Add SawtoothGenerator and fix a problem with Frequency Quantize when the input is zero

ProjectObsidian/ProtoFlux/Audio/SawtoothGenerator.cs

@@ -0,0 +1,197 @@
+using System;
+using ProtoFlux.Core;
+using ProtoFlux.Runtimes.Execution;
+using FrooxEngine.ProtoFlux;
+using FrooxEngine;
+using Elements.Assets;
+using Elements.Core;
+using System.Runtime.InteropServices;
+
+namespace ProtoFlux.Runtimes.Execution.Nodes.Obsidian.Audio
+{
+    public class SawtoothGeneratorProxy : ProtoFluxEngineProxy, IAudioSource
+    {
+        public float Frequency;
+
+        public float Amplitude;
+
+        public float Phase;
+
+        public double time;
+
+        private float[] tempBuffer;
+
+        public bool Active;
+
+        public bool IsActive => Active;
+
+        public int ChannelCount => 1;
+
+        private bool updateTime;
+
+        public void Read<S>(Span<S> buffer) where S : unmanaged, IAudioSample<S>
+        {
+            if (!IsActive)
+            {
+                buffer.Fill(default(S));
+                return;
+            }
+
+            tempBuffer = tempBuffer.EnsureSize(buffer.Length);
+            var temptime = time;
+            temptime %= (1f / Frequency);
+            var clampedAmplitude = MathX.Clamp01(Amplitude);
+            float advance = (1f / (float)base.Engine.AudioSystem.SampleRate);
+            for (int i = 0; i < buffer.Length; i++)
+            {
+                tempBuffer[i] = (2.0f * ((((float)temptime / (1f / Frequency)) + Phase) % 1.0f) - 1.0f) * clampedAmplitude;
+                if (tempBuffer[i] > 1f) tempBuffer[i] = 1f;
+                else if (tempBuffer[i] < -1f) tempBuffer[i] = -1f;
+                temptime += advance;
+            }
+            if (updateTime)
+            {
+                time = temptime;
+                updateTime = false;
+            }
+            double position = 0.0;
+            MonoSample lastSample = default(MonoSample);
+            MemoryMarshal.Cast<float, MonoSample>(MemoryExtensions.AsSpan(tempBuffer)).CopySamples(buffer, ref position, ref lastSample);
+        }
+
+        protected override void OnStart()
+        {
+            Engine.AudioSystem.AudioUpdate += () =>
+            {
+                updateTime = true;
+            };
+        }
+    }
+    [NodeCategory("Obsidian/Audio")]
+    public class SawtoothGenerator : ProxyVoidNode<FrooxEngineContext, SawtoothGeneratorProxy>, IExecutionChangeListener<FrooxEngineContext>
+    {
+        [ChangeListener]
+        [DefaultValueAttribute(440f)]
+        public readonly ValueInput<float> Frequency;
+
+        [ChangeListener]
+        [DefaultValueAttribute(1f)]
+        public readonly ValueInput<float> Amplitude;
+
+        [ChangeListener]
+        [DefaultValueAttribute(0f)]
+        public readonly ValueInput<float> Phase;
+
+        [PossibleContinuations(new string[] { "OnReset" })]
+        public readonly Operation Reset;
+
+        public Continuation OnReset;
+
+        public readonly ObjectOutput<IAudioSource> AudioOutput;
+
+        private ObjectStore<Action<IChangeable>> _enabledChangedHandler;
+
+        private ObjectStore<SlotEvent> _activeChangedHandler;
+
+        public bool ValueListensToChanges { get; private set; }
+
+        private bool ShouldListen(SawtoothGeneratorProxy proxy)
+        {
+            if (proxy.Enabled)
+            {
+                return proxy.Slot.IsActive;
+            }
+            return false;
+        }
+
+        protected override void ProxyAdded(SawtoothGeneratorProxy proxy, FrooxEngineContext context)
+        {
+            base.ProxyAdded(proxy, context);
+            NodeContextPath path = context.CaptureContextPath();
+            ProtoFluxNodeGroup group = context.Group;
+            context.GetEventDispatcher(out var dispatcher);
+            Action<IChangeable> enabledHandler = delegate
+            {
+                dispatcher.ScheduleEvent(path, delegate (FrooxEngineContext c)
+                {
+                    UpdateListenerState(c);
+                });
+            };
+            SlotEvent activeHandler = delegate
+            {
+                dispatcher.ScheduleEvent(path, delegate (FrooxEngineContext c)
+                {
+                    UpdateListenerState(c);
+                });
+            };
+            proxy.EnabledField.Changed += enabledHandler;
+            proxy.Slot.ActiveChanged += activeHandler;
+            _enabledChangedHandler.Write(enabledHandler, context);
+            _activeChangedHandler.Write(activeHandler, context);
+            ValueListensToChanges = ShouldListen(proxy);
+            proxy.Active = ValueListensToChanges;
+        }
+
+        protected override void ProxyRemoved(SawtoothGeneratorProxy proxy, FrooxEngineContext context, bool inUseByAnotherInstance)
+        {
+            if (!inUseByAnotherInstance)
+            {
+                proxy.EnabledField.Changed -= _enabledChangedHandler.Read(context);
+                proxy.Slot.ActiveChanged -= _activeChangedHandler.Read(context);
+                _enabledChangedHandler.Clear(context);
+                _activeChangedHandler.Clear(context);
+                proxy.Active = false;
+            }
+        }
+
+        protected void UpdateListenerState(FrooxEngineContext context)
+        {
+            SawtoothGeneratorProxy proxy = GetProxy(context);
+            if (proxy != null)
+            {
+                bool shouldListen = ShouldListen(proxy);
+                if (shouldListen != ValueListensToChanges)
+                {
+                    ValueListensToChanges = shouldListen;
+                    context.Group.MarkChangeTrackingDirty();
+                    proxy.Active = shouldListen;
+                }
+            }
+        }
+
+        public void Changed(FrooxEngineContext context)
+        {
+            SawtoothGeneratorProxy proxy = GetProxy(context);
+            if (proxy == null)
+            {
+                return;
+            }
+            proxy.Amplitude = Amplitude.Evaluate(context, 1f);
+            proxy.Phase = Phase.Evaluate(context, 0f);
+            proxy.Frequency = Frequency.Evaluate(context, 440f);
+        }
+
+        protected override void ComputeOutputs(FrooxEngineContext context)
+        {
+            SawtoothGeneratorProxy proxy = GetProxy(context);
+            AudioOutput.Write(proxy, context);
+        }
+
+        private IOperation DoReset(FrooxEngineContext context)
+        {
+            SawtoothGeneratorProxy proxy = GetProxy(context);
+            if (proxy == null)
+            {
+                return null;
+            }
+            proxy.time = 0f;
+            return OnReset.Target;
+        }
+
+        public SawtoothGenerator()
+        {
+            AudioOutput = new ObjectOutput<IAudioSource>(this);
+            Reset = new Operation(this, 0);
+        }
+    }
+}

ProjectObsidian/ProtoFlux/Math/FrequencyQuantize.cs

@@ -64,7 +64,9 @@ protected override void ComputeOutputs(FrooxEngineContext context)
             var offset = Offset.Evaluate(context);
             var rootNote = 69 + offset;
 
-            var midi = FreqToNearestMidi(freq);
+            int midi;
+            if (freq == 0) midi = 0;
+            else midi = FreqToNearestMidi(freq);
 
             bool inScale = false;
             List<int> scaleList;