Waveform/dutyCycle

audio-worklet/src/jsMain/kotlin/nl/astraeus/vst/chip/ChipProcessor.kt

@@ -49,6 +49,13 @@ class PlayingNote(
   var actualVolume = 0f
 }
 
+enum class Waveform {
+  SINE,
+  SQUARE,
+  TRIANGLE,
+  SAWTOOTH
+}
+
 @ExperimentalJsExport
 @JsExport
 class VstChipProcessor : AudioWorkletProcessor() {
@@ -57,6 +64,8 @@ class VstChipProcessor : AudioWorkletProcessor() {
       0
     )
   }
+  var waveform = Waveform.SINE.ordinal
+  var dutyCycle = 0.5
 
   init {
     this.port.onmessage = ::handleMessage
@@ -117,6 +126,27 @@ class VstChipProcessor : AudioWorkletProcessor() {
             noteOff(note)
           }
         }
+        0xc9 -> {
+          if (bytes.length >= 1) {
+            val waveform = bytes[1]
+
+            if (waveform < 4) {
+              this.waveform = waveform
+            }
+          }
+        }
+        0xb0 -> {
+          if (bytes.length == 3) {
+            val knob = bytes[1]
+            val value = bytes[2]
+
+            when(knob) {
+              0x4a -> {
+                dutyCycle = value / 127.0
+              }
+            }
+          }
+        }
       }
     }
   }
@@ -175,20 +205,39 @@ class VstChipProcessor : AudioWorkletProcessor() {
             note.releaseSamples--
             targetVolume *= (note.releaseSamples / 10000f)
           }
-          note.actualVolume += (targetVolume - note.actualVolume) * 0.005f
+          note.actualVolume += (targetVolume - note.actualVolume) * 0.001f
 
           if (note.state == NoteState.RELEASED && note.actualVolume <= 0) {
             note.state = NoteState.OFF
           }
 
-          left[i] = left[i] + sin(note.cycleOffset * PI2).toFloat() * note.actualVolume * 0.3f
-          right[i] = right[i] + sin(note.cycleOffset * PI2).toFloat() * note.actualVolume * 0.3f
+          val cycleOffset = note.cycleOffset
 
-          //left[i] = left[i] + if (note.cycleOffset < 0.5) { 0.3f } else { -0.3f } * note.actualVolume //sin(note.cycleOffset * PI2).toFloat() * note.actualVolume * 0.3f
-          //right[i] = right[i] + if (note.cycleOffset < 0.5) { 0.3f } else { -0.3f } * note.actualVolume //sin(note.cycleOffset * PI2).toFloat() * note.actualVolume * 0.3f
+          val waveValue: Float = when (waveform) {
+            0 -> {
+              sin(cycleOffset * PI2).toFloat()
+            }
+            1 -> {
+              if (cycleOffset < dutyCycle) { 1f } else { -1f }
+            }
+            2 -> when {
+              cycleOffset < 0.25 -> 4 * cycleOffset
+              cycleOffset < 0.75 -> 2 - 4 * cycleOffset
+              else -> 4 * cycleOffset - 4
+            }.toFloat()
+            3 -> {
+              ((cycleOffset * 2f) - 1f).toFloat()
+            }
+            else -> {
+              if (cycleOffset < 0.5) { 1f } else { -1f }
+            }
+          }
+
+          left[i] = left[i] + waveValue * note.actualVolume * 0.3f
+          right[i] = right[i] + waveValue * note.actualVolume * 0.3f
 
           note.cycleOffset += sampleDelta
-          if (note.cycleOffset > 1f) {
+          if (cycleOffset > 1f) {
             note.cycleOffset -= 1f
           }
         }

common/src/commonMain/kotlin/nl/astraeus/vst/Note.kt

@@ -15,16 +15,16 @@ enum class Note(
   val sharp: String,
   val flat: String
 ) {
-  NONE("---", "---"),
-  No02("C--","C--"),
-  NO03("C#-","Db-"),
-  NO04("D--","D--"),
-  NO05("D#-","Eb-"),
-  NO06("E--","E--"),
-  NO07("F--","F--"),
-  NO08("F#-","Gb-"),
-  NO09("G--","G--"),
-  NO10("G#-","Ab-"),
+  NO01("C--","C--"),
+  NO02("C#-","Db-"),
+  NO03("D--","D--"),
+  NO04("D#-","Eb-"),
+  NO05("E--","E--"),
+  NO06("F--","F--"),
+  NO07("F#-","Gb-"),
+  NO08("G--","G--"),
+  NO09("G#-","Ab-"),
+  NO10("A--","A--"),
   NO11("A#-","Bb-"),
   NO12("B--","B--"),
   C0("C-0","C-0"),
@@ -148,12 +148,13 @@ enum class Note(
   //A9("A-9","A-9"),
   //A9s("A#9","Bb9"),
   //B9("B-9","B-9"),
+  NONE("---", "---"),
   UP("^^^","^^^"),
   END("XXX","XXX"),
   ;
 
   // 69 = A4.ordinal
-  val freq: Double = round(440.0 * 2.0.pow((ordinal - 69)/12.0) * 100.0) / 100.0
+  val freq: Double = round(440.0 * 2.0.pow((ordinal - 69)/12.0) * 10000.0) / 10000.0
   val cycleLength: Double = 1.0 / freq
   var sampleDelta: Double = 0.0
 

src/jsMain/kotlin/nl/astraeus/vst/chip/midi/Midi.kt

@@ -3,6 +3,8 @@ package nl.astraeus.vst.chip.midi
 import kotlinx.browser.window
 import nl.astraeus.vst.chip.audio.VstChipWorklet
 import nl.astraeus.vst.chip.view.MainView
+import org.khronos.webgl.Uint8Array
+import org.khronos.webgl.get
 
 external class MIDIInput {
   val connection: String
@@ -77,7 +79,13 @@ object Midi {
     }
 
     currentInput?.onmidimessage = { message ->
-      console.log("Midi message:", message)
+      val data = message.data as Uint8Array
+      val hex = StringBuilder()
+      for (index in 0 until data.length) {
+        hex.append(data[index].toString(16))
+        hex.append(" ")
+      }
+      console.log("Midi message:", hex)
       VstChipWorklet.postMessage(
         message.data
       )