Add example code for WAT parsing and server-side plugins

Package.swift → Guest/Package.swift

@@ -1,24 +1,36 @@
 // swift-tools-version: 6.0
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
 import PackageDescription
 
 let embeddedSwiftSettings: [SwiftSetting] = [
- .enableExperimentalFeature("Embedded"), 
+ .enableExperimentalFeature("Embedded"),
  .enableExperimentalFeature("Extern"),
  .interoperabilityMode(.Cxx),
- .unsafeFlags(["-wmo", "-disable-cmo", "-Xfrontend", "-gnone"])
+ .unsafeFlags(["-wmo", "-disable-cmo", "-Xfrontend", "-gnone", "-disable-stack-protector"]),
 ]
 
 let embeddedCSettings: [CSetting] = [
- .unsafeFlags(["-fdeclspec"])
+ .unsafeFlags(["-fdeclspec"]),
 ]
 
 let linkerSettings: [LinkerSetting] = [
  .unsafeFlags([
  "-Xclang-linker", "-nostdlib",
- "-Xlinker", "--no-entry"
- ])
+ "-Xlinker", "--no-entry",
+ ]),
 ]
 
 let libcSettings: [CSetting] = [
@@ -33,13 +45,13 @@ let libcSettings: [CSetting] = [
 ]
 
 let package = Package(
- name: "swift-for-wasm-example",
+ name: "Guest",
  targets: [
  // Targets are the basic building blocks of a package, defining a module or a test suite.
  // Targets can depend on other targets in this package and products from dependencies.
  .executableTarget(
- name: "swift-audio",
- dependencies: ["VultDSP", "dlmalloc"],
+ name: "Plotter",
+ dependencies: ["dlmalloc"],
  cSettings: embeddedCSettings,
  swiftSettings: embeddedSwiftSettings,
  linkerSettings: linkerSettings
@@ -51,3 +63,15 @@ let package = Package(
  ),
  ]
 )
+
+for module in ["Kick", "HiHat", "Bass", "Mix"] {
+ package.targets.append(
+ .executableTarget(
+ name: module,
+ dependencies: ["VultDSP", "dlmalloc"],
+ cSettings: embeddedCSettings,
+ swiftSettings: embeddedSwiftSettings,
+ linkerSettings: linkerSettings
+ )
+ )
+}

Guest/Sources/Bass/Shared

@@ -0,0 +1 @@
+../Shared

Guest/Sources/Bass/main.swift

@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+@_expose(wasm, "main")
+@_cdecl("main")
+func main(contextIndex: Int) {
+ var sequencedBass = Sequencer(
+ instrument: Bass(),
+ sequence: [
+ .noteOn(.c.octave(1)), .noteOff, .noteOn(.d.octave(1)), .noteOff, .noteOn(.e.octave(1)),
+ .noteOff, .noteOn(.f.octave(1)), .noteOff, .noteOn(.g.octave(1)), .noteOff, .noteOn(.a.octave(1)),
+ ],
+ stepLengthInSeconds: 0.25
+ )
+
+ let totalLengthInSeconds = 6
+
+ let buffer = AudioBuffer(
+ capacity: sampleRate * totalLengthInSeconds,
+ source: &sequencedBass
+ )
+
+ Audio.encode(contextIndex: contextIndex, buffer)
+}

Guest/Sources/HiHat/Shared

@@ -0,0 +1 @@
+../Shared

Guest/Sources/HiHat/main.swift

@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+@_expose(wasm, "main")
+@_cdecl("main")
+func main(contextIndex: Int) {
+ var sequencedHiHat = Sequencer(
+ instrument: HiHat(),
+ sequence: [
+ .noteOff, .noteOff, .noteOff, .noteOff,
+ .noteOff, .noteOff, .noteOff, .noteOff,
+ .noteOn(.c.octave(1)), .noteOff, .noteOn(.c.octave(1)), .noteOff,
+ .noteOff, .noteOff, .noteOff, .noteOff,
+ ],
+ stepLengthInSeconds: 0.125
+ )
+
+ let totalLengthInSeconds = 6
+
+ let buffer = AudioBuffer(
+ capacity: sampleRate * totalLengthInSeconds,
+ source: &sequencedHiHat
+ )
+
+ Audio.encode(contextIndex: contextIndex, buffer)
+}

Guest/Sources/JavaScript/index.js

@@ -0,0 +1,116 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import { Encoder } from './encoder.js';
+
+const decoder = new TextDecoder();
+const loggerElement = document.getElementById('wasm-logger');
+const moduleInstances = [];
+
+function wasmMemoryAsString(i, address, byteCount) {
+ return decoder.decode(moduleInstances[i].exports.memory.buffer.slice(address, address + byteCount));
+}
+
+function wasmMemoryAsFloat32Array(i, address, byteCount) {
+ return new Float32Array(moduleInstances[i].exports.memory.buffer.slice(address, address + byteCount));
+}
+
+const contexts = [];
+
+const canvasImports = {
+ canvas: {
+ beginPath: (i) => contexts[i].beginPath(),
+ stroke: (i) => contexts[i].stroke(),
+ moveTo: (i, x, y) => contexts[i].moveTo(x, y),
+ lineTo: (i, x, y) => contexts[i].lineTo(x, y),
+ },
+}
+
+const plotterModule = await WebAssembly.instantiateStreaming(
+ fetch(".build/wasm32-unknown-none-wasm/release/plotter.wasm"),
+ { ...canvasImports }
+);
+
+function encodeAndPlot(audioBuffer, context) {
+ const wavEncoder = new Encoder(44100, 1);
+ wavEncoder.encode([audioBuffer]);
+ const blob = wavEncoder.finish();
+
+ const audioURL = URL.createObjectURL(blob);
+ document.getElementsByClassName('audio')[context].setAttribute('src', audioURL);
+
+ const byteCount = audioBuffer.length * 4;
+ const bufferPointer = plotterExports.allocateAudioBuffer(byteCount);
+ const memoryBytes = new Float32Array(plotterExports.memory.buffer);
+ memoryBytes.set(audioBuffer, bufferPointer / 4);
+ plotterExports.plot(context, 1000, 200, 10, bufferPointer, byteCount);
+ plotterExports.free(bufferPointer);
+}
+
+const plotterExports = plotterModule.instance.exports;
+
+const audioImports = {
+ audio: {
+ encode: (i, address, byteCount) => {
+ const audioBuffer = wasmMemoryAsFloat32Array(i, address, byteCount);
+
+ encodeAndPlot(audioBuffer, i);
+ },
+ },
+};
+
+const consoleImports = {
+ console: {
+ log: (i, address, byteCount) => {
+ loggerElement.innerHTML = wasmMemoryAsString(i, address, byteCount);
+ },
+ logInt: (x) => console.log(x),
+ logFloat: (x) => console.log(x),
+ }
+};
+
+const pluginElements = document.getElementsByClassName("plugin");
+
+for (let i = 0; i < pluginElements.length; ++i) {
+ const element = pluginElements[i];
+ const canvasElement = element.getElementsByClassName("plotter")[0];
+ const canvasContext = canvasElement.getContext('2d');
+ canvasContext.strokeStyle = 'white';
+
+ contexts.push(canvasContext);
+
+ const { instance } = await WebAssembly.instantiateStreaming(
+ fetch(element.dataset.modulePath),
+ { ...audioImports, ...consoleImports }
+ );
+
+ moduleInstances.push(instance);
+
+ instance.exports.main(i);
+}
+
+const mixElement = document.getElementById("tracks-mix");
+
+if (mixElement) {
+ const canvasElement = mixElement.getElementsByClassName("plotter")[0];
+ const canvasContext = canvasElement.getContext('2d');
+ canvasContext.strokeStyle = 'white';
+
+ contexts.push(canvasContext);
+
+ const response = await fetch("/mix");
+ const responseBlob = await response.blob();
+
+ const audioBuffer = new Float32Array(await responseBlob.arrayBuffer());
+
+ encodeAndPlot(audioBuffer, contexts.length - 1);
+}

Guest/Sources/Kick/Shared

@@ -0,0 +1 @@
+../Shared

Guest/Sources/Kick/main.swift

@@ -0,0 +1,30 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+@_expose(wasm, "main")
+@_cdecl("main")
+func main(contextIndex: Int) {
+ var sequencedKick = Sequencer(
+ instrument: Kick(),
+ sequence: [.noteOff, .noteOn(.c.octave(1)), .noteOff, .noteOn(.c.octave(1))],
+ stepLengthInSeconds: 0.25
+ )
+
+ let totalLengthInSeconds = 6
+
+ let buffer = AudioBuffer(
+ capacity: sampleRate * totalLengthInSeconds,
+ source: &sequencedKick
+ )
+
+ Audio.encode(contextIndex: contextIndex, buffer)
+}

Guest/Sources/Mix/Shared

@@ -0,0 +1 @@
+../Shared

Sources/swift-audio/main.swift → Guest/Sources/Mix/main.swift

@@ -11,7 +11,8 @@
 //===----------------------------------------------------------------------===//
 
 @_expose(wasm, "main")
-func main() {
+@_cdecl("main")
+func main(contextIndex: Int) {
  let sequencedKick = Sequencer(
  instrument: Kick(),
  sequence: [.noteOff, .noteOn(.c.octave(1)), .noteOff, .noteOn(.c.octave(1))],
@@ -38,6 +39,8 @@ func main() {
  stepLengthInSeconds: 0.25
  )
 
+ let totalLengthInSeconds = 6
+
  var mixer = Mixer(
  source1: sequencedHiHat,
  volume1: 0.05,
@@ -47,14 +50,10 @@ func main() {
  volume3: 0.1
  )
 
- let totalLengthInSeconds = 6
  let buffer = AudioBuffer(
  capacity: sampleRate * totalLengthInSeconds,
  source: &mixer
  )
- Audio.encode(buffer)
 
- Plotter<HTMLCanvas>(
- width: 1000, height: 200, margin: 10
- ).plot(buffer)
+ Audio.encode(contextIndex: contextIndex, buffer)
 }

Sources/swift-audio/Canvas.swift → Guest/Sources/Plotter/Canvas.swift

@@ -14,26 +14,26 @@
 /// implementation is required to provide these functions for drawing code in
 /// this module to work.
 protocol Canvas {
- static func beginPath()
- static func stroke()
- static func moveTo(x: Int, y: Int)
- static func lineTo(x: Int, y: Int)
+ static func beginPath(ctx: Int)
+ static func stroke(ctx: Int)
+ static func moveTo(ctx: Int, x: Int, y: Int)
+ static func lineTo(ctx: Int, x: Int, y: Int)
 }
 
 struct HTMLCanvas: Canvas {
  @_extern(wasm, module: "canvas", name: "beginPath")
  @_extern(c)
- static func beginPath()
+ static func beginPath(ctx: Int)
 
  @_extern(wasm, module: "canvas", name: "stroke")
  @_extern(c)
- static func stroke()
+ static func stroke(ctx: Int)
 
  @_extern(wasm, module: "canvas", name: "moveTo")
  @_extern(c)
- static func moveTo(x: Int, y: Int)
+ static func moveTo(ctx: Int, x: Int, y: Int)
 
  @_extern(wasm, module: "canvas", name: "lineTo")
  @_extern(c)
- static func lineTo(x: Int, y: Int)
+ static func lineTo(ctx: Int, x: Int, y: Int)
 }