} =
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freeShared(cast[ptr Amp](instance))
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proc extensionData(uri: cstring): pointer {.cdecl.} =
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return nil
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proc NimMain() {.cdecl, importc.}
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proc lv2Descriptor(index: cuint): ptr Lv2Descriptor {.
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cdecl, exportc, dynlib, extern: "lv2_descriptor".} =
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NimMain()
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if index == 0:
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result = createShared(Lv2Descriptor)
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result.uri = cstring(PluginUri)
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result.instantiate = instantiate
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result.connectPort = connectPort
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result.activate = activate
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result.run = run
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result.deactivate = deactivate
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result.cleanup = cleanup
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result.extensionData = extensionData
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