Fx

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

@@ -66,6 +66,11 @@ class VstChipProcessor : AudioWorkletProcessor() {
   }
   var waveform = Waveform.SINE.ordinal
   var dutyCycle = 0.5
+  var fmFreq = 0.0
+  var fmAmp = 0.0
+  var amFreq = 0.0
+  var amAmp = 0.0
+  val sampleLength = 1 / sampleRate.toDouble()
 
   init {
     this.port.onmessage = ::handleMessage
@@ -106,6 +111,7 @@ class VstChipProcessor : AudioWorkletProcessor() {
 
   private fun playMidi(bytes: Int32Array) {
     if (bytes.length > 0) {
+      //console.log("Received", bytes)
       when(bytes[0]) {
         0x90 -> {
           if (bytes.length == 3) {
@@ -119,6 +125,7 @@ class VstChipProcessor : AudioWorkletProcessor() {
             }
           }
         }
+
         0x80 -> {
           if (bytes.length >= 2) {
             val note = bytes[1]
@@ -126,6 +133,7 @@ class VstChipProcessor : AudioWorkletProcessor() {
             noteOff(note)
           }
         }
+
         0xc9 -> {
           if (bytes.length >= 1) {
             val waveform = bytes[1]
@@ -135,18 +143,44 @@ class VstChipProcessor : AudioWorkletProcessor() {
             }
           }
         }
+
         0xb0 -> {
           if (bytes.length == 3) {
             val knob = bytes[1]
             val value = bytes[2]
 
-            when(knob) {
+            when (knob) {
               0x4a -> {
                 dutyCycle = value / 127.0
               }
+
+              0x4b -> {
+                fmFreq = value / 127.0
+              }
+
+              0x4c -> {
+                fmAmp = value / 127.0
+              }
+
+              0x47 -> {
+                amFreq = value / 127.0
+              }
+
+              0x48 -> {
+                amAmp = value / 127.0
+              }
             }
           }
         }
+
+        0xe0 -> {
+          if (bytes.length == 3) {
+            val lsb = bytes[1]
+            val msb = bytes[2]
+
+            amFreq = (((msb - 0x40) + (lsb / 127.0)) / 0x40) * 10.0
+          }
+        }
       }
     }
   }
@@ -167,7 +201,7 @@ class VstChipProcessor : AudioWorkletProcessor() {
         notes[i].state = NoteState.ON
 
         val n = Note.fromMidi(note)
-        console.log("Playing note: ${n.sharp} (${n.freq})")
+        //console.log("Playing note: ${n.sharp} (${n.freq})")
         break
       }
     }
@@ -205,13 +239,16 @@ class VstChipProcessor : AudioWorkletProcessor() {
             note.releaseSamples--
             targetVolume *= (note.releaseSamples / 10000f)
           }
-          note.actualVolume += (targetVolume - note.actualVolume) * 0.001f
+          note.actualVolume += (targetVolume - note.actualVolume) * 0.0001f
 
           if (note.state == NoteState.RELEASED && note.actualVolume <= 0) {
             note.state = NoteState.OFF
           }
 
-          val cycleOffset = note.cycleOffset
+          var cycleOffset = note.cycleOffset
+          val fmModulation = sin(sampleLength * fmFreq * 10f * PI2 * note.sample).toFloat() * fmAmp * 5f
+          val amModulation = 1f + (sin(sampleLength * amFreq * 10f * PI2 * note.sample) * amAmp).toFloat()
+          cycleOffset += fmModulation
 
           val waveValue: Float = when (waveform) {
             0 -> {
@@ -233,13 +270,14 @@ class VstChipProcessor : AudioWorkletProcessor() {
             }
           }
 
-          left[i] = left[i] + waveValue * note.actualVolume * 0.3f
-          right[i] = right[i] + waveValue * note.actualVolume * 0.3f
+          left[i] = left[i] + waveValue * note.actualVolume * 0.3f * amModulation
+          right[i] = right[i] + waveValue * note.actualVolume * 0.3f * amModulation
 
           note.cycleOffset += sampleDelta
           if (cycleOffset > 1f) {
             note.cycleOffset -= 1f
           }
+          note.sample++
         }
       }
     }